Patent Application
20230192731
This application claims priority from European Patent Application No. EP20177581.4, filed May 29, 2020, the entire contents of which are incorporated herein by reference.
The present invention relates to a process for the stepwise production of silahydrocarbons, in particular to the stepwise production of silahydrocarbons bearing up to four different hydrocarbon groups. More specifically, the invention relates to a process for the stepwise synthesis of silahydrocarbons that enables the selective and efficient production of silahydrocarbons bearing one, two, three or four different hydrocarbon groups, wherein at least two substituents of the silahydrocarbon are introduced by separate hydrosilylation steps.
Silahydrocarbons constitute a class of functional fluids often displaying an excellent viscosity index and thermal stability characteristics. They were found to be magnificent candidates for hydraulic fluids useable over the −54 to 315° C. temperature range. They possess excellent viscosity-temperature properties and thermal stability and they are expected to be sufficiently hydrocarbon-like in their physical and chemical properties to permit hydraulic systems to be designed with a minimum of redesign compared to conventional systems.
Silahydrocarbons are defined as compounds of silicon substituted by four hydrocarbon groups SiR4. In general, R can be any hydrocarbon group and be either primary, secondary, or tertiary. In the silahydrocarbon molecule all four R groups can be identical, e.g. in Si(CH3)4, or Si can be substituted with two, three or four different groups R. The molecular shape of silahydrocarbons can be changed with proper selection of the R groups.
Accordingly, the properties of the silahydrocarbons, such as vapor pressure, boiling point, viscosity and thermal stability are controlled by the selection of the appropriate substituents R. For example, the length of the carbon chain in the substituent R affects the boiling point, and the viscosity as well as the thermal stability properties that are also a function of the molecular shape of the silahydrocarbon molecule. A comparison of the melting points of silahydrocarbons with their carbon analogues shows that silahydrocarbons have lower melting points. Additionally, the specific mass and the boiling points of silahydrocarbons are usually higher than those of the corresponding carbon analogues.
For example, tetraalkylsilanes, wherein two or more of the alkyl groups have between eight and thirty carbon atoms, have been shown to be useful and effective hydraulic fluids and lubricants, especially in aerospace and space vehicles.
In general, synthetic approaches involving organometallic intermediates such as Grignard reagents or organolithium and/or aluminum compounds offer the easiest synthetic procedures: In U.S. Pat. No. 4,973,724 the preparation of compounds RSiR′3, wherein R′ radicals may be identical or different, by reacting trialkylaluminum compounds with chloro- or alkylchlorosilanes is disclosed: Therein, the selectivity to tetra- or trialkylsilanes is controlled by the addition of particular alkaline metal salts to a reaction zone.
U.S. Pat. No. 5,177,235 discloses the synthesis of tetraalkylsilanes from the reaction of sodium tetrahydrocarbylaluminate obtained from molten metal and trihydrocarbonaluminum at T=100-130° C. with an organotrihalosilane.
U.S. Pat. No. 4,650,891 discloses a catalytic process for producing silahydrocarbons, wherein halo-substituted silanes are reacted with an organomagnesium compound in the presence of a catalytically effective amount of a cyanide.
An overview of general synthetic approaches to differently organo-substituted silahydrocarbons and their chemical and physical properties is provided in C. E. Snyder, L. J. Geschwender, C. Tamborski, G. J. Chen and D. R. Anderson (1982): Synthesis and Characterization of Silahydrocarbons—A Class of Thermally Stable Wide-Liquid-Range Functional Fluids, ASLE Transactions, 9, 299-308.
Recently, hydrosilylation chemistry is favoured for the buildup of silahydrocarbons. These reactions involve a reaction between a silylhydride and an unsaturated organic group. This is one basic route in the synthesis of commercial silicon-based products, wherein the hydrosilylation reactions are typically catalyzed by precious metal catalysts.
U.S. Pat. No. 4,578,497 discloses the preparation of tetraalkylsilanes from monosilanes RSiH3, RSiH2R1 and RSiH(R1)2 by hydrosilylation with at least one alpha olefin using an oxygenated, Pt-containing catalyst.
In J. Am. Chem. Soc. 119, (1997) 906-917, LaPointe et. al. reported the palladium-catalyzed hydrosilylation synthesis of tetraalkylsilanes from tertiary silanes and olefins.
In US 2014/0330036 A1 a process for the synthesis of saturated and unsaturated silahydrocarbons using iron-containing or cobalt-containing catalysts is disclosed. Starting from primary silanes RSiH3, secondary silanes (R′)2SiH2 or tertiary silanes (R′)3SiH silahydrocarbons R1R2R3R4Si are obtained. The catalysts used are difficult to synthesize, not commercially available or very expensive. Using primary or secondary silanes, all H-substituents on Si are reacted.
A stepwise production procedure for silahydrocarbons bearing different substituents is disclosed in Ind. Eng. Chem. Prod. Res. Dev. 1983, 22, 172-178 by Tamborski et al., wherein alkyltrichlorosilanes are subsequently brought to reaction with different alkyllithium or alkylmagnesium halides.
Another stepwise synthesis method for the production of tetraalkylsilanes bearing one short and three long alkyl groups involving a two-step hydrosilylation procedure is disclosed by Onopchenko et al. in J. Chem. Eng. Data, 1988, 33, 64-66. Therein, an alkyldichlorohydridosilane is hydrosilylated with an α-olefin, then the dialkyldichlorosilane is submitted to perhydrogenation with LiAlH4, and the resulting dialkyldihydridosilane is reacted to a tetraalkylsilane in a final hydrosilylation step.
However, the reaction of SiCl4 with Grignard reagents or other organometallic compounds for the preparation of silahydrocarbons with up to four different organo substituents at one silicon center (R1R2SiR3R4) mostly results in the formation of complex monosilane mixtures. The selective introduction of several different organo groups is highly challenging, as preparatively lavish procedures including the introduction of protecting groups and the subsequent refunctionalization of the silicon functionality, preferably by introduction of a chloro substituent at the Si atom, prevent the selective and efficient product formation. Alternatively, starting from SiH4 that is a highly explosive gas with a boiling point of −112° C., the hydrosilylation with 1-hexene and ethylene requires the use of LiAlH4 as catalyst (M. Kobayashi, M. Itoh, Chem. Lett. 1996, 25, 1013-1014) to synthesize hexyl- and ethylsilane with the introduction of the first organo substituent at silicon. Further reactions of primary (RSiH3) and secondary (R2SiH2) silanes inhibit platinum catalysis of hydrosilylation reactions, whereas no inhibition was observed in such reactions with rhodium, see e.g. Lewis et al., Organometallics 1990, 9, 621-625; the same is true for iron- or cobalt-containing catalysts (see, e.g., Lewis et al., U.S. Pat. No. 9,371,339 B2). While LaPointe et al. in J. Am. Chem. Soc. 1997, 119, 906-917, reported the Pd-catalyzed hydrosilylation synthesis of tetraalkylsilanes from tertiary silanes and olefins, Salimgareeva et al. pointed out that hydrosilylation of dimethylsilane Me2SiH2 afforded the use of functional olefins for silicon-carbon bond formation, see J. Organomet. Chem. 1978, 148, 23-27.
For the specific design and general synthetic approach to a wide variety of differently alkyl substituted silahydrocarbons, there is strong need for a new synthetic-protocol involving the stepwise introduction of up to four different groups at a silicon center by hydrosilylation reactions.
All literature reports up to now lack selective and efficient product formation of R1R2SiR3R4 starting from primary and secondary silanes RSiH3 and R2SiH2, respectively, by hydrosilylation reaction sequences.
The problem to be solved by the present invention is the provision of a process for the stepwise production of silahydrocarbons, in particular silahydrocarbons bearing up to four different organyl groups R, via bifunctional hydridochlorosilanes as intermediates. In particular, it is an object of the present invention to provide a new process with improved performance over the conventional methods regarding overall yield of the reaction, purity of the products obtained, selectivity of the conversions, convenience of the reaction procedures, convenience of the work-up procedures, ease of the handling of the reagents, atom efficiency, and cost efficiency of the process.
According to the present invention, this problem is solved as follows.
The present invention relates to a process for the production of silahydrocarbons of the general formula (I)
SiR1R2R3R4 (I)
wherein
R1 and R2 are independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, unsubstituted or substituted aryl groups, or unsubstituted or substituted alkenyl groups, each having 1 to 30 carbon atoms,
R3 and R4 are independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkenyl groups, unsubstituted or substituted alkaryl groups or unsubstituted or substituted aryl groups, each having 2 to 30 carbon atoms and having at least two carbon atoms adjacent to each other,
and wherein R1-R4 may be the same or be selected from two, three or four different groups, comprising
SiR1R21HCl (II)
SiR1R22Cl2 (III)
SiR1R23H2 (IV)
SiR1R23H2 (IV)
SiR1R23H2 (IV)
SiR1R2R31Cl (V)
SiR1R2R32H (VI)
SiR1R2R3R4 (I)
In the following, the present invention is described in detail.
Unless otherwise restricted, the residues R1, R2, R3 and R4 have the following meaning according to the invention:
R1 and R2 are each independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, unsubstituted or substituted aryl groups, or unsubstituted or substituted alkenyl groups, each having 1 to 30 carbon atoms,
R3 and R4 are each independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkenyl groups, unsubstituted or substituted alkaryl groups or unsubstituted or substituted aryl groups, each having 2 to 30 carbon atoms and having at least two carbon atoms adjacent to each other.
They may be used in any general structure representing the groups as defined above. For example this means that in formula (II) R21 is selected from a chloro group, hydrido group or R2, etc, Another example is that in formula (V): R31 is selected from a chloro group or R3, etc.
According to the present invention, an organyl group is any organic substituent group, regardless of functional type, having one free valence at a carbon atom thereof.
According to the invention, the products obtained from the process are silahydrocarbons of the general formula (I) SiR1R2R3R4 (I),
wherein R1, R2, R3 and R4 of the formula (I) are independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups.
All following definitions regarding R2 and R3 apply in the same manner to the groups R21, R22, R23, R31 and R32 of the general formulas (II), (III), (IV), (V) and (VI) when they are selected from aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups.
The groups R1 and R2 in general formula (I) can have 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and most preferably at least one of R1 and R2 is a methyl group.
The groups R3 and R4 in general formula (I) can have 2 to 30 carbon atoms, preferably 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, even more preferably at least one of R3 and R4 is different from the residues R1 and R2, still more preferably both R3 and R4 are different from the residues R1 and R2, most preferably both of R3 and R4 are different from the residues R1 and R2 and from each other.
All of the above-mentioned groups aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups that independently constitute R1, R2, R3 and R4 can be unsubstituted or substituted.
According to the invention, in general the term “unsubstituted” means that the respective hydrocarbyl residues do not contain any heteroatoms other than H and C, neither as substituents such as halogen substituents, amino or hydroxyl groups, nor as part of functional groups included in the carbon scaffold of the hydrocarbyl groups, such as ether groups, ester groups or amide groups. The term “substituted” according to the invention in general defines that the hydrocarbyl groups can contain heteroatoms other than H and C and functional groups containing heteroatoms other than C and H, such as halogen substituents, hydroxyl groups, amino groups, ester groups, amide groups, ether groups and heterocyclic groups.
In case of substituted residues according to the above definition, according to the invention all carbon atoms included in a heteroatom-containing functional group are taken into consideration in the determination of the carbon number of a residue. For instance, if the residue R1 is an octyl group substituted with a propoxy group, R1 is considered to be a C11 group.
Also according to the invention, the term “aliphatic” refers to all hydrocarbyl substituents which are non-aromatic.
It is preferred when R1 and R2 are independently selected from the group consisting of unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, unsubstituted or substituted aryl groups, or unsubstituted or substituted alkenyl groups, each having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, even more preferably 1 to 12 carbon atoms.
In the same manner it is preferred when R3 and R4 are independently selected from the group consisting of unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, unsubstituted or substituted aryl groups, or unsubstituted or substituted alkenyl groups, each having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, even more preferably 2 to 12 carbon atoms.
According to the present invention, the term “alkyl” generally includes straight, branched and cyclic alkyl groups. Preferred examples of unsubstituted alkyl groups are methyl, ethyl, propyl, hexyl, octyl, iso-butyl and tert-butyl.
Preferred substituted alkyl groups in the residues R1, R2, R3 and R4 are substituted with one or more groups selected from acyloxy groups, alkoxy groups, ester groups (—COOR), wherein the carbonyl C atom is considered to be a C atom of the substituent and R is a hydrocarbyl residue, in particular a C1-C12 alkyl group, amino groups, halogen groups, in particular fluoro, chloro or bromo groups, silyl groups or siloxy groups.
Preferred examples of substituted alkyl groups in the residues R1, R2, R3 and R4 are linear alkyl groups substituted with a methyl ester group, ethyl ester group, iso-butyl ester group, tert-butyl ester group,
linear alkyl groups substituted with one or more methoxy groups, ethoxy groups, propoxy groups, polyoxyethylene groups with 2-10, preferably 2-6 (CH2CH2O) repeating units, iso-butoxy groups or tert-butoxy groups,
linear alkyl groups substituted with one or more acetoxy groups or unsubstituted linear C3, C4, C16, C18, C19 or C20 acetoxy groups,
linear alkyl groups substituted with one or more NH2 groups or NMe2 groups,
linear alkyl groups substituted with one or more fluoro groups, chloro groups or bromo groups,
linear alkyl groups substituted with one or more SiMe3 groups, SiEt3 groups, Si(iPr)3 groups or Si(tBu)Me2 groups, and linear alkyl groups substituted with one or more Si(OMe)3 groups, Si(OEt)3 groups, Si(OiPr)3 groups or Si(OcyHex)3 groups (cyHex=cyclo hexyl).
It is clear that according to the invention, in general the substituted groups can bear several substituents selected from different types of functional groups or heteroatom substituents, and thus the substituted alkyl groups may also bear several substituents selected from different types of functional groups and heteroatom substituents.
According to the invention, the term “cycloaliphatic” in general includes all types of cyclic organyl substituents excluding cyclic aromatic substituents and cyclic heterocyclic substituents.
According to the invention, the term “alkaryl” in general describes an aryl group in which one or more hydrogen atoms have been substituted by the same number of alkyl groups, which alkyl groups may be the same or different from another. Preferred examples of alkaryl groups are tolyl groups and xylyl groups and mesityl groups, in particular para-tolyl groups.
According to the invention, the term “aralkyl” in general describes an alkyl group in which one or more hydrogen atoms have been substituted by the same number of aryl groups, which aryl groups may be the same or different from another. Preferred examples of aralkyl groups are benzyl groups and phenylethyl groups.
According to the invention, the term “aryl group” in general is defined as any aromatic hydrocarbon from which one hydrogen atom has been removed. An aryl may have one or more aromatic rings, which may be fused, connected by single bonds or other groups. Preferred examples of aryl groups are phenyl groups, biphenyl groups, naphthalenyl groups, phenyl groups are most preferred.
According to the invention, the term “alkenyl group” in general is defined as any straight, branched, or cyclic alkenyl group containing one or more carbon-carbon double bonds, wherein the point of substitution can be either at a carbon-carbon double bond or elsewhere in the group. Specifically, with regards to the residues R1, R2, R21, R22, R23, R3, R31, R32 and R4 (when they are selected from aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups) of the formulas (I) to (VI) according to the present invention, this means there is no limitation which carbon atom of an alkenyl group is bonded to the central Si atom.
Preferred examples of alkenyls are vinyl, propenyl, allyl, methallyl, and ethylidenyl norbornane, wherein vinyl is most preferred.
It is also preferred that the alkenyl groups in the residues R1, R2, R3 or R4 are bonded to the central Si atom of the silahydrocarbon by a terminal C-atom of the group which is at the same time a C atom of a carbon-carbon double bond, i.e. 1-alkenyl groups, wherein it is more preferred that the 1-alkenyl groups are C1-C12 1-alkenyl groups, most preferably unsubstituted C1-C12 1-alkenyl groups. Such preferred residues can be introduced by performing a hydrosilylation reaction of the corresponding terminal alkynes with hydridosilanes.
In step a) of the process according to the invention a bifunctional monosilane of the general formula SiR1R21HCl (II) is provided, wherein such bifunctional monosilane is either an organohydridodichlorosilane of the formula SiR1HCl2, an organodihydridochlorosilane of the formula SiR1H2Cl, or a diorganohydridochlorosilane of the formula SiR1R2HCl, wherein R1 and R2 are as defined above.
In step a) of the process according to the invention, the bifunctional intermediate of the general formula SiR1R21HCl (II) can be provided by a redistribution reaction of a organoperchloromonosilane of the general formula SiR1R22Cl2 (III), which can be an organotrichlorosilane of the formula SiR1Cl3 or a diorganodichlorosilane of the formula SiR1R2Cl2, wherein R1 and R2 are as defined above, and an organoperhydridosilane of the general formula SiR1R23H2(IV), which can be an organotrihydridosilane of the formula SiR1H3 or a diorganodihydridosilane of the formula SiR1R2H2, wherein R1 and R2 are as defined above, in the presence of a redistribution catalyst and optionally in the presence of a solvent.
According to the present invention, the term “redistribution reaction” describes the redistribution of hydrogen and chlorine substituents bonded to the silicon atoms of the silane compounds comprised in the reaction mixture of such reaction by exchange of these substituents. The exchange can be monitored in particular by 29Si NMR spectroscopy, by GC and/or GC/MS analysis.
On lab scale, the redistribution reactions are performed under inert conditions (N2- or Ar-atmosphere) and can be performed in normal laboratory glass ware, sealed ampules or in steal autoclaves (depending on the reaction conditions needed). The reaction vessels are equipped with a stirring bar for thoroughly mixing the reactants. Preferred temperatures are in a range of 40-200° C., wherein 60-140° C. are most preferred. For reactions performed in open-systems, the flasks are equipped with a reflux condenser. Preferred pressures are in a range of 1-20 bar, wherein 1-10 bar are most preferred, depending on the reaction vessel used. On technical scale and industrial scale, the same pressure and temperature ranges are preferred, and reaction vessels made from glass, metal alloys or any other material suitable for performing the reaction under such pressure and temperature conditions may be used.
Preferably, a mixing device is used in the reaction vessel, and the reactions may be performed batchwise or under continuous flow conditions.
Accordingly, the term “redistribution catalyst” applies to any compound or mixture of compounds increasing the rate of the above-defined redistribution reaction without itself undergoing a permanent chemical change.
Preferably, the redistribution catalyst, which may also be a mixture of two or more individual catalysts, is selected from the group consisting of the compounds
The redistribution reaction can be performed neat, i.e. in the absence of an additional solvent, or in the presence of a solvent, which is preferably an organic solvent that is practically inert under the reaction conditions.
According to the present invention, the term “organic solvent” refers to any organic compound or mixtures thereof which is in liquid state at room temperature, and which is suitable as a medium for conducting the redistribution reactions of a step a) therein. Accordingly, the organic solvent is preferably inert to the organohydridosilanes, organochlorosilanes, organohydridochlorosilanes and the redistribution catalysts according to present invention under reaction conditions. Furthermore, the starting materials of the general formulas (III), (IV) and the products of the general formula (II) are preferably soluble in the organic solvent or fully miscible with the organic solvent, respectively.
Preferably, the organic solvent is selected from optionally substituted, preferably unsubstituted linear or cyclic aliphatic hydrocarbons, aromatic hydrocarbons or ether compounds, without being limited thereto.
Herein, the term “ether compound” shall mean any organic compound containing an ether group —O— (one or more ether groups are possible), in particular of the formula R6—O—R7, wherein R6 and R7 are independently selected from an organyl group R as defined above. In general, the organyl group R can be selected for example from optionally substituted, preferably unsubstituted, alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, preferably from alkyl, alkenyl and aryl groups.
Preferably, R6 and R7 are substituted or unsubstituted linear or branched alkyl groups or aryl groups, which may have further heteroatoms such as oxygen, nitrogen, or sulfur. In the case of cyclic ether compounds, R6 and R7 can constitute together an optionally substituted alkylene or arylene group, which may have further heteroatoms such as oxygen, nitrogen, or sulfur, as for instance in dioxanes, in particular 1,4-dioxane.
The ether compounds can be symmetrical or asymmetrical with respect to the substituents at the ether group(s) —O—.
The term “ether compound” according to the invention also comprises linear ether compounds in which more than one ether group may be included, forming a di-, tri-, oligo- or polyether compound, wherein R6 and R7 constitute organyl groups when they are terminal groups of the compounds, and alkylene or arylene groups when they are internal groups. Herein, a terminal group is defined as any group being linked to one oxygen atom which is part of an ether group, while an internal group is defined as any group linked to two oxygen atoms being a constituent of ether groups.
Preferred examples of such compounds are dimethoxy ethane, glycol diethers (glymes), in particular diglyme or tetraglyme, without being limited thereto.
According to the present invention, the term “high-boiling ether compound” is defined as an ether compound according to the above definition with a boiling point at 1.013 bar (standard atmosphere pressure) of preferably at least 65° C., more preferably at least 85° C., even more preferably at least 100° C., and most preferably at least 120° C.
The application of high-boiling ethers in the present invention is favorable as it facilitates separation of the desired products of the general formula (I) from the reaction mixture containing the solvent and residual starting materials. The products of the general formula (I) in general have lower boiling points than the high-boiling ethers as defined herein.
For example, the boiling points of selected representative products of the general formula (I) are 35° C. (Me2SiHCl) and 41° C. (MeSiHCl2) at atmospheric pressure, while the representative higher-boiling ether compound diglyme has a boiling point of 162° C. at standard atmospheric pressure. Application of higher-boiling ether compounds as solvents allows higher reaction temperatures and allows a more efficient separation of the desired products from the reaction mixture by distillation.
In step a) of the process according to the invention, the bifunctional intermediate of the general formula SiR1R21HCl (II) can also be provided by a redistribution reaction of a organoperchloromonosilane of the general formula SiR1R22Cl2 (III), which can be an organotrichlorosilane of the formula SiR1Cl3 or a diorganodichlorosilane of the formula SiR1R2Cl2, wherein R1 and R2 are as defined above, with the in-situ formed hydrogenation products obtained by reacting the monosilane of the general formula (III), with a metal hydride reagent of the general formula MHx, wherein M represents one or more metals and x is an integer from 1 to 6, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2, in the presence of a redistribution catalyst and optionally in the presence of a solvent.
While the same redistribution catalysts and solvents are used as for the redistribution reaction of the compounds of the general formula (III) and (IV) as described above, the redistribution partners of the compounds of the general formula (III) are formed in situ. Herein, the term “formed in situ” according to the invention means that hydrogenated analogues, i.e. compounds in which one to all chlorine substituents of the compounds of the general formula (III) at the silicon atom have been replaced by hydrogen substituents, are formed from the compounds of the general formula (III) by contacting these compounds and the metal hydride reagent of the general formula MHx or an organometallic hydride donor as described above in the reaction vessel in which such reaction step a) is performed.
In accordance with the present invention, the term metal hydride reagent refers to any hydride donor containing at least one metal atom or metal ion, wherein it is specified that the metal hydride reagent according to the invention is of the general formula MHx with x=1-6. The formula MHx with x=1-6, wherein M may represent several different metal atoms, cations or metal atoms or cations contained in complex anions at the same time, explicitly includes complex metal hydrides.
The term “complex metal hydrides” according to the invention refers to metal salts wherein the anions contain both metal atoms or cations and hydride anions. Typically, complex metal hydrides contain more than one types of metal or metalloid element atoms. As there is neither a standard definition of a metalloid nor complete agreement on the elements appropriately classified as such, in the sense of present invention the term “metalloid” comprises the elements boron, silicon, germanium, tin, arsenic, antimony, tellurium, carbon, aluminum, selenium, polonium, and astatine. The most preferred example of a complex metal hydride is LiAlH4, which consists of lithium cations and tetrahydridoaluminate anions.
The term “organometallic hydride donor” according to the invention refers to any compound containing at least one metal atom bonded to at least one organyl residue, wherein further at least one metal atom or ion is bonded to a hydrogen atom covalently or as an organometallic cation-hydride ion pair.
Alternatively, in step a) of the process according to the invention the bifunctional intermediate of the general formula SiR1R21HCl (II) can also be provided by a chlorination reaction comprising the reaction of an organoperhydridomonosilane of the general formula (IV)
SiR1R23H2 (IV)
According to the invention, the at least one catalyst in this reaction is selected from the group consisting of:
Regarding the catalysts of the formula R84QZ, R8 is preferably an organyl group, more preferably an aliphatic hydrocarbon group, even more preferably an n-alkyl group, and most preferably a n-butyl group, Q is preferably phosphorus or nitrogen, and Z is chlorine. Particularly preferred examples of catalysts represented by the formula R84QZ are nBu4NCl, nBu4PCl, nBu4NBr and nBu4PBr, wherein nBu4NCl is most preferred.
According to the invention, the above-described chlorination reaction is carried out in the presence or absence of at least one solvent, which is preferably an organic solvent that is practically inert under the reaction conditions as described above.
The chlorination reaction is preferably carried out at a temperature in the range of about −40° C. to about 250° C., more preferably in the range of about 0° C. to 200° C., and most preferably in the range of about 40° C. to 160° C.
Likewise, according to the invention the chlorination reaction is preferably carried out at a pressure from about 0.1 to about 10 bar, more preferably at a pressure from 1 to 10 bar.
According to the invention, as all steps of the process according to the reaction, the chlorination reaction is preferably carried out under inert conditions.
The term “inert conditions” herein refers to conditions excluding the presence of moisture and oxygen, in particular moisture and oxygen from ambient air. Preferably, inert conditions are established by performing the reactions according to the invention in an inert gas atmosphere, such as a nitrogen atmosphere or argon atmosphere.
Further, in step a) of the process according to the invention, the bifunctional intermediate of the general formula SiR1R21HCl (II) can also be provided by a selective partial chlorination reaction of an organoperhydridomonosilane of the general formula SiR1R23H2(IV), which can be an organotrihydridosilane SiR1H3 or a diorganodihydridosilane SiR1R2H2 with R1 and R2 as defined above, by reacting the compound with an HCl/ether reagent, optionally in the presence of one or more further solvents.
The optional further solvents in this reaction step is preferably an organic solvent, which according to the invention is defined as any organic compound which is in liquid state under reaction conditions and which is suitable as a medium for conducting the partial chlorination step therein. Accordingly, the organic solvent is preferably inert to the organohydridosilanes, and HCl/ether reagents applied according to present invention under reaction conditions, as well as to the resulting organohydridochlorosilanes. In general, the solvents may be the same as defined for the above redistribution steps, wherein an ether compound or a mixture of solvents containing at least one ether compound are preferred.
The HCl/ether reagent effecting the partial chlorination reaction is obtained by absorption or dissolution of HCl by an ether compound, which may be performed before the HCl/ether reagent is introduced into the reaction vessel of step a), or in situ by contacting gaseous HCl or a HCl solution with the ether compounds or a mixture containing at least one ether compound in situ in the reaction vessel in which step a) is performed.
In the present invention, the term “ether compound” shall mean any organic compound containing an ether group —O—, in particular of the formula R6—O—R7, wherein R6 and R7 are independently selected from an organyl group as defined herein above.
The ether compounds can be symmetrical or asymmetrical with respect to the substituents at the ether group —O—, and the ether compound is selected from the group consisting of linear and cyclic ether compounds. Herein, a linear ether compound is a compound containing an ether group R1OR7 as defined above, in which there is no connection between the R6 and R7 group except the oxygen atom of the ether groups, as for example in the symmetrical ethers Et2O, n-Bu2O, Ph2O or diisoamyl ether (i-Pentyl2O), in which R6=R7, or in unsymmetrical ethers as t-BuOMe (methyl t-butyl ether, MTBE) or PhOMe (methyl phenyl ether, anisol).
A cyclic ether compound according to the invention is a compound in which one or more ether groups are included in a ring formed by a series of atoms, such as for instance tetrahydrofurane, tetrahydropyrane or 1,4-dioxane, which can be substituted e.g. by alkyl groups.
Preferably, the ether compound selected from the group consisting of linear and cyclic ether compounds is an aliphatic compound.
Also preferably, R6 and R7 are substituted or unsubstituted linear or branched alkyl groups or aryl groups, which may have further heteroatoms such as oxygen, nitrogen, or sulfur. In the case of cyclic ether compounds, R6 and R7 can constitute together an optionally substituted alkylene or arylene group, which may have further heteroatoms such as oxygen, nitrogen, or sulfur.
More preferably, R6 and R7 are independently selected from linear alkyl groups and linear alkoxyalkyl groups, most preferably from linear alkyl groups and linear alkoxyalkyl groups with 1 to 10 C atoms, and even more preferably the ether compound is selected from the group consisting of diethyl ether, di-n-butyl ether, diethylene glycol dimethyl ether (diglyme), tetraethylene glycol dimethyl ether (tetraglyme), and dioxane, preferably 1,4-dioxane, 2-methyltetrahydrofurane, tetrahydrofurane, tetrahydropyrane and dimethoxy ethane.
The use of a specific HCl/ether reagent is mostly determined by the boiling points of the products formed. For simplification of product isolation, for high boiling products the use of the hydrogen chloride/diethyl ether reagent is favored, while for low boiling organochlorosilanes of the general formula (II) high boiling ethers, e.g. diglyme, are preferred.
Preferably, the partial chlorination reaction with hydrogen chloride in the presence of at least one ether compound is performed in the absence of a metal-containing catalyst, more preferably in the absence of Lewis acid compounds containing a metal atom from group 13.
In the at least one step b) according to the invention, an organohydridochlorosilane of the formula (II) as defined above or HSiCl3 is submitted to a metal-catalyzed hydrosilylation reaction, preferably a precious metal-catalyzed hydrosilylation reaction, with a compound containing at least one C—C double or C—C triple bond, resulting in the formation of an organochlorosilane of the general formula SiR1R2R31Cl (V), which can be a diorganodichlorosilane SiR1R2Cl2 or a triorganochlorosilane SiR1R2R3Cl, wherein R1 and R2 are as defined above, and R3 is selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkenyl groups, unsubstituted or substituted alkaryl groups or unsubstituted or substituted aryl groups, each having 2 to 30 carbon atoms and having at least two carbon atoms adjacent to each other, or resulting in an intermediate of the formula R1SiCl3, wherein R1 is as defined for the intermediate of the general formula (V), if HSiCl3 is applied as starting material. Such step b) according to the invention requires the presence of a metal-based hydrosilylation catalyst.
According to the invention, a metal hydrosilylation catalyst can be any reagent containing metal atoms or metal ions which increases the rate of the hydrosilylation of C—C-unsaturated compounds by the organochlorohydridosilanes of the general formula (II) or by HSiCl3, and accordingly a precious metal hydrosilylation catalyst can be any reagent containing precious metal atoms or ions effecting the hydrosilylation of C—C-unsaturated compounds by the organochlorohydridosilanes of the general formula (II) or by HSiCl3.
In the present invention, the metals platinum, iridium, palladium, osmium, rhodium, ruthenium, copper, silver, gold and mercury are considered to be precious metals, and accordingly the hydrosilylation catalysts of steps b) according to the invention can be based on metals and in particular on the above-listed precious metals.
Preferably, the hydrosilylation catalyst of step b) of the process according to the invention is selected from the group of Mn, Fe, Co, Ni, Ir, Rh, Ru, Os, Pd and Pt compounds as taught in U.S. Pat. Nos. 3,159,601; 3,159,662; 3,419,593; 3,715,334; 3,775,452; 3,814,730; US 20130158281 A1; WO 2013090548 A1; WO 2011006049 A1; US 20110009573 A1; WO 2011006044 A2; US 20110009565 A1; U.S. Pat. No. 9,387,468; US 20180015449; US 20180201634; U.S. Pat. Nos. 9,890,182 and 9,371,339 all incorporated by reference into the present invention. Most preferred are platinum compounds.
The hydrosilylation catalyst of step b) is a catalyst compound which facilitates the reaction of C—C-unsaturated compounds by the organochlorohydridosilanes of the general formula (II) or by HSiCl3. The metal or organo metal compound is preferably based on a platinum group metal. Without wishing to be bound by theory, it is believed that the above-cited hydrosilylation catalyst includes complexes with sigma- and pi-bonded carbon ligands as well as ligands with S-, N, or P atoms, metal colloids or salts of the afore mentioned metals. The catalyst can be present on a carrier such as silica gel or powdered charcoal, bearing the metal, or a compound or complex of that metal. Preferably, the metal-based hydrosilylation catalyst is any platinum complex compound. The metal-based hydrosilylation catalyst may be immobilized on a support, such as silica, alumina, activated charcoal, carbon black, clays and organic polymeric materials or a polysiloxane-based material. Therein, immobilization on a silica support, a functionalized silica support, an activated charcoal or carbon black support, a polymeric organic material or a polysiloxane-based material is preferred.
A typical platinum containing catalyst component applied in step b) of this invention is any form of platinum (0), (II) or (IV) compounds, which are able to form complexes. Preferred complexes are Pt-(0)-alkenyl complexes, such alkenyl, cycloalkenyl, alkenylsiloxane such as vinylsiloxane. A particularly useful form of the platinum complexes are the Pt(0)-complexes with aliphatically unsaturated organosilicon compound such as a 1,3-divinyltetramethyldisiloxane (Vinyl-M2) or Karstedt catalyst:
as disclosed by e.g. U.S. Pat. No. 3,419,593 incorporated herein by reference, which are especially preferred, cyclohexene-Pt, cyclooctadiene-Pt and tetravinyltetramethyl-tetracyclosiloxane (Vinyl-D4)-Pt, e.g. Ashby's catalyst, a Pt(0) complex in tetramethyltetravinylcyclotetrasiloxane with the empirical formula Pt[(C3H6SiO)4]x.
Also preferred is a so-called Lamoreaux catalyst, which is a platinum (II) complex compound, obtained from chloroplatinic acid hexahydrate and octyl alcohol (as described for example in U.S. Pat. No. 3,197,432 or U.S. Pat. No. 3,220,972). Further preferred are Pt(0) or Pt(II) catalysts, with preference to Ashby and Lamoreaux platinum catalysts.
The amount of platinum-containing catalyst component that is used in the compositions of this invention is not narrowly limited as long as there is a sufficient amount to accelerate the hydrosilylation between C—C-unsaturated compounds and the organochlorohydridosilanes of the general formula (II) or by HSiCl3 at the desired temperature in the required time (B) for step b). The exact necessary amount of said catalyst component will depend upon the particular catalyst, the amount of other inhibiting compounds and the SiH to olefin ratio and is not easily predictable. However, for platinum catalysts said amount can be as low as possible due to cost reasons. Preferably, one should add more than one part by weight of platinum for every one million parts by weight of the organochlorohydridosilanes of the general formula (II) or HSiCl3 to ensure hydrosilylation in the presence of other undefined inhibiting traces. For the hydrosilylation reaction of step b) of this invention the amount of platinum-containing catalyst component to be applied is preferably in the range of from 1 to 200 ppm, preferably 2 to 100 ppm, especially preferred 4 to 60 ppm by weight platinum per weight of organochlorohydridosilanes of the general formula (II) or of HSiCl3. Preferably, said amount is at least 4 ppm platinum by weight of organochlorohydridosilanes of the general formula (II) or of HSiCl3.
The hydrosilylation step b) can be performed under the assistance of heat or light. Light-curing is then initiated by irradiation with light, in particular UV light having a wavelength maximum between 300 and 550 nm. Irradiation-initiated hydrosilylation is performed preferably at room temperature (25° C.).
Accordingly, the hydrosilylation catalyst can also be selected from the group of catalysts capable of being photoactivated. These photo-activatable catalysts preferably contain at least one metal selected from the group composed of Pt, Pd, Rh, Co, Ni, Ir or Ru. The catalysts capable of being photoactivated preferably comprise platinum compounds. Catalyst capable of being photo-activatable is preferably selected among organometallic compounds, i.e. comprise carbon-containing ligands, or salts thereof. Preferably, the photoactive hydrosilylation catalyst (C) has metal carbon bonds, including sigma- and pi-bonds. Also preferably, the catalyst capable of being photo-activated (C) is an organometallic complex compound having at least one metal carbon sigma bond, still more preferably a platinum complex compound having preferably one or more sigma-bonded alkyl and/or aryl group, preferably alkyl group(s). Sigma-bonded ligands include in particular, sigma-bonded organic groups, preferably sigma-bonded C1-C6-alkyl, more preferably sigma-bonded methyl groups, sigma-bonded aryl groups, like phenyl, Si and O substituted sigma bonded alkyl or aryl groups, such as trisorganosilylalkyl groups, sigma-bonded silyl groups, like trialkyl silyl groups. Most preferred photo-activatable catalysts include η5-(optionally substituted)-cyclopentadienyl platinum complex compounds having sigma-bonded ligands, preferably sigma-bonded alkyl ligands.
Further catalysts capable of being photoactivated include (η-diolefin)-(sigma-aryl)-platinum complexes (see e.g. U.S. Pat. No. 4,530,879).
The catalyst capable of being photoactivated can be used as such or supported on a carrier. Examples of catalysts capable of being photo-activated include η-diolefin-σ-aryl-platinum complexes, such as disclosed in U.S. Pat. No. 4,530,879, EP 122008, EP 146307 (corresponding to U.S. Pat. No. 4,510,094 and the prior art documents cited therein), or US 2003/0199603, and also platinum compounds whose reactivity can be controlled by way for example using azodicarboxylic esters, as disclosed in U.S. Pat. No. 4,640,939 or diketonates.
Platinum compounds capable of being photo-activated that can be used are moreover those selected from the group having ligands selected from diketones, e.g. benzoylacetones or acetylenedicarboxylic esters, and platinum catalysts embedded into photodegradable organic resins. Other Pt-catalysts are mentioned by way of example in U.S. Pat. No. 3,715,334 or U.S. Pat. No. 3,419,593, EP 1 672 031 A1 and Lewis, Colborn, Grade, Bryant, Sumpter, and Scott in Organometallics, 1995, 14, 2202-2213, all incorporated by reference here.
Catalysts capable of being photo-activated can also be formed in-situ in the reaction mixture of step b) by using Pt0-olefin complexes and adding appropriate photo-activatable ligands thereto.
The catalysts capable of being photo-activated that can be used here are, however, not restricted to these above-mentioned examples.
The most preferred catalyst capable of being photo-activated to be used in the process of the invention are (η5-cyclopentadienyl)-trimethyl-platinum, (η5-cyclopentadienyl)-triphenyl-platinum complexes, in particular, (15-methylcyclopentadienyl)-trimethyl-platinum.
The amount of the catalyst capable of being photo-activatable is preferably 1 to 500 ppm and preferably in the same lower range as defined for the heat-activatable hydrosilylation catalysts mentioned above.
The compound submitted to the hydrosilylation reaction of step b) can be any compound which in a hydrosilylation reaction is converted to a residue as defined for R3.
In general, the compound containing at least one C—C double bond or C—C triple bond can be selected from mono- or polyunsaturated alkenes, mono- or polyunsaturated alkynes, and compounds containing both C—C double bonds and C—C triple bonds, each having 2 to 30 carbon atoms.
Preferred compounds containing at least one C—C double bond or C—C triple bond applied in the hydrosilylation reaction of step b) are
In the at least one step c) according to the invention, a compound of the general formula (V) or of the general formula R1SiCl3 as defined above is submitted to a hydrogenation reaction, resulting in the formation of an intermediate of the general formula SiR1R2R32H (VI), which can be a diorganodihydrido silane SiR1R2H2 or a triorganohydrido silane SiR1R2R3H, wherein R1, R2 and R3 are as defined above, or of R1SiH3, wherein R1 is as defined above.
According to the invention, the hydrogenation reaction of step c) is any kind of reaction in which all chloro substituents at the silicon atom of the starting materials are replaced by hydrogen substituents.
Preferably, the hydrogenation of the organochlorosilanes is effected by reacting the compounds with metal hydrides, mixed metal hydrides, organometallic hydride donors or with hydrogen gas in the presence of a hydrogenation catalyst.
Preferred metal hydrides are LiH, NaH, KH, CaH2, AlH3 and BH3; LiH and NaH are most preferred, preferred mixed metal hydrides are LiAlH4, NaBH4, KBH4 and Zn(BH4)2, wherein LiAlH4 is most preferred, preferred organometallic hydride donors are diisobutyl aluminum hydride, LiEt3BH, K(sec-Bu)3BH, nBu3SnH, Me3SnH, Ph3SnH, nBu2SnH2, Me2SnH2, and Ph2SnH2, wherein nBu3SnH is most preferred, and preferred hydrogenation catalysts for the hydrogenation with hydrogen gas are based on the metals Ti, Zr, Hf, Ni, Pd, Pt, Mo, W, Nb, Ta, Ba, Sr, Ca, Mg, Ru, Rh, Ir and combinations thereof, which means the metals are either present in elemental state or as any kind of salt thereof.
In step d) of the process according to the invention, a compound of the general formula SiR1R2R32H (VI), which can be a diorganodihydrido-silane SiR1R2H2 or a triorganohydridosilane SiR1R2R3H, wherein R1, R2 and R3 are as defined above, is submitted to a hydrosilylation reaction with a compound containing one or more C—C double bonds or C—C triple bonds, resulting in the formation of the target compounds of the general formula (I).
Therein, preferably a metal catalyst as defined for step b) is applied in step d) for increasing the reaction rate of the hydrosilylation reaction of a compound of the general formula (VI) and a compound containing one or more C—C double bonds or C—C triple bonds, and the compound containing one or more C—C double bonds or C—C triple bonds is as defined for step b) as well. According to the invention, it is preferred that the intermediate submitted to step d) is a triorganohydridosilane SiR1R2R32H as defined above, i.e. R32≠H, which is in particular crucial for the selective synthesis of silahydrocarbons bearing three or four different substituents.
Preferably, the residues R1, R2, and R3 are selected from two or more, preferably three different residues.
Step d) is necessarily the final step of the process for the production of silahydrocarbons.
It is noted that according to the invention, in general the residue R21 is the same as R2 defined above or a chloro or a hydrido substituent, the group R22 is the same as R2 defined above or a chloro substituent, and the group R23 is the same as R2 defined above or a hydrido substituent, unless this range is explicitly restricted in a preferred range of a specific embodiment.
It is likewise noted that according to the invention, in general the residue R31 is the same as R3 defined above or a chloro substituent, and the group R32 is the same as R3 defined above or a hydrido substituent, unless this range is explicitly restricted in a preferred range of a specific embodiment.
In a preferred embodiment according to the invention, the four organyl substituents R1, R2, R3 and R4 at the silicon center of the silahydrocarbon product of the general formula (I) are selected from at least two, preferably from at least three, and most preferably from four different groups.
By the process of the present invention silahydrocarbons bearing up to four different substituents can be prepared in a selective manner. Therein, the process can be performed by submitting to the process compounds obtained by performing a hydrosilylation reaction using SiHCl3, or by submitting mono- and diorganochlorosilanes obtainable for instance from side-products of industrial processes. Accordingly, it is possible to introduce all four substituents independently by hydrosilylation, if desired. Performing the reactions as disclosed herein sequentially starting from mono- or diorganochlorosilanes or by the hydrosilylation of trichlorosilane (HSiCl3), the synthesis of a rather unlimited range of tetraorganosilanes is efficiently possible. The preferred bifunctional starting materials HSiCl3, MeSiHCl2 and Me2SiHCl are industrially available as compounds produced in the Siemens Process as well as the Rochow-Müller Process (Direct Process); more specifically, methylchlorosilanes are obtained from cleavage of disilanes MenSi2Cl6-n (n=1-5), isolated from the Direct-Process-Residue (N. Auner et al. Chem. Eur. J. 2019, 25, 3809-3815 and Chem. Eur. J. 2019, 25, 13202-13207) or, alternatively, from cleavage of disilanes MenSi2H6-n (n=1-5) and chlorination of methylhydridomonosilanes by ether/HCl solutions (M. C. Holthausen et al. Chem. Eur. J. 2019, 25, 8499-8502 and Chem Eur. J. 2018, 24, 17796-17801).
In a further preferred embodiment according to the invention, the four organyl substituents R1, R2, R3 and R4 at the silicon center of the silahydrocarbon product of the general formula (I) are selected from four different groups, preferably four different alkyl groups, more preferably four different linear alkyl groups, most preferably four different linear unsubstituted alkyl groups.
According to the invention, all four different groups can be introduced by four selective hydrosilylation reactions when the starting material of the general formula (III) is prepared by hydrosilylation of HSiCl3. A starting material of the formula (II) which is SiR1HCl2 can be further functionalized in a sequence including two steps b) and a final step d), or a starting material of the formula (II) which is SiR1R21HCl, wherein R1≠R21, can be transformed to a silahydrocarbon bearing four different substituents applying one step b) and step d).
It is preferred that in the silahydrocarbon bearing four different groups as substituents the overall number of carbon atoms is in the range from 8 to 80, more preferably in the range from 10 to 50, even more preferably in the range from 12 to 40.
In another preferred embodiment according to the invention, the residue R1 of the silahydrocarbon product of the general formula (I) is a methyl group or a phenyl group, preferably a methyl group.
Starting materials of the general formula (III) SiR1R22Cl2 as defined above with R1=Me or Ph, and R22=R1 or Cl are readily available, as all compounds selected from the group of MeSiCl3, Me2SiCl2, PhSiCl3 and Ph2SiCl2, which are preferred compounds of the formula (III) according to the invention, are produced on industrial scale for the application in silicones.
It is preferred that when R1 in the silahydrocarbon products of the general formula (I) are Me or Ph, R2 is the same as R1. More preferably, R1 is the same as R2, while both R3 and R4 are different from R1 and R2.
It is also preferred that when R1 is a methyl group or a phenyl group, at least one of the further groups R2, R3 and R4 is a C2 to C30 alkyl group, which may be substituted by one or more halogen groups, preferably one or more chloro, fluoro or bromo groups, or by one or more ester groups.
In still another preferred embodiment according to the invention, the residues R1 and R2 of the silahydrocarbon product of the general formula (I) are both independently selected from the group consisting of methyl groups, butyl groups, hexyl groups, phenyl groups, preferably both are independently selected from phenyl and methyl groups, most preferably both are methyl groups.
Therein it is preferred that R3 and R4 are independently different from the residues R1 and R2, and it is more preferred that at least one of R4 is a substituted hydrocarbyl residue.
In a preferred embodiment according to the invention, one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are alkenyl substituents, preferably 1-alkenyl substituents, even more preferably unsubstituted 1-alkenyl substituents.
Alkenyl substituents are either introduced by submitting compounds containing two or more C—C-double bonds to the hydrosilylation reactions of the steps b) and d), or by submitting alkynyl compounds to said process steps. In particular, 1-alkenyl substituents are obtained when submitting 1-alkynyl compounds to the hydrosilylation steps. The presence of alkenyl substituents can be useful in controlling the compounds physical properties, and it allows further functionalization of the silahydrocarbons.
Preferably alkenyl substituents are selected from the group consisting of butenyl, 2-methylbutenyl, 2-chlorobutenyl, cyclohexenyl, vinyl, allyl, propenyl, pentenyl, hexenyl, octenyl, nonenyl, decenyl, undecenyl and dodecenyl groups. Vinyl, allyl, 1-propenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, 1-octenyl, 1-nonenyl and 1-dodecenyl substituents are particularly preferred.
In a further preferred embodiment according to the invention, one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are residues substituted with one or more halogen substituents, preferably selected from chloro and bromo substituents, most preferably bearing one or more bromo substituents.
Functionalization by halogen substituents is useful for modifying and tailoring the physical properties of the silahydrocarbon compounds, for instance by applying fully or partially perfluorinated alkyl chains. The introduction of chloro and bromo substituents, which are compatible with the hydrosilylation conditions of the process according to the present invention, may also be useful for modification of the compounds' physical properties, and in addition the presence of chloro or bromo substituents may be used as a starting point for further functionalization of the silahydrocarbons.
It is preferred that at least one of the residues R3 and R4 is substituted by a single halogen atom selected from F, Cl and Br, more preferred at the terminal C-atom of the residue or residues. Therein, in case the substituent is branched, the C-atom most distant from the central Si atom is considered to be the terminal C-atom.
It is also preferred that at least one of the residues R3 and R4 contains at least one alkyl residue containing at least one difluoromethylene group or trifluoroalkyl group, more preferably at least one residue contains two or more structural moieties selected from trifluoromethyl groups and difluoromethylene groups.
In still a further preferred embodiment according to the invention, one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are residues comprising one or more aromatic groups, preferably one or two of the residues R3 and R4 comprise one or more phenyl groups, most preferably one or two of the residues R3 and R4 comprise one or more phenyl groups as substituents.
According to this embodiment of the invention, R3 and R4 preferably comprise one or more aromatic groups. Therein, it is preferred that the aryl groups are present as substituents of alkyl or alkenyl groups. The introduction of aryl groups, for instance phenyl groups, being R3 or R4 themselves would require the formation of arynes as substrates for hydrosilylation, which is viable, but rather inconvenient. It is more preferred that one or two of R3 and R4 are alkyl groups substituted with phenyl groups, naphthalenyl groups or biphenyl groups, most preferably one or two of R3 and R4 are phenylethyl groups, which result from hydrosilylation reactions involving styrene as unsaturated substrate.
In an even further preferred embodiment according to the invention, one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are residues comprising ester groups, preferably one or two of the residues R3 and R4 in the general formula (I) are residues comprising ester groups of C1-C6 alcohols, in particular methyl ester groups, more preferably the residues R3, R4 and R2 in the general formula (I) are residues comprising ester groups of C1-C6 alcohols, most preferably the residues R3, R4 and R2 comprise methyl ester groups.
Therein, it is preferred that R3 and R4 are alkyl groups terminated by an ester functional group, wherein, if the alkyl substituent is branched due to being obtained from a hydrosilylation reaction of an internal double bond or to being the Markovnikov product of the hydrosilylation reaction of a terminal alkene, preferably only one terminus of the alkyl substituent is terminated by a ester group.
In another preferred embodiment according to the invention, all four organyl substituents R1, R2, R3 and R4 at the silicon center of the silahydrocarbon product of the general formula (I) are independently selected from saturated hydrocarbon groups, preferably from unsubstituted alkyl groups, more preferably from unsubstituted alkyl groups, most preferably from linear unsubstituted alkyl groups.
When all four substituents R1, R2, R3 and R4 are selected from saturated hydrocarbon groups, the resulting silahydrocarbons are particularly stable compounds, which is an important feature for various applications.
It is preferred that at least two of the substituents R1-R4 are different regarding their number of carbon atoms, more preferably three or four of the substituents differ regarding their number of carbon atoms.
In still another preferred embodiment according to the invention, the silahydrocarbon product of the general formula (I) is selected from the group consisting of Me2SiHexPent, Me2SiHexHept, Me2SiHexOct, MeSiBu3, MeSiBu2Hept, MeSiBuHeptOct, MeSiHexHeptOct, MeSiHept2Oct, MeSiHeptOctDec, MeSiHeptOctHexdec, Bu2SiHexOct, BuSiHex2Oct, BuSiHexHeptOct, BuSiHexOctDec, BuSiHexOctHexdec, Bu3SiHex, BuSiHex3, BuSiHexHept2, BuSiHexDec2, OctHexSiPentHept, OctHexSiPentOctenyl (C1 and C2 substituted Octenyl), OctHexSiPentDec, OctHexSiPentHexadec, (11-bromoundecyl)MeSiBu2, (phenethyl)MeSiBu2, and methyl-11-(methyldibutylsilyl)undecenoate, preferably selected from the group consisting of Me2SiHexPent, Me2SiHexHept, Me2SiHexOct, MeSiBu3, MeSiBu2Hept, MeSiBuHeptOct, MeSiHexHeptOct, MeSiHept2Oct, MeSiHeptOctDec, MeSiHeptOctHexdec, Bu2SiHexOct, BuSiHex2Oct, BuSiHexHeptOct, BuSiHexOctDec, BuSiHexOctHexdec, Bu3SiHex, BuSiHex3, BuSiHexHept2, BuSiHexDec2 and OctHexSiPentHept, even more preferably selected from the group consisting of Me2SiHexPent, Me2SiHexHept, Me2SiHexOct, MeSiBu3, MeSiBuHeptOct, MeSiHexHeptOct, MeSiHeptOctDec, MeSiHeptOctHexdec, BuSiHexHeptOct, BuSiHexOctDec, BuSiHexOctHexdec and OctHexSiPentHept, and most preferably selected from Me2SiHexPent, Me2SiHexOct, MeSiBu3, MeSiHeptOctDec, MeSiHeptOctHexdec, BuSiHexHeptOct, BuSiHexOctDec and BuSiHexOctHexdec. According to the invention, the term “Hexdec” denotes a hexadecyl (C16H33) residue.
In a preferred embodiment according to the invention, the bifunctional monosilane intermediate of the general formula (II) in step a) is a compound of the formula SiR1H2Cl, wherein R1 is an unsubstituted or substituted alkyl group, preferably R1 is an unsubstituted alkyl group, more preferably R1 is an unsubstituted C1-C30 alkyl group, even more preferably R1 is an unsubstituted C1-C30 linear alkyl group, most preferably R1 is a methyl group.
By submitting such intermediate to the process step b), a compound of the formula SiR1R2R3Cl is obtained, wherein R1 is as defined according to this embodiment, R2=R3 and R3 is as defined above.
In an also preferred embodiment according to the invention, the bifunctional monosilane intermediate of the general formula (II) in step a) is a compound of the formula SiR1HCl2, wherein R1 is an unsubstituted or substituted alkyl group, preferably R1 is an unsubstituted alkyl group, more preferably R1 is an unsubstituted C1-C30 alkyl group, even more preferably R1 is an unsubstituted C1-C30 linear alkyl group, most preferably R1 is a methyl group.
By submitting such intermediate to the next step b), a compound of the formula SiR1R2Cl2 is obtained, wherein R1 is as defined according to this embodiment, and R2 is as defined above with the proviso that it has at least two carbon atoms adjacent to each other, i.e. being connected by a single or double bond.
In a further preferred embodiment according to the invention, the bifunctional monosilane intermediate of the general formula (II) in step a) is a compound of the formula SiR1R21HCl, wherein R1 and R21 are independently selected from unsubstituted or substituted alkyl groups, preferably R1 and R21 are independently selected from unsubstituted alkyl groups, more preferably R1 and R21 are independently selected from unsubstituted C1-C30 linear alkyl groups, even more preferably R1 is methyl and R21 is selected from unsubstituted C1-C30 linear alkyl groups, most preferably R1 and R21 are both methyl groups.
By submitting such intermediate to the next step b), a compound of the formula SiR1R2R3Cl is obtained, wherein R1 and R2 are as defined according to this embodiment, and R3 is as defined above.
In a still further preferred embodiment according to the invention, the bifunctional monosilane intermediate of the general formula (II) in step a) is selected from the group consisting of MeSiHCl2, MeSiH2Cl, Me2SiHCl, PhSiHCl2, PhSiH2Cl, Ph2SiHCl, MePhSiHCl, MeViSiHCl, BuSiHCl2, MeBuSiHCl, BuSiHexHCl, Hex2SiHCl, HexSiHCl2, HexSiH2Cl, OctSiHCl2, OctSiH2Cl, OctHexSiHCl, preferably MeSiHCl2, PhSiHCl2, MeViSiHCl, HexSiHCl2, Hex2SiHCl, Me2SiHCl, BuSiHCl2, or MeSiBuHCl, most preferred MeSiHCl2, Me2SiHCl, or BuSiHCl2.
The above-listed group of compounds is readily available and constitutes a starting point for the synthesis of silahydrocarbons bearing up to four different substituents, thus allowing the design of compounds having appropriate physical and chemical properties for a variety of applications. The substituents R1 and R21 of the compounds of the above-listed group are inert under process conditions and thus allow to perform the process steps in high yields and without the formation of by-products.
In another preferred embodiment according to the invention, the starting material for step a) of the general formula (III) is a compound of the general formula R1SiCl3, wherein R1 is selected from unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, or unsubstituted or substituted aryl groups, each having 1 to 30 carbon atoms, and is preferably obtained by a hydrosilylation reaction of HSiCl3 and a C—C-unsaturated compound having 2 to 30 carbon atoms.
Preferably, the starting material of the general formula (III) is obtained by a hydrosilylation reaction of HSiCl3 and a compound selected from the group consisting of linear alkenes and alkynes, more preferably unsubstituted linear alkenes and alkynes, even more preferably unsubstituted linear monoalkenes and monoalkynes, most preferably terminally unsaturated linear unsubstituted monoalkenes and monoalkynes.
Hydrosilylation of the readily available compound HSiCl3 allows to introduce a wide variety of residues which is only limited by the kinds of C—C unsaturated compounds available and appropriate for this reaction. Starting from HSiCl3, the process according to the invention allows to independently introduce all four substituents of the silahydrocarbon target in a selective manner by hydrosilylation reactions.
In a preferred embodiment according to the invention, the starting material for step a) of the general formula (IV) is a compound of the formula R1SiH3, wherein R1 is selected from unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, or unsubstituted or substituted aryl groups each having 1 to 30 carbon atoms, which is preferably obtained by a hydrosilylation reaction of HSiCl3 and subsequent hydrogenation with a metal hydride of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2.
It is preferred when the compound of the general formula (IV) according to this embodiment is submitted to a redistribution reaction with a compound of the general formula (III) that is the perchlorinated analogue of the compound of the formula (IV), i.e. R1 is the same in both compounds.
In a further preferred embodiment according to the invention, one or both of the starting materials of the general formulae (III) and (IV) applied in a reaction of step a) are obtained starting from HSiCl3, wherein the HSiCl3 is preferably obtained from the Siemens Process or from hydrogenation of SiCl4 with mono-, di- or triorganohydridosilanes.
In the Siemens Process for the production of highly pure polycrystalline silicon 98-99% pure silicon is grounded and reacted with gaseous hydrogen chloride at 300-350° C. in a reactor to obtain trichlorosilane. Then, trichlorosilane is pyrolyzed at T>1000° C. and in the presence of hydrogen gas (H2) with release of HCl gas to obtain the desired silicon. However, in this second step most of the trichlorosilane exits the reactor unreacted as an exhaust gas. It can be recycled or used in other applications. According to this embodiment, either the HSiCl3 from the exhaust gas of the above-described Siemens process is used to prepare the starting materials of the general formula (III) or (IV), or the HSiCl3 applied in this embodiment is obtained by treating the high-boiling side-products of the Siemens Process with an appropriate reaction-promoting agent, e.g. the ether/HCl reagent.
HSiCl3 can also be generated in the reaction of SiCl4 with mono-, di- or triorganohydridosilanes, for instance in the chlorination reaction which can be applied as a means for the provision of bifunctional starting materials in step a) of the process according to the invention. Use of thus generated HSiCl3 for the generation of starting materials according to the invention can render the process according to the invention more beneficial from both an economic as well as from an environmental perspective.
In an also preferred embodiment according to the invention, the starting material for step a) according to general formula (III) is MeSiCl3 or Me2SiCl2, preferably MeSiCl3 or Me2SiCl2 obtained from the Müller-Rochow-Direct Process.
Me2SiCl2 is the main product of the Müller-Rochow-Direct Process, its annual production worldwide is in the Million of tons range. MeSiCl3 is the next abundant product of the Müller-Rochow-Direct Process, and thus both Me2SiCl2 and MeSiCl3 are readily available. Both compounds can also be obtained from cleavage of high-boiling side-products of the Müller-Rochow-Direct Process, in particular of the disilane residue (DPR) mostly comprising compounds of the general formula MenSi2Cl6-n (n=2-6).
Both MeSiCl3 and Me2SiCl2 thus constitute readily available and cheap starting materials for the process according to the invention, which, due to the small size of the methyl group and its chemical robustness, allow the introduction of a wide variety of further substituents.
It is preferred that each of the starting materials MeSiCl3 or Me2SiCl2 is brought to reaction in a redistribution reaction with its hydrogenated analogue, MeSiH3 or Me2SiH2, respectively. In the case MeSiCl3 is selected as starting material, it is preferred when MeSiHCl2 is formed as product in the redistribution reaction.
In a further preferred embodiment according to the invention, the starting material for step a) according to general formula (IV) is MeSiH3 or Me2SiH2, preferably obtained by hydrogenation of MeSiCl3 or MeSiCl2 with a metal hydride of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2, even more preferably the starting material for step a) according to general formula (IV) is MeSiH3 or Me2SiH2 obtained by hydrogenation of MeSiCl3 or Me2SiCl2 obtained from the Müller-Rochow-Direct Process with a metal hydride of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2.
It is particularly preferred that the compounds MeSiH3 or Me2SiH2 are obtained by a reduction reaction using NaH, LiH or LiAlH4 as reductant.
In another preferred embodiment according to the invention, at least one intermediate of the general formula (II) is obtained by a redistribution reaction of a compound of the general formula (III) and a compound of the general formula (IV) as defined above, wherein the redistribution catalyst is selected from one or more compounds selected from the group consisting of
Preferably, the compound of the general formula (III) applied in the redistribution reaction is the chlorinated analogue of the compound of the general formula (IV) applied.
In a preferred embodiment according to the invention, at least one step a) is performed in the presence of a solvent, wherein the solvent is selected from the group consisting of ethers, alkanes or aromatic solvents, more preferably selected from the group consisting of THF, 1,4-dioxane, diglyme, tetraglyme, hexane and benzene, most preferably the solvent is THF.
In particular, for step a) being a redistribution reaction, THF, diglyme, 1,4-dioxane and tetraglyme are preferred solvents;
for step a) being a redistribution reaction with in situ reduction of the chlorosilane, THF, diglyme and tetraglyme are preferred solvents; and
for step a) being a partial chlorination using ether/HCl, 1,4-dioxane, n-Bu2O and diglyme are preferred solvents;
If SiCl4 is used as chlorination reagent for the provision of the target compounds of step a), no solvent is required, and although the presence of ether solvents does not hamper the chlorination reaction in general, it is preferred to perform the reaction under neat conditions.
In a further preferred embodiment according to the invention, the reaction temperature in at least one step a) is in the range from 0° C. to 180° C., preferably 20° C. to 160° C., and most preferably 60° C. to 120° C.
In particular, for step a) being a redistribution reaction the temperature is preferably in the range from 50 to 160° C., more preferably from 60 to 120° C.;
for step a) being a redistribution reaction with in situ reduction of the chlorosilane, the temperature is preferably in the range from 70 to 100° C.;
for step a) being a partial chlorination using ether/HCl, the temperature is preferably in the range from 0 to 80° C., more preferably in the range from 20 to 60° C., and for step a) being a chlorination using SiCl4, the temperature is preferably in the range from 55 to 140° C., more preferably from 60 to 120° C.
According to the invention, the reaction temperature in a step a) is the temperature of the reaction mixture, i.e. the temperature measured inside the reaction vessel in which the reaction is conducted.
In another preferred embodiment according to the invention, the redistribution partners in at least one step a) are selected from the group consisting of the couples MeSiCl3 and MeSiH3, Me2SiCl2 and Me2SiH2, MeSiCl3 and Me2SiH2, Me2SiCl2 and MeSiH3, Ph2SiCl2 and Me2SiH2, PhMeSiCl2 and Me2SiH2, MeSiHeptCl2 and MeSiHeptH2, MeSiOctCl2 and MeSiOctH2 or MeSiBuCl2 and MeSiBuH2, preferably from MeSiCl3 and MeSiH3, Me2SiCl2 and Me2SiH2, or from MeSiBuCl2 and MeSiBuH2.
The above-listed couples indicate that one of these specific pairs of compounds is submitted to a step a) without any further compounds of the general formula (III) or (IV) added to the reaction mixture before or during the reaction.
In still another preferred embodiment according to the invention, at least one intermediate of the general formula (II) in a step a) is obtained by a redistribution reaction of a compound of the general formula (III) and the in-situ formed hydrogenation products obtained by reacting one or more monosilanes of the general formula (III) with a metal hydride of the general formula MHx or an organometallic hydride donor in the presence of a redistribution catalyst, wherein the redistribution catalyst is selected from the group consisting of
It is particularly preferred that the redistribution catalyst is selected from n-Bu4PCl, n-Bu4NCl, Ph3P, n-Bu3N, and the reductant is LiH.
In a further preferred embodiment according to the invention, the solvent in the redistribution reaction involving in-situ reduction of the perchlorinated starting material is selected from the group consisting of ethereal solvents, more preferably THF, diglyme, 1,4-dioxane, triglyme, tetraglyme, DME (dimethoxyethane), most preferably THF, 1,4-dioxane, or diglyme.
In an also preferred embodiment according to the invention, the reaction temperature in the redistribution reaction involving in-situ reduction of the perchlorinated starting material is in the range from 0° C. to 180° C., preferably 20° C. to 160° C., and most preferably 60° C. to 140° C.
In another preferred embodiment according to the invention, the compounds of the general formula (III) are selected from the group consisting of MeSiCl3, Me2SiCl2, PhSiCl3, Ph2SiCl2, PhMeSiCl2, BuSiCl3 or MeSiBuCl2, preferably from the group consisting of MeSiCl3, BuSiCl3, MeSiBuCl2 and Me2SiCl2.
In a preferred embodiment according to the invention, at least one intermediate of the general formula (II) is obtained in a selective partial chlorination reaction of a compound of the general formula (IV) by reacting the compound with an HCl/ether reagent in step a), wherein the HCl/ether reagent is preferably selected from THF/HCl, diethyl ether/HCl, diglyme/HCl, 1,4-dioxane/HCl, dibutyl ether/HCl, more preferably selected from diglyme/HCl, diethyl ether/HCl, 1,4-dioxane/HCl, dibutyl ether/HCl, and most preferably selected from diethyl ether/HCl, or diglyme/HCl.
Preferably, the compound of the general formula (IV) submitted to partial chlorination according to the embodiment of the invention is selected from SiR1H3 or SiR1R2H2, wherein at least one, preferably both of R1 and R2 are independently selected from C1-C30 alkyl and C1-C30 alkenyl groups, more preferably from C1-C16 alkyl groups.
In another preferred embodiment according to the invention, at least one intermediate of the general formula (II) is obtained in a chlorination reaction of a compound of the general formula (IV) SiR1R23H2 with tetrachlorosilane (SiCl4) in the presence of at least one catalyst.
Chlorination of the perhydridosilane compounds of the formula (IV) with SiCl4 in order to obtain the bifunctional intermediates of the formula (II) is preferred because the reaction is conveniently performed using SiCl4 as a chlorination reagent of low cost. Further, HSiCl3 obtained as a side-product of the reaction can be reintroduced into the silicon deposition process of the Siemens Process or, alternatively, for hydrosilylation reactions and is thus of great economic value.
In a further preferred embodiment according to the invention, in at least one step a) the compounds of the general formula (IV) submitted to a partial chlorination reaction with an HCl/ether reagent or with SiCl4 in the presence of at least one catalyst are selected from the group consisting of MeSiH3, Me2SiH2, PhSiH3, Ph2SiH2, PhMeSiH2, BuSiH3, MeSiBuH2, HexSiH3, OctSiH3, Hex2SiH2, MeSiHexH2, MeSiHeptH2 and MeSiOctH2, preferably from MeSiBuH2, MeSiHexH2, MeSiHeptH2, and MeSiOctH2.
In a still further preferred embodiment according to the invention, the compounds of the general formula (IV) submitted to the partial chlorination reaction with an HCl/ether reagent or with SiCl4 in the presence of at least one catalyst are obtained by perhydrogenation of the analogous perchlorinated monosilanes using one or more metal hydride reagents or organometallic hydride donor reagents selected from NaBH4, LiAlH4, LiBH4, KH, LiH, NaH, MgH2, CaH2, nBu3SnH, Me3SnH, Ph3SnH, nBu2SnH2, Me2SnH2, and Ph2SnH2 or i-Bu2AlH, preferably from LiAlH4, NaH, LiH or nBu3SnH, more preferably from LiAlH4 or LiH, most preferably LiH.
In another preferred embodiment according to the invention, at least one metal-catalyzed hydrosilylation step (b) is performed using a Rh- or Pt-based catalyst, more preferably using a Pt-catalyst immobilized on a support, even more preferably using a Pt-catalyst immobilized on silica, most preferably a Pt-catalyst immobilized on silica comprising a metal-containing siloxane polymer matrix covalently bonded to the silica support, in particular Pt-nanoparticles encapsulated in a siloxane polymer matrix covalently bonded to a silica support.
A platinum-based catalyst which is preferred according to the invention is disclosed in the patent application US 2015/0051357 A1, which is incorporated herein by reference in its entirety. In particular, the catalyst disclosed therein in Example 2 is particularly preferred according to the invention.
In general, when a Pt-based catalyst immobilized on a support is applied in step b), it is preferred when the metal loading ranges from about 0.1 to about 5 percent by weight of the support material.
When a Pt-catalyst immobilized on silica comprising a metal-containing siloxane polymer matrix covalently bonded to the silica support is applied, it is preferred when the metal loading ranges from about 0.1 to about 1 percent by weight of the support material. In such case it is also preferred when the metal-containing polymer matrix is covalently bonded to the support material via a hydrophobic functional group chosen from an alkyldisilazane, a vinyl-containing silazane, or a combination thereof.
In still another preferred embodiment according to the invention, the bifunctional monosilane intermediate of the general formula (II) submitted to step b) is selected from R1SiHCl2 or R1SiH2Cl, wherein in each case R1 is selected from phenyl or a C1-C30 linear alkyl residue, or R1R21SiHCl, wherein R1 and R21 are independently selected from phenyl or a C1-C30 linear alkyl residue, preferably the intermediate is selected from the group consisting of MeSiHCl2, MeSiH2Cl, Me2SiHCl, PhSiH2Cl, PhSiHCl2, Ph2SiHCl or PhMeSiHCl, and most preferably the intermediate is selected from MeSiHCl2, MeSiH2Cl or Me2SiHCl.
According to this embodiment of the invention, it is further preferred that one of the residues R3 and R4 introduced by a hydrosilylation reaction step is a substituted alkyl or alkenyl group, more preferred an alkyl group bearing at least one bromo group, chloro group or ester group as substituent.
According to this embodiment of invention, it is also further preferred that one of the residues R3 and R4 introduced by a hydrosilylation step is a C8-C30 linear unsubstituted alkyl group or a C8-C30 linear unsubstituted alkenyl group.
In a preferred embodiment according to the invention, the compound containing at least one C—C double or C—C triple bond in the hydrosilylation reaction of step b) is selected from the group consisting of alkenes, cycloalkenes, polyenes, alkynes, cyclic alkynes, polyalkynes, preferably alkenes, cycloalkenes, alkynes, cyclic alkynes, more preferably alkenes, cycloalkenes, alkynes, even more preferably alkenes, and most preferably monounsaturated terminal alkenes.
In a further preferred embodiment according to the invention, at least one step b) is performed at a temperature within the range from 0° C. to 180° C., preferably 20° C. to 140° C., most preferably 60° C. to 100° C.
Therein, it is preferred when no additional solvent is used or the solvent is selected from THF, diglyme, 1,4-dioxane, benzene or toluene, preferably from THF, diglyme or 1,4-dioxane, more preferably from THF or 1,4-dioxane, most preferably the solvent is THF.
In another preferred embodiment according to the invention, in step c) the intermediate of the general formula (V) is hydrogenated by a reaction with a metal hydride reagent of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor reagent selected from the group consisting of nBu3SnH, Me3SnH, Ph3SnH, nBu2SnH2, Me2SnH2, and Ph2SnH2, preferably with a metal hydride reagent selected from the group consisting of NaBH4, LiAlH4, LiBH4, KH, LiH, NaH, MgH2, CaH2, i-Bu2AlH or nBu3SnH, more preferably consisting of LiAlH4, NaH, LiH, even more preferably from LiAlH4 and LiH, and most preferably the metal hydride reagent is LiH.
According to the invention, LiH is the most preferred metal hydride reagent for the reduction step c) as it is comparatively easy to handle, reduces chlorosilanes under convenient reaction conditions, i.e. at low temperatures and the resulting lithium chloride can be submitted to a recycling process for the recovery of LiH. NaH is also preferred due to its low cost and satisfying performance in the reduction of chlorosilanes.
In still another preferred embodiment according to the invention, the catalyst of the hydrosilylation reaction of step d) is selected from a Rh- or Pt-based catalyst, more preferably from a Pt-catalyst immobilized on a support, even more preferably from a Pt-catalyst immobilized on silica, most preferably from a Pt-catalyst immobilized on silica comprising a metal-containing siloxane polymer matrix covalently bonded to the silica support, in particular Pt-nanoparticles encapsulated in a siloxane polymer matrix covalently bonded to a silica support.
A platinum-based catalyst which is preferred according to the invention is disclosed in the patent application US 2015/0051357 A1, which is incorporated herein by reference in its entirety. In particular, the catalyst disclosed therein in Example 2 is particularly preferred according to the invention.
In general, when a Pt-based catalyst immobilized on a support is applied in step b), it is preferred when the metal loading ranges from about 0.1 to about 5 percent by weight of the support material.
When a Pt-catalyst immobilized on silica comprising a metal-containing siloxane polymer matrix covalently bonded to the silica support is applied, it is preferred when the metal loading ranges from about 0.1 to about 1 percent by weight of the support material. In such case it is also preferred when the metal-containing polymer matrix is covalently bonded to the support material via a hydrophobic functional group chosen from an alkyldisilazane, a vinyl-containing silazane, or a combination thereof.
In a further preferred embodiment according to the invention, the compound containing one or more C—C double bonds or C—C triple bonds submitted to the hydrosilylation reaction of step d) is selected from the group consisting of alkenes, cycloalkenes, polyenes, alkynes, cyclic alkynes, polyalkynes, preferably alkenes, cycloalkenes, alkynes, cyclic alkynes, more preferably alkenes, cycloalkenes, alkynes, even more preferably alkenes, and most preferably monounsaturated terminal alkenes.
In another preferred embodiment according to the invention, hydrogenation reaction of step c) and the hydrosilylation reaction of step d) are performed in a one-step procedure.
The present invention is further illustrated by the following examples, without being limited thereto.
General
Prior to the reactions the solvents used were carefully dried according to procedures known from the literature. Products were analyzed and characterized by standard procedures, especially by NMR spectroscopy and GC/MS analyses.
The hydrosilylation catalyst referred to herein as the immobilized-Pt catalyst “Y1 EX2” is a heterogenous platinum-based catalyst prepared according to the procedure disclosed in Example 2 of the U.S. Pat. No. 9,993,812 B2 (corresponds to the application US 2015/0051357 A1).
The hydrosilylation catalyst referred to herein as “B770011” is a commercial product named 3.6R210 containing 3.6% Platinum metal (500 nm) on Silica Type 210, as purchased from Johnson Matthey (JM).
While the bifunctional starting materials HSiCl3, MeSiHCl2 and Me2SiHCl are industrially available, a wide range of differently organo-substituted bifunctional hydridochloromonosilanes can be synthesized either by cleavage of organochlorodisilanes with suitable cleavage catalysts and reaction partners, e.g. phosphonium chlorides (see N. Auner et al., “Synthesis of Bifunctional Monosilanes by Disilane Cleavage with Phosphonium Chlorides”, Chem. Eur. J. 2019, 25, 3809-3815), or, alternatively by selective chlorination of the respective organohydridomonosilanes with ether/HCl solutions (see M. C. Holthausen et al., “Lewis Base Catayzed Selective Chlorination of Monosilanes”, Chem. Eur. J. 2018, 24, 17796-17801). The bifunctional monosilanes used in the examples of this application were synthesized by these two synthetic routes and by redistribution reactions of organochlorosilanes with organohydridosilanes, alternatively, chlorination of the respective hydridodosilanes with tetrachlorosilane (SiCl4) in the presence of suitable catalysts give bifuctional monosilanes in excellent yields (N. Auner, A. G. Sturm, EP 18193571.9). To obtain the organohydridosilanes used as starting materials, the chlorosilanes, in particular, the organochlorosilanes R3SiCl, R2SiCl2 and RSiCl3 (R=alkyl, aryl, alkenyl) were converted to the corresponding organomono-, di-, and trihydridosilanes R3SiH, R2SiH2 and RSiH3 by hydrogenation (reduction) with conventional reduction agents, in ethers as solvents. The redistribution reactions were performed by mixing the reaction partners, i.e. the hydridosilanes (0.1 mL) and the chlorosilanes (1.1-2.0 eq of the chlorosilanes based on the molar amount of the hydridosilanes), dissolved in 0.2-0.3 mL of THE or diglyme and the redistribution catalyst (1-3 wt % based on the amount of silane substrates added) in an NMR tube. After cooling the sample with liquid nitrogen (about −196° C.), the tube was evacuated (about 0.1 mbar), and sealed to avoid any losses of low boiling monosilanes such as Me2SiHCl (b.p. 35° C.), MeSiHCl2 (b.p. 41° C.), Me2SiH2 (b.p. −20° C.), MeSiH3 (b.p. −58° C.) and HSiCl3 (b.p. 32° C.), the boiling point of Me2SiCl2 is about 70° C. (all b.p. at normal pressure). NMR spectra were recorded depending on reaction time and temperature to control the product formation. The molar ratios of the products formed were determined by integration of the relevant NMR signals that were assigned to specific products in the mixture. After completion of the redistribution reactions (e.g. R2SiH2+R2SiCl2→2R2SiHCl) the NMR tube was opened to analyze the product mixture by GC-MS. Product identification was verified in all cases for the main products by 1H- and 29Si-NMR spectroscopy and GC-MS analysis.
The amount of products formed was estimated by the molar ratios as measured by NMR spectroscopy and the amount of starting materials submitted.
The optimum reaction conditions were identified by NMR-tube experiments and transferred to reactions in preparative scale in closed glass ampules or in open systems. The synthesis of Me2SiHCl from Me2SiCl2 and the organosilane Me2SiH2 in preparative scale is described exemplarily. NMR experiments as well as those in closed glass ampules were run in high boiling solvents, such as diglyme, to reduce the overall pressure at elevated temperatures. The glass ampules had a length of 200 mm, outer diameter of 30 mm and a wall thickness of 2 mm (internal volume ˜40 mL). For high boiling organosilanes, such as PhSiH3, reactions can be performed in open systems.
The hydrosilylation reactions of bifunctional monosilanes with 1-alkenes and 1-alkynes were generally performed as follows. 0.1 mL of the alkene or alkyne (1.1-3.5 eq based on the amount of bifunctional monosilane) were admixed with 0.05-0.15 mL of the monosilane (1.0 eq) and 10 wt % (based on the amount of the silane substrate) of the hydrosilylation catalyst (Y1 EX2, or Karstedt-catalyst, or B770011) in 0.2-0.3 mL THE as solvent in an NMR tube. After cooling the sample with liquid nitrogen (about −196° C.), the tube was evacuated (about 0.1 mbar), and sealed. After warming to r.t., NMR spectra were recorded from the starting mixture and subsequently the sample was heated. The course of the reaction was controlled by NMR spectroscopy, the frequency of measurements performed depending on reaction time and temperature. The molar ratios of products formed were determined by integration of the relevant NMR signals that were assigned to specific products within the mixture. In case the hydridosilane was completely added across the carbon-carbon double bond, the conversion rate was defined as 100%; in case only half of the hydridosilane was consumed the conversion rate of the hydridosilane was 50% accordingly. In some cases when the olefin reactant was partially isomerized, and/or hydrogenated (H2 from dehydrogenative silylation) due to the high reaction temperature applied, excess of hydridosilane remained. In case the olefin was completely consumed and the hydridosilane concentration was still 50%, then the conversion rate was defined as 50%. After completion of the hydrosilylation reaction the NMR tube was opened and the product mixture was investigated by additional GC-MS analysis.
Alternatively to hydrosilylation reactions in closed systems which constitute the preferred procedure for reacting compounds with low boiling points, the reaction can be run in open systems (reaction flask, magnetic stirrer, reflux condenser and dropping funnel, under inert atmosphere, e.g. Ar or N2) as well, if reaction partners with relatively high boiling points are reacted. This is especially recommended for the introduction of a third or fourth organo substituent at silicon. Although the high molecular tri- and tetraalkylsilanes are thermally very stable, it is recommended to purify these products by short path distillation procedures under reduced pressure conditions (p<10−2 mbar) to avoid thermal decomposition of the organosilanes.
In some cases the products have not been further purified or isolated (diluted in THE or impurities of other silane compounds), thus, yields are either based on the amount of the starting material used, or the respective product proportions are given in relation to the starting materials.
Identification of Compounds
Products were analyzed by 1H and 29Si and 1H-29Si-HSQC NMR spectroscopy. The spectra were recorded on a Bruker AV-500 spectrometer equipped with a Prodigy BBO 500 S1 probe. 1H-NMR spectra were calibrated to the residual solvent proton resonance ([D6]benzene δH=7.16 ppm). Product identification was additionally supported by GC-MS analyses and verified the identification of the main products.
GC-MS analyses were performed with a Thermo Scientific Trace GC Ultra coupled with an ITQ 900MS mass spectrometer. The stationary phase (Macherey-Nagel PERMABOND Silane) had a length of 50 m with an inner diameter of 0.32 mm. 1 μL of analyte solution was injected, 1/200 thereof was transferred onto the column with a flow rate of 1.7 mL/min carried by helium gas. The temperature of the column was first kept at 50° C. for 10 minutes. Temperature was then elevated at a rate of 20° C./min up to 250° C. and held at that temperature for another 25-160 minutes (depending on the steric demand or length of the alkyl-substituents at the silicon center). After exiting the column, substances were ionized with 70 eV and cationic fragments were measured within a range of 34-600 m/z (mass per charge). 29Si NMR chemical shifts and mass fragments for the starting materials and reaction products formed are listed in Table 1.
29Si-
1)RT = retention time on GC-column;
2)The product specific mass fragment is often characterized by loss of one alkyl leaving group
3)M = molecular weight calculated;
29Si-
1)RT = retention time on GC-column;
2)The product specific mass fragment is often characterized by loss of one alkyl leaving group;
3)M = molecular weight calculated;
4)b.p. at 102 mbar;
5)b.p. at 40 mbar.
Table 2 shows the molecular structures of selected silahydrocarbons synthesized in the subsequently described Examples as well as their precursors and intermediates in synthesis. The target compounds of the process according to the invention are marked with an asterisk (*).
Step a): Synthesis of Bifunctional Monosilanes
1) Redistribution Reactions of Hydrido- and Chlorosilanes to Yield Bifunctional Monosilanes
indicates data missing or illegible when filed
Entries A1-A3/Table 3: Target Reaction: 1 Me2SiH2+1 Me2SiCl2→2 Me2SiHCl
As can be seen from Table 3, the redistribution reactions gave Me2SiHCl in excellent yields (ca. 85%) related to the hydridosilane reacted and under moderate conditions (100° C./24 h). The yield of Me2SiHCl is increasing with increasing excess of Me2SiCl2; Me2SiH2 is nearly quantitatively consumed, thus simplifying the separation of Me2SiCl2 from Me2SiHCl by low temperature condensation and/or distillation at normal pressure. Notably, in all redistribution reactions the catalyst n-Bu4PCl remained unreacted and could be recycled easily.
Entry A4/Table 3: Target Reaction: Me2SiH2+MeSiCl3→Me2SiHCl+MeSiHCl2
After 2 h at 80° C. Me2SiH2 was quantitatively transferred into Me2SiHCl (51%), while MeSiCl3 was increasingly reduced to finally give MeSiH3 in 8% with increasing reaction times/temperatures. With prolonged reaction times and/or increasing temperatures Me2SiHCl was increasingly chlorinated to Me2SiCl2, while the molar ratio of methylmonochloro- and methyldichlorosilanes (MeSiH2Cl and MeSiHCl2) remains rather constant. The optimum conditions for the synthesis of the target compounds are 80° C./2 h. Notably, under those conditions, the overall yield in hydridomonosilanes was 81%, the catalyst remained unchanged.
Entry A5/Table 3: Target Reaction: 1 Me2SiH2+1 MeSiCl3→1 Me2SiHCl+1 MeSiHCl2
Entry A5 demonstrates that the redistribution equilibrium is strongly shifted to give monomethylsilanes MeSiH2Cl and MeSiHCl2 in 55% at 80° C./16 h: Longer reaction times as compared to entry A4 (Table 3) favored monomethylsilane formation, while Me2SiH2 was completely chlorinated to give Me2SiCl2; the catalyst remained unchanged.
Entries A6 and A7/Table 3: Target Reaction: 1 MeSiH3+2 MeSiCl3→3 MeSiHCl2
As shown in entries A6 and A7, Table 3, as well as Table 3/A71 and 3/A72 below, the target compound MeSiHCl2 was formed already within 2 h at 80° C. Based on the amount of MeSiH3 reacted and with an excess of MeSiCl3, the redistribution reaction was quantitative. Table 3/A72 demonstrates that MeSiHCl2 was already formed in more than 70% at r.t., but with longer reaction times. The yield of MeSiH2Cl was slightly increased running the redistribution reaction at higher temperatures. In both experiments of entries A6 and A7, n-Bu4PCl was used as catalyst and remained unchanged.
Entry A8/Table 3: Target Reaction: 1 HexSiH3+2 HexSiCl3→3 HexSiHCl2
Already after 14 h at 80° C. the target compounds HexSiHCl2 (66%) and HexSiH2Cl (23%) were formed in excellent yields (ca. 90%), related to the amount of starting material HexSiH3 used; thus the redistribution was nearly quantitative. With prolonged reaction times and temperatures (120° C./42 h) the relative amount of the targeted HexSiHCl2 increased to 72%, while the amount of educts as well as of HexSiH2Cl (20%) decreased slightly.
Entry A9/Table 3: Target Reaction: 1 MeSiHeptH2+1 MeSiHeptCl2→2 MeSiHeptHCl
A 55:45 mixture of MeSiHeptH2 and MeSiHeptCl2 was reacted with n-Bu4PCl as redistribution catalyst at 100° C. (3 h), 120° C. (16 h) and 140° C. (18 h) in a sealed NMR tube. After each heating period product distribution was controlled by NMR spectroscopy. Redistribution reaction started already at r.t. to give 30% of MeSiHeptHCl. By further heating of the sample to 120° C., the redistribution reaction was almost completed yielding 64% of MeSiHeptHCl.
Entries A101 and A102/Table 3: Target Reaction: 1 MeSiBuH2+1 MeSiBuCl2→2 MeSiBuHCl
The redistribution reactions of an equimolar mixture of MeSiBuH2 and MeSiBuCl2 (molar ratio 50:50) in THF and in diglyme as solvent at 120° C. (17 h) each gave identical product distributions: The bifunctional target compound MeSiBuHCl was formed in about 60% based on the sum of the molar amounts of the chlorosilane and the hydridosilane.
Entry A11/Table 3: Target Reaction: 1 BuSiHexH2+1 BuSiHexCl2→2 BuSiHexHCl
124 mg of n-Bu4PCl, 5 mL THF, BuSiHexH2 (7 mmol dissolved in 10 mL THF) and 4.82 g (20 mmol) BuSiHexCl2 were placed in an ampule equipped with an NMR tube, cooled to −196° C. and sealed in vacuo. Reaction was performed at 120° C. for 109 h. The ampule was opened, and the liquid product mixture was transferred into a Schlenk-flask. Volatile products as well as the silane reactants were condensed off in vacuo to be separated from phosphonium chloride, which remained unchanged in the redistribution reaction. The THF was distilled off and a mixture consisting of BuHexSiHCl (2.69 g, 13 mmol) and BuSiHexCl2 (3.14 g, 11 mmol) was obtained.
Entry A12/Table 4: Target Reaction: Ph2SiCl2+Me2SiH2→Me2SiHCl+Ph2SiHCl
A mixture of Me2SiH2 (0.9 mmol) and Ph2SiCl2 (1.1 mmol) was solved in diglyme (0.35 ml) with an admixture of a catalytic amount of n-Bu4PCl (0.02 mmol). As shown in Table 4 the targeted hydridochlorosilanes Me2SiHCl and Ph2SiHCl were formed in 34 and 30% (80° C., 16 h), respectively. While Me2SiH2 was consumed nearly quantitatively, Ph2SiH2 was formed in 13%: Monosilane Me2SiH2 was chlorinated to give Me2SiHCl and Me2SiCl2 (9%) while Ph2SiCl2 was reduced to yield Ph2SiHCl and Ph2SiH2. With prolonged reaction time at 100° C., the amount of Ph2SiCl2 increased from 30 to 35%, while that of the Me2SiHCl decreased from 34 to 25%. Higher temperatures did not shift the redistribution equilibrium, the system remained constant.
Entry A13/Table 4: Target Reaction: Me2SiCl2+Et2SiH2→Me2SiHCl+Et2SiHCl
In a redistribution reaction of Me2SiCl2 (1.0 mmol) and diethylsilane (Et2SiH2, 0.8 mmol) in diglyme (0.35 ml) and n-Bu4PCl (0.02 mmol) as catalyst, Me2SiHCl and Et2SiHCl were formed in 37% and 26%, respectively at 140° C./13 h. At lower temperatures (80° C./13 h) formation of Et2SiHCl was favored over the methyl substituted counterpart Me2SiHCl (32 vs. 20% yield). While starting compound Et2SiH2 was nearly quantitatively consumed at 140° C. to even give the dichloro derivative (Et2SiCl2), Me2SiH2 was formed in 10%. This experiment convincingly demonstrates that the formation of the targeted differently organo substituted hydridochlorosilanes was effectively controlled by the reaction conditions.
Entry A14/Table 4: Target Reaction: PhMeSiCl2+Me2SiH2→PhMeSiHCl+Me2SiHCl
In a redistribution reaction, similar to entry A12, Me2SiH2 (1.1 mmol) was reacted with PhMeSiCl2 (1.1 mmol) in diglyme (0.35 ml) and n-Bu4PCl (0.02 mmol) as catalyst to give the target compounds Me2SiHCl (30%) and PhMeSiHCl (33%) at 140° C./48 h. Notably, the starting compounds were mostly consumed already at 80° C. yielding Me2SiHCl in 40% and PhMeSiHCl in 19%. As discussed for entries A12 and A13, the formation of differently organo substituted target compounds is depending on reaction conditions, thus making product formation controllable.
Entry A15/Table 4: Target Reaction: ViMeSiCl2+Me2SiH2→ViMeSiHCl+Me2SiHCl
Redistribution reactions of Me2SiH2 (1.1 mmol) and ViMeSiCl2 (1.1 mmol) in diglyme (0.35 mol) and n-Bu4PCl (0.02 mmol) as catalyst were similar to those described for entries A12-A14. The target compounds Me2SiHCl and ViMeSiHCl were already formed at 80° C./2 h in nearly 70% yield. While the molar amounts of ViMeSiHCl remained constant with increasing reaction temperatures, the amount of Me2SiHCl was steadily decreasing by chlorination to give dichlorosilane Me2SiCl2 (13%).
Upscaling into Preparative Scale:
In a 250 ml three-necked flask equipped with a dropping funnel, reflux condenser and a magnetic stirrer were placed 7.22 g (0.88 mol, 97%) lithium hydride (LiH), suspended in 100 ml of thoroughly dried tetrahydrofurane (THF) under an inert nitrogen atmosphere. The THF/LiH suspension was carefully scaled from oxygen/air by degassing in vacuo and refilling with gaseous nitrogen to establish inert conditions. To the vigorously stirred suspension 56.84 g (53.6 ml, 0.44 mol) of dimethyldichlorosilane (Me2SiCl2) were slowly added over the dropping funnel. Upon addition, the reduction of Me2SiCl2 started after an induction period of 5 minutes with self-heating of the solution to about 54° C. Dimethylsilane (Me2SiH2, b.p.: −20° C.), formed continuously, evaporated and was frozen in a cooling trap (−196° C.) which was connected with the top of the reflux condenser. After Me2SiCl2 addition was completed (1 h, final temperature 50° C.), the mixture was subsequently heated to reflux (75° C. oil bath temperature) for an additional hour and then cooled down to r.t. To completely collect Me2SiH2 in the cooling trap, the reaction flask was applied to vacuum and the product was pumped off. The product mixture inside the cooling trap was then condensed into an ampule with attached NMR tube and the ampule was sealed (31.28 g product mixture). Subsequently, 0.5 ml of the product mixture was poured from the ampule into the NMR tube, which was then sealed and disconnected from the ampule. 1H and 29Si NMR spectroscopic measurements revealed the following product distribution:
Me2SiH2: 25.4 g, 0.42 mol, 96% yield.
Me2SiCl2: 2.28 g, 0.018 mol, 4%.
Upon chlorosilane reduction with lithium hydride lithium chloride is formed and precipitated from the solution. LiCl was isolated by filtration and dried in vacuo. Formed LiCl was obtained in 36.05 g (96% conversion of LiH into LiCl; theoretical yield after 100% conversion: 37.56 g), which is in line with the amount of formed Me2SiH2.
In an glass ampule were placed 0.41 g (1.39 mmol) n-Bu4PCl, 40 ml of thoroughly dried THE and 84.82 g (657.21 mmol) Me2SiCl2. The ampule was cooled to −196° C. and a Me2SiH2/THF mixture (30.42 g; ca. 22.69 g Me2SiH2) was added via condensation. Subsequently, the ampule was evacuated in vacuo, sealed and heated to 100° C. for 24 h. After the reaction was completed, the ampule was cooled to −196° C., opened and the products condensed into a flask. After warming the reaction mixture to −80° C. (to liquefy all products), 0.6 ml were taken for 1H, 29Si and 31P NMR spectroscopy. The product mixture obtained was as follows:
Me2SiHCl: 51.4 g, 0.54 mol, 55%
Me2SiCl2: 49.8 g, 0.39 mol, 39%
Me2SiH2: 5.6 g, 0.06 mol, 6%
For isolation of Me2SiHCl, the glass ampule was again cooled to −196° C., opened and the whole product mixture condensed into a 250 ml flask. Final distillation over a 25 cm Vigreux column at normal pressure with an oil bath temperature of up to 68° C. and a cooled receiving flask (−80° C.) gave 52.70 g distillate, with the following product distribution:
Me2SiHCl: 41.2 g, 0.435 mol, 82%
Me2SiCl2: 3.7 g, 0.028 mol, 3%
Me2SiH2; 3.6 g, 0.060 mol, 15%
93.95 g residue remained after distillation, which was also analyzed by 1H and 29Si NMR spectroscopy. The corresponding product distribution was:
Me2SiHCl: 9.3 g, 0.099 mol, 26%
Me2SiCl2: 46.9 g, 0.363 mol, 74%
Combining the product distillate and the residue, the overall yield of Me2SiHCl was 50.48 g (0.53 mol), Me2SiH2 remained after redistribution and distillation in 3.61 g (0.06 mol). Related to the reacted amount of Me2SiH2 the (isolated) yield of Me2SiHCl was 71%, integration of signals in the product mixture (glass ampule after redistribution) gave an overall yield of 82% Me2SiHCl.
boiling points:
In conclusion, the synthesis of Me2SiH2 works in 96% yield and the redistribution selectively gave Me2SiHCl with some remaining Me2SiH2, wherein the losses of the hydridosilane are due to the low boiling point and the work up procedure. Careful distillation of the product mixture with subsequent post-processing of remaining Me2SiH2 (chlorination with HCl/ether or with SiCl4 or a second redistribution with Me2SiCl2) gives the target compound Me2SiHCl nearly quantitatively.
2) One-Step Chlorosilane Reduction with Subsequent Redistribution Reactions to Yield Bifunctional Monosilanes
1)n-Bu4PCl was added to the redistribution mixture in 0.1-10 wt % related to the amount of chlorosilanes (in grams);
Entry A16/Table 5: One-Step Reduction and Redistribution Reaction of MeSiBuCl2 to MeSiBuHCl
LiH (150 mg, 18.3 mmol, 1 eq) and n-Bu4PCl (31.4 mg, 0.1 mmol, 0.5 mol %) were suspended in 10 mL of dry THF and 1 mL of dry C6D6 in an ampule equipped with an NMR tube. The ampule was frozen at −196° C., subsequently MeSiBuCl2 (3 mL, 18.3 mmol, 1 eq) was added, the ampule was evacuated and sealed in vacuo. After 65 h at 140° C., the NMR spectroscopic analysis indicated that MeSiBuHCl was formed in about 50% besides 23% of unreacted MeSiBuCl2 and hydrogenated MeSiBuH2 (27%). Further heating of the sample to 160° C. (32 h) increased the amount of MeSiBuHCl (72%) while the molar amounts of MeSiBuCl2 (20%) and MeSiBuH2 (5%) decreased.
Entry A17/Table 5: One-Step Reduction and Redistribution Reaction of MeSiCl3 to MeSiH2Cl and MeSiHCl2
LiH (340 mg, 43 mmol, 1.9 eq) and n-Bu4PCl (51.7 mg, 0.2 mmol, 0.1 mol %) were suspended in 5 mL of dry THF and 1 mL of dry C6D6 in an ampule equipped with an NMR-tube. The ampule was frozen at −196° C., subsequently MeSiCl3 (2.6 mL, 22 mmol, 1 eq) was added, the ampule was evacuated and sealed. After 65 h at 120° C., NMR spectroscopic analysis indicated that MeSiH2Cl was formed in about 29% besides MeSiHCl2 (61%), MeSiH3 (5%) and unreacted MeSiCl3 (5%).
Entry A18/Table 5: One-Step Reduction and Redistribution Reaction of BuSiCl3 to BuSiHCl2
LiH (290 mg, 0.38 eq, 36.5 mmol) and n-Bu4PCl (124 mg, 0.4 mmol, 0.4 mol %) were placed in an ampule equipped with an NMR tube and suspended in 12 mL of dry THF. The ampule was frozen (−196° C.) and BuSiCl3 (16 mL, 97 mmol, 1 eq) was added and the ampule was sealed in vacuo. After heating the sample to 120° C. for 14.5 h, NMR analysis indicated formation of BuSiHCl2 in 30%. The ampule was opened, and all volatiles were condensed in vacuo to separate from n-Bu4PCl. BuSiHCl2 (yield: 80% rel. to LiH, 29.1 mmol, 4.57 g), dissolved in THF, was used without further purification. (δ29Si=33.95 ppm, RT=13.95 min).
3) Chlorination of Hydridosilanes with an Et2O/HCl Solution, Exemplified for the Chlorination of MeSiBuH2 into MeSiBuHCl (Entry A19)
MeSiBuH2 (1.06 g, 10.4 mmol) was admixed with an Et2O/HCl solution (15 mL, 5 M, 75 mmol). The reaction mixture was stirred at r.t for 2 h, resulting in the formation of MeSiBuHCl in only 10% (GC/MS-analysis). Increasing the reaction time (+16 h) increased the conversion of MeSiBuH2 to MeSiBuHCl to 67%. Addition of another 5 ml of the 5 M Et2O/HCl solution and stirring for additional 5 h at r.t. gave MeSiBuHCl in 90% (isolated yield) after fractional distillation besides unreacted MeSiBuH2 as detected by GC-MS and NMR spectroscopy.
4) Chlorination Reactions of the Hydridomonosilanes R1SiH3 and R1R2SiH2 with SiCl4
a)conversion rates in mol %
b)n-Bu4NCl as catalyst;
c)n-Bu3N as catalyst
Entry A20, Table 6, Target Reaction: OctSiH3+SiCl4→OctSiHCl2+HSiCl3
OctSiH3 (74 mL, 0.41 mol), n-Bu4NCl (4 mmol, 1 mol %) and SiCl4 (130 mL, 1.1 mol, 3.0 eq) were reacted in a Schlenk-flask at 60° C. for 3 h. GC-MS analysis proved that OctSiH3 was stepwise converted to give OctSiHCl2 (25%). For full conversion of the OctSiH2Cl to yield OctSiHCl2, the reaction mixture was heated to 90° C. for 64 h. After separation of the low boiling compounds HSiCl3, SiCl4 and THE by distillation, OctSiHCl2, contaminated with OctSiCl3, was isolated in 82.4 g (81.4 g of OctSiHCl2, 0.38 mol, 93% yield, contaminated with 1.0 g of OctSiCl3, 4.0 mmol). This mixture was used without further purification for the subsequent hydrosilylation reaction.
Entry A21, Table 6, Target Reaction: HexSiH3+SiCl4→HexSiHCl2+HSiCl3
HexSiH3 (79 g, 0.58 mol, 1.0 eq), n-Bu3N (4 mmol, 4 mol %) and SiCl4 (540 mL, 3.4 mol, 5.0 eq) were reacted in a Schlenk-flask at 90° C. for 52 h. GC-MS-analysis proved the stepwise conversion of HexSiH3 to HexSiH2Cl. For full conversion of HexSiH2Cl into HexSiHCl2, HSiCl3, admixed with SiO4, was distilled off and additional SiCl4 (50 mL, 0.4 mol, 0.4 eq) was added to the reaction mixture and heated to 130° C. for 18 h. After separation of the low boiling compounds HSiCl3 and SiCl4 by distillation, HexSiHCl2 was isolated in 87 g (0.47 mol, 81% yield).
Entry A22, Table 6, Target Reaction: MeHexSiH2+SiCl4→MeHexSiHCl+HSiCl3
MeHexSiH2 (0.29 mol, 1.0 eq), SiCl4 (63 mL, 0.55 mol, 1.9 eq) and n-Bu3N (1 mL, 1 mol %) were reacted in a Schlenk-flask at 55° C. (9.5 h) and at r.t. (32.5 h). After distillation, the desired product MeHexSiHCl was isolated in 81% yield (38.5 g, 0.234 mol, admixed with 2.6 g THF, as calculated from 1H-NMR spectroscopy).
Entry A23, Table 6, Target reaction: OctHexSiH2+SiCl4→OctHexSiHCl+HSiCl3
OctHexSiH2 (79 g, 0.34 mol, 1.0 eq), n-Bu3N (1 mL, 1 mol %) and SiCl4 (190 mL, 1.6 mol, 4.8 eq) were reacted in a Schlenk-flask at 100° C. for 40 h. A mixture consisting of HSiCl3 and SiCl4 (50 mL) was separated from the reaction mixture by distillation. The remaining residue was further reacted at 100° C. for 16 h. GC-MS-analysis of the reaction mixture proved OctHexSiH2 conversion into OctHexSiHCl in 94%. After separation of the low boiling compounds HSiCl3 and SiCl4 by distillation and fractional distillation, OctHexSiHCl was isolated in 86 g (0.33 mol, 96% yield, post chlorination by thermal work up, 106° C. at 40 mbar, RT=22.8 min).
Step b): Hydrosilylation Reactions of the Bifunctional Monosilanes HSiCl3, R1SiHCl2 and R1R2SiHCl (Organohydridochlorosilanes Obtained by Step a))
a)Y1EX2-immobilized Pt-catalyst;
b)Karstedt-catalyst);
c)B770011 (Pt on Silica 210);
d)diglyme as solvent;
1) Hydrosilylation Reactions of HSiCl3
Entry B1/Table 7: Target Reaction: HSiCl3+1-Butene→BuSiCl3
192 mg of the hydrosilylation catalyst (Y1 EX2) were placed in an ampule equipped with an NMR tube. 10 mL of dry THF, 0.8 mL C6D6 and HSiCl3 (20 ml, 1.0 eq, 0.11 mol) were added. The reaction mixture was frozen (−196° C.) and 1-butene (9.4 g, 1.4 eq, 0.16 mol) was added by condensation in vacuo. Subsequently the ampule was sealed in vacuo. After heating the sample to 70° C. (17.5 h) NMR analysis indicated full conversion of HSiCl3 to BuSiCl3. The ampule was opened, and the reaction mixture was distilled. The product was isolated in 19.7 g (103 mmol, 96% yield, b.p.: 149° C. (normal pressure), δ29Si=13.11 ppm, RT=15.28 min).
Entry B2/Table 7: Target Reaction: HSiCl3+1-Hexene→HexSiCl3
HSiCl3 (100 mL, 1.0 mol), 126 mL (1.3 mol, 1.3 eq) of 1-hexene and 0.25 mL of the Karstedt-catalyst were reacted at 60° C. for 30 min. THE and the alkene were separated via condensation in vacuo. The product was isolated by distillation in vacuo in 192.0 g (87 mol, 87% yield, b.p.: 25° C. (10−2 mbar), δ29Si=13.0 ppm, RT=18.21 min).
Entry B3/Table 7: Target Reaction: HSiCl3+1-Octene→OctSiCl3
HSiCl3 (50 mL, 0.49 mol), 100 ml of dry THE and 101 mL (0.64 mol, 1.3 eq) of 1-octene were added to 50 mg of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (85° C.) for 14 h, GC-MS analysis proved full conversion of HSiCl3 into OctSiCl3. THE and the alkene were separated via condensation in vacuo and the product was isolated by distillation in vacuo in 109.7 g (0.44 mol, 90% yield. b.p.: 75° C. (10−2 mbar), δ29Si=13.0 ppm, RT=21.03 min).
2) Hydrosilylation Reactions of R1SiHCl2
Entry B4/Table 7: Target Reaction: MeSiHCl2+1-Butene→MeSiBuCl2
MeSiHCl2 (15.3 ml, 0.15 mol, 1.0 eq), dry THE (10 mL) and 70 mg of the catalyst (Y1EX2) were mixed in an ampule with an attached NMR tube. The ampule was frozen at −196° C. and but-1-ene (9.0 g, 0.16 mol, 1.1 eq) was condensed onto the reaction mixture. The ampule was sealed in vacuo and placed in an oven at 100° C. for 64 h. NMR analysis proved a quantitative conversion of MeSiHCl2 into MeSiBuCl2. The ampule was opened, and the product mixture was distilled to yield 23.2 g (0.135 mol, 93% yield) of the product. (b.p.: 148-151° C., δ29Si=33.3 ppm, RT=15.40 min).
Entry B5/Table 7: Target Reaction: MeSiHCl2+1-Hexene→MeHexSiCl2
The Pt-catalyst (260 mg) was placed in an ampule and suspended with 70 mL dry THF and 63 mL (0.5 mol, 1.1 eq) of 1-hexene. The mixture was frozen with liquid nitrogen and subsequently MeSiHCl2 (0.45 mol, 1.0 eq) was added, the ampule was evacuated and sealed. After the reaction mixture was heated to 100° C. for 62 h, the ampule was opened and the product MeHexSiCl2 was isolated in 94% yield, contaminated by small amounts of THF. Distillation under reduced pressure gave MeSiHexCl2 (84.26 g, 0.423 mol) and 2.80 g THF (0.039 mol); molar ratio: 92/8; (b.p.: 145° C. (stationary vacuum), δ29Si=32.6 ppm, RT=18.36 min).
Entry B6/Table 7: Target Reaction: MeSiHCl2+1-Heptene→MeSiHeptCl2
120 mg of the catalyst (Y1 EX2) were placed in a flask and suspended with 30 mL of dry THF, 7 mL (1.0 eq, 64 mmol) of MeSiHCl2, and 10 ml (1.1 eq, 70 mmol) of hept-1-ene. The reaction mixture was stirred at r.t. for 1 h, but no conversion to the dialkyldichlorosilane was detected by GC-MS. Heating of the reaction mixture to 100° C. (oil-bath temperature) gave 100% of MeSiHeptCl2 as identified by GC-MS and 29Si-NMR spectroscopy. After distillation from the solvent MeSiHeptCl2 was isolated in 10.4 g (80% yield) by fractional distillation in vacuo (34 mbar, b.p.: 100° C., δ29Si=32.5 ppm, RT=18.47 min).
Entry B7/Table 7: Target Reaction: BuSiHCl2+1-Hexene→BuSiHexCl2
To BuSiHCl2, admixed with THF (Table 5, entry A18) and contaminated with small amounts of BuSiCl3, were added 120 mg of the catalyst (Y1 EX2), 7.5 mL of 1-hexene and 20 mL of THF in a Schlenk-flask. After heating the reaction mixture to reflux (100° C.) for 19 h, GC-MS analysis proved full conversion of BuSiHCl2 into BuSiHexCl2. THF, BuSiCl3 and the alkene were separated via condensation in vacuo. The product was isolated by distillation at 120° C. in vacuo to yield 4.82 g of BuSiHexCl2 (20 mmol, 74% yield, b.p.: 75° C. (vacuo), δ29Si=33.3 ppm, RT=19.83 min).
Entry B8/Table 7: Target Reaction: HexSiHCl2+1-Octene→OctHexSiCl2
HexSiHCl2 (82 g, 0.44 mol, 1.3 eq), 150 mL of dry THF and 110 mL (0.69 mol, 1.5 eq) of 1-octene were added to 80 mg of the catalyst (B770011) in a Schlenk-flask. After heating the mixture to reflux (100° C.) for 79 h, GC-MS analysis proved conversion of HexSiHCl2 into OctHexSiCl2 in 100%. THF and the alkene were separated via condensation in vacuo. The product was isolated by distillation in vacuo in 117.5 g (0.40 mol, 91% yield, b.p.: 135° C. (10−2 mbar), δ29Si=33.2 ppm, RT=24.3 min).
Entry B9/Table 7: Target Reaction: OctSiHCl2+1-Hexene→OctHexSiCl2
OctSiHCl2 (50 mL, 0.49 mol, admixed with OctSiCl3), 50 ml of dry THE and 58 mL (0.46 mol, 1.2 eq) of 1-hexene were added to 50 mg of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 20 h, GC-MS analysis of the reaction mixture proved conversion of OctSiHCl2 into OctHexSiCl2 in 86%. For full conversion to the desired product, additional 1-hexene (10 mL, 80 mmol, 0.2 eq) and 25 mg of the catalyst (B770011) were added and the reaction mixture was heated to 100° C. for 2 h. THE and the alkene were separated via condensation in vacuo and the product was isolated by fractional distillation in vacuo in 77.0 g (0.26 mol, 68% yield, δ29Si=33.2 ppm, RT=24.3 min).
3) Hydrosilylation Reactions of R1R2SiHCl
Entry B10/Table 7: Target Reaction: Me2SiHCl+1-Hexene→Me2SiHexCl
The Pt-catalyst (Y1 EX2, 230 mg) was placed in an ampule and suspended with 60 mL (0.48 mol, 1.5 eq) of 1-hexene and 36 mL (0.32 mol, 1.0 eq) of Me2SiHCl. The mixture was frozen with liquid nitrogen and the ampule was sealed in vacuo. The reaction mixture was heated to 100° C. for 67 h, then the ampule was opened and the product Me2SiHexCl was isolated by distillation under reduced pressure (b.p.: 140° C. (stationary vacuum) in 56 g, 0.31 mol, 97% yield, δ29Si=30.8 ppm, RT=17.82 min).
Entry B11/Table 7: Target Reaction: Me2SiHCl+1-Heptene→Me2SiHeptCl
The catalyst (Y1 EX2, 12 mg), Me2SiHCl (1 eq) and 1-heptene (1.1 eq) were placed in an NMR tube. Dry THE (0.3 mL) and 0.1 mL of dry C6D6 were added and the NMR tube was frozen at −196° C., evacuated and sealed in vacuo. After warming the sample to r.t. the reaction mixture was heated to 70° C. for 14 h, 29Si-NMR spectroscopy proved full conversion of the hydridochlorosilane into the triorganochlorosilane (Me2SiHeptCl: δ29Si=33.2 ppm, RT=24.3 min).
Entry B12/Table 7: Target Reaction: MeSiBuHCl+1-Butene→MeSiBu2Cl
The product mixture obtained from entry A101/Table 3 was transferred into an ampule that was equipped with an NMR tube to monitor product distribution in a closed system, containing 34 mg of the catalyst (Y1 EX2) and 5 mL of dry THF. Subsequently, 2.32 g of but-1-ene were condensed onto the reaction mixture that was cooled to −196° C. The ampule was evacuated, sealed in vacuo and placed in a drying cabinet for 21 h at 120° C. MeSiBuHCl was fully converted into MeSiBu2Cl as identified by NMR-spectroscopy and GC-MS analysis. After separation of all volatiles by condensation in vacuo, MeSiBu2Cl (1.78 g, 9.3 mmol, 99% yield) was isolated still dissolved in 5 mL THF. The mixture was used without further purification. (MeSiBu2Cl: δ29Si=31.5 ppm, RT=17.82 min).
Entry B13/Table 7: Target Reaction: MeSiBuHCl+1-Butene→MeSiBu2Cl
The product mixture obtained from entry A101 was transferred into an ampule that was equipped with an NMR tube to monitor product distribution in a closed system, containing 25 mg of the catalyst (Y1 EX2). 2.94 g of but-1-ene were added by condensation onto the reaction mixture cooled to −196° C. The ampule was evacuated, sealed in vacuo and placed in a drying cabinet for 21 h at 120° C. MeSiBuHCl was completely converted into MeSiBu2Cl as identified by NMR-spectroscopy and GC-MS analysis. The product (18.3 mmol, 3.5 g), dissolved in 10 mL of THF, was used without further purification for the reduction step with LiH. (MeSiBu2Cl: δ29Si=31.5 ppm, RT=17.82 min).
Entry B14/Table 7: Target Reaction: MeHexSiHCl+1-Heptene→MeHexSiHeptCl
The Pt-catalyst (100 mg) was suspended in 40 mL (0.28 mol, 1.2 eq) of 1-heptene and 41 g (0.23 mol, 1.0 eq) of MeHexSiHCl. The reaction mixture was heated to 100° C. for 19 h, the volatile compounds were condensed off in vacuo and the desired product was isolated in 59.3 g (0.22 mol, 97% yield, δ29Si=31.6 ppm, RT=22.49 min).
Entry B15/Table 7: Target Reaction: MeSiHeptHCl+1-Octene→MeSiHeptOctCl
40 mg of the catalyst (Y1 EX2) were placed in a flask and a mixture of MeSiHeptCl2, MeSiHeptHCl (entry A9, Table 3), and 1-octene (3 mL) were added. This mixture was refluxed for 62.5 h and GC-MS analysis proved full conversion of the hydridosilane into the corresponding MeSiHeptOctCl. All volatiles (THF, excess 1-octene) were separated by condensation in vacuo and MeSiHeptCl2 remained as residue. Final distillation in vacuo at 300° C. gave the trialkylchlorosilane in 68% yield (1.55 g, 5 mmol, δ29Si=31.48 ppm, RT=23.22 min).
Entry B16/Table 7: Target Reaction: OctHexSiHCl+1-Pentene→OctHexSiPentCl
OctHexSiHCl (85 g, 0.33 mol, 1.0 eq), 150 mL of dry diglyme and 143 mL (0.75 mol, 2.3 eq) of 1-pentene were added to 500 mg of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 82 h, diglyme and the alkene were separated via distillation in vacuo. The product was isolated by fractional distillation in vacuo in 102.2 g (0.31 mol, 94% yield, b.p.: 135° C. (10−2 mbar), δ29Si=31.6 ppm, RT=28.6 min).
Entry B17/Table 7: Target Reaction: BuSiHexHCl+1-Octene→BuSiHexOctCl
BuSiHexHCl (15.7 mmol), admixed with THE (15 mL) and the silane compounds BuSiHexH2 (2.7 mmol) and BuSiHexCl2 (8.6 mmol) (Table 3, entry L), were added to 120 mg of the catalyst (Y1EX2), 5 mL of 1-octene and 20 mL of THE in a Schlenk-flask. After heating to reflux (100° C.) for 13 h, GC-MS analysis proved full conversion of BuSiHexHCl into BuSiHexOctCl. THF and the alkene were separated via condensation under vacuo. The product mixture was isolated by distillation in vacuo at 400° C. and comprises BuSiHexOctCl and BuSiHexCl2 (molar ratio: 2:1) in a yield of 2.1 g (1.5 g, 4.8 mmol, 30% yield of BuSiHexOctCl, δ29Si=31.98 ppm, RT=24.97 min, admixed with 0.6 g, 2.4 mmol of BuSiHexCl2).
4) Hydrosilylation Reactions of HSiCl3, MeSiHCl2 and of MeSiBu2H with Functional Unsaturated Hydrocarbons
General Procedure for the Syntheses According to Entries B18-B32/Table 8:
0.1 mL (1 eq) of the hydridosilane, the catalyst (8-25 mg), 0.3 mL THF, 0.2 mL C6D6 and 1.2 eq of the corresponding unsaturated hydrocarbon (in the case of 2,3-dimethylbutadiene 0.5 eq) were placed in an NMR tube. The tube was frozen (−196° C.) and sealed in vacuo. Heating of the samples to 80° C. (2 h) and, in case the hydridosilane was not completely consumed, to 100° C. (7 h) and 120° C. (24 h) gave the expected products. Product mixtures were analyzed by NMR spectroscopy and GC-MS after full conversion of the Si—H to the Si—C functionality, or, in case the alkene was fully consumed.
Additional Remarks for Entries B22, B27 and B32/Table 8
In these three experiments double silyl-substituted products were detected by GC/MS and 29Si-NMR spectroscopy. But they were formed only to a minor extend (5-12 mol %). According to NMR and GC-MS analysis, the molecular structures of products formed are shown below:
Step c): Synthesis of Hydridosilanes by Reduction of Chlorosilanes
General Procedure for the Syntheses According to Entries C1-C13/Table 9
LiH, suspended in dry THF, was placed in a three necked flask that was equipped with a magnetic stirrer, reflux condenser and dropping funnel. The respective chlorosilane was added over the dropping funnel. After a short induction time of some minutes or started by heating the reaction mixture to 60-80° C., the chlorosilane reduction started by LiCl precipitation. After hydridosilane formation was completed (controlled by 29Si-NMR spectroscopy and GC/MS analysis), LiCl was separated by filtration and the respective hydridosilane was purified by fractional distillation.
Entry C1/Table 9: Target Reaction: HexSiCl3→HexSiH3
LiH (54 g, 5.5 mol, 6.4 eq) was suspended in 300 mL of dry THF. Then HexSiCl3 (192 g, 0.87 mmol, 1.0 eq) was added and the reaction mixture was heated to 80° C. for 2 h and stirred over night at r.t. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated by filtration from LiCl and HexSiH3 (67 g, 0.85 mol, 67% yield), still dissolved in THF (46 g), was obtained after distillation (b.p.: 80-110° C., δ29Si=−60.0 ppm, RT=11.60 min).
Entry C2/Table 9: Target Reaction: OctSiCl3→OctSiH3
LiH (13.8 g, 1.7 mol. 3.9 eq) was suspended in 300 mL of dry THF. Then OctSiCl3 (110 g, 0.44 mol, 1.0 eq) was added and the reaction mixture was heated to 80° C. for 13 h and subsequently stirred over night at r.t. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated by filtration from precipitated LiCl and OctSiH3 was obtained by distillation in 55 g (0.38 mol, 87% yield, b.p.: 162° C., δ29Si=−60.0 ppm, RT=16.04 min).
Entry C3/Table 9: Target Reaction: MeSiHeptCl2→MeSiHeptH2
LiH (375 mg, 3.4 eq, 47.2 mmol) was suspended in 10 mL of dry THF. Subsequently, 3 mL (1.0 eq, 13.8 mmol) of MeSiHeptCl2 were added at r.t. via a dropping funnel. The reaction mixture was heated to 100° C. for 1 h and stirred over night at r.t. GC-MS analysis proved 100% conversion of the dichloro- into the dihydridosilane. After separation from LiCl by filtration, fractional distillation of the reaction mixture gave 1.31 g (9.1 mmol) of MeSiHeptH2, yield 67% (δ29Si=−34.0 ppm, RT=15.16 min).
Entry C4/Table 9: Target Reaction: MeSiBuCl2→MeSiBuH2
MeSiBuCl2 (10 mL, 61 mmol, 1.0 eq) was added dropwise via a dropping funnel to a vigorously stirred suspension of LiH (1.21 g, 95 mmol, 2.5 eq) in 10 mL of dry THF. The reaction mixture was heated to reflux (90° C., oil bath) for 1 h and GC-MS analysis proved full conversion of the chlorosilane into the hydridosilane MeSiBuH2. After separation of precipitated LiCl from the reaction mixture by filtration, MeSiBuH2 (6.2 g, 61 mmol, 100% yield) was isolated still admixed with 10 mL of THF. (MeSiBuH2: δ29Si=−33.6 ppm, RT=6.10 min).
Entry C5/Table 9: Target Reaction: MeHexSiCl2→MeHexSiH2
LiH (13.6 g, 1.7 mol, 6 eq) was suspended in 120 mL of dry THF. Then MeHexSiCl2 (60 mL, 290 mmol) was added and the reaction mixture was heated to 80° C. for 1.5 h. NMR spectroscopic analyses verified full conversion of MeHexSiCl2 into MeHexSiH2. MeHexSiH2 was separated together with THF from LiCl by distillation (37.8 g, 0.29 mol, 100% yield, δ29Si=−33.9 ppm, RT=14.36 min).
Entry C6/Table 9: Target Reaction: OctHexSiCl2→OctHexSiH2
LiH (8.6 g, 1.1 mol. 4.2 eq) was suspended in 150 mL of dry THF. OctHexSiCl2 (77 g, 0.26 mmol, 1.0 eq) was added, heated to 80° C. for 1 h, and stirred over night at r.t. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated by filtration from LiCl and OctHexSiH2 was isolated by distillation in 48 g (0.21 mol, 81% yield, b.p.: 70° C., 10−2 mbar, δ29Si=−28.8 ppm, RT=21.14 min).
Entry C7/Table 9: Target Reaction: BuSiHexCl2→BuSiHexH2
LiH (320 mg, 40 mmol, 5.7 eq) was suspended in 10 mL of dry THF. Then BuSiHexCl2 (1.70 g, 7 mmol, 1.0 eq) was added. The reaction mixture was degassed, heated to 100° C. for 9 h, and stirred over night at r.t. GC-MS analysis proved 100% conversion of all chloro- to hydrido-substituents. BuSiHexH2 (1.2 g, 7 mmol), dissolved in 10 mL of THF, was isolated by filtration (δ29Si=−28.90 ppm, RT=17.32 min). This mixture was used without further purification for subsequent redistribution with BuSiHexCl2.
Entry C8/Table 9: Target Reaction: MeSiBu2Cl→MeSiBu2H
MeSiBu2Cl (4 mL, 21 mmol, 1.0 eq) was added dropwise via a dropping funnel to a vigorously stirred suspension of LiH (0.76 g, 95 mmol, 4.5 eq) in 10 mL of dry THF. The reaction mixture was heated to reflux (90° C.) for 1 h and GC-MS analysis proved full conversion of the chlorosilane into the hydridosilane MeSiBu2H. After separation of the precipitated LiCl from the reaction mixture by filtration, MeSiBu2H (δ29Si=−10.1 ppm, RT=15.85 min) was obtained still dissolved in THF. The product solution was used without further purification.
Entry C9/Table 9: Target Reaction: MeSiHeptOctCl→MeSiHeptOctH
LiH (500 mg, 62.9 mmol, 11.8 eq) was suspended in 10 mL of dry THF and MeSiHeptOctCl (1.55 g, 5.3 mmol, 1.0 eq) was subsequently added. The reaction mixture was heated to 100° C. for 9 h and stirred over night at r.t. GC-MS analysis proved 100% conversion of MeSiHeptOctCl into MeSiHeptOctH. This hydridosilane (δ29Si=−10.0 ppm, RT=21.27 min) was separated from precipitated LiCl by filtration and used without further purification for subsequent hydrosilylation reactions with different alkenes.
Entry C10/Table 9: Target Reaction: BuSiHexOctCl→BuSiHexOctH
LiH (220 mg, 28.0 mmol, 5.8 eq) was suspended in 5 mL of dry THF. Subsequently, 2.1 g of a mixture comprising of BuSiHexOctCl (1.5 g, 4.8 mmol) and BuSiHexCl2 (0.6 g, 2.4 mmol) was added. The reaction mixture was heated to 100° C. for 3 h and stirred over night at r.t. GC-MS analysis proved 100% conversion of all chlorine- into hydrido- substituents. After condensation of volatile compounds in vacuo at r.t., the temperature was increased to 300° C. to obtain the high boiling fraction (1.3 g) which comprises small amounts of BuSiHexH2 (8%, 0.5 mmol, δ29Si=−28.90 ppm, RT=17.32 min) and the desired product BuSiHexOctH (92%, 4.2 mmol, δ29Si=−6.80 ppm, RT=22.56 min), which was used without further purification for hydrosilylation reactions with different alkenes. The product yield was determined by integration of the signals in the 29Si NMR spectrum of the product mixture.
Entry C11/Table 9: Target Reaction: MeHexSiHeptCl→MeHexSiHeptH
LiH (5.1 g, 0.62 mol, 3.1 eq) was suspended in 70 mL of dry THF. MeHexSiHeptCl (53 g, 0.20 mol) was added dropwise to the vigorously stirred suspension at 70° C. The reaction mixture was heated to 70° C. for 15 h and then the liquid phase was separated by filtration from LiCl. THF was distilled off and MeHexSiHeptH was isolated in 90% yield (41.3 g, 0.18 mol, δ29Si=−10.1 ppm, RT=20.74 min).
Entry C12/Table 9: Target Reaction: Me2SiHexCl→Me2SiHexH
LiH (5.0 g, 0.63 mol, 2.0 eq) was suspended in 60 mL of dry THF. Then Me2SiHexCl (56 g, 0.31 mol, 1. eq) was added dropwise to the vigorously stirred solution at 70° C. The reaction mixture was heated to 70° C. for 14 h, subsequently THF was distilled off and Me2SiHexH was isolated under reduced pressure in 78% yield (35 g, 0.24 mol, δ29Si=−13.4 ppm, RT=15.44 min).
Entry C13/Table 9: Target Reaction: OctHexSiPentCl→OctHexSiPentH
LiH (10.7 g, 1.3 mol. 4.6 eq) was suspended in 200 mL of dry THF. OctHexSiPentCl (102 g, 0.31 mmol, 1.0 eq) was added to the suspension, heated to 90° C. for 16 h and additionally at 120° for 18 h. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated from LiCl by filtration and OctHexSiPentH was isolated by fractional distillation in 76 g (0.26 mol, 86% yield, b.p.: 120° C., 10−2 mbar, δ29Si=−6.7 ppm, RT=24.82 min).
Step d): Synthesis of Tetraorganosilanes by Hydrosilylation Reactions of Trialkylhydridosilanes
a)Y1EX2 (immobilized Pt catalyst)-;
b)B770011 (Pt on silica type 210);
c)Karstedt-catalyst;
d)nBu2O as solvent;
e)diglyme as solvent;
General Procedure for the Syntheses According to Entries D1-D10/Table 10:
0.1 mL of the hydridosilane-solution (according to step c) entries C8 and C9), the catalyst (8-12 mg), 0.3 mL THF, 0.2 mL C6D6 and 0.2 mL of the corresponding alkenes were placed in an NMR tube. The reaction mixture was frozen (−196° C.) and the NMR tube was sealed under vacuo. Heating periods are given separately for each alkene used for hydrosilylation. Product mixtures were analyzed by NMR spectroscopy and GC-MS after full conversion of the Si—H into the Si—C moiety, or, in case the alkene was fully consumed. According to the literature, 1-alkenes might be thermally isomerized and/or hydrogenated (H2 from dehydrogenative silylation) including transition metal catalysis (e.g. Pt) in the course of hydrosilylation reactions. [J. Organomet. Chem. 2011, 696, 3687-3692; Chem. Cat. Chem. 2019, 11, 2843-2854]. This might be the reason for reduced conversion rates in the reactions listed in Table 10. Tetraalyksilanes R1R2SiR3R4 (R3=R4) formed from side reactions result from R1R2SiH2 impurities (8 mol %) in the corresponding hydridosilane solutions (entries D6-D10). This double hydrosilylation is only detected for long chain substituents R1 and R2 (R>C4), but not for R=Me, Et (see J. Organomet. Chem. 1978, 148, 23-27).
Entry D1/Table 10: Target Reaction: MeSiHeptOctH+1-Butene→MeSiHeptOctBu
Reaction time: 80° C. (22 h, conversion: 50%); 100° C. (10 h, full conversion of Si—H) (δ29Si=2.54 ppm, RT=23.87 min).
Entry D2/Table 10: Target Reaction: MeSiHeptOctH+1-Hexene→MeSiHexHeptOct Reaction time: 80° C. (22 h, conversion: 50%); 100° C. (10 h, full conversion of Si—H) (δ29Si=2.54 ppm, RT=26.40 min).
Entry D3/Table 10: Target Reaction: MeSiHeptOctH+1-Heptene→MeSiHept2Oct
Reaction time: 80° C. (22 h, conversion: 50%); 100° C. (10 h, full conversion of Si—H) (δ29Si=2.54 ppm, RT=28.20 min).
Entry D4/Table 10: Target Reaction: MeSiHeptOctH+1-Decene→MeSiHeptOctDec
Reaction time: 80° C. (22 h, conversion: 50%); 100° C. (10 h, full conversion of Si—H) (δ29Si=2.56 ppm, RT=36.96 min).
Entry D5/Table 10: Target Reaction: MeSiHeptOctH+1-Hexadecene→MeSiHeptOctHexdec
Reaction time: 80° C. (22 h, conversion: 60%); 100° C. (10 h, full conversion of Si—H) (δ29Si=2.56 ppm, RT=91.15 min).
Entry D6/Table 10: Target Reaction: BuSiHexOctH+1-Butene→Bu2SiHexOct
Reaction time: 80° C. (16 h, conversion: 16%); 100° C. (32 h, conversion: 31%); 120° C. (31.5 h, conversion: 80%); 140° C. (10 h, full conversion of Si—H, 100%); (δ29Si=2.71 ppm, RT=25.35 min). In addition to the targeted product formation, Bu3SiHex (8 mol %) was formed and identified in the GC(RT=21.48) of the sample, indicating double hydrosilylation of BuSiHexH2.
Entry D7/Table 10: Target Reaction: BuSiHexOctH+1-Hexene→BuSiHex2Oct
Reaction time: 80° C. (16 h, conversion: 12%); 100° C. (32 h, conversion: 29%); 120° C. (31.5 h, conversion: 75%); 140° C. (10 h, conversion: 80%, no alkene remained); (δ29Si=2.73 ppm, RT=28.40 min). Additionally, BuSiHex3 (8 mol %) was detected at RT=25.05 in the GC of the sample, indicating double hydrosilylation of BuSiHexH2.
Entry D8/Table 10: Target Reaction: BuSiHexOctH+1-Heptene→BuSiHexOctHept
Reaction time: 80° C. (16 h, conversion 14%); 100° C. (32 h, conversion: 54%); 120° C. (31.5 h, conversion: 77%); 140° C. (10 h, conversion: 80%, no alkene remained); (δ29Si=2.74 ppm, RT=30.65 min). Additionally, BuSiHexHept2 (8 mol %) was detected at RT=28.30 in the GC of the sample, indicating double hydrosilylation of BuSiHexH2.
Entry D9/Table 10: Target Reaction: BuSiHexOctH+1-Decene→BuSiHeptOctDec
Reaction time: 80° C. (16 h, conversion: 3%); 100° C. (32 h, conversion: 11%); 120° C. (31.5 h, conversion: 47%); 140° C. (10 h, conversion: 50%, no alkene remained); (δ29Si=2.75 ppm, RT=41.64 min). Moreover, BuSiHexDec2 (8 mol %) was detected at RT=54.18 in the GC of the sample, indicating double hydrosilylation of BuSiHexH2.
Entry D10/Table 10: Target Reaction: BuSiHexOctH+1-Hexadecene→BuSiHeptOctHexdec
Reaction time: 80° C. (16 h, conversion: 2%); 100° C. (32 h, conversion: 7%); 120° C. (31.5 h, conversion: 40%); 140° C. (10 h, conversion: 44%, no alkene remained); (δ29Si=2.75 ppm, RT=109.35 min).
Entry D11/Table 10: Target Reaction: MeHexSiHeptH+1-Pentene→MeHexSiHeptPent
The Pt-catalyst (40 mg) was placed in an ampule, suspended with 33 mL (0.3 mol, 3.6 eq) of 1-pentene, 17.7 g (0.08 mol, 1.0 eq) of MeHexSiHeptH and 5 mL of dry nBu2O. The mixture was frozen with liquid nitrogen and the ampule was sealed in vacuo. The reaction mixture was heated to 140° C. for 142 h. Then, the ampule was opened, and the NMR-analysis verified full conversion of the hydridosilane to MeHexSiHeptPent.
Entry D12/Table 10: Target Reaction: MeHexSiHeptH+1-Nonene→MeHexSiHeptNon
The Pt-catalyst (80 mg) was placed in an ampule and suspended with 3 g (0.02 mol, 1.2 eq) of 1-nonene, 4.4 g (0.02 mol, 1.0 eq) of MeHexSiHeptH and 5 mL of dry nBu2O. The mixture was frozen with liquid nitrogen and the ampule was sealed in vacuo. The reaction mixture was heated to 140° C. for 64 h. Subsequently, the ampule was opened and NMR-analysis indicated that the desired product was formed in 60% yield (0.012 mol). Notably, no alkene remained in the reaction mixture.
General Procedure for Entries D13-D15/Table 10: Target Reactions: Me2SiHexH+1-Pentene→Me2SiHexPent, Me2SiHexH+1-Heptene→Me2SiHexHept, Me2SiHexH+1-Octene→Me2SiHexOct
The Pt-catalyst (8-10 mg) was placed in an ampule and suspended with Me2SiHexH (1.0 eq) and the respective alkenes (2.5 eq). The mixtures were frozen with liquid nitrogen and the ampules were sealed in vacuo. The reaction mixtures were heated to 140° C. for 70 h. Subsequently the ampules were opened, and the products were isolated by distillation of the volatile components in vacuo.
Entry D16/Table 10: Target Reaction: OctHexSiPentH+1-Heptene→OctHexSiPentHept
OctHexSiPentH (8.2 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 7.8 mL (0.068 mol, 2.5 eq) of 1-heptene were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, GC-MS analysis of the reaction mixture proved the formation of the desired product in 45%. For full conversion of the hydridosilane into the corresponding tetraalkylsilane, the reaction mixture was transferred into an ampule and admixed with an additional equivalent of 1-heptene (0.027 mol) and 0.5 mL of the Karstedt-catalyst. The reaction mixture was cooled to −196° C., the ampule was sealed under vacuo and placed in a drying oven at 150° C. for 60 h. Then the ampule was opened, all volatiles were distilled off and OctHexSiPentHept was isolated by fractional distillation in vacuo in 4.0 g (0.01 mol, 37% yield. b.p.: 140° C. (10−2 mbar), δ29Si=2.8 ppm, RT=36.53 min).
Entry D17/Table 10: Target Reaction: OctHexSiPentH+1-Octyne→OctHexSiPentOctenyl
OctHexSiPentH (8.2 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 6.1 mL (0.041 mol, 1.5 eq) of 1-octyne were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, GC-MS analysis of the reaction mixture proved that the hydridosilane was consumed quantitatively. Volatile components were condensed off and the residue was distilled under vacuo. OctHexSiPentOctenyl (10.8 g) was isolated as a mixture consisting of 1-alkene- (9.2 g, 89%) and 2-alkene- (1.6 g, 11%) substituted silanes; the molar ratio was determined by product relevant signals in the corresponding GC and 29Si-NMR spectrum of the sample.
OctHexSiPent(1-Octenyl): δ29Si=−2.3 ppm, RT=38.41 min.
OctHexSiPent(2-Octenyl): δ29Si=−2.3 ppm, RT=39.31 min.
Entry D18/Table 10: Target Reaction: OctHexSiPentH+1-Decene→OctHexSiPentDec
OctHexSiPentH (8.0 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 12.7 mL (0.068 mol, 2.5 eq) of 1-decene were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, 29Si-NMR spectroscopic analysis of the reaction mixture indicated that 66% of the desired product were formed. For full conversion of the hydridosilane, the reaction mixture was transferred into an ampule and admixed with an additional equivalent of 1-decene (5.1 mL, 0.027 mol) and 0.5 mL of the Karstedt-catalyst. The mixture was cooled to −196° C., the ampule was sealed under vacuo and placed in a drying oven at 150° C. for 60 h. Then, the ampule was opened, all volatiles were condensed off and OctHexSiPentDec was isolated by fractional distillation in vacuo in 4.8 g (0.01 mol, 40% yield, b.p.: 165° C. (10−2 mbar), δ29Si=2.8 ppm, RT=53.01 min).
Entry D19/Table 10: Target Reaction: OctHexSiPentH+1-Hexdecene→OctHexSiPentHexdec
OctHexSiPentH (8.0 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 9.4 mL (0.068 mol, 2.5 eq) of 1-hexadecene were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, 29Si-NMR spectroscopic analysis of the reaction mixture proved the formation of the desired product in 66%. For full conversion of the hydridosilane, the reaction mixture was transferred into an ampule and admixed with an additional equivalent of 1-heptene (3.8 mL, 0.027 mol) and 0.5 mL of the Karstedt-catalyst. The reaction mixture was cooled to −196° C., the ampule was sealed under vacuo and placed in a drying oven at 150° C. for 60 h. Then, the ampule was opened, all volatile compounds were condensed off and the residue was purified by filtration over a 2 cm column filled with silica-gel and hexane as solvent. After removal of the solvent in vacuo OctHexSiPentHexdec (where Hexdec is C16H31) was isolated in 5.7 g (0.011 mol, 41% yield, δ29Si=2.8 ppm, RT=160.98 min).
Entry D20/Table 8: Target Reaction: MeSiBu2H+1-Butene→MeSiBu3
MeSiBu2H (7.5 mL, 46 mmol, 1 eq) was placed in an ampule equipped with an NMR tube. The catalyst (Y1 EX2) was added and 3.78 g (67 mmol, 1.5 eq) of but-1-ene were condensed at −196° C. onto the reaction mixture. The ampule was evacuated and sealed under vacuo and placed in a drying cabinet for 65 h at 140° C. NMR-analysis indicated full conversion (100%) to the desired product MeSiBu3. MeSiBu3 was isolated by distillation in 75% yield (34 mmol, 7.34 g, b.p.: 76 (34 mbar), δ29Si=2.6 ppm, RT=18.65 min).
Entry D21/Table 10: Target Reaction: MeSiBu2H+1-Heptene→MeSiBu2Hept
50 mg of the catalyst (Y1 EX2) were placed in a Schlenk-flask and suspended with 3 mL of dry THF, 0.5 mL (1.0 eq, 2.4 mmol) of MeSiBu2H and 0.4 mL (1.1 eq, 2.6 mmol) of hept-1-ene. The reaction mixture was stirred at r.t. for 1 h and no conversion to the tetraalkylsilane was detected by GC-MS. Heating of the reaction mixture to 100° C. (oil-bath temperature) for 1 h gave 96% conversion into MeSiBu2Hept as identified by GC-MS and 29Si-NMR spectroscopy (MeSiBu2Hept: δ29Si=2.6 ppm, RT=20.65 min).
Selected Examples: Stepwise Synthesis of Tetraorganosilanes R1R2SiR3R4 with Four Different Organo Substituents (R1≠R2≠R3≠R4)
a) MeSiHCl2+1-Hexene→MeHexSiCl2
The Pt-catalyst (Y1 EX2, 260 mg) was placed in an ampule and suspended with 70 mL dry THF and 63 mL (0.5 mol, 1.1 eq) of 1-hexene. The mixture was frozen with liquid nitrogen and subsequently MeSiHCl2 (0.45 mol, 1.0 eq) was added, the ampule was evacuated and sealed. After the reaction mixture was heated to 100° C. for 62 h, the ampule was opened and the product MeHexSiCl2 was isolated in 94% yield, contaminated by small amounts of THF. Distillation under reduced pressure gave MeSiHexCl2 (84.26 g, 0.423 mol) and 2.80 g THF (0.039 mol); molar ratio: 92/8; (b.p.: 145° C. (stationary vacuum), RT=18.36 min). The mixture was used without further purification for subsequent hydrogenation.
1H-NMR (500.2 MHz, C6D6): δ=1.39-1.29 (m, 2H, Si—CH2—), 1.27-1.08 (m, 6H, —CH2—), 0.89-0.78, (m, 5H, —CH2—CH3), 0.50-0.43 (m, 3H, Si—CH3) ppm.
29Si-NMR (99.4 MHz, C6D6): δ=32.6 ppm.
13C-NMR (125.8 MHz, C6D6): δ=32.4, 31.7, 22.9, 22.8, 21.8, 14.35, 5.1 ppm.
b) MeHexSiCl2+LiH→MeHexSiH2
LiH (13.6 g, 1.7 mol, 6 eq) was suspended in 120 mL of dry THF. Then MeHexSiCl2 (60 mL, 290 mmol) was added and the reaction mixture was heated to 80° C. for 1.5 h. NMR spectroscopic analyses verified full conversion of MeHexSiCl2 into MeHexSiH2. MeHexSiH2 was separated together with THF from LiCl by distillation (37.8 g, 0.29 mol, 100% yield, RT=14.36 min). The mixture comprising THF and MeSiHexH2 was used without further purification for the subsequent chlorination reaction.
1H-NMR (500.2 MHz, C6D6): δ=3.83-3.78 (m, 2H, Si—H), 1.39-1.12 (m, 8H, —CH2—), 0.90-0.80, (m, 3H, —CH3), 0.04-0.00 (m, 3H, Si—CH3) ppm.
29Si-NMR (99.4 MHz, C6D6): δ=−33.9 ppm.
13C-NMR (125.8 MHz, C6D6): δ=32.9, 31.9, 25.5, 23.0, 14.2, 10.8, −8.7 ppm.
c) MeHexSiH2+SiCl4→MeHexSiHCl+HSiCl3
MeHexSiH2 (0.29 mol, 1.0 eq), SiCl4 (63 mL, 0.55 mol, 1.9 eq) and n-Bu3N (1 mL, 1 mol %) were reacted in a Schlenk-flask at 55° C. (9.5 h) and at r.t. (32.5 h). After distillation, the desired product MeHexSiHCl was isolated in 81% yield (38.5 g, 0.234 mol, admixed with 2.6 g THF, as calculated from 1H-NMR spectroscopy). The mixture was used without further purification for subsequent hydrosilylation reaction.
1H-NMR (500.2 MHz, C6D6): δ=4.81-4.76 (m, 1H, Si—H), 1.36-1.27 (m, 2H, —CH2—), 1.26-1.12 (m, 6H, —CH2—), 0.91-0.80 (t, 3H, —CH3), 0.71-0.64 (m, 2H, —CH2—), 0.27-0.22 (m, 3H, Si—CH3) ppm.
29Si-NMR (99.4 MHz, C6D6): δ=12.9 (d, 1J=219.8 Hz) ppm.
13C-NMR (125.8 MHz, C6D6): δ=32.7, 31.9, 23.3, 23.0, 17.3, 14.4, −0.4 ppm.
d) MeHexSiHCl+1-Heptene→MeHexSiHeptCl
The Pt-catalyst (Y1 EX2, 100 mg) was suspended in 40 mL (0.28 mol, 1.2 eq) of 1-heptene and 41 g (0.23 mol, 1.0 eq) of MeHexSiHCl. The reaction mixture was heated to 100° C. for 19 h, the volatile compounds were condensed off in vacuo and the desired product was obtained in 59.3 g (0.22 mol, 97% yield, RT=22.49 min). The mixture was used without further purification for subsequent hydrogenation reaction.
1H-NMR (500.2 MHz, C6D6): δ=1.41-1.31 (m, 5H), 1.31-1.17 (m, 14H), 0.91-0.86 (m, 5H), 0.76-0.63 (m, 4H), 0.25 (s, 3H) ppm.
29Si-NMR (99.4 MHz, C6D6): δ=31.6 (s) ppm.
13C-NMR (125.8 MHz, C6D6): δ=33.5, 33.2, 32.2, 31.9, 29.4, 23.5-23.3, 23.1, 23.0, 18.0, 14.4, 0.0 ppm.
e) MeHexSiHeptCl+LiH→MeHexSiHeptH
LiH (5.1 g, 0.62 mol, 3.1 eq) was suspended in 70 mL of dry THF. MeHexSiHeptCl (53 g, 0.20 mol) was added dropwise to the vigorously stirred suspension at 70° C. The reaction mixture was heated to 70° C. for 15 h and then the liquid phase was separated by filtration from LiCl. THE was distilled off and MeHexSiHeptH was isolated in 90% yield (41.3 g, 0.18 mol, RT=20.74 min).
1H-NMR (500.2 MHz, C6D6): δ=3.98 (oct, 1H, Si—H), 1.45-1.18 (m, 18H, —CH2—), 0.95-0.84 (m, 6H, —CH2—), 0.63-0.53 (m, 4H, —CH2—), 0.05 (d, 3H, Si—CH3) ppm.
29Si-NMR (99.4 MHz, C6D6): δ=−10,1 (d, 1J=179.6 Hz) ppm.
13C-NMR (125.8 MHz, C6D6): δ=33.7, 33.4, 32.2, 32.0, 29.5, 25.0, 24.9, 23.1, 23.0, 14.3, 13.1, −6.1 ppm.
f) MeHexSiHeptH+1-Pentene→MeHexSiHeptPent
The Pt-catalyst (Y1EX2, 40 mg) was placed in an ampule, suspended with 33 mL (0.3 mol, 3.6 eq) of 1-pentene, 17.7 g (0.08 mol, 1.0 eq) and 5 mL of dry nBu2O. The mixture was frozen with liquid nitrogen and the ampule was sealed in vacuo. The reaction mixture was heated to 140° C. for 142 h. Then, the ampule was opened, and the NMR-analysis verified full conversion of the hydridosilane to MeHexSiHeptPent.
1H-NMR (500.2 MHz, C6D6): No assignment of the 1H-NMR data due to signal overlap.
29Si-NMR (99.4 MHz, C6D6): δ=2.6 (s) ppm.
13C-NMR (125.8 MHz, C6D6): δ=36.6, 34.4, 34.1, 32.6, 32.5, 29.6, 24.5, 24.2, 23.3, 23.2, 22.9, 14.4, 14.3, 14.3, 14.2, −4.9 ppm.
q) MeHexSiHeptH+1-Nonene→MeHexSiHeptNon
The Pt-catalyst (Y1 EX2, 80 mg) was placed in an ampule and suspended with 3 g (0.02 mol, 1.2 eq) of 1-nonene, 4.4 g (0.02 mol, 1.0 eq) of MeHexSiHeptH and 5 mL of dry nBu2O. The mixture was frozen with liquid nitrogen and the ampule was sealed in vacuo. The reaction mixture was heated to 140° C. for 64 h. Subsequently, the ampule was opened, and NMR-analysis indicated that the desired product was formed in 60% yield (0.012 mol). Notably, no alkene remained in the reaction mixture. The silahydrocarbon MeHexSiHeptNon (or (CH3)(C6H11)Si(C7H13)(C9H17) was obtained and characterized as follows:
1H-NMR (500.2 MHz, C6D6): No assignment of the 1H-NMR data due to signal overlap.
29Si-NMR (99.4 MHz, C6D6): δ=2.6 (s) ppm.
13C-NMR (125.8 MHz, C6D6): No assignment of the 13C-NMR data due to signal overlap.
a) HSiCl3+1-Octene→OctSiCl3
HSiCl3 (50 mL, 0.49 mol), 100 ml of dry THE and 101 mL (0.64 mol, 1.3 eq) of 1-octene were added to 50 mg of the catalyst (B770011) in a Schlenk flask. After heating to reflux (85° C.) for 14 h, GC-MS analysis proved full conversion of HSiCl3 into OctSiCl3. THE and the alkene were separated via condensation in vacuo and the product was isolated by distillation in vacuo in 109.7 g (0.44 mol, 90% yield. (b.p.: 75° C./10−2 mbar), RT=21.03 min).
1H-NMR: (500.2 MHz, C6D6): δ=1.37-1.34 (m, 2H, Si—CH2—), 1.28-1.02 (m, 12H, —CH2), 0.90-0.86 (m, 3H, —CH3) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=13.0 ppm.
13C-NMR: (125.8 MHz, C6D6): δ=32.3, 32.2, 29.5, 29.4, 24.5, 23.1, 22.6 ppm.
b) OctSiCl3+LiH→OctSiH3
LiH (13.8 g, 1.7 mol. 3.9 eq) was suspended in 300 mL of dry THF. Then OctSiCl3 (110 g, 0.44 mol, 1.0 eq) was added and the reaction mixture was heated to 80° C. for 13 h and subsequently stirred over night at r.t. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated by filtration from precipitated LiCl and OctSiH3 was obtained by distillation in 55 g (0.38 mol, 87% yield, b.p.: 162° C., RT=16.04 min).
1H-NMR: (500.2 MHz, C6D6): δ=3.79-3.38 (m, 3H, Si—H), 1.35-1.22 (m, 12H, —CH2—), 0.88 (t, 3H, —CH3, 3J=7.0 Hz), 0.62-0.56 (m, 2H, Si—CH2—) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=−60.0 (q, 1J=192 Hz) ppm.
13C-NMR: (125.8 MHz, C6D6): δ=33.1, 32.5, 29.8, 26.9, 23.2, 14.4, 6.3 ppm.
c) OctSiH3+SiCl4→OctSiHCl2+HSiCl3
OctSiH3 (74 mL, 0.41 mol), n-Bu4NCl (4 mmol, 1 mol %) and SiCl4 (130 mL, 1.1 mol, 3.0 equiv.) were reacted in a Schlenk-flask at 60° C. for 3 h. GC-MS analysis proved that OctSiH3 was stepwise converted to give OctSiHCl2 (25%). For full conversion of the OctSiH2Cl to yield OctSiHCl2, the reaction mixture was heated to 90° C. for 64 h. After separation of the low boiling compounds HSiCl3, SiCl4 and THE by distillation, OctSiHCl2, contaminated with OctSiCl3, was isolated in 82.4 g (81.4 g of OctSiHCl2, 0.38 mol, 93% yield, contaminated with 1.0 g of OctSiCl3, 4.0 mmol). This mixture was used without further purification for the subsequent hydrosilylation reaction.
1H-NMR: (500.2 MHz, C6D6): δ=5.3 (t, 1H, Si—H, 1J=2.0 Hz), 1.4-1.1 (m, 12H, —CH2—), 0.89 (t, 3H, —CH3, 3J=6.2 Hz) 0.86-0.82 (m, 2H, Si—CH2—) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=11.3 (d, 1J=276.3 Hz) ppm.
13C-NMR: (125.8 MHz, C6D6): δ=32.5, 32.3, 29.6, 29.5, 29.4, 24.5, 23.1, 22.6, 22.1, 20.5, 14.4 ppm.
d) OctSiHCl2+1-Hexene→OctHexSiCl2
OctSiHCl2 (50 mL, 0.49 mol, admixed with OctSiCl3), 50 ml of dry THE and 58 mL (0.46 mol, 1.2 eq) of 1-hexene were added to 50 mg of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 20 h, GC-MS analysis of the reaction mixture proved conversion of OctSiHCl2 into OctHexSiCl2 in 86%. For full conversion to the desired product, additional 1-hexene (10 mL, 80 mmol, 0.2 eq) and 25 mg of the catalyst (B770011) were added and the reaction mixture was heated to 100° C. for 2 h. THE and the alkene were separated via condensation in vacuo and the product was isolated by fractional distillation in vacuo in 77.0 g (0.26 mol, 68% yield, RT=24.3 min).
1H-NMR: (500.2 MHz, C6D6): δ=1.44-1.37 (m, 4H, Si—CH2—), 1.29-1.11 (m, 16H, —CH2—) 0.91-0.85 (m, 10H, —CH2—CH3) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=33.2 ppm.
13C-NMR: (125.8 MHz, C6D6): δ=32.9, 32.6, 32.4, 31.7, 29.7, 29.6, 23.2, 22.9, 22.8, 20.7, 14.4, 14.3 ppm.
e) OctHexSiCl2+LiH→OctHexSiH2
LiH (8.6 g, 1.1 mol. 4.2 eq) was suspended in 150 mL of dry THF. OctHexSiCl2 (77 g, 0.26 mmol, 1.0 eq) was added, heated to 80° C. for 1 h, and stirred over night at r.t. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated by filtration from LiCl and OctHexSiH2 was isolated by distillation in 48 g (0.21 mol, 81% yield, b.p.: 70° C., 10−2 mbar, RT=21.14 min).
1H-NMR (500.2 MHz, C6D6): δ=3.87-3.84 (p, 2H, Si—H, 2J=3.7 Hz), 1.35-1.20 (m, 20H, —CH2—), 0.89 (dt, 6H, —CH3, 3J=7.15 Hz), 0.67-0.61 (m, 4H, —CH2—CH3) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=−28.8 (t, 1J=184 Hz) ppm.
13C-NMR: (125.8 MHz, C6D6): δ=33.5, 33.2, 32.5, 32.1, 29.9, 29.8, 26.1, 26.0, 23.2, 23.1, 14.4, 9.7 ppm.
f) OctHexSiH2+SiCl4→OctHexSiHCl+HSiCl3
OctHexSiH2 (79 g, 0.34 mol, 1.0 eq), n-Bu3N (1 mL, 1 mol-%) and SiCl4 (190 mL, 1.6 mol, 4.8 eq) were reacted in a Schlenk-flask at 100° C. for 40 h. A mixture consisting of HSiCl3 and SiCl4 (50 mL) was separated from the reaction mixture by distillation. The remaining residue was further reacted at 100° C. for 16 h. GC-MS-analysis of the reaction mixture proved OctHexSiH2 conversion into OctHexSiHCl in 94%. After separation of the low boiling compounds HSiCl3 and SiCl4 by distillation and fractional distillation, OctHexSiHCl was isolated in 86 g (0.33 mol, 96% yield, post chlorination by thermal work up, b.p.: 106° C. at 40 mbar, RT=22.8 min).
1H-NMR (500.2 MHz, C6D6): δ=4.76 (s, 1H, Si—H), 1.42-1.34 (m, 4H, Si—CH2—), 1.30-1.18 (m, 16H, —CH2—), 0.90-0.85 (m, 6H, CH3), 0.77-0.71 (m, 4H, CH2—CH3) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=14.9 (d, 1J=217 Hz) ppm.
13C-NMR: (125.8 MHz, C6D6): δ=33.2, 32.9, 32.4, 31.9, 29.7, 23.6, 23.5, 23.2, 23.0, 16.1, 14.5, 14.4 ppm.
q) OctHexSiHCl+1-Pentene→OctHexSiPentCl OctHexSiHCl (85 g, 0.33 mol, 1.0 eq), 150 mL of dry diglyme and 143 mL (0.75 mol, 2.3 eq) of 1-pentene were added to 500 mg of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 82 h, diglyme and the alkene were separated via distillation in vacuo. The product was isolated by fractional distillation in vacuo in 102.2 g (0.31 mol, 94% yield, b.p.: 135° C. (10−2 mbar), RT=28.6 min).
1H-NMR (500.2 MHz, C6D6): δ=1.24-1.18 (m, 6H, Si—CH2—), 1.08-0.87 (m, 26H, —CH2—), 0.69 (t, 9H, —CH3, 3J=7.5 Hz) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=31.6 ppm.
13C-NMR: (125.8 MHz, C6D6): δ=35.9, 33.8, 33.4, 32.5, 32.0, 29.8, 29.7, 23.5, 23.5, 23.2, 22.7, 16.7, 16.6, 14.5, 14.3 ppm.
h) OctHexSiPentCl+LiH→OctHexSiPentH
LiH (10.7 g, 1.3 mol. 4.6 eq) was suspended in 200 mL of dry THF. OctHexSiPentCl (102 g, 0.31 mmol, 1.0 eq) was added to the suspension, heated to 90° C. for 16 h and additionally at 120° for 18 h. GC-MS analysis of the reaction mixture proved 100% conversion of all chlorine- against hydrido-substituents. The liquid phase was separated from LiCl by filtration and OctHexSiPentH was isolated by fractional distillation in 76 g (0.26 mol, 86% yield, b.p.: 120° C., 10−2 mbar, RT=24.82 min).
1H-NMR (500.2 MHz, C6D6): δ=3.94 (s, 1H, Si—H), 1.40-1.28 (m, 26H, CH2), 0.90 (t, 9H, CH3), 0.65-0.60 (m, Si—CH2, 6H) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=−6.7 (d, 1J=178 Hz) ppm.
13C-NMR: (125.8 MHz, C6D6): δ=36.2, 34.0, 33.7, 32.5, 32.2, 29.9, 29.9, 25.3, 25.3, 23.2, 23.2, 22.9, 14.5, 14.4, 11.9, 11.8 ppm.
i) OctHexSiPentH+1-Heptene→OctHexSiPentHept
OctHexSiPentH (8.2 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 7.8 mL (0.068 mol, 2.5 eq) of 1-heptene were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, GC-MS analysis of the reaction mixture proved the formation of the desired product in 45%. For full conversion of the hydridosilane into the corresponding tetraalkylsilane, the reaction mixture was transferred into an ampule and admixed with an additional equivalent of 1-heptene (0.027 mol) and 0.5 mL of the Karstedt-catalyst. The reaction mixture was cooled to −196° C., the ampule was sealed under vacuo and placed in a drying oven at 150° C. for 60 h. Then the ampule was opened, all volatiles were distilled off and OctHexSiPentHept was isolated by fractional distillation in vacuo in 4.0 g (0.01 mol, 37% yield, b.p.: 140° C. (10−2 mbar), RT=36.53 min).
1H-NMR (500.2 MHz, C6D6): δ=1.33-1.28 (m, 36H, —CH2—), 0,90-0,88 (m, 12H, —CH3), 0.55 (m, 8H, Si—CH2—) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=2.8 ppm.
13C-NMR: (125.8 MHz, C6D6): δ=36.8, 34.6, 34.5, 34.2, 32.6, 32.5, 32.2, 30.0, 29.9, 29.6, 24.6, 24.6, 24.5, 24.2, 23.3, 22.9, 14.5, 14.4, 13.1, 13.0 ppm.
j) OctHexSiPentH+1-Decene→OctHexSiPentDec
OctHexSiPentH (8.0 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 12.7 mL (0.068 mol, 2.5 eq) of 1-decene were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, 29Si-NMR spectroscopic analysis of the reaction mixture indicated that 66% of the desired product were formed. For full conversion of the hydridosilane, the reaction mixture was transferred into an ampule and admixed with an additional equivalent of 1-decene (5.1 mL, 0.027 mol) and 0.5 mL of the Karstedt-catalyst. The mixture was cooled to −196° C., the ampule was sealed under vacuo and placed in a drying oven at 150° C. for 60 h. Then, the ampule was opened, all volatiles were condensed off and OctHexSiPentDec was isolated by fractional distillation in vacuo in 4.8 g (0.01 mol, 40% yield, b.p.: 165° C. (10−2 mbar), RT=53.01 min).
1H-NMR (500.2 MHz, C6D6): δ=1.36-1.28 (m, 42H, —CH2—), 0.92-0.88 (m, 12H, —CH3), 0.63-0.54 (m, 8H, Si—CH2—) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=2.8 ppm.
13C-NMR: (125.8 MHz, C6D6): δ=36.7, 34.6, 34.2, 32.5, 32.2, 30.2, 29.9, 24.6, 24.2, 23.3, 22.8, 14.5, 13.1 ppm.
k) OctHexSiPentH+1-Hexadecene→OctHexSiPentHexdec
OctHexSiPentH (8.0 g, 0.027 mol, 1.0 eq), 20 mL of dry diglyme and 9.4 mL (0.068 mol, 2.5 eq) of 1-hexadecene were added to 200 mg (2.5 wt %) of the catalyst (B770011) in a Schlenk-flask. After heating to reflux (100° C.) for 60 h, 29Si-NMR spectroscopic analysis of the reaction mixture proved the formation of the desired product in 66%. For full conversion of the hydridosilane, the reaction mixture was transferred into an ampule and admixed with an additional equivalent of 1-hexadecene (3.8 mL, 0.027 mol) and 0.5 mL of the Karstedt-catalyst. The reaction mixture was cooled to −196° C., the ampule was sealed under vacuo and placed in a drying oven at 150° C. for 60 h. Then, the ampule was opened, all volatile compounds were condensed off and the residue was purified by filtration over a 2 cm column filled with silica-gel and hexane as solvent. After removal of the solvent in vacuo, the silahydrocarbon OctHexSiPentHexdec (Hexdec is C16H31) was isolated in 5.7 g (0.011 mol, 41% yield, δ29Si=2.8 ppm, RT=160.98 min).
1H-NMR (500.2 MHz, C6D6): δ=1.22-1.14 (m, 52H, —CH2—), 0.78-0.74 (m, 12H, —CH3), 0.43-0.42 (m, 8H, Si—CH2—) ppm.
29Si-NMR: (99.4 MHz, C6D6): δ=2.8 ppm.
13C-NMR: (125. MHz, C6D6): δ=36.7, 34.6, 34.3, 32.5, 32.2, 30.9, 30.0, 24.6, 24.2, 23.3, 22.9, 14.5, 13.1 ppm.
In the following the preferred embodiments of the invention are shown.
A process for the production of silahydrocarbons of the general formula (I)
SiR1R2R3R4 (I)
wherein
R1 and R2 are independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, an unsubstituted or substituted aryl group, or an unsubstituted or substituted alkenyl group, each having 1 to 30 carbon atoms,
R3 and R4 are independently selected from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkenyl groups, unsubstituted or substituted alkaryl groups or unsubstituted or substituted aryl groups, each having 2 to 30 carbon atoms and having at least two carbon atoms adjacent to each other, and wherein R1—R4 may be the same or be selected from two, three or four different groups, comprising
SiR1R21HCl (II)
SiR1R22Cl2 (III)
SiR1R23H2 (IV)
SiR1R23H2 (IV)
SiR1R23H2 (IV)
SiR1R2R31Cl (V)
SiR1R2R32H (VI)
by a hydrogenation reaction of a compound of the general formula (V) as obtained in a step b) wherein in the general formulae (V) and (VI)
R1 and R2 are selected from a group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, an unsubstituted or substituted aryl group, or an unsubstituted or substituted alkenyl group, each having 1 to 30 carbon atoms,
R31 is as defined above,
and R32 is selected from a hydrido group or from the group consisting of aliphatic, cycloaliphatic, aryl, alkaryl and aralkyl groups, in particular unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkenyl groups, unsubstituted or substituted alkaryl groups or unsubstituted or substituted aryl groups, each having 2 to 30 carbon atoms and having at least two carbon atoms adjacent to each other,
or of producing an intermediate of the general formula R1SiH3 by a hydrogenation reaction of a compound of the formula R1SiCl3, wherein R1 is as defined for the intermediate of the general formula (VI), and
SiR1R2R3R4 (I) as defined above,
wherein the intermediate is preferably a tertiary silane of the general structure SiR1R2R32H
with R32≠H. (VI)
The process according to embodiment 1, wherein the four organyl substituents R1, R2, R3 and R4 at the silicon center of the silahydrocarbon product of the general formula (I) are selected from at least two, preferably from at least three, and most preferably from four different groups.
The process according to the embodiments 1 and 2, wherein the four organyl substituents R1, R2, R3 and R4 at the silicon center of the silahydrocarbon product of the general formula (I) are selected from four different groups, preferably four different alkyl groups, more preferably four different linear alkyl groups, most preferably four different linear unsubstituted alkyl groups.
The process according to the embodiments 1 to 3, wherein R1 of the silahydrocarbon product of the general formula (I) is a methyl group or a phenyl group, preferably a methyl group.
The process according to any of the previous embodiments, wherein R1 and R2 of the silahydrocarbon product of the general formula (I) are both independently selected from the group consisting of methyl groups, butyl groups, hexyl groups, phenyl groups, preferably both are independently selected from phenyl and methyl groups, most preferably both are methyl groups.
The process according to any of the previous embodiments, wherein one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are alkenyl substituents, preferably 1-alkenyl substituents, even more preferably unsubstituted 1-alkenyl substituents.
The process according to any of the previous embodiments, wherein one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are residues substituted with one or more halogen substituents, preferably selected from chloro and bromo substituents, most preferably bearing one or more bromo substituents.
The process according to any of the previous embodiments, wherein one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are residues comprising one or more aromatic groups, preferably one or two of the residues R3 and R4 comprise one or more phenyl groups, most preferably one or two of the residues R3 and R4 comprise one or more phenyl groups as substituents.
The process according to any of the previous embodiments, wherein one or two of the substituents R3 and R4 of the silahydrocarbon product of the general formula (I) are residues comprising ester groups, preferably one or two of the residues R3 and R4 in the general formula (I) are residues comprising ester groups of C1-C6 alcohols, in particular methyl ester groups, more preferably the residues R3, R4 and R2 in the general formula (I) are residues comprising ester groups of C1-C6 alcohols, most preferably the residues R2, R3 and R4 comprise methyl ester groups.
The process according to the embodiments 1 to 5 or 7 to 9, wherein all four organyl substituents R1, R2, R3 and R4 at the silicon center of the silahydrocarbon product of the general formula (I) are independently selected from saturated hydrocarbon groups, preferably from unsubstituted alkyl groups, more preferably from unsubstituted alkyl groups, most preferably from linear unsubstituted alkyl groups.
The process according to any of the previous embodiments, wherein the silahydrocarbon product of the general formula (I) is selected from the group consisting of Me2SiHexPent, Me2SiHexHept, Me2SiHexOct, MeSiBu3, MeSiBu2Hept, MeSiBuHeptOct, MeSiHexHeptOct, MeSiHept2Oct, MeSiHeptOctDec, MeSiHeptOctHexdec, Bu2SiHexOct, BuSiHex2Oct, BuSiHexHeptOct, BuSiHexOctDec, BuSiHexOctHexdec, Bu3SiHex, BuSiHex3, BuSiHexHept2, BuSiHexDec2, OctHexSiPentHept, OctHexSiPentOctenyl (C1 and C2 substituted Octenyl), OctHexSiPentDec, OctHexSiPentHexadec, (11-bromoundecyl)MeSiBu2, (phenethyl)MeSiBu2, and methyl-11-(methyldibutylsilyl)undecenoate, preferably selected from the group consisting of Me2SiHexPent, Me2SiHexHept, Me2SiHexOct, MeSiBu3, MeSiBu2Hept, MeSiBuHeptOct, MeSiHexHeptOct, MeSiHept2Oct, MeSiHeptOctDec, MeSiHeptOctHexdec, Bu2SiHexOct, BuSiHex2Oct, BuSiHexHeptOct, BuSiHexOctDec, BuSiHexOctHexdec, Bu3SiHex, BuSiHex3, BuSiHexHept2, BuSiHexDec2 and OctHexSiPentHept, even more preferably selected from the group consisting of Me2SiHexPent, Me2SiHexHept, Me2SiHexOct, MeSiBu3, MeSiBuHeptOct, MeSiHexHeptOct, MeSiHeptOctDec, MeSiHeptOctHexdec, BuSiHexHeptOct, BuSiHexOctDec, BuSiHexOctHexdec and OctHexSiPentHept, and most preferably selected from Me2SiHexPent, Me2SiHexOct, MeSiBu3, MeSiHeptOctDec, MeSiHeptOctHexdec, BuSiHexHeptOct, BuSiHexOctDec and BuSiHexOctHexdec.
The process according to any of the previous embodiments, wherein the bifunctional monosilane intermediate of the general formula (II) in step a) is a compound of the formula
SiR1H2Cl
wherein R1 is an unsubstituted or substituted alkyl group,
preferably R1 is an unsubstituted alkyl group, more preferably R1 is an unsubstituted C1-C30 alkyl group, even more preferably R1 is an unsubstituted C1-C30 linear alkyl group, most preferably R1 is a methyl group.
The process according to any of the previous embodiments, wherein the bifunctional monosilane intermediate of the general formula (II) in step a) is a compound of the formula
SiR1HCl2
wherein R1 is an unsubstituted or substituted alkyl group,
preferably R1 is an unsubstituted alkyl group, more preferably R1 is an unsubstituted C1-C30 alkyl group, even more preferably R1 is an unsubstituted C1-C30 linear alkyl group, most preferably R1 is a methyl group.
The process according to any of the previous embodiments, wherein the bifunctional monosilane intermediate of the general formula (II) in step a) is a compound of the formula
SiR1R21HCl,
wherein R1 and R21 are independently selected from unsubstituted or substituted alkyl groups, preferably R1 and R21 are independently selected from unsubstituted alkyl groups, more preferably R1 and R21 are independently selected from unsubstituted C1-C30 linear alkyl groups, even more preferably R1 is methyl and R21 is selected from unsubstituted C1-C30 linear alkyl groups, most preferably R1 and R21 are both methyl groups.
The process according to any of the previous embodiments, wherein the bifunctional monosilane intermediate of the general formula (II) in step a) is selected from the group consisting of MeSiHCl2, MeSiH2Cl, Me2SiHCl, PhSiHCl2, PhSiH2Cl, Ph2SiHCl, MePhSiHCl, MeViSiHCl, BuSiHCl2, MeBuSiHCl, BuSiHexHCl, Hex2SiHCl, HexSiHCl2, HexSiH2Cl, OctSiHCl2, OctSiH2Cl, OctHexSiHCl, preferably MeSiHCl2, PhSiHCl2, MeViSiHCl, HexSiHCl2, Hex2SiHCl, Me2SiHCl, BuSiHCl2, or MeSiBuHCl, most preferred MeSiHCl2, Me2SiHCl, or BuSiHCl2.
The process according to any of the previous embodiments, wherein the starting material for step a) of the general formula (III) is a compound of the general formula R1SiCl3, wherein R1 is selected from unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, or unsubstituted or substituted aryl groups, each having 1 to 30 carbon atoms, and is preferably obtained by a hydrosilylation reaction of HSiCl3 and a C—C-unsaturated compound having 2 to 30 carbon atoms.
The process according to any of the previous embodiments, wherein the starting material for step a) of the general formula (IV) is a compound of the formula R1SiH3, wherein R1 is selected from unsubstituted or substituted alkyl groups, unsubstituted or substituted cycloaliphatic groups, unsubstituted or substituted alkaryl groups, unsubstituted or substituted aralkyl groups, or unsubstituted or substituted aryl groups each having 1 to 30 carbon atoms, which is preferably obtained by a hydrosilylation reaction of HSiCl3 and subsequent hydrogenation with a metal hydride of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2.
The process according to the previous embodiments 16 and 17, wherein one or both of the starting materials of the general formulae (III) and (IV) applied in a reaction of step a) are obtained starting from HSiCl3, wherein the HSiCl3 is preferably obtained from the Siemens Process or from hydrogenation of SiCl4 with mono-, di- or triorganohydridosilanes.
The process according to the previous embodiments 1 to 18, wherein the starting material for step a) according to general formula (III) is MeSiCl3 or Me2SiCl2, preferably MeSiCl3 or Me2SiCl2 obtained from the Müller-Rochow-Direct Process.
The process according to the previous embodiments, wherein the starting material for step a) according to the general formula (IV) is MeSiH3 or Me2SiH2, preferably obtained by hydrogenation of MeSiCl3 or MeSiCl2 with a metal hydride of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2, even more preferably the starting material for step a) according to general formula (IV) is MeSiH3 or Me2SiH2 obtained by hydrogenation of MeSiCl3 or Me2SiCl2 obtained from the Müller-Rochow-Direct Process with a metal hydride of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor selected from diisobutylaluminum hydride, Me3SnH, nBu3SnH, Ph3SnH, Me2SnH2, nBu2SnH2 and Ph2SnH2.
The process according to any of the previous embodiments, wherein at least one intermediate of the general formula (II) is obtained by a redistribution reaction of a compound of the general formula (III) and a compound of the general formula (IV) as defined above, wherein the redistribution catalyst is selected from one or more compounds selected from the group consisting of
The process according to any of the previous embodiments, wherein at least one step a) is performed in the presence of a solvent, wherein the solvent is selected from the group consisting of ethers, alkanes or aromatic solvents, more preferably selected from the group consisting of THF, 1,4-dioxane, diglyme, tetraglyme, hexane and benzene, most preferably the solvent is THF.
The process according to any of the previous embodiments, wherein the reaction temperature in at least one step a) is in the range from 0° C. to 180° C., preferably 20° C. to 160° C., and most preferably 60° C. to 120° C.
The process according to any the previous embodiments, wherein the redistribution partners in at least one step a) are selected from the group consisting of the couples MeSiCl3 and MeSiH3, Me2SiCl2 and Me2SiH2, MeSiCl3 and Me2SiH2, Me2SiCl2 and MeSiH3, Ph2SiCl2 and Me2SiH2, PhMeSiCl2 and Me2SiH2, MeSiHeptCl2 and MeSiHeptH2, MeSiOctCl2 and MeSiOctH2 or MeSiBuCl2 and MeSiBuH2, preferably from MeSiCl3 and MeSiH3, Me2SiCl2 and Me2SiH2, or from MeSiBuCl2 and MeSiBuH2.
The process according to any of the previous embodiments, wherein at least one intermediate of the general formula (II) in a step a) is obtained by a redistribution reaction of a compound of the general formula (III) and the in-situ formed hydrogenation products obtained by reacting one or more monosilanes of the general formula (III) with a metal hydride of the general formula MHx or an organometallic hydride donor in the presence of a redistribution catalyst, wherein the redistribution catalyst is selected from the group consisting of
The process according to any of the previous embodiments, wherein the solvent in the redistribution reaction involving in-situ reduction of the perchlorinated starting material is selected from the group consisting of ethereal solvents, more preferably THF, diglyme, 1,4-dioxane, triglyme, tetraglyme, DME, most preferably THF, 1,4-dioxane, diglyme, and the reaction temperature is in the range from 0° C. to 180° C., preferably 20° C. to 160° C., and most preferably 60° C. to 120° C.
The process according to any of the previous embodiments, wherein the compounds of the general formula (III) are selected from the group consisting of MeSiCl3, Me2SiCl2, PhSiCl3, Ph2SiCl2, PhMeSiCl2, BuSiCl3 or MeSiBuCl2, preferably from the group consisting of MeSiCl3, BuSiCl3, MeSiBuCl2 and Me2SiCl2.
The process according to any of the previous embodiments, wherein at least one intermediate of the general formula (II) is obtained in a selective partial chlorination reaction of a compound of the general formula (IV) by reacting the compound with an HCl/ether reagent in step a), wherein the HCl/ether reagent is preferably selected from THF/HCl, diethyl ether/HCl, diglyme/HCl, 1,4-dioxane/HCl, dibutyl ether/HCl, more preferably selected from diglyme/HCl, diethyl ether/HCl, 1,4-dioxane/HCl, dibutyl ether/HCl, and most preferably selected from diethyl ether/HCl, or diglyme/HCl.
The process according to any of the previous embodiments, wherein at least one intermediate of the general formula (II) is obtained in a chlorination reaction of a compound of the general formula (IV) SiR1R23H2 with tetrachlorosilane (SiCl4) in the presence of at least one catalyst.
The process according to any of the previous embodiments, wherein in at least one step a) the compounds of the general formula (IV), submitted to a partial chlorination reaction with an HCl/ether reagent or with SiCl4 in the presence of at least one catalyst, are selected from the group consisting of MeSiH3, Me2SiH2, PhSiH3, Ph2SiH2, PhMeSiH2, BuSiH3, MeSiBuH2, HexSiH3, OctSiH3, Hex2SiH2, MeSiHexH2, MeSiHeptH2 and MeSiOctH2, preferably from MeSiBuH2, MeSiHexH2, MeSiHeptH2, and MeSiOctH2.
The process according to any of the previous embodiments, wherein the compounds of the general formula (IV), submitted to the partial chlorination reaction with an HCl/ether reagent or with SiCl4 in the presence of at least one catalyst, are obtained by perhydrogenation of the analogous perchlorinated monosilanes using one or more metal hydride reagents or organometallic hydride donor reagents selected from NaBH4, LiAlH4, LiBH4, KH, LiH, NaH, MgH2, CaH2, nBu3SnH, Me3SnH, Ph3SnH, nBu2SnH2, Me2SnH2, and Ph2SnH2 or i-Bu2AlH, preferably from LiAlH4, NaH, LiH or nBu3SnH, more preferably from LiAlH4 or LiH, most preferably LiH.
The process according to any of the previous embodiments, wherein at least one metal-catalyzed hydrosilylation step (b) is performed using a Rh- or Pt-based catalyst, more preferably using a Pt-catalyst immobilized on a support, even more preferably using a Pt-catalyst immobilized on silica, most preferably a Pt-catalyst immobilized on silica comprising a metal-containing siloxane polymer matrix covalently bonded to the silica support, in particular Pt-nanoparticles encapsulated in a siloxane polymer matrix covalently bonded to a silica support.
The process according to any of the previous embodiments, wherein the bifunctional monosilane intermediate of the general formula (II) submitted to step b) is selected from R1SiHCl2 or R1SiH2Cl, wherein in each case R1 is selected from phenyl or a C1-C30 linear alkyl residue, or R1R21SiHCl, wherein R1 and R21 are independently selected from phenyl or a C1-C30 linear alkyl residue, preferably the intermediate is selected from the group consisting of MeSiHCl2, MeSiH2Cl, Me2SiHCl, PhSiH2Cl, PhSiHCl2, Ph2SiHCl or PhMeSiHCl, most preferably the intermediate is selected from MeSiHCl2, MeSiH2Cl or Me2SiHCl.
The process according to any of the previous embodiments, wherein the compound containing at least one C—C double or C—C triple bond in the hydrosilylation reaction of step b) is selected from the group consisting of alkenes, cycloalkenes, polyenes, alkynes, cyclic alkynes, polyalkynes, preferably alkenes, cycloalkenes, alkynes, cyclic alkynes, more preferably alkenes, cycloalkenes, alkynes, even more preferably alkenes, and most preferably monounsaturated terminal alkenes.
The process according to any of the previous embodiments, wherein at least one step b) is performed at a temperature within the range from 0° C. to 180° C., preferably 20° C. to 140° C., most preferably 60° C. to 100° C., and wherein further preferably no additional solvent is used or the solvent is selected from THF, diglyme, 1,4-dioxane, benzene or toluene, preferably from THF, diglyme or 1,4-dioxane, more preferably from THF or 1,4-dioxane, most preferably the solvent is THF.
The process according to any of the previous embodiments, wherein in step c) the intermediate of the general formula (V) is hydrogenated by a reaction with a metal hydride reagent of the general formula MHx, wherein M and x are as defined above, or an organometallic hydride donor reagent selected from the group consisting of nBu3SnH, Me3SnH, Ph3SnH, nBu2SnH2, Me2SnH2, and Ph2SnH2, preferably with a metal hydride reagent selected from the group consisting of NaBH4, LiAlH4, LiBH4, KH, LiH, NaH, MgH2, CaH2, i-Bu2AlH or nBu3SnH, more preferably consisting of LiAlH4, NaH, LiH, even more preferably from LiAlH4 and LiH, and most preferably the metal hydride reagent is LiH.
The process according to any of the previous embodiments, wherein the catalyst of the hydrosilylation reaction of step d) is selected from a Rh- or Pt-based catalyst, more preferably from a Pt-catalyst immobilized on a support, even more preferably from a Pt-catalyst immobilized on silica, most preferably from a Pt-catalyst immobilized on silica comprising a metal-containing siloxane polymer matrix covalently bonded to the silica support, in particular Pt-nanoparticles encapsulated in a siloxane polymer matrix covalently bonded to a silica support.
The process according to any of the previous embodiments, wherein the compound containing one or more C—C double bonds or C—C triple bonds submitted to the hydrosilylation reaction of step d) is selected from the group consisting of alkenes, cycloalkenes, polyenes, alkynes, cyclic alkynes, polyalkynes, preferably alkenes, cycloalkenes, alkynes, cyclic alkynes, more preferably alkenes, cycloalkenes, alkynes, even more preferably alkenes, and most preferably monounsaturated terminal alkenes.
The process according any of the previous embodiments, wherein the hydrogenation reaction of step c) and the hydrosilylation reaction of step d) are performed in a one-step procedure.
In
| Number | Date | Country | Kind |
|---|---|---|---|
| 20177581.4 | May 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/034736 | 5/28/2021 | WO |
