Homogeneous hydroformylation catalysis with silyl substituted alkyl diaryl phosphine metal complexes

BACKGROUND OF THE INVENTION
This invention relates to trihydrocarbyl silyl-substituted alkyl diaryl phosphine transition metal complex carbonylation catalysis.
More particularly, the subject of this invention is homogeneous, selective, low pressure alpha-olefin hydroformylation with tris-(silylalkyl diaryl phosphine) rhodium carbonyl hydride complex catalysts in the presence of excess phosphine ligand.
One aspect of the invention is the derivation of the silylalkyl diphenyl phosphine ligands via the anti-Markovnikov addition of a diaryl phosphine to the appropriate alkenyl silane.
Another apsect is concerned with the preparation of the transition metal complexes of these ligands via displacement reactions. Syntheses starting with tris(triphenyl phosphine) rhodium carbonyl hydride and dicarbonyl acetylacetonato rhodium are specifically described.
A special aspect of the invention is concerned with the physicochemical and catalytic properties of the novel complexes, i.e., phosphine basicity and stereochemistry versus complex formation, equilibria and stability. The selectivity and rate of hydroformylation are correlated with temperature, concentration of excess ligand, carbon monoxide partial pressure and the presence of aldolization catalyst.
Finally, a special concern of the present invention is a continuous low pressure hydroformylation of alpha-olefins, particularly butene-1, propylene and pentenes at elevated temperatures. An exemplary feature of such hydroformylation involves a continuous product flashoff operation. In this process, gaseous reactants are continuously introduced into, and a mixture of gaseous products and unreacted feed is continuously removed from, the solution of the present homogeneous catalyst complex.
The main objective of the present invention is to provide selective silyl substituted alkyl diphenyl phosphine rhodium carbonyl hydride catalysts which are more stable, and can be used in an improved hydroformylation process at higher temperatures, than the widely used triaryl phosphine rhodium carbonyl hydride catalysts.
Transition metal complexes of both triphenyl phosphine and trialkyl phosphines are widely studied catalysts employed in hydroformylation, hydrogenation, etc., reactions. The monograph of Juergen Falbe, "New Syntheses with Carbon Monoxide," Springer Verlag, N.Y., 1970, deals with the use of these materials in reactions of carbon monoxide, particularly carbonylations. In the realm of rhodium catalyzed hydroformylations of alpha-olefins, catalyst systems of triaryl phosphine and other trivalent phosphorus compound rhodium complexes in the presence of excess phosphine ligand which exhibited improved selectivity to normal aldehydes (over iso aldehydes) are described by R. L. Pruett and J. A. Smith in U.S. Pat. No. 3,527,809. In that patent, it is stated as being essential that the phosphorus ligands be of weakly basic character possess a half neutralization potential value at least 425, preferably at least 500, smaller than that of N,N' diphenylguanidine. The .DELTA.HNP is only about 400 for simple alkyl diphenyl phosphines which are too basic according to Pruett and Smith.
Morrell and Sherman in German Offenlegungschrift No. 2,802,922 disclose unsubstituted alkyl diphenyl phosphines as components of stabilized tris-(triphenyl phosphine) rhodium carbonyl hydride plus excess triphenyl phosphine catalyst systems for hydroformylation of alpha-olefins with CO/H.sub.2 to give aldehydes.
In the area of silyl substituted alkyl phosphine transition metal complexes, the work of Grish Chandra is of importance. British Pat. Nos. 1,419,769; 1,420,982; 1,421,136 Chandra disclose rhodium complexes of silyl alkyl phosphines, in each of which the rhodium had attached to it a halogen. These materials are disclosed as being useful for hydro-silylation, hydrogenation and hydroformylation. Specific examples are given only for the preparation of silylmethyl phosphine complexes and their use in hydrosilylation.
British Pat. Nos. 1,412,257; 1,414,662 and U.S. Pat. No. 3,856,837 (all to Chandra) describe nickel, palladium and platinum complexes of silylalkyl phosphines and their use of hydrosilylation, hydrogenation, and polymerization. In these patents, the transition metal has attached to it a halogen of --SCN group or --S-- wherein -- represents an alkyl radical having less than 18 carbon atoms or the phenyl radical.
In G.B. No. 1,412,257 the material is identified as a bridged binuclear complex.
In G.B. No. 1,414,662 the nickel, palladium or platinum transition group metal may have associated with it a hydrogen atom or other anionic ligand (X) which may be for example, H, Cl, Br, I, --NO.sub.2, --NO.sub.3, --SCN, --OCOCH.sub.3, an alkyl, aryl, alkaryl or aralkyl radical. However, materials wherein X is Br are the only ones actually prepared.
In U.S. Pat. No. 3,856,837, the nickel, palladium or platinum also have only halogens associated with them as anionic ligands (X).
G.B. No. 925,721 to H. Niebergall deals broadly with the addition of secondary phosphines to unsaturated silanes to provide silylhydrocarbyl phosphines. He discloses materials of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are alkyl, cycloalkyl, aryl, alkaryl, aralkyl; R.sub.3 and R.sub.4 are alkyl, cycloalkyl, aryl, alkaryl, aralkyl or hydrogen; A is a halo, alkoxy, hydroxy, alkyl, alkaryl, cycloalkyl, aryl or aralkyl radical; Z is a hydrocarbon residue having from 1 to 10 carbon atoms and is preferably a saturated straight or branched chain hydrocarbon residue (or Z is a silicon to carbon linkage). If phosphorous is pentavalent, y is oxygen or sulfur; if phosphorous is trivalent, y is no substituent; n is 0 to 3. This patent contains no teaching that these materials can be complexed with transition metals to yield homogeneous catalysts useful in hydroformylation reactions.
Owen and Cooper disclose the preparation of similar compounds via displacement reactions of chlorophosphines and silylalkyl Grignard compounds or sodium phosphides and silylalkyl halides in British Pat. No. 1,179,242.
To obtain the vinyl triphenyl silane intermediate, vinyl trichloro silane was reacted with phenyl magnesium bromide in an ether-THF solvent mixture. The cement reactions of chloro-phosphines and silylalkyl Grignard compounds or sodium phosphides and silylalkyl halides.
U.S. Pat. No. 3,067,227 to Fekete describes the preparation of alkoxysilylalkylphosphines via the method of reacting alkoxy silanes and unsaturated phosphines.
G.B. No. 1,182,763 to Jacques and Owen also disclose silylhydrocarbylphosphine intermediates useful in the preparation of the complexes of the present invention.
U.S. Pat. Nos. 3,762,809 and 3,832,404 to Allum et al disclose heterogeneous hydroformylation catalysts (and processes using these catalysts). These heterogeneous catalysts are silylhydrocarbyl phosphine transition metal complexes, bonded to a support by the interaction of a reactive group on the silicon with at least one reactive hydroxyl group on the support which may also be silicon. See also U.S. Pat. Nos. 3,907,852 and 4,083,803 to Oswald and Murrell.

DESCRIPTION OF THE FIGURES
FIG. 1 shows the key steps and equilibria in the phosphine rhodium complex catalyzed hydroformylation of olefins.
FIG. 2 shows the .sup.31 P nmr spectra of rhodium carbonyl hydride complexes formed with excess TPP (triphenylphosphine) and SEP (trimethylsilylethyldiphenylphosphine) ligands and their mixtures.
FIG. 3 illustrates by .sup.31 P nmr spectra ligand exchange rates of TPP and SEP complexes at various temperatures.
FIG. 4 outlines the different methods of feed gas introduction for hydroformylation on a schematic drawing of an autoclave.
FIG. 5A and 5B indicate catalyst stability of the TPP and SEP complex during hydroformylation at 145.degree. C. and 100.degree. C., respectively.
FIG. 6 shows the effect of SEP liqand to rhodium ratio on the n/i ratio of the aldehyde products at 145.degree. C. and 170.degree. C.
FIG. 7 shows the effect of CO partial pressure of the n/i ratio of aldehyde products at 120.degree. C.
FIG. 8 shows the aldehyde production rate during continuous butene hydroformylation.

SUMMARY OF THE INVENTION
By this invention, there is provided a carbonylation process comprising reacting an organic compound with CO in the presence of reaction mixture comprising a catalyst complex of the formula:
[(Ar.sub.2 PQ).sub.y SiR.sub.4-y ].sub.g . (MX.sub.n).sub.s
wherein Ar is a substituted or unsubstituted C.sub.6 to C.sub.10 aromatic radical, Q is a substituted or unsubstituted C.sub.1 to C.sub.30 saturatedopen chain alkylene radical, R is an unsubstituted or monosubstituted C.sub.1 to C.sub.10 hydrocarbyl radical, M is a Group VIII transition metal selected from the group consisting of Co, Rh, Ir, Ru, Fe or Os, X isan anion or organic ligand, excluding halogen, satisfying the valence and coordination sites of the metal, y is 1 to 4, g is 1 to 6 with the provisothat g times y is 1 to 6, n is 2 to 6, and s is 1 to 3, said substituents on said aromatic radical, on said alkylene radical and on said hydrocarbylradical being chemically unreactive with materials used in, and the products of, a carbonylation reaction.
DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
Compositions encompassed and used in the present invention process are hydrocarbylsilyl alkyl diaryl phosphine complexes of selected Group VIII transition metals free of metal bound halogen. The scope of the compositions is co-extensive with that described in the parent case, Ser. No. 011,238, which is hereby incorporated by reference for that purpose. They are represented by the formula:
[(Ar.sub.2 PQ).sub.y SiR.sub.4-y ].sub.g . (MX.sub.n).sub.s
wherein Ar is the same or different C.sub.6 to C.sub.10 substituted or non substituted aromatic hydrocarbyl radical, preferably phenyl, mono-, di- ortri- substituted phenyl, most preferably phenyl; Q is a C.sub.1 to C.sub.30saturated open chain alkylene radical, preferably a straight chain alkyleneradical, more preferably a C.sub.2 to C.sub.14 unsubstituted or monosubstituted alkylene diradical; R is the same or different C.sub.1 to C.sub.10 unsubstituted hydrocarbyl or C.sub.1 to C.sub.6 unsubstituted hydrocarbyl radical, preferably C.sub.1 to C.sub.6 alkyl, C.sub.5 and C.sub.6 cycloalkyl, phenyl, C.sub.1 to C.sub.6 monosubstituted alkyl, monosubstituted phenyl, more preferably C.sub.1 to C.sub.6 alkyl or phenyl, M is a Group VIII transition metal selected from Fe, Co, Rh, Ru, Ir, Os, preferably Co, Rh, Ir, and Ru, more preferably Co, Rh, most preferably Rh; y is 1 to 4, preferably 1 or 2, most preferably 1; g is 1 to 6 and g times y is 1 to 6 , preferably 1 to 4, more preferably 2 or 3, most preferably 3; X is an anion or organic ligand which satisfies the valence and coordination sites of the metal, with the proviso that X cannot be halogen, preferably X is H, Co and tertiary phosphine, most preferably H, CO; n is 2 to 6, preferably 2; s is 1 to 3. Preferably all the organic radicals are unsubstituted. However, if said Ar, R and Q moieties are substituted, the substituents must generally be unreactive with the products of, and during, carbonylation reaction and particularly during hydroformylation reaction. Representative non-limiting examples aredescribed below.
Representative examples of the aromatic Ar groups include phenyl, fluorophenyl, difluorophenyl, tolyl, xylyl, benzoyloxyphenyl, carboethoxyphenyl, acetylphenyl, ethoxyphenyl, phenoxyphenyl, biphenyl, naphthyl, hydroxyphenyl, carboxyphenyl, trifluoromethylphenyl, tetrahydronaphthyl, furyl, pyrryl, methoxyethylphenyl, acetamidophenyl, dimethylcarbamylphenyl, and the like. If substituted, mono- and disubstituted phenyl groups are preferred.
Preferred substituents of the Ar aromatic groups include C.sub.1 to C.sub.30, preferably C.sub.1 to C.sub.12 alkyl, alkoxy, acyl, acyloxy, acrylamido, carbamido, carbohydrocarbyloxy, halogen, phenoxy, hydroxy, carboxy and the like.
Representative R organic groups include C.sub.1 to C.sub.10 hydrocarbyl, preferably C.sub.1 to C.sub.6 unsubstituted alkyl, and particularly preferred, phenyl, and C.sub.1 to C.sub.3 alkyl. Specific examples includemethyl, propyl, hexyl, cyclohexyl, methylcyclopentyl, i-propyl, decyl, fluoropropyl benzyl, phenyl, naphthyl, fluorophenyl, tolyl, and the like. Particularly preferred R groups are methyl and phenyl.
The Q moiety in the composition include substituted and unsubstituted divalent alkylene radicals bridging the P and Si atoms. when unsubstituted, the polymethylene radical is the formula (CH.sub.2).sub.m wherein m is 2 to 14, preferably 2 to 3, and particularly preferred being 2, ethylene. The first segment of the Q alkylene group bound to the phosphorous is preferably a --CH.sub.2 CH.sub.2 -- group. Such a group is desired to avoid undue steric hindrance of the phosphine ligand. When the Q radical is substituted, the alkylene chain can also be interrupted with a heteroatom such as ether oxygen, sulfide, and the like, and also by the phenylene group.
Representative examples of Q radicals include ethylene, trimethylene, tetradecamethylene, xylylene, oxy-bis ethyl, sulfone-bis ethyl, trimethylsilylethyl substituted trimethylene, and the like.
Representative examples of anions and organic ligands, represented by the symbol X, are the following: H--, alkyl.sup.-, aryl.sup.-, substituted aryl.sup.-, CF.sub.3.sup.31 , C.sub.2 F.sub.5.sup.-, CN.sup.-, N.sub.3.sup.-, COR.sup.-, where R is alkyl or aryl, acetate, acetylacetonate, SO.sub.4.sup.2-, PF.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3, O.sub.2.sup.-, CH.sub.3 O.sup.-, CH.sub.2 .dbd.CHCH.sub.2.sup.-CO, C.sub.6 H.sub.5 CN, CH.sub.3 CN, NO, NH.sub.3, pyridine, (C.sub.4 H.sub.9).sub.3 P, (C.sub.2 H.sub.5).sub.3 N, chelating olefins, diolefins and triolefins, tetrahydrofuran, CH.sub.3 CN, triphenyl phosphine. Preferred organic ligands are H, CO and tertiary phosphine and most preferably H and CO. Halogens may not be directly bonded to the transitionmetal.
Representative examples of groups represented by the symbol (MX.sub.n).sub.s are Rh(CO)H, Ir(CO)H, Co (CO).sub.3 H Ru(CO).sub.2 H, andparticularly preferred is Rh(CO)H.
The values of the integers represented by the symbols y, n, s, g in the above-defined formula depend on the number of mono versus divalent organicradical substituents (R vs. Q) on the silicon, and the coordination number of the metal. Accordingly, these values, as defined above, are interrelated to satisfy the valence requirements of the silicon and the transition metal.
Although the complex catalyst compositions of the present invention are preferably non-charged, they include compounds containing positively charged transition metal, particularly rhodium. These complexes are preferably of the general formula:
[Ar.sub.2 P(CH.sub.2).sub.m SiR.sub.3 ].sub.2 Rh.sup.+ (CO).sub.3 X.sup.-
wherein the meaning of Ar, R and m is the same as before, and X.sup.- is ananion, preferably a non-coordinating anion, preferably selected from the group consisting of borate, aluminate, perchlorate, sulfonate, nitrate, fluorophosphate, and fluorosilicate. Representative examples of formulas include PH.sub.4 B.sup.-, F.sub.4 B.sup.-, ClO.sub.4.sup.-, Ph.sub.3 SO.sub.3.sup.-, CF.sub.3 SO.sub.3.sup.-, NO.sub.3.sup.-, F.sub.6 P.sup.-, and F.sub.6 Si.sub.2.sup.2-.
Dependent on the subclass of the silylalkyl phosphine component used as an intermediate different types of the present complexes are derived, whereinthe value of g is 1 to 6 and the value of g times y is 1 to 6; i.e.,
[Ar.sub.2 PQSiR.sub.3 ].sub.g. (MX.sub.n)s; g=1-6; y=1
[(Ar.sub.2 PQ).sub.2 SiR.sub.2 ].sub.g. (MX.sub.n)s; 2g=1-6; y=2
[(Ar.sub.2 PQ).sub.3 SiR].sub.g. (MX.sub.n)s; 3g=1-6; y=3
[(Ar.sub.2 PQ).sub.4 Si].sub.g. (MX.sub.n)s; 4g=1-6; y=4
Preferred hydroformylation catalyst compositions of the present invention are non-chelated trisphosphine and bisphosphine rhodium carbonyl hydride compositions of the generic formulae:
[(Ar.sub.2 PQ).sub.y SiR.sub.4 -y].sub.g. Rh(CO)H, and
{[Ar.sub.2 P(CH.sub.2).sub.m ].sub.y SiR.sub.4-y }.sub.g Rh(CO)H
wherein the meaning of Ar and R is as previously defined; m is 2 to 14, preferably 2 to 3, most preferably 2; y is 1 to 4, preferably 1 to 3, mostpreferably 2; g is 2 to 3, preferably 3.
Among this class of trihydrocarbylsilyl alkyl phosphine rhodium complexes, preferred subgeneric classes are the following:
{[(Ar.sub.2 P(CH.sub.2).sub.m ]SiR.sub.3 }.sub.3 Rh(CO)H
{[Ar.sub.2 P(CH.sub.2).sub.m ]SiR.sub.2 }.sub.3 Rh(CO)H
{[Ar.sub.2 P(CH.sub.2).sub.m ].sub.3 SiR}.sub.3 Rh(CO)H
{[Ar.sub.2 P(CH.sub.2).sub.m ].sub.4 Si}.sub.3 Rh(CO)H
Some specifically preferred silylalkyl phosphine rhodium complexes possess short straight chain alkylene bridges between Si and P, e.g.,
[(.phi..sub.2 P(CH.sub.2).sub.m ].sub.y SiR.sub.4-y ].sub.g [Rh(CO)H]
wherein m is 2 to 14, preferably 2 to 3, R being C.sub.1 -C.sub.6 alkyl, and wherein the complexes can be oligomeric whenever the silylalkyl phosphine has more than one phosphine group.
Among the preferred subgeneric examples of such compositions are the following:
[.phi..sub.2 P(CH.sub.2).sub.m Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H
[.phi..sub.2 P(CH.sub.2).sub.m Si.phi..sub.3 ].sub.3 Rh(CO)H
{[.phi..sub.2 P(CH.sub.2).sub.m ].sub.2 Si.phi..sub.2 }.sub.3 Rh(CO)H
{[.phi..sub.2 P(CH.sub.2).sub.m ].sub.2 Si(CH.sub.3).sub.2 }.sub.3 Rh(CO)H
{[.phi..sub.2 P(CH.sub.2).sub.m ].sub.3 SiCH.sub.3 }.sub.3 Rh(CO)H
{[.phi..sub.2 P(CH.sub.2).sub.m ].sub.4 Si}.sub.3 (Rh(CO)H).sub.s
Representative examples of specifically preferred rhodium complexes which are non-limiting include:
[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H
[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(n--C.sub.3 H.sub.7).sub.3 ].sub.3 Rh(CO)H
[Ph.sub.2 PCH.sub.2 CH.sub.2 SiPh.sub.3 ].sub.3 Rh(CO)H
[(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 ].sub.3 Rh(CO)H
[Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H
[Ph.sub.2 PCH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H
[(Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 ].sub.3 Rh(CO)H
[(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 SiPh.sub.2 ].sub.3 Rh(CO)H
[(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.3 Si(CH.sub.3)].sub.3 Rh(CO)H
[(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.4 Si].sub.3 (Rh(CO)H).sub.s
Examples of preferred types of subgeneric complexes of other transition metals are:
(.phi..sub.2 PQSiR.sub.3).sub.3 Ir(CO)H
(.phi..sub.2 PQSiR.sub.3).sub.2 Ru(CO).sub.2 H.sub.2
(.phi..sub.2 PQSiR.sub.3)Co(CO).sub.3 H
Specific non-limiting examples of the above are the following:
{[.phi..sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ]Co(CO).sub.3 }.sub.2
[.phi..sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si.phi..sub.3 ].sub.3 Ir(CO)H
[.phi..sub.2 PCH.sub.2 CH.sub.2 Si(n--C.sub.3 H.sub.7).sub.3 ]Ru(CO).sub.2 H.sub.2
PREPARATION OF COMPLEXES AND SILYLALKYL PHOSPHINE INTERMEDIATES THEREFOR
For the preparation of the present compositions, standard methods of organometallic chemistry synthesis are discussed in a comprehensive test, "Advanced Inorganic Chemistry" by F. A. Cotton and G. Wilkinson (Interscience Publishers, New York, 1972) and are exemplified in the series on "Inorganic Syntheses" particularly volume XV, edited by G. W. Parshall and published by McGraw-Hill Book Co., New York, 1974, and in U.S. Pat. No. 4,052,461 by H. B. Tinker and D. E. Morris.
For the preparation of the rhodium complexes, one of the specifically preferred direct method of synthesis starts with rhodium chloride. This method can be employed, e.g., for the synthesis of tris-(trihydrocarbylsilylalkyl diaryl phosphine) rhodium carbonyl hydride according to the following general scheme: ##STR2##
Other preferred direct methods of complex preparation include the reaction of transition metal carbonyls or oxides, such as those of rhodium with thesilylalkyl phosphine ligand and Co/H.sub.2. Specifically preferred is the use of dicarbonyl acetylacetonate rhodium to form the subject process complex is in which excess silyl phosphine ligand is reacted with the carbonyl complex and the resulting complex reduced with hydrogen. Organic salts of transition metals such as acetates can also be reacted with the ligand.
The complexes can also be prepared via an indirect method by reaction of the corresponding complexes of a triaryl phosphine, preferably triphenyl phosphine, with the desired silylalkyl phosphine ligand, as defined hereinabove, preferably in excess, e.g.,
(.phi..sub.3 P).sub.3 Rh(CO)H+3.phi..sub.2 PQSiR.sub.3 .fwdarw.(.phi..sub.2PQSiR.sub.3).sub.3 Rh(CO)H+3.phi..sub.3 P
This ligand exchange method is one of the preferred embodiment in the process. The above ligand exchange methods involving dicarbonyl acetylacetonate rhodium and (PH.sub.3 P).sub.3 Rh(CO)H can be preferably used to form the active catalyst in situ during the process, especially during hydroformylation. The silyl ligand used is [(Ar.sub.2 PQ).sub.y Si.sub.4-y ], as defined herein.
In the case of rhodium catalysts, it is essential that the final complex formation be conducted in the absence of reactive halogen, i.e., metal bound halogen. Presence of halide in rhodium hydroformylation has been found to lead to severely reduced catalytic activity. Preferably less than1 ppm by weight of halide ion, e.g., chloride ion, is present per gram of phosphine ligand in the reaction medium.
The above methods are also applicable to forming useful complexes in the subject process where the metal is Fe, Co, Ru, Os and Ir.
In general, the silylalkyl diaryl phosphine ligands are more basic than thecorresponding triaryl phosphines. This basicity difference is a positive factor in the above ligand substitutions providing the novel, completely or partially exchanged complexes, e.g., ##STR3##
The intermediate silylalkyl phosphine ligands employed in the present invention are prepared by any number of standard techniques. U.S. Pat. No.3,907,852 and U.S. Pat. No. 4,083,803 to Oswald and Murrell and G.B. No. 925,721 to Niebergall are representative of techniques which may be successfully employed to prepare the intermediates.
One preferred synthesis technique involves the addition of diaryl phosphines to unsaturated silanes: ##STR4##wherein k ranges from 0 to 28 and y ranges from 1 to 4. Such additions are preferably carried out via a radical mechanism in a free radical manner employing either a chemical initiator such as azobisisobutyronitrile, or radiation initiator. It is preferred that such reactions be conducted in the presence of from a 5 to 100% excess over the stoichiometric amount required of the phosphine. Use of this excess has been found to improve the selectivity of the process.
It has also been observed that additions of phosphines to vinylic silanes (k=0) occur with ease in the presence of radiation particularly ultraviolet light. The reactivity of the vinyl silanes is in marked contrast to the rather sluggish behavior of the olefins having analogous structures. In addition to the vinyl silanes, allyl silanes (k=1) are another preferred class of reactant.
Another technique which may be employed in the preparation of the silyl hydrocarbyl phosphine intermediate involved in the present invention is the addition of silanes to unsaturated phosphines: ##STR5##wherein k ranges from 0 to 28 and y ranges from 1 to 4.
These additions occur in an anti-Markovnikov manner via the mechanism discussed by C. Eaborn in the monograph "Organosilicon Compounds," Academic Press, Inc., Publishers, New York, 1960, and in the patent references previously identified. Again, the preferred reactants are the vinylic and allylic materials, this time the phosphines.
Other methods for silylalkyl phosphine preparation employ displacement reactions. One type of reaction starts with phosphides, particularly alkali metal phosphides, and chloro-, bromo-, or iodo-alkyl silanes:
yAr.sub.2 PME+[--(CH.sub.2).sub.m ].sub.y SiR.sub.4-y .fwdarw.[Ar.sub.2 P(CH.sub.2).sub.m ].sub.y SiR.sub.4-y +Mez
wherein Me is Na, K, Li; m is 1 to 30; Z is Cl, Br, I. It is important thatmonophenylalkylphosphine be absent to insure high reactivity and purity of the final product. Another technique starts with diaryl chloro or bromo phosphines and the corresponding Grignard derivatives of the silicon compounds:
Ar.sub.2 P--+[--Mg(CH.sub.2).sub.m ].sub.y SiR.sub.4-y .fwdarw.[Ar.sub.2 P(CH.sub.2).sub.m ].sub.y SiR.sub.4-y +yMg--.sub.2
wherein -- is chlorine, bromine. Particular care is to be taken to remove all impurities containing reactive halogen, e.g. by the extraction of the product by aqueous caustic.
CARBONYLATION PROCESSES EMPLOYING HOMOGENEOUS SILYLALKYL PHOSPHINE-TRANSITION METAL COMPLEX CATALYSTS
It has been discovered that carbonylation reaction, particularly hydroformylation reactions, which involve the reaction of unsaturated organic compounds with CO, or CO and hydrogen mixtures can be successfullypracticed in the presence of catalytically effective amounts of silylalkyl diaryl phosphine-Group VIII Transition metal complexes, described hereinabove. Carbonylation reactions are described in detail in the earlier referred to Falbe monograph. Main types of carbonylation reactionscatalyzed by the present complexes are the Roelen reaction (hydroformylation) of olefins with CO and H and subsequent aldolization reactions; the Reppe reaction (metal carbonyl catalyzed carbonylation) mainly of olefins, acetylenes, alcohols and activated chlorides with CO alone or with CO plus either alcohol or amine or water; and ring closure reactions of functional unsaturated compounds such as unsaturated amides with CO. The organic reactants are preferably olefinically unsaturated compounds, more preferably olefinic hydrocarbons.
The most preferred type of carbonylation reaction, encompassed within the scope of the subject invention process, is a selective hydroformylation comprising reacting a C.sub.n olefinically unsaturated compound with a mixture of carbon monoxide and hydrogen in the presence of a hydrocarbyl silylalkyl diaryl phosphine halogen free rhodium complex as a catalyst, asdescribed hereinabove, to produce mainly a C.sub.n+1 aldehyde, preferably via hydroformylation at the less substituted vinylic carbon. By the term "C.sub.n ", as used herein, is meant an olefinically unsaturated compound containing "n" carbon atoms. By the process of hydroformylation, through which the elements of formaldehyde, i.e., H and CHO, are added to a doublebond linkage, a C.sub.n olefinically unsaturated organic compound will be converted to a C.sub.n+1 aldehyde, assuming hydroformylation of one doublebond. Where said C.sub.n compound contains more than one double bond, the carbon number will be increased by one for each double bond undergoing hydroformylation. Thus, multiple hydroformylation of a diolefin and higheris also encompassed within the intent of this subject process. Where said C.sub.n+1 aldehyde further undergoes aldolization, the resulting compound is termed herein, a C.sub.2n+2 aldol aldehyde. In addition to the aldol aldehyde, higher aldehydes are also formed, such as trimers, tetramers andthe like.
Preferred catalysts for use in the subject hydroformylation process are of the formula:
{[(C.sub.6 H.sub.5).sub.2 P(CH.sub.2).sub.m ].sub.y SiR.sub.4-y }g[Rh(CO)H]
wherein m ranges from 1 to 30, preferably 2 to 14, most preferably 2 to 3; y ranges from 1 to 4, preferably 1 or 2, most preferably 1; g is 2 to 3, most preferably 3; R is C.sub.1 to C.sub.6 alkyl or phenyl, preferably methyl, ethyl, n- or i- propyl or phenyl.
Specific preferred catalysts are:
{[(C.sub.6 H.sub.5).sub.2 P(CH.sub.2).sub.2 ].sub.2 Si(CH.sub.3).sub.2 }.sub.3 [Rh(CO)H];
{[(C.sub.6 H.sub.5).sub.2 P(CH.sub.2).sub.2 ]Si(CH.sub.3).sub.3 }.sub.3 Rh(CO)H;
{[(C.sub.6 H.sub.5).sub.2 PCH.sub.2 CH.sub.2 ].sub.3 SiCH.sub.3 }.sub.3 Rh(CO)H; and
{[(C.sub.6 H.sub.5).sub.2 PCH.sub.2 CH.sub.2 ].sub.4 Si}.sub.3 Rh(CO)H;
and particularly the first two species.
Particularly in the case of the rhodium complex hydroformylation catalysts,organic solvents, other than simple hydrocarbons can be used which are preferably of weak, nonsubstituting ligand character. Representative solvents include triaryl phosphines, such as triphenyl phosphine, triaryl stibines; triaryl arsines. Other representative organic solvents are ketones such as acetophenone, diphenyl ketone; hydrocarbyloxyethyl alcohols, including phenoxyethanol, and methoxytriglycol; polyethylene glycol, 2-ethylhexylacetate, dipropyl adipate, ethylene glycol diacetate, 1,4-butanediol, dimethyl formamide, n-methylpyrrolidine, 4-hydroxybutyl-2-ethylhexanoate, organic silicone compounds such as diphenyl dipropyl silane, and the like. More preferred ligand solvents aretriaryl phosphines, or an excess of the same silylalkyl phosphine ligand [(Ar.sub.2 PQ).sub.y Si.sub.4-y ], as described hereinabove, which is complexed with the (MX.sub.n)s group. In general, the preferred solvents, particularly the ligands, stabilize the catalyst system and increase its selectivity, particularly the ratio of linear versus branched products.
In case of continuous hydroformylations of olefins, particularly higher olefins, ethylene wherein the volatile primary aldehyde reaction products are continuously removed, the nonvolatile secondary condensation products tend to become the main solvents. Such inert, nonvolatile oxygenated organic solvents, preferably of carboxylic ester and alcohol character, are advantageously used.
The hydroformylation of olefins can be advantageously run in the present process in a manner coupling it with aldol condensation. The catalyst useful in combined hydroformylation-aldolization is the rhodium catalyst complex of the above-described general subject formula. For example, in the case of butene-1, the following conversions can be carried out in a combined process: ##STR6##To realize such a conversion of a C.sub.n olefin to an unsaturated or saturated C.sub.2n+2 aldol aldehyde, the present catalyst systems preferably contain a base aldol condensation catalyst such as KOH. A preferred concentration of the base, i.e., alkali hydroxide, is between about 0.01 and 1%, and preferably between 0.05 and 0.5 wt% of the total reaction mixture.
To insure high n.i. ratios in the process, preferably ether alcohols are utilized as solvents such as methoxytriglycol, phenoxy-ethanol and the like to insure preferably a homogeneous reaction medium.
Further details of the process include the necessary use of an isolation/recovery step wherein at least a portion of liquid reaction mixture is removed from the reaction zone in the process and recovering the product C.sub.2n+2 aldehyde, thereby conventional methods. Hydrogenated products of the resulting aldol aldehydes are also formed in the reaction mixture, which can be insolated. A preferred catalyst for usein the process is tris(2-trimethylsilylethyl diphenyl phosphine) rhodium carbonyl hydride. Preferably the H.sub.2 /CO molar ratio is greater than three, the ligand/Rh metal molar ratio is greater than 140, and the temperature is between 120.degree.-175.degree. C. Further description of the details of the general process using similar Rh-type catalysts can be found in Ser. No. 120,971 and PCT No. US80/00213, published Aug. 21, 1980,both hereby incorporated by reference.
HYDROFORMYLATION PROCESS CONDITIONS
The carbonylation processes catalyzed by the present silylalkyl phosphine catalysts described herein can be carried out advantageously under the usual reaction conditions such as those described in the earlier referenced Falbe monograph.
The reaction and particularly the rhodium complex catalyzed hydroformylation of olefinic compounds, preferably olefins in the 2 to 40 carbon range, especially olefinic hydrocarbons such as mono-, di- and triolefins can be advantageously carried out, however, over a broad range of process conditions. This above-stated carbon range is not limiting, however, since uncross-linked polybutadiene of MW up to 15,000, and the like, is also operable.
The olefinic reactants in the present hydroformylation process can be terminally or internally unsaturated and be linear or branched open chain or of cyclic structure. The internal olefins must contain at least one, preferably two, hydrogens on the vinylic carbons. Details of olefin reactivities are incorporated by reference to Ser. No. 120,971. Terminallyolefinic reactants, particularly alpha-olefins are preferred. Among the most preferred olefin reactants are C.sub.2 to C.sub.12 olefins. Representative examples include 1-tricosene, cyclohexane, ethylene, propylene, butenes and pentenes, hexenes, octenes, decenes, dodecenes, andthe like particularly propylene, 3-methylbutene-1, butene-1, butene-2, including cis and trans isomers, isobutylene, 2-ethylexene-1, octene-1, hexene-1, hexene-3, pentene-1, octene-1, ethylene, and mixtures thereof. Particularly preferred are propylene, butene-1 and mixtures thereof with butene-2.
Exemplary diolefin reactants are divinyl cyclohexane and 1,7-octadiene. Di-and polyolefin reactants are preferably non-conjugated in character.
Substituted olefinic reactants can be also advantageously used as long as the substitutent does not interfere with the catalyst system and is stableunder the reaction conditions. Exemplary substituted olefins are acrylonitrile, methyl acrylate, trivinyl cyclohexane acrolein dimethyl acetal, allylacetate, allyl t-butylether allyl alcohol, methyl oleate, 3-butenyl acetate, diallyl ether, allyl chlorobenzene, dicyclopentadiene, 6-hydroxyhexene.
It is to be noted that refinery streams of olefins, containing paraffins, inert gases, or entrained inert aromatics, are also applicable within the scope of this invention process.
The hydroformylation of a C.sub.n olefin, with the exception of ethylene, leads to a mixture of terminally and internally substituted C.sub.n+1 aldehydes. For example, the hydroformylation of propylene leads to a mixture of iso- and n-butyraldehydes and hydroformylation of butene-1 leads to a mixture of C.sub.5 aldehydes, n-valeraldehyde and isovaleraldehyde, said mixtures having an "n/i" ratio of products. The subject process, in general, can yield high n/i ratios during hydro formylation of about 4:1 and higher.
Concentrations of the transition metal complex catalysts and particularly the preferred rhodium complex catalysts can be employed in the range of about 1.times.10.sup.-6 to 1.times.10.sup.-1 mole metal complex per liter of reaction mixture. Preferred concentrations are in the range of 1.times.10.sup.-5 to 1.times.10.sup.-1 molar and more preferably, 1.times.10.sup.-4 to 1.times.10.sup.-2 molar. The catalyst concentrations used are directly affected by the concentration of free ligand present, especially the excess silylalkyl phosphine ligand. In general, the higher the ligand concentration, the higher the metal level required for a certain reaction rate. In addition to the above-stated ranges, higher and lower levels of complex catalyst may be effectively employed in the process.
The amount of tertiary organo phosphine ligand used in the process can be from about 1 to 95 weight percent of the entire reaction mixture, which includes tertiary phosphine used in the silyl complex and an amount of excess phosphine. Preferably, the amount of excess ligand in the reaction mixture is from about 10 wt. percent to about 65 weight percent. Concentrations of the excess phosphine ligand can be from 0.2 to 3, preferably 0.5 to 2.7, or most preferably 0.5 to 1.5 phosphine equivalent per liter. In the case of trimethylsilylethyl diphenyl phosphine, the latter range means a weight concentration ranging from about 14 to about 47%. At an appropriate rhodium concentration, the reaction can be carried out using the excess phosphine as the solvent. However, in general, the phosphine concentration is limited to 75 weight percent of the reaction mixture. Sufficient excess phosphine concentration is used in the preferred process to carry out the reaction at the desired temperature under the desired conditions with the desired selectivity and activity maintenance. The rhodium complex concentration is then adjusted to achievethe desired reaction rate.
The mole ratio of total tertiary phosphine ligand to mole equivalent rhodium complex, L/Rh, is generally above 100, preferably being above 120,more preferably above 240, most preferably above 400. In general, higher ratios are selected when the desired operation is a continuous, rather than a batchwise operation. However, there may be instances where very lowL/Rh ratios below 100 are desired and these also are encompassed within thescope of this invention.
In general, ligands of high phosphorus content are desired to achieve the required phosphine equivalency by using the minimum weight. However, to reduce the volatility of the phosphine ligands, phosphines of high molecular weight are desired. These two factors can be best compromised, for example, by using non-chelating bis-phosphine and polyphosphine ligands such as (Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 and(PH.sub.2 PCH.sub.2 CH.sub.2).sub.3 SiCH.sub.3.
The selectivity of the present rhodium complex hydroformylation catalysts generally also depends on the molar ratio of the gaseous H.sub.2 and CO reactants. To keep the partial pressure of CO desirably low, this H.sub.2 /CO ratio is generally above about 1 and preferably between 2 to 100, and preferably between 2 and 20.
The present process can be suitably operated at low total process pressures. Generally desired pressures are between about 15 and 1000 psia,and more preferably between about 55 and 500 psia.
The above pressure limitations reflect a moderate sensitivity of the rhodium complex catalyst employed to the partial pressure of CO used. Although higher values can be effectively used, the total partial pressureof CO in the feedstream is preferably less than about 400 psia more preferably less than 100 psia, and most preferably in the range of 50-1 psia. In general, when the CO partial pressure is too high and the phosphine concentration is too low, the catalyst complex can become deactivated due to the formation of carbonyl derivatives.
The partial pressure of hydrogen in general has no critical upper limit by itself from the viewpoint of hydroformylation. Preferred partial pressure of hydrogen are between about 50 and 300 psia, although higher and lower partial pressures are also operable. When the H.sub.2 /CO ratio is too high and/or the CO concentration is insufficient, however, the relative rates of competing hydrogenation and isomerization reactions tend to increase.
In the upper temperature range of the present process, i.e., 130.degree.-200.degree. C. a significant part of the total pressure can bemaintained by the addition to the olefin feedstock of either a volatile, reactive or unreactive olefin, such as butene-2, or a saturated, aliphatichydrocarbon, such as C.sub.1 to C.sub.40 paraffinic hydrocarbon, or aromatic hydrocarbon, or by an inert gas. A preferred mode of operation incorporates a paraffinic hydrocarbon in the olefin feed and allows a facile continuous product flashoff while assuring a higher solubility of the gaseous reactants in the liquid reaction mixture. A C.sub.1-C.sub.12 and preferably, C.sub.1-C.sub.5, paraffin possesses higher volatility and thus is especially preferred for the hydroformylation of C.sub.2 to C.sub.5 olefins.
The operation of the present process can be optimized in a surprisingly broad temperature range. The range of temperature is preferably between 50.degree. and 200.degree. C., and preferably between 120.degree. and 175.degree. C. In addition, our novel catalysts are operable above 145.degree. C. to 170.degree. C. for the hydroformylation of C.sub.4 and higher olefin. Compared to the TPP catalyst system, the maintenance of thecatalyst activity and selectivity at the highest temperatures is particularly unique. High rates of selective hydroformylation of 1-n-olefins can be realized and maintained to high conversion at 145.degree. C. when using the present catalyst.
The present hydroformylation process can be carried out either in the liquid, vapor or in the gaseous state. A preferred process employs a liquid, more preferably homogeneous liquid, reaction phase with the present catalyst system dissolved, i.e., homogeneous catalyst.
CATALYTIC INTERMEDIATES IN RHODIUM HYDROFORMYLATION
The silyl alkyl diaryl phosphine rhodium complex catalyst compositions of the present process were previously disclosed and exemplified. From the view-point of selective hydroformylation, it is emphasized that in solution, and particularly under reaction conditions, the tris- and bis-phosphine rhodium complexes are present.
While we do not wish to be bound by the following theory, it is believed that the equilibration of tris- and bis-phosphine rhodium carbonyl hydridecomplexes as established via 31 P nmr studies: ##STR7##is related to the activity and selectivity of the present catalyst according to the mechanism shown by FIG. 1.
Equilibration of the stable tris-phosphine complex to provide some of the highly reactive, coordinatively unsaturated trans-bis-phosphine is to occur in an active catalytic system. However, it is believed that in the case of stable selective catalysts, most of the rhodium is present in the stable tris-phosphine complex form.
The equilibration involves the reversible elimination and addition of a phosphine ligand. Its rate was found to depend on the temperature. As such, it was determined by 31 P nmr. It was also found that the maintenance of the equilibrium on the tris-phosphine side and the stabilization of the system, require an excess concentration of the phosphine ligand. The maintenance of the yellow color of catalyst solutions and the high selectivity of hydroformylation indicated the stability of the complex catalyst.
Comparative 31 P nmr studies of the known TRP catalyst plus TPP system showed that its mechanism is similar. However, the thermal activation and catalyst destabilization of this system occurs at lower temperatures (FIG.3). In other words, the present tris(silyl diaryl phosphine) rhodium carbonyl hydride plus excess phosphine based systems are suprisingly improved high temperature catalysts.
The stronger complexation of the trihydrocarbyl silyl alkyl diaryl phosphine ligands to form the corresponding tris-phosphine rhodium carbonyl hydride complexes could also be established in competitive complexation with triaryl phosphines (FIG. 2). When equimolar amounts of the two different phosphines, such as SEP and TPP were used, mostly the tris-SEP rhodium carbonyl hydride was formed. However, there were some tris-phosphine complexes containing both types of ligands. When the ratio of SEP to TPP was about 6, only the spectrum of the tris-SEP complex was observed. When the SEP to Rh ratio was 10 or higher, even a large excess of TPP, e.g. TPP/Rh ratio 100, would not lead to the formation of the tris-TPP complex.
The coordinatively unsaturated trans-bis-phosphine rhodium carbonyl hydridecan react with both olefins and carbon monoxide in a reversible manner. Complete reaction with CO leads to the formation of nonselective catalyticintermediates, i.e., mono-phosphine dicarbonyl hydrides ##STR8##and/or irreversible catalyst deactivation (see FIG. 1).
It was found, via further 31 P nmr studies of catalyst solutions under pressure of synthesis gas of varying H.sub.2 /CO ratio, that the ratio of monocarbonyl versus dicarbonyl complexes was increased by employing a highratio of H.sub.2 /CO and a high excess of the phosphine ligand. Comparativestudies of the SEP versus TPP catalyst system have shown that the TPP system had a higher tendency to form the undesired dicarbonyl complexes.
The results of 31 P nmr studies of the tris-phosphine rhodium complex formation were correlated with catalyst activity. Those silylalkyl diphenyl phosphines, which do not form tris-phosphines at room temperature, are not preferred ligands for the present selective catalysis. Substitution of the .alpha.-carbon and multiple substitution ofthe .beta.-carbon of the alkyl group Q in the generic branch and o-o'-substitutions of the aryl groups Ar, generally interfere with complete complexation because of steric hindrance, i.e., the desired catalyst formation.
CONTINUOUS HYDROFORMYLATION
Due to the improved thermal stability of the silyl alkyl diaryl phosphine rhodium complex catalysts, a continuous mode of operation is particularly preferred for olefin hydroformylation. When using a homogeneous liquid catalyst system, such an operation can be of a continuous plug flow type, including a step for catalyst recovery and then recirculation. A quasi continuous use of the catalyst may consist of the cyclic operation of a unit for hydroformylation and then for product flashoff. Catalyst concentration by continuous product flashoff or other methods of catalyst recovery may involve complete or partial recycle, such as "recycle flashoff process" and by this term is meant separation/isolation of products out of the reactor by means fo drawing off liquid reaction mixture and conducting separation by conventional techniques, e.g., distillation under reduced pressure, generally under different process conditions, than those which are present in the reactor. However, a preferred method of operation involves continuous product flashoff, wherein the mixture of product aldehydes is continuously removed from the vapor phase of the reaction mixture.
In the present continuous product flashoff process, the aldehyde product ofthe hydroformylation is continuously removed as a component of a vapor mixture while the CO, H.sub.2 and olefin reactants are continuously introduced. This process preferably includes the recirculation of most of the unreacted reactants in the gaseous state and the condensation and thereby removal of most of the aldehyde and aldehyde derivative products. Additional olefin, CO and H.sub.2 are added as required to maintain aldehyde production and optimum process parameters. The space velocity of the gas stream is appropriately adjusted and additional gas purge is used as required to maintain production and catalyst activity. Since the rhodium complex is not volatile, no catalyst losses occur. If the phosphine ligand is volatile, additional phosphine is added occasionally to maintain its concentration in the reaction mixture.
Also, an embodiment of this invention is a process for continuous hydroformylation which comprises reacting a C.sub.2 to C.sub.6 olefin, preferably a 1-n-olefin and particularly preferred olefins being propyleneand butene-1, with CO and H.sub.2 in the presence of a tris- and bis-(silylalkyl diaryl phosphine) rhodium carbonyl hydride catalyst as described above and in the presence of excess phosphine ligand. According to this method, reactants, preferably all the reactants, are continuously introduced into a reactor comprising dissolved catalyst and ligand in a liquid reaction mixture having preferably no added solvent and wherein at least some, preferably most, of the aldehyde products being a mixture of C.sub.5 aldehydes where butene-1 is the reactant, are continuously removedin the vapor phase. It is preferred in this process to have at least some of the reagents and products recirculated. The process is carried out by having an appropriately limited partial pressure of carbon monoxide, preferably below 200 psi and appropriately high concentration of excess phosphine ligand relative to the catalyst complex, preferably above 1 weight percent, more preferably above 5 weight percent. These improvementsproduce and maintain an effective catalyst system of high selectivity to aldehyde products.
Specifically preferred embodiments included in the above description is wherein the process is a continuous hydroformylation process for converting butene-1 to a mixture of C.sub.5 aldehydes, or converting propylene to a mixture of butyraldehydes preferably having an n/i ratio ofabove about 4:1, wherein said catalyst is [(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 ].sub.3 Rh(CO)H, and said product aldehydes can be continuously removed from the vapor phase of said reaction mixture or recovered by recycle flashoff as described herein.
During the continuous product flashoff operation, relatively non-volatile aldehyde oligomers are formed and concentrated in the liquid reaction mixture. The oligomeric hydroxy substituted carboxylic ester condensation and redox disproportionation products formed during propylene hydroformylation were disclosed in U.S. pat. No. 4,148,830 by Pruett and Smith. This recent patent of Pruett and Smith claims the use of aldehyde condensation products as solvents in triphenyl phosphine (TPP) rhodium complex catalyzed alpha-olefin hydroformylation. Another recent patent by Brewester and Pruett, i.e., U.S. Pat. No. 4,247,486, claims a TPP-Rh complex catalyzed continuous product flashoff process in such solvents.
In the present work, it was found that derivatives, mainly trimers, analogous to the butyraldehyde trimers, are formed during 1-butene hydroformylation from valeraldehydes. The general structure of the isomeric trimers formed during the hydroformylation of C.sub.3 to C.sub.6 is the following: ##STR9##wherein R is C.sub.2 to C.sub.5, preferably C.sub.3 alkyl.
The above aldehyde trimer is generally the main derivative and at the equilibrium conditions of the preferred continuous flashoff process, it can automatically become the main solvent component. When this occurred during 1-butene hydroformylation with the present catalysts, selectivity and production rate could be maintained and the concentration of the trimer could be limited to an equilibrium value.
In the continuous product flashoff operation, carbonylations, especially the hydroformylation of olefins is advantageously carried out at a low olefin conversion, preferably at a 20 to 80% olefin conversion. Aldehyde production rates are preferably between 0.1 to 5 g mole/liter/hour, more preferably beween 0.5 and 2 g mole/liter/hour. The loss of catalyst activity is preferably less than 0.3% per day.
Operating in this manner, with optimized reactant ratios, particularly highlinear to branched aldehyde product ratios are obtained from 1-n-olefins.
The continuous process can be also employed for the selective or complete conversion of different types of olefins. For example, a mixture of 1- and2-butenes can be hydroformylated to produce mainly n-valeraldehyde and 2-butene. Similarly, a mixture of 1-butene, 2-butene and i-butene can be converted selectively to varying degrees. The olefin feedstream can also contain C.sub.1 -C.sub.40 paraffinic hydrocarbons, preferably C.sub.1 -C.sub.12 and more preferably C.sub.1 -C.sub.5 paraffinic hydrocarbons.
Using the present catalysts of improved thermal stability, the application of continuous or batch flashoff processes can be extended to higher olefins lieading to non-volatile products. The preferred olefins for continuous product flashoff are of the C.sub.2 to C.sub.6 range and n-1-olefin type. 1-Butene is a particularly preferred reactant.
A further embodiment of the subject process is a combined isomerization-hydroformylation process wherein an internal olefin, such asbutene-2, is catalytically isomerized to provide an equilibrium mixture containing a terminal olefin, i.e., butene-1, which is then preferentiallyhydroformylated.
Catalysts capable of performing both functions are preferably cobalt catalysts of the formula:
[(Ar.sub.2 PQ).sub.y SiR.sub.4-y ].sub.g . (CoX.sub.n).sub.s
wherein Ar, Q, y, R, g, X, n, s are as defined hereinabove.
The process can be conducted under generally the same process conditions asdescribed in the previously referred Falbe monograph, for hydroformylation with respect to temperature, pressure, H.sub.2 and CO partial pressures, catalyst and excess ligand concentrations, batch and continuous mode operations, and the like. It is particularly preferred to have temperatures between 150.degree. and 200.degree. C. and pressures between 500 to 2000 psia.
A peferred catalyst for use in this embodiment is [Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ]Co(CO).sub.3 H, and a preferred internal olefin reactant being butene-2, being converted to butene-1.
The following examples are illustrative of the best mode of carrying out the invention process, as contemplated by us, and should not be construed to be limitations on the scope or spirit of the instant invention.
EXAMPLES
I Preparation of Silylalkyl Diaryl Phosphine Ligands
Examples 1-8
The silylalkyl diaryl phosphine ligand components of the present rhodium complexes were prepared during the present work.
The generally employed method for ligand preparation was the free radical chain addition of diphenyl phosphine to a vinylic compound in an antiMarkovnikov manner.
Ph.sub.2 PH+CH.sub.2 .dbd.CHR.fwdarw.Ph.sub.2 PCH.sub.2 CH.sub.2 R
As a rule, such additions were initiated in a homogeneous liquid phase by broad spectrum ultraviolet light at 15.degree. C. The rate of addition depended strongly on the type of the olefinic compound employed. In general, compounds of vinylic substitution were highly reactive while allylic derivatives were sluggish to react. The reaction times were accordingly varied. The selectivity of the additions could be improved by using more than the equivalent amount, generally 10% excess, of the phosphine adding agent. In the case of vinylic derivatives, this reduced the oligomerization of the unsaturated component. In general, no added solvents were used. During the reaction, the conversion of reactants to products (and by-products) was followed by gas liquid chromatography (glc)and/or proton magnetic resonance spectroscopy (pmr). Usually the glc peak intensities were used to make quantitative estimates of the compositions. For identification of the product structures mainly nmr was used.
When the desired conversion was reached, the reaction mixture was usually fractionally distilled in high vacuo to obtain the pure adduct product. Most of the pure adducts were clear, colorless, liquids at room temperature. The monophosphines were mobile, the bis-phosphines were viscous.
The expected structures of the isolated products were confirmed by pmr. Elemental analyses were also performed to check the product compositions.
The pure phosphines were studied to determine their basicity, by potentiometric titration and indirectly by .sup.31 p nmr. The results of direct basicity determination will be given in the overview tables, together with the other analytical characteristics of the free phosphine ligands. The .sup.31 p nmr chemical shift values for the free ligands willbe listed as comparative values when discussing the .sup.31 p nmr of their rhodium complexes.
The phosphine basicity determinations via potentiometric titrations were performed according to the method of C. A. Streuli. For reference see Analytical Chemistry, Vol. 31, pages 1652 to 1654 in 1959 and Vol. 32, pages 985 to 987 in 1960. Half neutralization potentials (HNP's) of the phosphines were determined using perchloric acid as a titrant and pure nitromethane, free from weakly basic impurities, as a solvent. The values obtained wre subtracted from the HNP of a stronger organic base, diphenyl-guanidine, which served as a daily standard reference. The resulting .DELTA.HNP values of the phosphines are indirectly related to their basicity. In case of phosphines, which were also studied by Streuli,somewhat different .DELTA.HNP values were obtained in the present work. Since ion exchange resin purified nitromethane was used in the present work, the reported values should be more correct.
A number of trihydrocarbylsilylethyl and -propyl diphenyl silanes were prepared by adding diphenyl phosphine to the corresponding vinylic or allylic silane. The preparation, physical properties and analytical composition of seven compounds are summarized in Table I. The table also shows the basicity characteristics of the products as characterized by their .DELTA.HNP values. It is noted that all the trihydrocarbylsilylalkyldiphenyl phosphines are much stronger bases than triphenyl phosphine (Ph.sub.3 P: .DELTA.HNP=510).
TABLE I__________________________________________________________________________Preparation, Physical Properties and Composition of Silyl SubstitutedAlkyl Diphenyl Phosphine Ligands LigandEx- Bp, .degree.C.,/am- mm Distd. Elemental Composition, Inverseple Unsaturated (Mp., Yield Calcd. Found Basicity,No. Structure of Ligand Reactant Used .degree.C.) .about.% C H P C H P .DELTA.__________________________________________________________________________ HNP1 Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 CH.sub.2 .dbd.CHSi(CH.sub.3).sub.3.sup.a 115-118/ 81 71.29 8.09 10.81 71.98 8.12 10.59 385 0.0752 Ph.sub.2 PCH.sub.2 CH.sub.2 Si(C.sub.3 H.sub.7).sub.3 CH.sub.2 .dbd.CHSi(C.sub.3 H.sub.7).sub.3.sup.b 155-156/ 63 74.54 9.52 8.36 74.35 9.23 8.37 385 0.103 Ph.sub.2 PCH.sub.2 CH.sub.2 SiPh.sub.3 CH.sub.2 .dbd.CHSiPh.sub.3.sup.c (128- -- 81.32 6.19 6.55 80.97 6.18 6.71 413 131.sup.d)4 (Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 (CH.sub.2 .dbd.CH).sub.2 Si(CH.sub.3).sub.2.sup.a 238-239/ 84 74.35 7.07 12.78 73.65 6.90 12.59 434 0.205 Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 CH.sub.2 .dbd.CHCH.sub.2 Si(CH.sub.3).sub.3.sup.a 150/0.10 50 71.96 8.38 10.31 72.27 8.29 10.25 4086 Ph.sub.2 PCH.sub.2 Si(CH.sub.3).sub.3 [ClCH.sub.2 Si(CH.sub.3).sub.3 ].sup.e 129-130/ 86 70.55 7.77 11.37 70.01 7.64 11.36 404 0.27 (Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 (CH.sub.2 .dbd.CHCH.sub.2).sub.2 Si(CH.sub.3.sup.a).sub. 2 248-250/ 48 74.97 7.45 12.08 74.96 7.45 12.00 420 0.1__________________________________________________________________________ .sup.a The reactant was a purchased chemical reagent. .sup.b The reactant was prepared from tripropyl chloro silane by reacting it with vinyl magnesium bromide. .sup.c The reactant was prepared from vinyl trichloro silane by reacting it with the appropriate Grignard reagent. .sup. d The product was recrystallized from cyclohexanetoluene. .sup.e The product was prepared from chloromethyl trimethyl silane by reacting it with lithium diphenyl phosphide. .sup.f Relative half neutralization potential compared to that of diphenyguanidine.
Accounts of the individual experiments are given in the following.
EXAMPLE 1
Trimethylsilylethyl Diphenyl Phosphine
Ph.sub.2 PH+CH.sub.2 .dbd.CHSi(CH.sub.3).sub.3 .fwdarw.Ph.sub.2 PCH.sub.2 CH.sub.2 SI(CH.sub.3).sub.3
A magnetically stirred mixture of 46.5 g (0.25 mole) diphenyl phosphine and25 g (0.25 mole) of vinyl trimethyl silane, in a closed cylindrical quartz tube, was irradiated from about 3 cm distance with two 75 Watt Hanau tube immersion lamps, with a wide spectrum of ultraviolet irradiation, in a 15.degree. C. water bath for 26 hours. A proton magnetic resonance spectrum of a sample of the resulting mixture exhibited no significant peaks in the vinyl region indicating a substantially complete addition.
The reaction mixture was distilled in vacuo to obtain 61 g (81%) of the desired trimethylsilylethyl diphenyl phosphine adduct, as a clear colorless liquid, having a boiling range of 109.degree.-110.degree. at 0.1mm (Table I).
The selectivity to provide the desired adduct was increased when the diphenyl phosphine reactant was employed in a 10 mole % excess.
EXAMPLE 2
Tripropylsilylethyl Diphenyl Phosphine ##STR10##
To prepare the vinyl tripropyl silane reactant, chloro tri-n-propyl silane was reacted with vinyl magnesium bromide in refluxing tetrahydrofuran.
After removing the THF solvent by distillation, the residual product was taken up in ether, then washed with ice water and then with 5% aqueous sodium hydrogen carbonate. The ether solution was then dried over anhydrous sodium sulfate and distilled to obtain vinyl tripropyl silane, bp. 75.degree.-77.degree. C. at 11 mm.
The vinyl tripropyl silane was then reacted with diphenyl phosphine with u.v. initiation for 86 hours in a manner described in the previous example. The conversion was about 95%. The mixture was fractionally distilled to yield the pure product as a clear, colorless, mobile liquid (see Table I).
EXAMPLE 3
Triphenylsilylethyl Diphenyl Phosphine ##STR11##
To obtain the vinyl triphenyl silane intermediate, vinyl trichloro silane was reacted with phenyl magnesium bromide in an ether-THF solvent mixture.The resulting product was worked up in a manner described in the previous example. The product was a low melting solid which could be distilled in vacuo using a hot condenser. At room temperature, the distillate solidified to yield a white crystalline compound, mp. 60.degree.-65.degree. C. Pmr confirmed the expected vinyl triphenyl silanestructure.
Anal. Calcd. for C.sub.20 H.sub.18 Si: C, 83.86; H, 6.33. Found: C, 83.92; H, 6.34.
The vinyltriphenyl silane was reacted with 10% excess of diphenyl phosphine. To maintain a homogeneous reaction mixture, a temperature of 80.degree. C. and cyclohexane solvent were employed. After the usual u.v. initiated addition, the reaction mixture was allowed to cool to room temperature. This resulted in the crystallization of the triphenylsilylethyl diphenyl phosphine adduct. To obtain it in a pure form, the adduct was filtered and recrystallized from a four to one mixture of cyclohexane and toluene. A white crystalline product having theproperties shown in Table I was obtained.
EXAMPLE 4
Bis-(Diphenylphosphinoethyl) Dimethyl Silane ##STR12##
A mixture of 9.0 g (0.8 mole) dimethyl divinyl silane and 32.7 g (0.176) diphenyl phosphine (10% excess over equivalent amounts) was reacted for 22hours in the manner described in Example 1. The reaction mixture was fractionated in vacuo to obtain minor amounts of a clear, colorless, slightly viscous liquid monoadduct, and major amounts of a clear, colorless, highly viscous liquid diadduct, i.e., the desired bis-(diphenylphosphinoethyl) dimethyl silane (Table I). The latter solidified to a crystalline solid on standing and was readily recrystallized from hexane.
EXAMPLE 5
Trimethylsilypropyl Diphenyl Phosphine
Ph.sub.2 PH+CH.sub.2 .dbd.CHCH.sub.2 SiCH.sub.3).sub.3 .fwdarw.Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3
A mixture of 22.8 g (0.2 mole) allyl trimethyl silane and 27.2 g (0.2 mole)diphenyl phosphine was reacted for 158 hours in the manner described in Example 1. A subsequent fractional distillation, yielded the desired pure adduct as a clear, colorless liquid (Table 1).
EXAMPLE 6
Trimethylsilylmethyl Diphenyl Phosphine
Ph.sub.2 PLi+ClCH.sub.2 Si(CH.sub.3).sub.3 .fwdarw.Ph.sub.2 PCH.sub.2 Si(CH.sub.3).sub.3
The known but unavailable trimethylsilylmethyl diphenyl phosphine was derived via reacting chloromethyl trimethyl silane with lithium diphenyl phosphide in an ether-hexane mixture. After removing the lithium chloride by-product by filtration, the product was isolated as a clear, colorless liquid by fractional distillation in vacuo (Table 1).
EXAMPLE 7
Bis-(Diphenylphosphinopropyl) Dimethyl Silane ##STR13##
A mixture of 70 g (0.5 mole) dimethyl diallyl silane and 204.6 g (1.1 m mole, 10% excess over equivalent amounts) of diphenyl phosphine was reacted in the manner described in Example 1 at 40.degree. C. The additionwas slow. After 24 hours, only about 10% of the diphenyl phosphine reacted.The irradiation of the reaction mixture was continued for a total of 160 hours. A subsequent fractional distillation provided 46 g of monoadduct, as a clear, slightly viscous liquid monoadduct of bp. 122.degree.-134.degree. C. at 0.05 mm and 113 g of the desired diadduct (Table 1) as a clear, light yellow, viscous liquid.
Anal. Monoadduct C.sub.20 H.sub.27 PSi. Calcd.: C, 73.57; H, 8.34, P, 9.59.Found: C, 73.79; H, 8.26; P, 9.66.
EXAMPLE 8
Bis-(Diphenylphosphinoethyl) Diphenyl Silane ##STR14##
About 2 moles of diphenyl phosphine were added sequentially to one mole of divinyl diphenyl silane to yield mostly the desired diadduct which crystallized on standing; recrystallization from heptane provided the pureproduct.
EXAMPLE 9
Tris-(Diphenylphosphinoethyl) Methyl Silane ##STR15##
A mixture of 37.3 g (0.3 mole) trivinyl methyl silane and 175.8 g (0.945 mole) diphenyl phosphine was reacted at 95.degree. C. with u.v. light initiation in quartz pressure tube, in the manner described in Example 1, unitl about 50% of the diphenyl phosphine was converted. A subsequent distillation of the resulting reaction mixture in vacuo under nitrogen resulted in the isolation of the expected adducts.
The monoadduct (29 g) was obtained as a clear, colorless mobile liquid of about pb. 132.degree. C. at 0.05 mm. the diadduct (51 g) was slightly hazy, colorless viscous liquid at room temperature. It distilled at about 240.degree. C. at 0.05 mm. The distillation residue (50 g, 24.5%) mostly consisted of the triadduct.
In another experiment, the reaction mixture was further irradiated until most of the diphenyl phosphine has reacted. The excess diphenyl phosphine (14.5 g) was then recovered from the reaction mixture by vacuum stripping at 220.degree. C. for recrystallization, the residual product was dissolved in a 3 to 2 mixture of hot toluene and methanol to obtain a 28% solution. On cooling to -30.degree. C., the desired triadduct crystallizedand was isolated by filtration with suction and washed with methanol. The dry product weighed 160 g (78%) and melted between 98.degree. and 101.degree. C. A proton nmr spectrum of the product supported the assumed tris-(diphenylphosphinoethyl) methyl silane structure.
EXAMPLE 10
Tetrakis-Diphenylphosphinoethyl) Silane
Si(CH.dbd.CH.sub.2).sub.4 +4 Ph.sub.2 PH.fwdarw.Si(CH.sub.2 CH.sub.2 PPh.sub.2).sub.4
A mixture of 27.2 g (0.2 mole) of tetravinyl silane and 149.5 g (0.804 mole) diphenylphosphine was reacted in a quartz pressure tube at 200.degree. C. with u.v. light initiation until most of the diphenyl phosphine was converted. The hot, molten reaction mixture was added to 720g of hot toluene with stirring. The tetraaduct product precipitated from the solution as a white crystalline solid. The mixture was allowed to coolto ambient temperature and then filtered with suction. After washing with toluene and drying in vacuo, 84 g (47.7%) of crude product was obtained. This was recrystallized from 1200 ml of xylene to obtain 69 g of the pure tetrakis-(diphenylphosphinoethyl) silane of mp. 198.degree.-199.degree. C.
Anal. Calcd. for C.sub.56 H.sub.56 SiP.sub.4 : C, 76.34; H, 6.41; P, 14.06.Found: C, 76.44; H, 6.38; P, 13.71.
Similar additions are carried out using di-4-tolyl phosphine and di-4-fluorophenyl phosphine and the above unsaturated reactants to yield the corresponding ring substituted products.
II Preparation of Tris(Silylalkyl Diaryl Phosphine) Rhodium Carbonyl Hydride Complexes (Examples 11 to 32)
A. Preparation from Rhodium Chloride
EXAMPLE 11
Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride
3Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 +RhCl.sub.3.3H.sub.2 O.fwdarw.[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H
To a vigorously stirred, refluxing, nitrogenated solution of 11.4 g (40 mmol) of tris-(trimethylsilylethyl) diphenyl phosphine of Example 1 in 400ml of ethanol, a hot solution of 1.04 g (0.4 mmole) of rhodium trichloride trihydrate in 80 ml ethanol was added at once. After a delay of 15 seconds, 40 ml warm aqueous (37% formaldehyde solution and, immediately thereafter, 80 ml hot ethanolic solution of 3.2 g of potassium hydroxide were added. The resulting clear orange liquid reaction mixture was refluxed for 10 minutes. During the heating, the color changed to deep orange.
The mixture was cooled to -25.degree. C. to crystallize the complex product. Crystallization started at -10.degree. C. and was completed on standing for about 2 hours at -25.degree. C. The crystalline complex was separated by filtration through a precooled Buechner funnel with suction and washing successively with 20 ml cold portions of ethanol, water, ethanol and n-hexane. The complex was then dried in the presence of anhydrous calcium chloride at 0.1 mm over the weekend. As a result, 2.2 g (2.2 mole, 55%) of dry tris-(trimethylsilylethyl diphenyl phosphine) rhodium carbonyl hydride complex was obtained as a fine crystalline orange-yellow powder. In a sealed capillary tube, the complex melted between 126.degree.-129.degree. C. to a clear dark red liquid. In an open capillary, complete melting occurred at 121.degree. C. There was no sign of decomposition on heating up to 140.degree. C. in either case.
The infrared spectrum of the complex in Nujol showed a strong carbonyl bandof 1985 cm.sup.-1 and a band of medium intensity at 1900 cm.sup.-1.
Analyses Calcd. for C.sub.52 H.sub.70 OP.sub.3 RhSi: C, 63.01; H, 7.12; P, 9.38; Found: C, 62.89; H, 7.06; P, 9.59.
B. Preparation from Tris-(Triphenyl Phosphine) Rhodium Carbonyl Hydride ViaLigand Displacement (Examples 10-19).
EXAMPLES 12-22
Tris-(Silylalkyl Diphenyl Phosphine) Rhodium Carbonyl Hydrides ##STR16##
The tris-(alkyl diaryl phosphone) rhodium carbonyl hydride complexes were prepared by reacting commercially available tris-(triphenyl phosphine) rhodium carbonyl hydride (from Engelhard Minerals and Chemicals Corporation, Newark, NJ) with the corresponding alkyl diaryl phosphines. Generally, the reactions were prefored in a 90 to 10 mixture of toluene and deuterated benzene as a solvent under a nitrogen blanket. The deuterated benzene component was used as a primary nmr standard.
At first, an about 5% solution of the alkyl diaryl phosphine reactant was prepared. To samples of the solution, TPP rhodium carbonyl hydride was added in equivalent and half equivalent amounts. The resulting mixtures were magnetically stirred until homogeneous liquids were obtained. Additional amounts of the toluene solvent were used if needed. The homogeneous reaction mixture was then studied by .sup.31 p nmr spectroscopy, Chemical shifts were measured by assigning a shift of 0 ppm to the frequency at which 1M H.sub.3 PO.sub.4 would resonate.
The .sup.31 p NMR experiments were carried out using a JEOL FX 90Q multinuclear nmr spectrometer. When required, the experimental conditions were adjusted, i.e., the .sup.1 H-.sup.31 p decoupling was removed and longer delays between pulses were employed, to determine the relative populations of free and rhodium bound alkyl diphenyl phosphine and TPP.
In general, three and six moles of a silylalkyl diphenyl phosphine were used per mole of tris TPP rhodium carbonyl hydride. .sup.31 p NMR spectroscopy of the resulting solution showed that the added ligand displaced the TPP. The doublet signal of the bound TPP essentially disappeared and the singlet signal of free TPP appeared instead. In the mixtures having 3 moles of the added silylalkyl phosphine, most of the added ligand was bound and as such exhibited a doublet signal upfield fromthat of bound TPP. Although the doublet of the silylalkyl diphenyl phosphine complexes have chemical shift values different from that of TPP,the coupling constants are about the same for both types of complexes. The coupling constant and chemical shift difference between bound and free ligand indicates that both types of ligands form tris-phosphine rhodium carbonyl hydrides. Finally, it was noted that the mixture having six molesof added alkyl diphenyl phosphine ligand had about equal amounts of free and bound ligand plus the originally bound TPP as additional free ligand.
The nmr parameters of the trihydrocarbylsilylalkyl diphenyl phosphine complexes are shown in Table II (Examples 11-19). The most characteristic parameter is the chemical shift value of the rhodium complexed ligand. Forcomparison, the chemical shift values of the free ligands are also tabulated. Complexation by rhodium of the phosphine apparently produced a similar downfield change of the shift values. Finally, it is also noted inreference to the table, that even the limited exposure of the rhodium complexed phosphines to air resulted in some oxidation to the corresponding phosphine oxides. The latter exhibited sharp singlets slightly upfield from the complexed phosphine, in general.
The data of Table II show that, with the exception of the sixth compound all the phosphine ligands form similar, well characterizable complexes at room temperature. The line shapes of the signals showed little but varyingbroadening, i.e., ligand exchange.
The .sup.31 p nmr parameters were similarly determined for the rhodium complexes of triethylsilylethyl diphenyl phosphine, tris-(diphenylphosphinoethyl) methyl silane and tetrakis-(diphenylphosphinoethyl) silane. The monophosphine complex exhibited a simple doublet of .sigma.34.7 ppm and J P-Rh of 151 cps. The tris-phosphine complex showed a more complex signal of what appeared to betwo doublets having chemical shifts of 35.3 and 36.8 ppm and identical coupling constants of 154 cps. Finally, the tetraphosphine complex gave aneven more complex signal, apparently consisting of three doublets, having the following chemical shift values and coupling constants: 37.6 (154); 37.0 (151) and 35.9 (149) [Examples 21 and 22].
EXAMPLE 23
Mixed Tris-Phosphines Rhodium Carbonyl Hydride Complex Species in TPP and/or SEP Based Catalyst Systems ##STR17##
TABLE II__________________________________________________________________________.sup.31 P Nuclear Magnetic Resonance Parameters of Free andRhodium-Complexed Trihydrocarbylsilylalkyl Diphenyl Phosphines Coupling Chemical Chemical Shift Chemical Shift Constant, Shift DifferenceExample Example .delta., ppm P--Rh .delta., .DELTA..delta., ppmNo. of No. of Free Complexed Complexed Phosphine ComplexComplex Ligand Chemical Structure of Complex Ligand Ligand Ligand Oxide Ligand__________________________________________________________________________-- -- (Ph.sub.3 P).sub.3 Rh(CO)H(Reference) -7.5 +38.3 155 45.813 1 [Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 -12.2)H +34.6 150 +27.0 46.714 2 [Ph.sub.2 PCH.sub.2 CH.sub.2 Si(C.sub.3 H.sub.7).sub.3 ].sub.3 Rh(CO)H -11.2 +34.8 151 +29.9 46.015 3 (Ph.sub.2 PCH.sub. 2 CH.sub.2 SiPh.sub.3).sub.3 Rh(CO)H -10.6 +35.5 151 +21.1 46.116 4 [(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub. 2 ].sub.3 [Rh(CO)H] -12.2 +35.1 150 +27.2 47.317 5 [Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H -19.7 +26.6 154 +24.6 46.318 6 (Ph.sub.2 PCH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H -24.4 +17.0 .sup. 133.sup.a +23.9 41.419 7 [(Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2).sub.2 Si(CH.sub.3).sub.2 ].sub.3 Rh(CO)H 19.5 26.5 156 46.220 8 [(Ph.sub.2 PCH.sub.2 CH.sub.2).sub.2 SiPh.sub.2 ].sub.3 -11.6)H 35.3 151 27.2 46.9__________________________________________________________________________ .sup.a The .sup.31 P--.sup.103 Rh coupling was not resolved at room temperature but was clearly resolved at -60.degree. C.
As it is illustrated by the above reaction scheme, the displacement of the triaryl phosphine ligands from their tris-phosphine rhodium carbonyl hydride complexes is a stepwise reaction. The scheme indicates that 2 "mixed phosphine complexes" are intermediates in such displacements. Each of these complexes should exhibit two doublet .sup.31 P nmr peaks with further P-P splitting.
Starting with the tris-TPP complex, experiments were carried out with varying amounts of the SEP ligand to determine what ranges of SEP/TPP ratios will result in major amounts of mixed complexes. These studies werecarried out in the manner described in the previous example. However, to slow down ligand exchange they were carried out at -60.degree. C. This should improve the detection of minor complex species. The results are illustrated by FIG. 2.
For reference, FIG. 2 shows the .sup.31 P nmr spectra of the TPP and SEP complexes in the presence of a three-fold molar excess of TPP and SEP, respectively. These spectra are to be compared with that of two mixtures containing a low and a high ratio of SEP to TPP.
The first mixture contained 2 moles of SEP and 3 moles of TPP per rhodium. Its spectrum has shown that, nevertheless, the tris-SEP complex was a primary component. There are four other major doublets in the complex spectrum of this mixture. These are apparently due to the two mixed phosphine complexes. It is interesting to observe that there are no significant amounts of the TPP complex present. Accordingly, there are major amounts of the free TPP and the minor amounts of the free SEP ligand. As it is indicated by the line broadening of the free SEP peak, the ligand undergoes a fast ligand exchange with the mixed complexes, evenat -60.degree., i.e., faster than TPP.
The second mixture contained 60 moles of SEP ligand per 30 moles of TPP andone atom of Rh. This means a SEP to TPP ratio of 20. At this high ratio, only the doublet signal of the tris-SEP complex is exhibited. All the triphenyl phosphine shows up as being free. Its extremely narrow peak indicates that there is essentially no participation by TPP in the ligand exchange process.
EXAMPLE 24
Comparative Rates of the Formation of bis-TPP and bis-SEP Rhodium Carbonyl Hydrides Via the Thermal Dissociation of Their Respective Tris-Phosphine Complexes
In the case of the tris-(trimethylsilylethyl diphenyl phosphine), tris-SEP,rhodium carbonyl hydride complex, there was moderately slow ligand exchangebetween free and complexed phosphines as indicated by the broadening of the .sup.31 nmr signals. The exchange mechanism is illustrated for the SEP complex by the following: ##STR18##as indicated by this mechanism the exchange rates are directly related to the rate of the dissociation of the tris-phosphine complex.
The line shapes of signals for the SEP complex and the known TPP complex are compared by FIG. 3 at various temperatures. At first, the 30.degree. C. spectra will be discussed. These spectra indicate that at 30.degree. C., there is a similar, ligand exchange rate between the new SEP and the known TPP complex.
The tris-SEP complex and most of the other trihydrocarbylsilylethyl diphenyl phosphine complexes showed a very similar ligand exchange behavior at 30.degree. C. The tripropylsilylethyl diphenyl phosphine complex (Example 12) exhibited a definitely slower exchange rate. The exchange rate of the triphenylsilylethyl diphenyl phosphine complex (Example 13) was even much slower than that. It appeared that substituted alkyl diphenyl phosphine ligands of increasing bulkiness had decreasing ligand exchange rates. In both cases though, the TPP ligand exchanged lessrapidly than the alkyl diphenyl phosphine.
Finally, it is noted that when even a moderately bulky alkyl substitutent was too close to the phosphorus, i.e., in the case of trimethylsilylmethyldiphenyl phosphine, the complexation of phosphorus to the rhodium was inhibited. In that case, there was no distinct complex formation with the sterically hindered ligand at 30.degree. C. At -60.degree. C., a stable complex was formed. However, this complex was decomposed when its solutionwas heated under hydroformylation process conditions.
As far as ligand exchanges rates at higher temperature are concerned, the results shown by FIG. 3 are typical. FIG. 3 shows the comparison of two systems: tris-triphenyl phosphine rhodium carbonyl hydride plus triphenyl phosphine and tris-trimethyl-silylethyl diphenyl phosphine plus triphenyl phosphine. The latter system is the result of equilibrating the TPP complex with trimethylsilylethyl diphenyl phosphine (SEP): ##STR19##SEP being a substituted alkyl diphenyl phosphine, was found to be a stronger complexing agent than TPP. The spectra of both systems were takenunder comparative conditions at 30.degree., 60.degree. and 90.degree. C.
The line shapes of the signals of the 30.degree. spectra showed little signal broadening in both cases. This indicated comparably slow exchange rates of about 25 per second. In alternative terms, relatively long average exchange lifetimes, in the order 2.times.10.sup.-2 sec, were indicated for both trisphosphine complexes. At 60.degree., considerable line broadening occurred, indicating a much faster exchange. The exchange acceleration was greater in the case of the TPP system (k=600 vs. 80 sec.sup.-1). The average lifetime was about 3.times.10.sup.-3 sec for the TPP system and 6.times.10.sup.-3 sec for the SEP system. At 90.degree., only a single, broad signal could be observed for the TPP system while theSEP system still exhibited separate, although extremely broad, chemical shift ranges for the complexes and free phosphorus species. Apparently, the exchange acceleration in the case of the PP system was tremendous. Theaverae lifetime between exchanges was reduced by about two orders of magnitude to 5.times.10.sup.-5 sec (k=10,000 sec.sup.-1). In the case of the SEP system, the average lifetime dropped by about one order to 5.times.10.sup.-4 sec (k= 1,500 sec.sup.-1). It must be emphasized that the exchange rates and lifetimes reported here may change somewhat when the lineshape is subjected to a rigorous computer analysis. The relative order of their values will remain unaltered, however.
It is interesting to note that there was no great change of equilibria withthe increasing exchange rates. Apparently, both ligand elimination and addition increase similarly in this temperature range. The tris-phosphine rhodium species remained the dominant form of complexes. In the SEP complex plus free TPP system, the rhodium remained predominantly complexedto the SEP.
The role of excess phosphine ligand is apparently to maintain the equilibria in favor of the tris-phosphine complex, i.e. to reduce both theconcentration and average lifetime of the unstable and highly reactive bisphosphine complex. The increased ligand exchange rate provides enough active bis-phosphine complex catalytic species for fast hydroformylation, without leading to noncatalytic side reactions, i.e., catalyst decomposition.
In summary, the above and similar ligand exchange rate studies indicate that, in the presence of excess ligand, the silyl alkyl diaryl phosphine rhodium complexes are catalytically activated at higher temperatures than the known triaryl phosphine rhodium complexes. Less ligand exchange at comparable temperature also meant a higher temperature for the irreversible thermal dissociation, i.e., decomposition of the catalyst complex.
C Preparation from Dicarbonyl Acetylacetonato Rhodium Via Ligand Displacement and Hydrogenation
For the isolation of pure complexes, one usually starts with an about 0.8% ethanolic solution of the dicarbonyl acetonato rhodium starting compound. Then a threefold molar excess of the phosphine ligand in slight excess is added to provide a solution of the intermediate complex. This is then reduced by hydrogen. The complex is usually formed as a precipitate.
EXAMPLE 25
Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride
3Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 +Acac.sup.- Rh.sup.+ (CO).sub.2 +H.sub.2 .fwdarw.[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Rh(CO)H+AcacH
To a magnetically stirred solution of 0.258 g (0.001 mole) dicarbonyl acetylacetonato rhodium in ethanol, 0.887 g (0.0031 mole) of trimethylsilylethyl diphenyl phosphine was added under nitrogen. Instantaneous displacement of one of the carbonyl ligands was indicated bythe evolution of CO gas. The resulting dark orange solution of the intermediate was transferred to a glass pressure tube equipped with a Teflon screw valve and a magnetic stirrer, for hydrogenation.
The reaction tube was evacuated until the solvent started to boil. Then it was filled and pressured with hydrogen to a pressure of about 2 Atm.
On stirring the reaction mixture, rapid hydrogenation occurred. The color of the solution started to become lighter. After an hour, yellow crystalline solids started to precipitate. The reaction mixture was stirred overnight under hydrogen pressure to complete the reduction. The hydrogen was then released and the mixture was filtered with suction undernitrogen. A light orange filtrate and yellow crystals were obtained.
The crystals were washed twice with 2 ml portions of ethanol and dried under a pressure of 0.1 mm and at room temperature. The resulting pure tris-SEP rhodium carbonyl hydride was 0.65 g, i.e., about 65% of the theoretical yield. Its solid state .sup.31 P nmr spectrum supported the expected structure.
The .sup.31 P nmr spectrum of the combined filtrates showed that essentially all the phosphorus was in the form of the same tris-SEP complex. this indicated that the reaction was quantitative.
The tris-SEP complex was also formed in aromatic hydrocarbon and aldehyde solvents. Hydrogen could be effectively used for reduction at atmospheric pressure. The reaction was complete within a few hours in aromatic hydrocarbons.
EXAMPLES 26-30
Other Tris-(Silylalkyl Diphenyl Phosphine) Rhodium Carbonyl Hydrides
In a manner similar to the SEP complex preparation described in the previous example, analogous complexes of other silylalkyl diphenyl phosphines were obtained. The trimethylsilylpropyl diphenyl posphine complex formed a crystalline precipitate. The two bis-(diphenyl phosphinoalkyl) silane complexes were oily. The tripropylsilylethyl and triphenylsilylethyl diphenyl phosphine complexes remained in solution whenthis procedure was used. On removing the ethanol in vacuo, oily complexes were obtained.
EXAMPLE 31
Mixed Tris-Phosphine Rhodium Carbonyl Hydride Complex Species in Octyl Diphenyl Phosphine and SEP Based Catalyst Systems
Complex equilibria can be studied by .sup.31 P nmr between different alkyl diaryl phosphine complexes via the hydrogenation of their mixtures with dicarbonyl acetylacetonato rhodium. Typically, 3 moles of each of two phosphine ligands are used per mole dicarbonyl acetylacetonato rhodium. The rhodium reactant is used in amounts corresponding to 2 weight percent of the solvent, typically a 9/1 mixture of toluene and deuterobenzene. Thephosphine reactants are then added to prepare a solution of the intermediate. This solution is then placed into a pressure tube equipped with a Teflon valve. This tube, properly shaped and fitted doubles as a reactor and an nmr sample container. It is pressured by hydrogen to 30 psi, i.e., about 2 atm. Then it is shaken, usually overnight. This resultsin the formation of tris-phosphine rhodium carbonyl hydride complexes plus 3 moles of free phosphine. If the binding strength of the two phosphines is equal, a statistical distribution results between the four potential complexes as indicated: ##STR20##Such a distribution was the approximate result of the competition between the SEP ligand [R=(CH.sub.3).sub.3 SiCH.sub.2 CH.sub.2 ] and n-octyl diphenyl phosphine [R=CH.sub.2 (CH.sub.7)]. The signals of the two free ligands were of equal intensity. The relative amounts of the free phosphine ligands are usually in a simple indirect relationship to the strength of complexation with the rhodium.
EXAMPLE 32
Tris-t-Phosphine Rhodium Carbonyl Hydride Equilibria at High P/Rh Ratios Among SEP and Ar.sub.3 P Complexes
Using the .sup.31 P nmr technique of the previous example, equilibria amongtris-SEP rhodium carbonyl hydride and complexes including one or more triaryl phosphine ligands were also studied at high P/Rh ratios. Rh to SEPto Ar.sub.3 P ratios of 1:20:80 were used in the absence of added solvent with TPP and 4-chlorophenyl diphenyl phosphine (Cl-TPP) as the Ar.sub.3 P ligand. Cl-TPP was employed because of its relatively low mp. (45.degree. C.).
The results of these variable temperature experiments showed that, due to the fairly high SEP/Rh ratio, complexes containing SEP predominated, even though the Ar.sub.3 P/Rh ratio was much higer. Substituted triaryl phosphine components were preferred because of their generally higer solubility.
EXAMPLE 33
Bis-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride and Excess Ligand Coordinated with n-Valeraldehyde
Complex equilibria with coordinating solvents can be also established at different concentrations and temperatures. Interactions with aldehydes areparticularly important since the aldehyde products are always present in the hydroformylation mixtures. Comparative low temperature .sup.31 P nmr studies of tris-(alkyl diaryl phosphine) rhodium carbonyl hydride solutions in aromatic hydrocarbons and valeraldehyde have shown that valeraldehyde facilitates the dissociation of tris-phosphine complexes andthe formation in turn of carbonyl dimer derivatives of the bis-phosphine complex. Under hydrogen pressure, the latter is in equilibrium with the tris-phosphine complex. Aldehydes appear important in the stabilization ofthe key active intermediate, the coordinatively unsaturated trans-bis-(alkyl diaryl phosphine) rhodium carbonyl hydride, e.g., the bis-SEP complex,
[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3].sub.2 Rh(CO)H
EXAMPLE 34
Trimethylsilylethyl Diphenyl Phosphine Rhodium Dicarbonyl Complexes
Complex equilibria between various catalytic intermediates derived from trans-bis-phosphine carbonyl hydride could be also studied via similar methods in the presence of varying amounts of excess phosphine ligand. Theresults of these studies contrast the behavior of the SEP and TPP complexestoward CO and show the influence of excess phosphine ligand in stabilizing the desired catalyst structures.
When solutions of the tris-phosphine rhodium carbonyl hydride complexes andexcess phosphine were placed under pressure of CO and varying mixtures of H.sub.2 and CO rapid exchange and the formation of bis-carbonyl complexes leading to non-selective hydroformylation were observed. At low temperature, the rate of the ligand exchange was decreased and the .sup.31P doublet signals originating from several different rhodium complexes, including the tris-phosphine rhodium carbonyl hydride and bis-phosphine rhodium dicarbonyl hydride, could be observed. It was noted that the ratioof the monocarbonyl complexes to the dicarbonyl complexes increased with increasing H.sub.2 /CO and P/Rh ratios. Under comparable conditions less of the undesired dicarbonyl complex was formed in the SEP system than in the TPP system. Also, the dicarbonyl SEP complex were converted back to the monocarbonyl complex more readily than the dicarbonyl TPP complex.
The experiments have shown that in the catalyst systems for selective hydroformylation. The concentration of the tris-phosphine rhodium carbonylhydride is optimized. This complex then acts as a dynamic, stabilizer reservoir and source of the active trans-bis-phosphine carbonyl hydride. The latter is highly reactive in a reversible manner toward olefins as it is indicated by the increased ligand exchange under ethylene pressure.
III Preparation of Tris-Silylalkyl Diphenyl Phosphine Complexes of Other Transition Metals
The novel silyl substituted alkyl diphenyl phosphine complexes of other transition metals can be prepared via known methods which were developed to prepare triaryl or trialkyl phosphine complexes. A method discovered during the course of the present work starts with the readily available triphenyl phosphine complexes of transition metals to prepare the corresponding complexes of silylalkyl diphenyl phosphines via ligand exchange.
EXAMPLE 35
Tris-(Trimethylsilylethyl Diphenyl Phosphine) Iridium Carbonyl Hydride
(Ph.sub.3).sub.3 Ir(CO)H+3Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 .fwdarw.[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ].sub.3 Ir(CO)H+3Ph.sub.3 P
Tris-(triphenyl phosphine) iridium carbonyl hydride was reacted with the SEP ligand in the manner described in Example 11 to 19. .sup.31 P nmr spectroscopy of the liquid reaction mixture indicated that the singlet signal of the TPP complex reactant at 12.4 ppm mostly disappeared and an intense signal for the liberated TPP appeared instead. The formation of the SEP complex was shown by the intense new singlet having a chemical shift value of 10.4 ppm.
EXAMPLE 35A
Trimethylsilylethyl Diphenyl Phosphine Cobalt Tricarbonyl Dimer
[Ph.sub.3 PCo(CO).sub.3 ].sub.2 +2Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 .fwdarw.[Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3Co(CO).sub.3 ].sub.2 +2Ph.sub.3 P
The cobalt tricarbonyl dimer of TPP was reacted with SEP to yield the desired product of ligand exchange.
IV Testing of Tris-(Silyl Alkyl Diaryl Phosphine) Rhodium Complex Based Hydroformylation Catalyst Systems
A. General method of Hydroformylation
The hydroformylation of butene-1 to provide linear pentanal and branched 2-methyl butanal products was selected for comparative studies of the catalytic properties of alkyl diaryl phosphine) rhodium carbonyl hydride complexes. The complexes studied were either ,solated before use or generated in situ. In some cases, the desired complex was generated from the known tris-(triphenyl phosphine) rhodium carbonyl hydride by the addition of the appropriate ligand in varying amounts. According to another standard method, di-carbonyl acetylacetonato rhodium and the appropriate alkyl diaryl phosphine were used as catalyst precrusors. In that case, the desired rhodium carbonyl hydride complex was generated by hydrogenation during the hydroformylation experiment. Tris-triphenyl phosphine rhodium carbonyl hydride in the presence of varying excess of triphenyl phosphine was used as a known catalyst standard for comparison.
The experiments were carried out in a 300 ml stainless steel (S) and a 300 ml Hastelloy (H) autoclave, respectively. Both autoclaves were equipped with identical highly effective, impeller type stirrers, operating at 1500rpm during the experimental runs. The other standard autoclave instrumentation was identical for both units. However, a slightly lower normal to iso aldehyde product ratio (n/i) was observed in unit H. In those cases where the type of autoclave was not specified, a stainless steel unit was used.
The standard batch hydroformylation procedure was the following: the appropriate amounts of rhodium complex were dissolved in 80 g of the proper mixture of free phosphine and solvent. 2-Propylheptyl valerate or 2-ethylhexyl acetate were generally used as standard solvents. Most often,the amount of complex employed provided 100 ppm rhodium concentration. Thismeant 100 mg, i.e., about 0.1 mole, rhodium per 100 g. Accordingly, 100 mg per kg, about 1 mmole per kg rhodium would be present in 1 kg starting mixture. The excess ligand added to the solvent was usually calculated to provide a ligand to rhodium ratio (L/Rh) of about 140.
The 100 g rhodium complex-ligand solution was placed into the autoclave which was then deaerated by repeated pressurization with nitrogen. The solution under atmospheric nitrogen pressure was then sealed and heated tothe reaction temperature, usually 100.degree. C.
When the solution reached 100.degree., 20 g liquid butene was pressured into the autoclave with a 1 to 4 carbon monoxide-hydrogen initial gas mixture. The butene was followed by the CO/H.sub.2 mixture until a pressure of 350 psig was reached. At that point, the supply of 1:4 to 1:5 CO/H.sub.2 was shut off and the autoclave was connected to a cylinder of about 1 liter volume containing an about 1:1 CO/H.sub.2 feed gas mixture at 1000 psig. The connection was made through a pressure regulating valve set to provide the 1:1 CO/H.sub.2 gas to the autoclave to maintain a 350 psig pressure during the reaction. The exact H.sub.2 /CO ratio of the feedgas was often varied to maintain the initial H.sub.2 /CO ratio in the autoclave. The reaction was typically run to an 80% conversion on the basis of the H.sub.2 /CO consumed.
In the standard tests, the autoclaves used were equipped with synthesis gasfeed lines adjoining the autoclave above the Magnedrive stirred assembly unit (FIG. 4). It is to be noted that this manner of introducing synthesisgas feed far from the upper level of the liquid reaction mixture (Method A)resulted in an incomplete equilibration of the synthesis gas mixture between the gas and liquid phase. Particularly in those cases where the initial synthesis gas mixture (used to pressure up the reaction mixture) had a H.sub.2 to CO ratio of 10 or higher, the CO component of the subsequent one to one feed gas was not effectively delivered from the top into the liquid reaction mixture due to mass transfer limitations. Therefore, the reaction mixture was often "starved" of CO during the earlyfast phase of the reaction. As a consequence, the H.sub.2 /CO ratio in the liquid temporarily rose to very high values. This resulted in particularlyhigh n- to i-aldehyde product ratios. Also, olefin hydrogenation and isomerization became important side reactions. For comparison, the widely studied tris-TPP rhodium carbonyl hydride catalyst system was used as a standard throughout the work. Generally, the reaction was run to an 80% conversion on the basis of the H.sub.2 /CO consumed when using this method.
In those instances where the effect of H.sub.2 to CO ratios and the effect of CO partial pressure were especially studied, the synthesis gas feed wasintroduced at the side of the autoclave through a side arm just above the liquid level (FIG. 4, Method B). This method of operation largely avoided any temporary rise of H.sub.2 /CO ratios and drastically reduced hydrogenation and isomerization in cases where the initial H.sub.2 /CO ratio was high.
In the third method of operation, the synthesis gas was introduced into theliquid reaction mixture at the bottom, close to the stirrer through a sintered inductor to assure small bubble size and instantaneous mixing (FIG. 4, Method C). This method was the best for avoiding higher than equilibrium H.sub.2 /CO ratios during the reaction. As such the method gave the smallest n/i ratios of isomeric aldehyde products and the least hydrogenation and isomerization of the olefin, i.e., the highest selectivity for total, i.e., n+i, aldehyde products. Using this method, the reaction was usually run to 50% conversion on the basis of the consumed synthesis gas. Special studies were also made in a continuous feed introduction and product flashoff operation. This allowed a continuous control or partial pressures and such provided the most accurate results.
The progress of the hydroformylation was followed on the basis of the amount of 1:1 CO/H.sub.2 consumed. The latter was calculated on the basis of the pressure drop in the 1 liter CO/H.sub.2 cylinder. Reactant conversion calculated on the basis of CO consumption was plotted against the reaction time to determine the reaction rate. The reaction rate was expressed as the fraction of the theoretical CO/H.sub.2 requirement consumed per minute (k min.sup.-1). The reaction was discontinued when thereaction rate drastically dropped. Dependent of the side reaction, such as butene-1 hydrogenation and butene-1 to butene-2 isomerization, the reaction temperature and the stability of the catalyst complex in the mixture, such a rate drop occurred generally between 80-98% CO conversion.
When the reaction was to be discontinued, the CO/H.sub.2 feed valve was shut and the autoclave was immediately cooled with cool water. In case of low conversions, ice bath was used. When cooling was complete, the synthesis gas was released slowly. The residual liquid was visually observed for catalyst decomposition. A dark orange to brown color of the originally yellow mixture indicated increasing degrees of catalyst decomposition. Severe catalyst decomposition usually resulted in the precipitation of dark solids.
Analyses of the residual liquid mixture were carried out using gas chromatography. The liquids were analyzed in a gc instrument using flame ionization detector. By this instrument, the C.sub.4 hydrocarbons were detected. Due to the lower response of this detector to the aldehydes, theintensity of the hydrocarbon peaks was multiplied usually by 0.7 to obtain the necessary concentration correction. The individual, gaseous C.sub.4 hydrocarbons were separated by another chromatograph. At first, these gases were separated from the liquids and then the individual components of the gas were chromatographed and detected by a thermal conductivity detector.
B. 1-Butene Hydroformylation (Examples 36-43)
The following description of 1-butene hydroformylation catalysis will be exemplified by a detailed description of the tris-(trimethylsilylethyl diphenyl phosphine) rhodium carbonyl hydride, i.e., SEP complex, plus SEP system. For comparison, detailed data will also be provided on the known tris-(triphenyl phosphine) rhodium carbonyl hydride, i.e., TPP complex, plus TPP system. For comparison, detailed data is also provided on the known tris-(triphenyl phosphine) rhodium carbonyl hydride, i.e., TPP complex plus TPP, system. It is noted that Method A, introducing the synthesis gas feed at the top of the reactor assembly, was used in severalExamples as indicated hereafter. Consequently, CO starvation did occur at high reaction rates and these data are not available for determining physicochemical constants, such as activation energies.
EXAMPLE 36
Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride as aCatalyst in the Presence of 140-Fold Ligand Excess at Different Temperatures
The complex of Example 10 was studied at the 107 ppm rhodium level in the presence of 140-fold (0.14M) trimethylsilylethyl diphenyl phosphine (SEP) ligand as a butene hydroformylation catalyst using the general procedure describe above for Method A. Comparative experiments were run using 107 ppm rhodium as a tris-(triphenyl phosphine) carbonyl hydride complex with 140-fold triphenyl phosphine (TPP). Reaction rates, n/i product ratios, conversions and byproducts were determined at various temperatures. The results are shown by Table III.
The data of the table show that both the SEP and the TPP based catalyst systems are highly active and produce a high ratio of n/i products at mosttemperatures. However, the temperature dependence on the two systems is very different. The procedure used in the runs was that of Method A.
TABLE III__________________________________________________________________________HYDROFORMYLATION AT DIFFERENT TEMPERATURES Feed: Butene-1 and 1:4 CO/H.sub.2 at 350 psi Catalyst: L.sub.3 Rh(CO)H, Rh 107 ppm, Rh/L = 140 SEP Ligand: (CH.sub.3).sub.3 SiCH.sub.2 CH.sub.2 P.phi..sub.2 TPP Ligand: .phi..sub.3 PVariable Conditions Reaction Rates and Selectivitiesof Catalysis By-Product, Details Reaction Fraction of Product Reaction Butene Mole % in ExactSeq. Catalyst Temp., CO/H.sub.2 Reacted n/i Time Conversion Product Mixture Rh Conc.No. Ligand .degree.C. k, min.sup.-1 Ratio Min. % Butane Butene-2 ppm__________________________________________________________________________1 SEP 100 0.03 6.1 35 86.9 2.0 3.8 1062 120 0.10 6.2 35 96.5 9.4 6.2 1063 140 0.21 5.7 15 97.5 14.5 12.4 1084 145 0.27 5.0 15 95.2 11.9 12.1 1095 TTP 100 0.21 7.5 35 98.9 10.7 12.1 1076 120 0.34 5.9 10 97.3 9.3 12.2 1047 140 0.38 3.4 10 98.2 11.2 21.9 1058 145 0.27 2.4 15 97.7 11.9 26.0 103__________________________________________________________________________
The novel SEP catalyst system exhibits an increasing activity with elevatedtemperatures. At 100.degree. and 120.degree. the n/i ratio of products is about the same and there is only a small n/i drop at 145.degree.. High butene conversion is observed at all temperatures. The only adverse effectof temperature increase is the increased hydrogenation and isomerization ofthe butene-1 reactant. The SEP system remains clear, bright yellow in appearance, even at 145.degree..
The known TPP catalyst system exhibits the same increased activity at 120.degree. and 140.degree.. However, the n/i ratios in this case are monotonously reduced with increasing temperatures. At 145.degree., the n/iratio of products is significantly lower in the TPP than in the SEP system.At 145.degree., the reaction rate of the TPP system also drops. Decomposition of this system at this temperature is indicated by darkeningof the reaction mixture.
EXAMPLE 37
Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride Complex as a Catalyst in the Presence of 1 M Excess Ligand at Different Temperatures
The SEP-rhodium complex catalyst system and the corresponding TPP-rhodium systems were also compared as butene hydroformylation catalysts using Method C. This comparison was made in considerable detail of systems containing a high excess, i.e., 1 molal concentration of excess ligand in the starting reaction mixture. Data were obtained at temperatures ranging from 100.degree.-160.degree. C. The results are shown in Table IV.
To assess the effect of changing the experimental procedure from Method A to C, Table IV also shows some data at 0.14 M excess ligand concentration (Seq. Nos. 1, 2 and 8). This ligand concentration was widely used in the previous examples with Method A. The comparison with Table III shows that the use of Method C results in a lower n/i ratio of aldehydes but a highern+i aldehyde selectivity, i.e., lower by-product formation.
TABLE IV__________________________________________________________________________Hydroformylation of 1-Butene with Tris-Phosphine Rhodium CarbonylHydrideCatalyst Using Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 (DTS) orPh.sub.3 P (TPP)Reactions at 350 psi (24.7 atm) of 5/1 H.sub.2 /CO with 20 g 1-butene and80 g of phosphine plus 2-ethylhexylacetate solvent, using AcacRh(CO).sub.2 as catalyst precursor andintroducing the feed gas into the stirredreaction mixture. H.sub.2 /CO Consumption By-product Dependent Factors Aldehyde Product Parameters Selectivity,Catalyst System Parameters (50% Conversion) Linearity Hydroformylation %Experiment M in Rh Feed H.sub.2 / Rate Reaction n .times. 100 Selectivity 2-Seq. Run Temp. Mix at Conc. P.sup.b / Ratio CO Constant Time n/i n + i n + i n- i- Bu- Bu-No. No. .degree.C. start m--M Rh H.sub.2 /CO Final k, min.sup.-1 min. Ratio % % % % tenes tanes__________________________________________________________________________DTS1 245 145 0.14 0.25 560 54/46 5.9 0.083 8.5 4.9 82.9 89.8 74.5 15.3 6.8 3.52 246 145 0.14 0.10 140 54/46 5.5 0.035 19 4.6 82.2 90.7 74.6 16.1 6.5 2.83 249 110 1.0 4.0 250 52/48 4.9 0.032 22 7.6 88.4 93.9 83.0 10.9 4.3 1.84 142 125 1.0 1.0 1000 52/48 4.6 0.026 27 8.2 89.1 94.1 83.8 10.2 4.0 1.95 138 135 1.0 1.0 1000 53/47 5.1 0.046 15 9.8 90.8 90.2 81.9 8.3 5.9 3.96 101 145 1.0 1.0 1000 54/46 6.9 0.073 10 11.4 91.9 89.3 82.1 7.2 6.8 3.97 247 160 1.0 0.5 2000 56/44 6.9 0.065 11 11.3 91.9 82.8 76.1 6.7 10.8 6.4TPP8 171 145 0.14 0.05 280 54/46 5.8 0.040 18 4.1 80.2 83.0 66.6 16.5 13.4 3.59 135 110 1.0 0.5 2000 52/48 5.1 0.017 40 13.0 92.8 91.3 84.7 6.5 5.7 3.010 130 125 1.0 0.5 2000 52/48 4.7 0.058 12 11.9 92.3 89.1 82.2 6.9 7.9 3.111 129 135 1.0 0.5 2000 54/46 6.5 0.078 9 12.8 92.7 84.2 78.1 6.1 10.7 5.112 128 145 1.0 0.5 2000 54/46 5.4 0.104 7 10.7 91.5 80.4 73.6 6.9 13.2 6.413 144 160 1.0 0.25 4000 56/44 5.6 0.064 11 7.6 88.4 78.9 69.7 9.2 15.8 5.3__________________________________________________________________________
In general, the use of the high 1 M, ligand excess increased both the n/i ratio and the n+i selectivity in both the SEP and the TPP systems at all temperatures (Seq. Nos. 3 to 7 and 9 to 13). The use of the SEP system always resulted in a somewhat higher total aldehyde selectivity. However, in the 145.degree.-160.degree. C. range, the selectivity of the SEP systemwas considerably better, apparently due to its increased thermal stability.The n/i ratio of the aldehydes produced in the SEP catalyzed reaction was even slightly increased as the temperature was raised from 110.degree. to 145.degree. C. This was probably due to the reduced CO concentrations in the liquid reaction mixture at increased temperatures.
The general lesser total (n+i) aldehyde selectivity of the TPP system is mainly due to the significant isomerization of the 1-butene reactant to 2-butenes at 160.degree. C., the n/i ratio of the aldehydes is also decreased greatly in the TPP system. At this temperature, the TPP catalystsystem is basically changed, although no gross instability could be observed during the short reaction period. The behavior of the SEP and TPPsystems is compared by FIGS. 5A and 5B.
EXAMPLE 38
Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride as aCatalyst at Different Levels of Excess Ligand Concentrations
The complex catalyst of Example 10 was tudied mainly at the 105 ppm rhodiumlevel and at 100.degree. reaction temperature to determine the effect of the excess trimethylsilylethyl diphenyl phosphine ligand. (SEP). The SEP concentration used ranged from 5 to 149 mmole per liter. Some comparative experiments were also carried out using tris-(triphenyl phosphine) rhodiumcarbonyl hydride and varying excess concentrations of the corresponding triphenyl phosphine ligand. (TTP). The results of these studies are shown in Table V. The procedure used in the runs was that of Method A.
TABLE V__________________________________________________________________________HYDROFORMYLATION AT DIFFERENT LEVELS OF EXCESS LIGAND CONCENTRATIONSFeed: Butene-1 and 1:4 CO/H.sub.2 at 350 psiCatalyst: L.sub.3 Rh(CO)H SEP Ligand: (CH.sub.3).sub.3 SiCH.sub.2CH.sub.2 P.phi..sub.2 TPP Ligand: .phi..sub.3 PVariable Conditions of Catalysts Reaction Rates and Selectivities Excess Rhodium Ligand to Fraction of Product Reaction COSeq. Catalyst Reaction Auto- Ligand Conc. Conc. Rh Ratio CO/H.sub.2 Reacted Linearity Time ConversionNo. Ligand Temp., .degree.C. Clave mMole/lit. ppm L/Rh k min.sup.-1 Ratio, n/i min. %__________________________________________________________________________1 SEP 100 H 5 105 5.2 0.24 3.5 20 88.72 24 105 24.2 0.09 4.0 35 87.13 S 28 105 28 0.12 4.4 35 88.04 56 217 28 0.12 5.4 30 94.25 143 105 143 0.03 6.1 35 83.66 120 S 29 105 29 0.30 4.5 15 93.07 60 210 30 0.25 5.7 15 89.68 149 105 0.10 6.2 35 88.19 TTP 100 H 5 105 5 0.28 3.0 15 80.810 142 102 142 0.17 3.8 35 96.511 S 27 105 27 0.31 4.7 15 86.612 143 104 143 0.03 6.1 35 83.6__________________________________________________________________________
As is seen, there is an apparent inhibition and stabilization of both systems at high ligand concentrations. However, the behavior of the two catalysts is significantly different at relatively low excess ligand concentrations.
The novel SEP catalyst system leads to higher n/i product ratio than the TPP system at five mmole/1 excess ligand concentration (Seq. No. 1 vs. Seq. No. 9). At the intermediate SEP concentration of 56 mmole, there is agood selectivity and sufficient reaction rate (Seq. No. 4). It is interesting to observe that the positive effect of increasing catalyst complex concentration on the reaction rate can be counterbalanced by the inhibiting effect of increased SEP concentration (compare Seq. Nos. 3 vs. 4 and 6 vs. 7). Clearly, the SEP concentration is more important than the SEP/Rh ratio. At the high SEP level of 143, there is some further increaseof the n/i ratio, but the reaction rate is cut to about one fourth (compareSeq. Nos.4 and 5). At this level, the rate can be increased while maintaining the high n/i ratio by increasing the reaction temperature (seeSeq. No. 8 and the table of the previous example).
The effect of different ligand to rhodium ratios on the n/i ratios of butene hydroformylation at different temperatures was further examined. The results are summarized by FIG. 6.
The figure shows that as the SEP/Rh ratio changes from about 140 to about 1000, the n/i ratio at 80% conversion and 170.degree. C. reaction temperature changes from about 2 to 7. The major change in the percentage of the n-aldehyde product occurs in the 140 to 500 L/Rh range. It was shown in additional experiments that there was very little further selectivity increase when the SEP ligand was used as the solvent (i.e., inabout 75% concentration).
The increased selectivity to linear aldehyde is a consequence of the increased catalyst stability in these experiments. The increased catalyst stability is also reflected in a decreasing darkening of the reaction mixture with increasing ligand concentration. Another sign of the increased stability is the better maintenance of the hydroformylation ratewith increasing conversion. Finally, it was also noted that the increased ligand concentration resulted in a moderate suppression of the rate of hydrogenation. Nevertheless, hydrogenation remained significant enough to cause a decreasing H.sub.2 /CO ratio during the reaction.
Similar studies of the effect of increased SEP/Rh ratio were carried out at160.degree., 145.degree. and 120.degree. C. The data obtained at 145.degree. are also shown in FIG. 6. The lower the reaction temperature, the less effect of increased L/Rh ratios was observed. At decreasing temperatures most of the effects were observed in the range of increasingly low L/Rh ratios. Also, the main effect was on selectivity rather than on stability.
EXAMPLE 39
Hydroformylation Selectivity of Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Carbonyl Hydride Excess Ligand Catalyst System at Different Olefin Conversions.
Butene-1 was hydroformylated in the Hastelloy unit according to the generalprocedure by Method A. The catalyst and ligand concentrations were higher than usual and the reaction conditions milder as shown in Table VI. The reaction mixture was frequently sampled during the process and the sampleswere analyzed by gc to determine the relative selectivites to n- and i-aldehyde products and hydrocarbon by-products as a function of butene-1 conversion. The detailed data are given in Table VI.
The data of Table VI indicate that the n-to i-ratio of aldehydes in the reaction is decreasing as the conversion increases. Up to about 60% buteneconversion, the n/i ratio stays above 18.5, although it is steadily dropping (see Sample Nos. 1-2). In the 72-78% conversion range, the n/i ratio is about 14. Once butene-1 conversion reaches 90%, the n/i ratio of the product mixture is down to about 11.5.
It was also observed that during the conversion of about 25% of the butene,the total aldehydes to hydrocarbon by-products ratio was lower than at higher conversions (about 70/30 versus 90/10). It is believed that this isdue to uncontrolled nonequilibrium conditions early during the reaction. Almost all the hydrogenation occurred during the first 10 minutes of the reaction. During the early, very fast past of the reaction, the liquid reaction medium became starved of CO. Due to the resulting low CO partial pressure, the n/i product ratio became very high. However, the amount of CO during some of this period was so insufficient that much hydrogenation and isomerization occurred. In a continuous process, where the low optimumconcentration of CO could be more accurately maintained, high selectivity to aldehydes could probably be better achieved without producing significant amounts of by-products.
TABLE VI__________________________________________________________________________HYDROFORMYLATION SELECTIVITY AT DIFFERENT OLEFIN CONVERSION LEVELSFeed: Butene-1 and 1:4 CO/H.sub.2 at 130 psi at 110.degree. C. under 130psiCatalyst: L.sub.3 RH(CO)H, Rh 212 ppm, L Excess 300 mMole, L/Rh 140L: .phi..sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3Conversion Related Data Aldehyde Mole % Selectivity to Various Compounds Butene-1 Conversion, % Reaction Product Aldehyde Butene 2-ButeneSample Conversion Based on Time, Linearity Products Hydrogenation By-ProductsNo. % CO/H.sub.2 Consumed Min Ratio, n/i n i Product cis trans__________________________________________________________________________1 26.4 21.9 10 26 68.4 2.7 11.9 9.7 7.32 46.9 36.0 15 25 77.9 3.1 7.4 6.7 4.93 61.6 50.0 20 18.5 79.7 4.3 6.1 5.8 4.24 72.0 61.4 25 13.9 80.2 5.8 5.2 5.2 3.75 78.0 69.4 30 14.0 79.6 5.7 5.4 5.4 3.96 90.0 79.9 40 11.6 82.1 7.1 3.9 4.0 2.97 90.5 87.9 60 11.3 81.9 7.2 4.0 4.0 3.0__________________________________________________________________________
EXAMPLE 40
Hydroformylation with the Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Complex System Derived Via Ligand Exchange from Tris-(Triphenyl Phosphine) Rhodium Carbonyl Hydride
In a series of experiments, tris-(triphenyl phosphine) rhodium carbonyl hydride was reacted with a varying excess concentration of the novel substituted alkyl diphenyl alkyl phosphines. This resulted in the formation of the novel catatlysts of the present invention which were studied for their catalytic properties in the usual manner in the Hastelloy unit (H).
Tris-(triphenyl phosphine) rhodium carbonyl hydride, 0.1 g (0.1 mmole), wasmixed with 80 g of a mixture of 4 g (14 mmole) of trimethylsilylethyl diphenyl phosphine and 76 g 2-propylheptyl valerate to provide an SEP catalyst system. For comparison, the same complex was also mixed with 80 gof a mixture of 3.7 g (14 mmole) of triphenyl phosphine to provide a TPP catalyst system. This provided two systems having 105 ppm rhodium and a 140 fold ligand excess.
Butene hydroformylations were then carried out with both catalyst systems at 100.degree. C. as described by Method A. The results indicated that themain catalytic species of the SEP system is an SEP complex. The reaction rate of the SEP system was about 1/6 of the TPP system (k min-1 values of 0.02 and 0.12, respectively). The n/i product ratios were about the same (4.2).
Other SEP catalyst systems were made up the same way except for the different L/Rh ratios: 25 and 5:1. They were also employed successfully for butene hydroformylation.
EXAMPLE 41
Hydroformylation with the Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Complex System at Different H.sub.2 /CO Ratios
For a further study of the effect of the H.sub.2 /CO ratios on hydroformylation selectivity, the feed gas was provided through the side arm of the autoclave as described in Method B to provide conditions duringthe reaction which are closer to equilibrium.
The SEP complex catalyst was formed in situ during hydroformylation from acetylacetonato dicarbonyl rhodium. The H.sub.2 /CO ratios of both the initial H.sub.2 /CO gas and the final unreacted synthesis gas, in the headspace of the autoclave, were analyzed. The H.sub.2 /CO ratio of the feed gas was adjusted to keep the initial and final H.sub.2 /CO ratios the sameas much as possible.
The results are shown by Table VII. The data show that as the H.sub.2 /CO ratio was increased from 1 to 20 the ratio of n- to i-aldehydes was increased. It is also interesting to note that having the side arm feed resulted in much less 1-butene isomerization and hydrogenation than obtained previously with top feeding.
Comparative side arm feed experiments were also carried out using the knownTPP catalyst system at the same concentration. At 120.degree. C., significant side reactions continued to occur. Apparently, equilibrium conditions were not sufficiently approached. Consequently, further experiments were carried out at 90.degree. C. where the reaction rate is sufficiently smaller to avoid side reactions. The results are also shown by Table VII. They show that TPP at 90.degree. C. exhibits a similar behavior to that of SEP at 120.degree. C. The n/i ratios are slightly higher for TPP, apparently due to a higher average of H.sub.2 /CO ratios.
TABLE VII__________________________________________________________________________1-BUTENE HYDROFORMYLATION WITH SYNTHESIS GAS OF VARYING H.sub.2 /CO RATIOIN THE PRESENCE OFSEP COMPLEX AND TPP COMPLEX CATALYSTSTotal Pressure 360 psi (260 Atm.); Catalyst: L.sub.3 Rh(CO)H; L/RH = 140,Rh = 110 ppmSolvent: 2-Ethylhexyl Acetate Aldehyde CO Partial Fraction of ProductReac- Pressure H.sub.2 CO Reacted Linearity Selectivities to Varioustion H.sub.2 /CO Ratio pCO, psi Rate Conver- Reaction %, Compounds, %Seq. Li- Temp. Ini- Ini- Constant sion Time, Ratio 100n AldehydesNo. gand .degree.C. tial Feed Final tial Final k, min.sup.-1 % Min. n/i n + i n i Butane 2-Butene__________________________________________________________________________1 SEP 120 1.18 1.08 1.36 160 149 0.115 81 13 3.09 7.56 73.7 23.8 0.6 1.82 SEP 120 5.0 1.08 4.8 59 60 0.082 81 22 4.56 8.20 78.2 17.1 1.7 2.93 SEP 120 10.0 1.08 7.8 31 39 0.090 82 30 6.60 86.8 80.8 12.2 2.8 3.24 SEP 120 15.0 1.17 10.4 22 30 0.116 81 15 8.22 89.2 80.4 9.8 4.4 5.35 TPP 90 1.08 1.08 1.8 168 125 0.060 81 29 3.76 79.0 77.0 20.5 0.8 1.76 TPP 90 5.0 1.08 9.0 59 35 0.059 81 28 5.50 84.6 80.5 14.7 1.2 3.67 TPP 90 10.0 1.08 10.5 31 30 0.062 80 26 6.70 87.0 81.0 12.1 2.0 4.88 TPP 90 15 1.17 18 22 18 0.062 80 26 8.70 89.7 80.2 9.2 4.6 6.0__________________________________________________________________________
EXAMPLE 42
Hydroformylation with the Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Complex System at Different Co Partial Pressures
The results of the type of experiments described in Example 39 were plottedin FIG. 7 to show the dependence of n/i aldehyde product ratios on the CO partial pressures. In additional experiments, the H.sub.2 /CO ratios were kept constant with changing CO partial pressures by maintaining an appropriate fraction of the total 350 psi (26 Atm) total gas pressure by N.sub.2 gas.
There was relatively little change of reaction rates.
The figure shows that decreasing CO partial pressures results in higher n/iproduct ratios even though the H.sub.2 /CO ratio is kept constant. The dependence of the n/i ratios is particularly strong in the low CO partial pressure range.
EXAMPLE 43
Comparative Hydroformylation with Tris-(Trihydrocarbylsilylalkyl Diphenyl Phosphine) Rhodium Carbonyl Hyrdride Based Catalyst Systems
In a series of experiments, shown by Table VIII, various silyl substituted alkyl diphenyl phosphine complexes of Examples 11 to 16 were tested as 1-butene hydroformylation catalysts under conditions of Method A using topsynthesis gas feed. The data indicate, that with the exception of the last catalyst, the complexes tested show the same type of catalyst behavior as the previously discussed SEP complex. The last complex tested, i.e., the one based on the tri-methylsilylmethyl ligand showed less selectivity thanthe others even at the relatively low hydroformylation temperature used in this case.
TABLE VIII__________________________________________________________________________1-BUTENE HYDROFORMYLATION IN THE PRESENCE OF VARIOUS TRIS(SILYLSUBSTITUTEDALKYL DIPHENYL PHOSPHINE) RHODIUM CARBONYL HYDRIDE COMPLEX CATALYSTSCatalyst: L.sub.3 Rh(CO)H, Rh = 107 ppm, Rh/L = 140Pressure: 350 psi (26 Atm) Fraction of H.sub.2 / CO Ex- Reacted Selec- Selec- ample Rate Re- tivity tivity to No. Reac- Con- Con- act- Aldehyde By-Products, of tion start ver- tion Ra- %, Products %Seq. Ligand Com- Temp. H.sub.2 / CO Ratios k, sion Time tio 100n % Bu- 2-Bu-No. Structure, L plex .degree.C. Initial Feed Final min.sup.-1 % Min. n/i n+i n i tane tene__________________________________________________________________________1a Ph.sub.2 PCH.sub.2 CH.sub.2 Si(C.sub.3 H.sub.7).sub.3 50 120 5 1.08 3.6 0.072 80 30 8.90 89.9 63.4 7.1 20.2 9.31b Ph.sub.2 PCH.sub.2 CH.sub.2 Si(C.sub.3 H.sub.7).sub.3 50 145 5 1.27 3.8 0.274 80 8 9.62 90.6 61.1 6.4 18.4 14.32 Ph.sub.2 PCH.sub.2 CH.sub.2 SiPh.sub.3 51 145 5 1.27 7.1 0.132 80 30 7.59 88.4 73.6 9.7 8.3 8.33 [Ph.sub.2 PCH.sub.2 CH.sub.2 ].sub.2 Si(CH.sub.3).sub.2 52 145 .about.4 .about.1 -- 0.157 80 12 7.6 88.4 -- -- -- --4a Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 53 120 5 1.03 3.7 0.069 81 34 8.34 89.3 69.9 8.4 13.2 8.54b Ph.sub.2 PCH.sub.2 CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 53 145 4 .about.1 2.3 0.260 82 9 5.80 85.3 67.6 11.7 10.9 9.85 Ph.sub.2 PCH.sub.2 Si(CH.sub.3).sub.3 54 100 5 1.05 5 0.056 78 60 6.24 86.2 54.3 8.1 31.8 5.9__________________________________________________________________________*Experiments of Seq. No. 1a and 1b were carried out in 2ethylhexyl acetate as a solvent. The rest were in 2propylheptyl valerate.
EXAMPLE 44
Hydroformylation with the Tris-(Trimethylsilylethyl Diphenyl Phosphine) Rhodium Complex System at High Concentrations of Excess Ligand at 145.degree. C.
The effect of very high concentrations of excess phosphine ligands on rhodium catalyst stability and selectivity was examined in a comparative study of the TPP and SEP system. The study was carried out at an approximate H.sub.2 /CO ratio of 5to 1, with feed gas introduction into the stirred catalyst solution (Method C) at 145.degree. C. At this temperature the TPP rhodium complex system is unstable at low excess phosphine concentration.
It should be noted that at low phosphine concentrations, e.g., 0.14 M, the n/i ratio of the products is much lower when using the present procedure than the n/i ratios observed in previous examples. As discussed earlier, lower n/i ratios result when CO starvation is eliminated.
The results of comparative experiments with TPP and SEP are shown in Table IX. The molar concentrations of both ligands in the reaction mixture rangewidely from about 0.14 to 3. This meant that the weight ratio of the 2-ethylhexyl acetate solvent to the phosphine ligand in the starting catalyst solution was decreased from about 20 to 0. In the extreme, the phosphine ligand was the solvent in both cases.
TABLE IX__________________________________________________________________________HYDROFORMULATION OF 1-BUTENE WITH TRIS-PHOSPHINE RHODIUM CARBONYL HYDRIDECATALYST INTHE PRESENCE OF INCREASING TPP AND SEP LIGAND EXCESSReactions at 145.degree., 350 psi (24.7 Atm) of 5/1 H.sub.2 CO (54/46H.sub.2 /CO)Feed and 20 g 1-Butene Plus 80 g Mixture of Phosphine Plus2-Ethylhexyl Acetate, using Acac Rh(CO).sub.2 as catalyst Precursor andIntroducing the Feed Gas into the Stirred Reaction Mixture H.sub.2 /CO Consumption Dependent Factors Aldehyde Product By-Product (50% Conversion) Hydroformylation Selectivity,Catalyst System Parameters Reac- Linearity Selectivity %[Ligand,L] L Concentration Rh Rate tion n.times.100 Total 2-Seq. Run M in Mix. % Weight Conc. H.sub.2 /CO Constant Time n/i n+1 n+1 n- i- Bu- Bu-No. No. at Start in Solvent 10.sup.3 .times.M L/Rh Final k, min.sup.- 1 min. Ratio % % % % tenes tane__________________________________________________________________________I: .phi..sub.3 P1 681 0.14 4.7 0.5 280 5.3 0.34 2.25 4.4 81.5 81.8 66.7 15.1 13.0 5.22 772 0.56 18.5 2 280 4.9 0.57.sup.a 1.5 7.2 87.8 80.0 70.3 9.7 14.0 5.93 724 0.56 18.5 0.25 2240 3.1 0.08 9.0 7.6 88.4 82.3 73.5 9.7 11.7 5.14 771 1.00 32.9 2 500 5.2 0.44.sup.a 2.0 11.1 91.7 82.1 75.3 6.8 12.7 5.35a 796 2.20 72.1 2 1100 5.2 0.18 4.0 21.5 95.0 81.0 77.4 3.6 13.5 5.55b 824 2.20 72.1 0.5 4400 7.2 0.07.sup.a 11 18.1 94.8 90.3 85.6 4.7 7.1 2.66 774 3.00 100 2 1500 3.6 0.096 9.5 31.0 96.9 73.3 71.0 2.3 19.6 7.1II: .phi..sub.2 PC.sub.2 H.sub.4 SiMe.sub.31 711 0.14 5.0 0.5 280 5.4 0.18 4.0 5.1 83.5 86.2 72.0 14.2 7.6 6.22b 807 0.56 20.0 2 280 6.0 0.21 3.5 9.9 90.9 86.1 78.2 7.9 8.2 5.73b 802 1.00 35.9 2 500 5.9 0.14 5.0 11.7 92.1 86.4 79.6 6.8 7.4 6.24 803 2.20 78.7 2 1100 5.6 0.07 9.5 15.1 93.8 84.0 78.8 5.2 9.1 6.97 805 2.80 100 2 1400 5.6 0.05 15.0 20.1 95.2 82.8 78.9 3.9 9.1 8.0__________________________________________________________________________ .sup.a The reaction rate was decreasing with increasing conversion.
With few exceptions, all the reaction mixtures had the same rhodium concentration, 2.times.10.sup.-3 M. In the case of both TPP and SEP, the reaction rate decreased with increasing ligand concentration. The rate haddecreased to about one third of the original as the ligand concentration quadrupled from 0.56 to 2.2 M. The rate of the TPP complex catalyzed reactions was about three times greater than those of the SEP catalyzed reactions. In fact, several of the TPP runs were too fast for a reliable control of the reaction conditions. In spite of this, the reaction rates were well maintained in most of the TPP mixtures. All of the SEP mixtures showed the same rate during the reaction, up to 50% conversion.
The n/i ratio of the aldehyde products strongly depended on the phosphine excess in both cases. Although the P/Rh ratio was kept constant when increasing the ligand concentration from 0.14 to 0.56, the n/i ratio almost doubled for both TPP and SEP.
The selectivity for n-plus i-aldehydes stayed about the same in both cases when the phosphine concentration was between 0.14 and 2.2. The total aldehydes were about 82% for TPP and about 86T for SEP. However, it appeared that the total aldehyde selectivity decreased in both cases when the ligand was the only added solvent. The use of TPP as a solvent led to a drastic decrease, i.e., to about 71% total aldehydes. When SEP was the solvent, a minor decrease to about 83% aldehydes was observed.
The selectivity of 1-butene conversion to the 2-butenes and n-butane by-products was, of course, inversely proportional to the selectivity for total aldehydes. In general, the use of the TPP system resulted in more undesired 1-butene isomerization to 2-butenes, about 12% versus about 8%. However, the selectivity of some of the TPP systems were adversely affected by the extremely high reaction rates which results in some CO starvation of such mixtures.
Overall, it appears that for both the TPP and the SEP based catalyst systems there is an optimum concentration. This concentration is rather high. It is in the 1 to 2.2 M range. This corresponds to a 33 to 79 weight% range. In other words, under these conditions, it appears preferable to operate in catalyst solution having the phosphine as the major component.
EXAMPLE 45
Hydroformylation with Bis-(Diphenylphosphinopropyl) Dimethyl Silane, i.e., BDS, Rhodium Complex System at Increasing Concentrations of Excess Ligand and Increased CO Partial Pressure
Two series of experiments were carried out using the BDS bis-phosphine ligand of Example 4 for the rhodium hydroformylation of 1-butene with Method C. In the first series to tests (Seq. Nos. 1-5) the hydroformylations were carried out at 145.degree. C. using starting reaction mixtures of increasing phosphorus equivalency, in the 0.14 to 2.2N range (Table X, A). The second series of tests (Seq. Nos. 6-12) were carried out in the presence of high concentrations of BDS, at increasing temperatures and CO partial pressure (Table X, B).
The results of the first series of tests (Seq. Nos. 1-5) showed that the increased BDS concentration resulted in increased selectivities for n-versus i-aldehyde. However, at the same rhodium concentration, the increased BDS excess adversely affected the reaction rate. The results of the second series of Tests (Seq. Nos. 6-12) showed that, at the high BDS concentration, active hydroformylations can be carried out at temperaturesup to 170.degree. C. Surprisingly, increased CO partial pressures resulted in decreased hydroformylation rates and increased activities for total aldehydes under these conditions (Seq. Nos. 8-10).
TABLE X__________________________________________________________________________Hydroformylation of 1-Butene with Tris-Phosphine Rhodium Carbonyl HydrideCatalystUsing Bis-(Diphenylphosphinoethyl) Dimethyl Silane (BDS) LigandReactions with 20 g 1-butene and 80 g of phosphine plus 2-ethylhexylacetate solvent, using AcacRh(CO.sub.2)as catalyst precursor and introducing the feed gas into the stirredreaction mixture.__________________________________________________________________________ H.sub.2 /CO Consumption Dependant Factors Catalyst System Parameters (50% Conversion)Experiment Rh Total Approx Feed H.sub.2 /CO Rate RxnSeq. Run Temp. N.sup.a in Mix Conc Pressure Pco Ratio Ratio Constant timeNo. No. .degree.C. at start m--M P.sup.b /Rh (psi) (psi) H.sub.2 /CO Initial Final Kg min.sup.-1 min.__________________________________________________________________________1 202 145 0.14 0.25 560 350 60 54/46 5.1 6.4 0.052 152 196 145 0.56 0.50 1120 350 60 54/46 5.1 7.2 0.038 193 194 145 1.00 0.50 2000 350 60 54/46 5.0 5.5 0.025 284 75 145 1.50 1.0 1500 350 60 54/46 5.5 5.7 0.040 165 197 145 2.20 1.0 2200 350 60 54/46 5.1 5.5 0.025 286 200 155 1.50 0.50 3000 350 60 54/46 5.0 5.5 0.030 237 203 155 1.50 0.50 3000 700 120 54/46 5.0 5.7 0.035 198 201 170 1.50 0.25 6000 350 60 56/44 5.0 5.1 0.021 309 207 170 1.50 0.25 6000 700 120 56/44 4.9 6.5 0.033 2310 208 170 1.50 0.25 6000 700 280 51/49 1.5 1.7 0.044 1611 216 170 2.20 0.50 4400 700 120 56/44 5.0 5.8 0.047 1712 214 170 2.20 0.25 8800 700 280 51/49 1.5 1.5 0.014 60__________________________________________________________________________ Aldehyde Product Parameters Linearity Hydroformylation By-product Experiment n .times. 100 Selectivity Selectivity, % Seq. Run n/l n + 1 n + 1 n- l- 2- No. No. Ratio % % % % Butenes Butane__________________________________________________________________________ 1 202 6.49 86.7 89.2 77.3 11.9 7.5 3.3 2 196 10.95 91.6 88.9 81.5 7.4 7.4 3.7 3 194 11.89 92.2 88.7 81.8 6.9 7.8 3.5 4 75 13.38 93.2 89.4 83.4 6.1 7.0 3.6 5 197 16.60 94.3 93.5 88.2 5.3 4.5 2.0 6 200 14.44 93.5 85.7 80.2 5.6 9.6 4.7 7 203 9.24 90.2 91.3 82.4 8.9 6.8 2.9 8 201 11.49 92.0 80.4 74.0 6.4 13.3 6.3 9 207 9.71 90.7 88.0 79.8 8.2 7.4 4.6 10 208 5.79 85.3 93.0 79.3 13.7 5.3 1.7 11 216 10.09 91.0 87.3 79.5 7.9 6.7 5.0 12 214 6.42 86.5 93.9 81.2 12.7 4.8 1.3__________________________________________________________________________ .sup.a Phosphorus equivalent per kg of starting reaction mixture. .sup.b Phosphorus to rhodium ratio.
However, as expected, the n/i ratio of aldehydes decreased by increasing COpartial pressure. Another, non-chelating bis-phosphine ligand bis-(diphenylphosphinopropyl) dimethyl silane was also studied at high concentration in rhodium hydroformylation in a similar manner. The resultsagain showed a highly active production of n-valeraldehyde from 1-butene.
EXAMPLE 46
Hydroformylation with the Rhodium Carbonyl Hydride Complex of Tris-(Diphenylphosphinoethyl) Methyl Silane, TDS and Tetrakis-(Diphenylphosphinoethyl) Silane
The rhodium hydroformylation of 1-butene at 145.degree. C. in the presence of the non-chelating tris-phosphine of Example 9 was also studied under the standard conditions of the previous examples using Method C. The TDS ligand was present at the 0.14 and 1.0 phosphorus equivalent per kg reaction mixture concentration. The H.sub.2 CO ratio was held at about 5 to 1.
At the low TDS concentration, a n/i ratio of about 7.3 was obtained, i.e., an exceptionally high value. At the higher ligand concentration, the n/i ratio was about 10.1, a typical value for silylalkyl diaryl phosphine rhodium complex systems under these conditions.
The rhodium complex of the tetrakis-(diphenylphosphinoethyl) silane was even move unique in leading high n/i ratio of aldehyde products at relatively low P/Rh ratios. This behavior is probably due to the steric crowding of the starting tetra-phosphine ligand, described in Example 10, and its complex derivatives.
EXAMPLE 47
Hydroformylation with Tris-Phosphine Rhodium Carbonyl Hydride System HavingDifferent Ratios of the TPP and SEP Ligands at a Total of 1 M Phosphine Concentration at 145.degree. C.
The hydroformylation of 1-butene was also studied using Method C at a 1 M phosphine concentration under the standard conditions of the previous examples using TPP/SEP mixtures. The results are shown by Table XI.
In general, the data of Table XI show that the n/i ratio of the aldehyde products showed very little of any dependence on the TPP/SEP ratio. However, as the mole percentage of SEP in the total phosphine ligand has increased the amount of the total aldehyde (n+i) was also increased.
It is interesting to observe that the use of 10 mole % SEP produces quite asignificant increase in the total selectivity to aldehydes (Seq. No. 2). The increased selectivity to n+i aldehydes was maintained when the SEP content of the phosphine ligand was increased to 20 mole %. Surprisingly, no significant decrease of the rate of hydroformylation has occured up to this point. The use of further increased amounts of SEP resulted in further increased total aldehyde selectivity and also in reduced hydroformylation rate as expected.
Overall, the data indicate that TPP-SEP mixtures, containing 10 to 90, preferably 20 to 90 mole %, SEP, are unexpectedly advantageous hydroformylation catalyst systems, presumably due to the preferential complexation of SEP with rhodium. The weight percentage of SEP in these mixtures is most preferably between about 25 to 50%. Similar preferred molar ratios and weight percentages apply to mixtures of alkyl diaryl phosphines and triaryl phosphine, in general.
TABLE XI__________________________________________________________________________1-BUTENE HYDROFORMYLATION WITH TRIS-PHOSPHINE RHODIUM COMPLEX SYSTEMSHAVING VARYING RATIOS OF TPP AND DTS LIGANDSReaction at 145.degree. C., 350 psi (24.7 Atm) of 5/1 H.sub.1 /COreactant, 20 g 1-Butene Feed, 1 M Total Phosphine in 2-EthylhexylAcetate, 0.5 mM Rh as AcacRh(CO).sub.2 Catalyst Precursor, Introducing54/46 H.sub.2 /CO Feed Gas into Reaction Added MixtureCatalyst System H.sub.2 /CO Consumption Aldehyde Product ParametersParameters Dependent Factors HydroformylationPhosphine (50% Conversion) Linearity Selectivity By-ProductComponent SEP Rate Reaction n .times. 100 Total Selectivity, %Seq. Run Mole % to Rh H.sub.2 /CO Constant Time n/i n + i n + i n- i- 2-No. No. TPP SEP Ratio Final k, min.sup.-1 min. Ratio % % % % Butenes Butane__________________________________________________________________________1 9 100 -- -- 6.5 0.10 7 12.3 92.5 80.8 74.7 6.1 13.6 5.62 16 100 -- -- 5.7 .sup. 0.05.sup.a 14 11.2 91.8 81.2 74.6 6.7 13.3 5.53 10 98 2 40 6.9 0.10 7 12.5 92.6 81.1 75.1 6.0 13.2 5.64 12 90 10 200 6.3 0.09 8 13.0 92.9 84.0 78.0 6.0 10.6 5.45 23 80 20 400 5.9 0.07 10 12.6 97.7 83.8 77.7 6.2 10.3 5.96 14 50 50 1000 6.6 0.04 16 13.3 93.0 88.2 82.0 6.2 7.3 4.67 15 10 90 1800 7.0 0.03 21 12.5 92.6 88.3 81.8 6.5 7.1 4.68 923 -- 100 2000 6.5 0.03 22 11.8 92.2 88.3 81.4 6.9 7.1 4.7__________________________________________________________________________ .sup.a [Rh] = 0.25 mM
Similar results were obtained using similar mixtures of bis-(diphenylphosphinoethyl) dimethyl silane, BDS, and TPP. A mixture of 20 phosphorus equivalent BDS and 80 phosphorus equivalent TPP led to a n/iratio of about 12 and a total aldehyde selectivity of 86.6%.
EXAMPLE 48
Hydroformylation with SEP Rhodium Complex System Using a Concurrent Addition of 1-Butene and H.sub.2 /CO
To explore the potential effect of minimal 1-butene concentration during the reaction on the selectivity a hydroformylation experiment was carried out under the conditions of the previous experiment but with a slow introduction of the 1-butene reactant. The SEP ligand was used in one molar concentration with Method C. However, 1-butene addition was started only after the catalyst mixture was reached reaction condition, i.e., 145.degree. C. and 350 psi. The 1-butene was introduced over the period ofabout one hour, concurrent with the H.sub.2 /CO feed gas. A subsequent analysis of the reaction mixture showed substantially the same selectivitypreviously obtained when starting with an appropriate solution of 1-butene,and then subsequently feeding in the H.sub.2 /Co feed gas.
C Hydroformylation of Other Olefinic Compounds (Example 48A-51)
EXAMPLE 48A
Hydroformylation of Propylene with the SEP Rhodium Complex System
The complex of Example 10 was studied at the 458 ppm rhodium level, in the presence of a one hundred fold excess of trimethylsilylethyl diphenyl phosphine ligand, as a propylene hydroformylation catalyst. The reaction temperature was 100.degree., the 1:4 CO/H.sub.2 pressure was 400 psi. The general procedure previously employed for butene hydroformylation was usedto carry out the reaction according to Method A.
The reaction rate was found to be k=0.04 min.sup.-1, expressed as the fraction reacted. In 60 minutes, 82% conversion was reached based on the CO/H.sub.2 consumed. The ratio of n-butyraldehyde to methylpropanal products was 5.0. The selectivity to these aldehydes was 87.5%. The selectivity to the by-product propane was only 2.5%.
EXAMPLE 49
Hydroformylation of Miscellaneous Olefinic Compounds with the SEP Rhodium Complex System
In a series of experiments, summarized in Table XII, a number of olefins were hydroformylated using the tris-SEP complex based catalyst system (Seq. Nos. 1-7) under conditions of Method A.
Using a high L/Rh ratio, 1-pentene was selectively hydroformylated at 170.degree. (Seq. No. 1). A lower L/Rh ratio was successfully used at 145.degree. C. for the selective hydroformylation of 1-octane (Seq. No. 2).
A comparison of the n/i selectivities indicated that, in the absence of isomerization, 1-n-olefins of increasing carbon number react with incrasing selectivity. Branching of terminal olefins further increased n/iselectivity.
TABLE XII__________________________________________________________________________HYDROFORMYLATION OF VARIOUS OLEFINIC COMPOUNDS IN THE PRESENCE OF SEP -RHODIUM COMPLEX BASED CATALYST SYSTEMSCatalysts: L.sub.3 Rh(CO)H; L = SEP = Ph.sub.2 PCH.sub.2 CH.sub.2Si(CH.sub.3).sub.3 ; Precursor: Dicarbonyl Acetylacetonato Rhodium;Total Pressure 350 psi (.about.26 Atm) Solvent: 2-Ethylhexyl Acetate Fraction of Aldehyde H.sub.2 /CO Reacted Product Reac- Con- Reac- Linearity Selectivities to Rh tion H.sub.2 /CO Ratio Rate ver- tion Ra- %, Various CompoundsSeq. Olefinic Conc., Temp., Ini- Constant sion Time, tio 100n Aldehydes Bu- 2-Bu-No. Reactant ppm L/Rh .degree.C. tial Feed Final k, min.sup.-1 % Min. n/i n + i n i tane tenes__________________________________________________________________________1 1-Pentene 105 510 170 5.0 117 3.0 0.193 80 12 7.5 88.2 53.3 7.1 19.3 20.22 1-Octene 113 98 145 4.0 1.04 0.257 80 8 6.8 87.23 141 165 4.0 1.04 0.521 80 4 5.9 85.54 3-Methyl- 110 140 145 5.0 1.27 6.6 0.274 81 10 23.9 96.0 70.8 3.0 25.2 0 butene5* Cis-2- 447 256 170 5.0 1.27 3.6 0.018 80 150 1.0 49.5 38.7 41.4 6.1 Butene6** 2-Ethyl- 553 28 120 1.08 1.08 1.45 0.007 40 135 .infin. 100 100 Nil Nil Nil hexene7** Diallyl 112 140 120 5.0 1.08 31 0.434 80 5.5 3.6 78.3 Ether__________________________________________________________________________*There was a 2.6% selectivity to amyl alcohols. Both mono and bishydroformylated products were formed.**Method B was used.
This is shown by the example of 3-methylbutene (Seq. No. 4). Internal olefins could be also hydroformylated as shown in the case of cis-butene-2-hydroformylation (Seq. No. 5). It is important to note that isomerization to 1-butene also occurred as indicated by the formation of n-valeraldehyde.
A terminal olefin having a substituent on a vinylic carbon, such as 2-ethylhexene showed an essentially specific terminal reaction to produce only the linear aldehyde derivative (Seq. No. 6).
Finally, an oxygenated diolefinic compound, diallyl ether, was also successfully hydroformylated without an apparent, major hydrogenation sidereaction on (Seq. No. 7). Both the mono- and bis-hydroformylated products could be selectively produced. At low conversions, the primary unsaturatedaldehyde products predominated. At high conversions, a high yield of the dialdehyde products was obtained. Other oxygenated compounds hydroformylated are allyl alcohol, allyl acetate, ethyl acrylate and formaldehyde.
EXAMPLE 50
Hydroformylation of an Isomer Mixture of Pentenes with the SEP Rhodium System
Two exemplary hydroformylation experiments using a mixed pentenes feed are presented in Table XIII to show that all or certain components of olefin mixtures can be reacted. The conditions of Method A were used.
In the experiments shown by the table, the tris-SEP rhodium complex was used in the usual manner. However, no added solvent was employed.
The data show that the 1-n-olefin component (1-pentene) was the most reactive among the significant olefin components in both runs (Nos. 1 and 2). The minor branched olefin (3-methyl butene-1) was also highly reactive.
TABLE XIII__________________________________________________________________________HYDROFORMYLATION OF MIXED PENTENES WITH TRIS-(TRIMETHYLSILYETHYL DIPHENYL PHOSPHINE) RHODIUM COMPLEXCATALYST SYSTEMCatalyst: L.sub.3 Rh(CO)H, L = SEP, L/Rh, 139; Precursor: DicarbonylAcetylacetonato Rhodium; Olefin: 100 g Mixed Pentenes without AddedSolvent__________________________________________________________________________ Reaction ConditionsNumber O: Feed 1 2__________________________________________________________________________Temperature, .degree.C. 120 120-145Time, Min. 300 360Olefin Conversion, % 30 55Rh Conc. ppm 109 293__________________________________________________________________________ Composition of Reaction Mixture Mole % Mole % Conv. % Mole % Conv. %__________________________________________________________________________C.sub.2 Hydrocarbons3-Methylbutene 0.31 0 100 0 100i-Pentane 0.45 0.53 -- 1.02 --1-Pentene 8.04 0.89 89 0.71 912-Methylbutene 24.61 19.13 22 7.14 71n-Pentane 4.14 5.10 -- 6.10 --t-2-Pentene 28.97 19.95 31 5.63 81c-2-Pentene 12.32 7.35 40 2.19 822-Methylbutene-2 21.04 22.22 0 22.46 0Aldehydes None2-Methylpentanal -- 13.86 27.333-methylpentanal -- 5.69 16.974-methylpentanal -- -- --n-hexanal -- 5.27 10.46__________________________________________________________________________
High conversions of the internal olefin components (cis- and trans-pentene-2's) and the olefinically substituted terminal olefin (2-methylbutene) could be also realized under the more forcing conditions of Run No. 2. It is noted that under the latter conditions some darkening of the reaction mixture occurred indicating some long term instability.
EXAMPLE 51
Hydroformylation 2-Butene with the SEP Cobalt Complex System ##STR21##
2-Butene was hydroformylated with a SEP complex of cobalt, presumably SEP tricarbonyl cobalt hydride, because cobalt compounds often catalyze olefinisomerization as well as hydroformylation. In the case of 2-butene, combined isomerization-hydrofomylation is desired to obtain n-valeraldehyde via 1-butene.
As a precursor of the cobalt complex, discobalt octacarbonyl was used in decane solution to provide a cobalt concentration of 0.2%. The SEP/Co ratio was 4. The main solvent was 2-ethylhexylacetate. About 20 g of the 2-butene reactant was used in the 100 g reaction mixture. The olefin was added at 175.degree. C. The reaction was run at that temperature having 1/1 H.sub.2 /CO initial gas followed by 52/48 run gas introduced at the bottom (Method C) of the mixture at a total pressure of 1000 psi (about 68Atm) total pressure to a CO/H.sub.2 consumption based conversion of 50% in 47 minutes.
An analysis of the reaction mixture by glc showed the formation of 38 mole % valeraldehydes of a n/i ratio of 5.2. About 15% of the two isomeric amylalcohols of a n/i ratio of 13.4 were also formed. The mixture also contained 3.1 mole % 1-butene isomerization product and 3.3 mole % butane hydrogenation product.
D Continuous Hydroformylation
EXAMPLE 52
Continuous Hydroformylation with the SEP and TPP Systems
The tris-(trimethylsilylethyl diphenyl phosphine) rhodium carbonyl hydride catalyst system was extensively studied in a continuous hydroformylation unit. The feed was butene-1 and the products were continuously removed together with the unreacted volatile components of the reaction mixture. The typical reaction temperature for the SEP based system was 120.degree. C. Comparative runs were also carried out with a similar TPP based system at 100.degree. C. Both systems could be successfully operated on the shortrun although it appeared that the known degradation reactions and the stripping of the valeraldehyde trimer by-product at 100.degree. C. could become a problem with TPP. The SEP system showed an excellent long term stability and activity maintenance.
A representative 30 day continuous operation of the operation of the SEP catalyst system is illustrated by FIG. 8. With regard to the continuous operating conditions, it is noted that the total synthesis gas pressure was lower (125 psi, 8.5 Atm) and the H.sub.2 /CO ratio higher (10/1) than in most of the batch studies. Also a higher concentration of rhodium (270 ppm) and a higher L/Rh ratio (210) were employed. Under these conditions abatch experiment produced results similar to those found in the continuous operation.
In the continuous hydroformylation the catalyst was generated from dicarbonyl acetylacetonato rhodium in situ. In a typical operation 1-butene was introduced into the reactor at a rate of 4.4 mole per hour. The rate of CO was typically 2 standard cubic feet per hour (SCFH). The hydrogen was introduced in the 15 to 25 to SCFH range. By changing the hydrogen/CO ratio the aldehyde production rate and other parameters could be appropriately and reversibly controlled.
During the reaction isomeric valeraldehyde trimers and some tetramers were formed. At an equilibrium concentration they were in the concentration range from about 50 to 80% by wt.
After the reaction system came to an equilibrium, the rate of hydrogen gas feed introduction was decreased from 19.2 to 17.6 SCFH (standard cubic feet per hour; 1 SCFH=28.3 dm.sup.3 /hr) during the seventh day of the run. This resulted in an increased production rate. As expected, this process was fully reversible. Also, a increase of the synthesis gas feed rate above the initial level of 2.45 SCFH on the 15th day resulted in the expected decreased production rate.
On the nineteenth day, the reaction temperature was raised to 125.degree. C. This resulted in about 39% reaction rate increase as expected on the basis of an activation energy of 15.4 kcal. Subsequent changes of the space velocity of the synthesis gas feed at this higher temperature resulted in the expected reaction rate changes.
On the basis of the kinetic changes observed during the approximately 3 weeks of operation shown by the figure and on the basis of other continuous hydroformylations with the same catalyst system, a rate equation was developed. The rate equation did fit all the data. The rate constant remained unchanged after the startup equilibrium period for the 25 days shown. It is noted that the lack of change of the rate constant means that there is no loss of catalyst activity during this period. The only long term change in the catalyst system was some oxidation, probably by oxygen, of the phosphine ligand to the corresponding phosphine oxide. In the presence of excess phosphine, this oxidation had no adverse effect on the reaction rate. Combined gas chromatography and mass spectroscopy studies could not show any evidence of a ligand degradation similar to that reported to occur via o-phenylation in the TPP system.
EXAMPLE 53
Comparative Performance of Rhodium Complex Catalyst Systems based on SEP and TPP in Continuous Hydroformylation
Operating with the SEP rhodium system at 120.degree. C. hydroformylation selectivities could be obtained which were similar to those obtained at 100.degree. C. with the TPP rhodium system. However, higher conversion could be realized with SEP. The comparative operational parameters and theselectivities to products and by-products obtained are shown in Table XIV.
The data of the table show that the most important parameters for high 1-butene conversion per pass are the reaction temperature and the stripping gas rate. These parameters control the rate of product flashoff.At the stripping gas rate of 38 g mole per hour per liter, a 38-50% 1-butene conversion was obtained when the thermally more stable SEP systemwas used at 120.degree. C. The same stripping rate resulted in only 25-27% 1-butene conversion at 100.degree. C. with the TPP system. This shows thatthe higher stability of the SEP system can be used to advantage in a high conversion process. The n/i ratio of the aldehydes and the selectivity to by-products are about the same for both catalyst systems.
TABLE XIV______________________________________COMPARATIVE PERFORMANCE OF RHODIUMCOMPLEX SYSTEMS BASED ON SEP AND TPP INCONTINUOUS 1-BUTENE HYDROFORMYLATION IN APRODUCT FLASHOFF MODE Rhodium Complex of SEP SEP TPP______________________________________Operating ParametersTemperature, .degree.C. 120 120 100Pressure, psia 150 150 1151-Butene feedrate, M/hr 4.0 4.0 4.0H.sub.2 /CO ratio in feed 7.5 8.0 7.5Rhodium, ppm 260 480 260P/Rh ratio 250 135 140Stripping gas rate, 26 38 38g mole/hr/literConversion and Products1-Butene conversion, % 25-27 38-40 25-27Valeraldehyde production 1.0-1.1 1.4-1.5 1.0-1.1rate, m/hr/1n/i Aldehyde ratio 20-25 20-23 20-23Selectivity to By-ProductsButane 2-3 2-5 1-22-Butenes 2-5 2-5 3-5Aldehyde dimers 0.2 0.2 0.1Aldehyde trimers 0.2-0.4 0.2-0.4 0.3______________________________________
EXAMPLE 54
Continuous Hydroformylation using 1-Butene and Mixed Butenes Feed at 145.degree. C.
The SEP rhodium catalyst system was also employed for the continuous hydroformylation of 1-butene at 145.degree. C. For maintaining catalyst selectivity and stability at this temperature, the ligand concentration was increased to 1 mole/liter. The rhodium concentration was also increased to 4.17 mmoles/liter to assure high olefin conversion per pass in a continuous product flashoff operation. The hydroformylation process was carried out under identical pressure, temperature and H.sub.2 CO feed rate conditions, using a pure 1-butene feed at first for a period of six days, and then a mixture of 1- and 2-butenes for a subsequent six-day period. Details of the reaction conditions and results are shown by Table XV.
The pure and the mixed feeds were introduced at a different rate into the reactor to provide the 1-butene reactant at the same rate. In the case of the pure reactant, the performance was compared with that of the TPP-rhodium system.
A comparison of the data of Table XV shows that 1-butene was selectively hydroformylated to n-valeraldehyde regardless of the feed used. The selectivities were nearly identical. The stability of the SEP complex systems was excellent in both cases during the six day reaction period. The only change was due to the loss of some of the ligand by flash-off.
The comparative experiment with the TPP-rhodium system and 1-butene reactant showed ligand degradation. About 1/2% per day of butyl diphenyl phosphine was derived from the TPP in this system. This resulted in a significant activity loss during the reaction. Also, more C.sub.4 by-products, particularly 2-butenes, were obtained.
TABLE XV__________________________________________________________________________Continuous Hydroformylation of Mized n-Butenesand Pure 1-Butene Feed in a Product Flashoff Modeat 140.degree. C. During a Six-Day PeriodAll the reaction mixtures contain 1 P-equivalent/1 ligand,4.17 mM/1 (460 ppm) rhodium complex (P/Rh = 240). Thetotal pressure is 185 psi. The rate of feed introductionin mL is the following: H.sub.2, 23.4; CO, 4.8 (H.sub.2 /CO 4.9) Rhodium Complex of SEP SEP TPP BDS.sup.(b)__________________________________________________________________________1-Butene Reactant Employed Mixture.sup.(a) Pure Pure PureReactant feed rate, 1-butene, m/hr 2.75 2.75 2.75 2.75total feed, m/hr 4.60 2.75 2.75 2.75Conversion and Selectivity1-Butene conversion, % 56.1-51.8 57.4- 54.8 82.1-65.5 57.0Total aldehydes, % 82.8 85.2 77.9 85.5n/i aldehyde ratio 13.1 12.3 11.7 14.4Selectivity to By-Products, %Butane 4.4 3.8 5.9 4.12-Butenes 9.1 7.6 12.9 7.1Aldehyde dimers 0.7 0.5 0.1 0.6Aldehyde trimers 0.4 0.6 0.4 0.6Alcohols 2.6 2.3 2.8 2.0__________________________________________________________________________ .sup.(a) The percentage composition of the reactant mixture is 1butene, 59.6; 2butenes, 31.0; n and ibutanes, 6.8; ibutene, 1.4 and butadiene, 0.02; others, 1.1. .sup.(b) Bis(2-diphenylphosphinoethyl) dimethyl silane of Example 4.
A non-volatile silyl substituted bis-phosphine, bis-(2-diphenylphosphinoethyl) dimethyl silane, BDS based rhodium complex catalyst was also tested for 1-butene hydroformylation under the same conditions. As is shown by Table XV, the use of this ligand led to slightly improved, but generally similar catalyst selectivities. However, the activity of the catalyst and the composition of the catalyst complex did not change whatsoever under the reaction conditions.
COMBINED HYDROFORMYLATION-ALDOLIZATION (EXAMPLES 55-58)
Example 55
Combined Hydroformylation-Aldolization of 1-Butene at 120.degree. C. in thePresence of Tris-(Trimethylsilylethyl Diphenyl Phosphine [SEP]) Rhodium Carbonyl Hydride Complex ##STR22##
The combined hydroformylation, aldolization and hydrogenation of butene-1 was studied under typical conditions of the present hydroformylation process. The SEP rhodium complex was utilized as a typical substituted alkyl diaryl phosphine rodium complex catalyst for hydroformylation and hydrogenation. Potassium hydroxide in methoxytriglycol was employed as an aldolization catalyst. The methoxytriglycol was also used as the solvent for the other components of the mixture. The catalyst system was employed at the 110 ppm rhodium concentration level. The ligand to rhodium ratio was 140. The 1-butene reactant was employed in a standard manner. The initial H.sub.2 /CO mixture used to pressure the mixture to 350 psi (25 atm) had a 5/1 mole ratio. The feed gas to maintain this pressure was a 1.5 to 1 mixture. The latter ratio was employed because it is theoretically needed to produce the n,n- and i,n-anals. The feed gas was introduced at the top of the reactor according to Method A.
The reaction and product parameters of a group of experiments designed to observe the effect of varying concentrations of KOH are summarized in Table XIV.
TABLE XVI__________________________________________________________________________Combined Hydroformylation-Aldolization of 1-Butene at 120.degree. C. and350 psi (.about.2 atm.)in the Presence of SEP Rhodium Complex and Varying Amounts of KOHSEP = L = Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ; L/Rh = 140; Rh= 110 ppm Fraction of Approx. Selectivities H.sub.2 /CO Reacted to AldehydesRun Rate Con- Reaction Mole % % SelectivitySeq. No. KOH, H.sub.2 /CO Ratio Constant version Time C.sub.5's n,n(i)- n,n- n/i 100n to n-ButaneNo. 7132 % Initial Feed Final k, min.sup.-1 % Min. i n anal enal Ratio n+1 mole__________________________________________________________________________ %1 280 Nil 5 1.08 2.7 0.056 80 50 9.2 90.8 9.9 14.02 306 Nil 5 1.5 24.1 0.051 80 42 3.0 97.0 32.1 97.0 18.83 307 Nil 5 1.5 26.8 0.05 15 4 3.3 96.7 29.1 96.7 80 48 3.1 96.9 31.5 96.9 15.14 286 Nil 5 1.50 21.3 0.042 15 6 6.7 93.3 13.8 45 15 5.8 94.2 16.3 60 24 5.5 94.5 17.2 80 80 6.2 93.8 15.0 93.8 17.75 283 0.05 5 1.50 47 0.059 80 34 4.1 47.5 8.4 40.0 34.9 97.2 28.96 285 0.05 5 1.50 17.7 0.061 15 4 6.1 81.6 0.8 11.7 17.6 94.6 30 18 5.5 76.8 1.0 16.7 20.5 95.4 45 11 5.4 72.9 1.5 20.2 21.6 95.6 60 16 5.2 67.3 2.7 24.7 23.5 95.9 80 30 5.9 51.5 7.8 34.8 23.2 95.9 17.77 301 0.10 5 1.17 6.52 0.062 15 5 2.9 17.8 3.0 50.2 42.9 94.3 80 32 9.3 34.1 13.0 43.6 15.8 77.1 15.08 281 0.10 5 1.50 5.0 0.048 80 42 3.4 27.1 18.3 51.2 49.2 98.0 31.39 279 0.20 5 1.50 5.0 0.043 80 40 2.9 16.0 16.0 65.2 60.5 98.4 28.810 288 0.20 5 1.50 13.6 0.049 15 3 -- -- 10.8 89.2 .infin. -- 0.028 30 5 3.7 -- 11.5 84.9 50.6 98.0 45 12 3.0 -- 12.0 85.0 64.4 98.5 60 16 3.3 7.5 13.6 75.8 57.1 98.3 80 32 3.6 17.7 18.6 60.1 48.0 98.0 92 62 4.9 14.1 34.5 46.5 35.9 97.3 16.0__________________________________________________________________________
The product parameters, i.e., selectivities to the various products were obtained by glc analyses. For the analyses of the C.sub.5 and C.sub.10 aldehydes, a special 2m Carbowax column 10% CW on Chromosorb P diatomaceous earth was used. This was provided by Supelco, Inc., Supelco Park, PA. It provided good separation of the n,n-enal was not good. The small quantities of the i,n-enal formed could not be determined. Therefore, the overall n,i-ratios in the reaction mixtures with KOH could not be exactly determined. The aldehyde selectivity to the main final C.sub.10 aldehyde products, the n,n-enal, also includes minor quantities of the i,n-anal. However, this inclusion causes less than 10% change in the composition, since the minor i-C.sub.5 aldehyde is cross-aldolized at a very slow rate. The glc percentages are indicated on the basis of the peak intensities. No corrections were made for the possibly different glc response to C.sub.5 and C.sub.10 compounds.
In the first four experiments, the hydroformylation of butene was studied in methoxytriglycol but in the absence of KOH aldolization catalyst (Seq. Nos. 1 to 4), for comparison. All three experiments started with 5/1 H.sub.2 /CO gas. In the first experiment, the H.sub.2 /CO ratio of the feed gas was close to one as usual. This experiment gave the usual high n/i ratio of C.sub.5 aldehydes. This indicated that the solvent is an acceptable one.
The rest of the experiments used the same initial H.sub.2 /CO ratio of 5 but a different H.sub.2 /CO feed of 1.5. Also, the contents of the third and fourth reaction mixture were sampled for comparison with the experiments using added KOH. This and other sampled runs provided less reliable absolute values than the uninterrupted experiments. However, theygave comparative relative numbers which showed the change of selectivity with the increasing conversion.
The second experiment (Seq. No. 2) showed a much increased n/i ratio compared to the first. This was the consequence of the increasing H.sub.2 /CO ratio, i.e., decreasing CO partial pressure due in the reaction. Due to decreased availability of CO, this run also resulted in more hydrogenation of the 1-butene starting material and isomerized 2-butenes to n-butane.
The results of the first sampled experiment are somewhat similar. This experiment shows that as a consequence of increasing H.sub.2 /CO ratio, the selectivity is much higher at 80% conversion (Seq. No. 3).
The fourth experiment (Seq. No. 4) was sampled four times during the run. It showed that up to 60% conversion, the n/i ratio was moderately increasing as an apparent consequence of the increasing H.sub.2 /CO ratio in the reaction mixture.
The second group of experiments (Seq. Nos. 5-10) was run using varying amounts of KOH, in the 0.05 to 0.2% range, under the same conditions. The data indicated that 0.2% KOH was sufficient for the rapid conversion of the primary n-C.sub.5 aldehyde product eq. Nos. 7 and 8). The aldolizationrate was much slower when 0.05% KOH was used (Seq. Nos. 5 and 6). The rate of the hydroformylation was estimated on the basis of the measured rate ofsynthesis gas consumption.
Increasing H.sub.2 /CO ratios generally resulted in increased n/i ratios and increased percentages of n-butane formation. Due to apparent CO starvation, the non-sampled mixtures gave rise to significantly higher H.sub.2 /CO ratios than those frequently sampled during the run.
The hydrogenation of the unsaturated aldehyde to the saturated aldehyde wasrelatively low. At 45% synthesis gas conversion, the percentage n,n-anal formed was less than 10% of the n,n-enal present. At that conversion, the overall selectivity to the n,n-enal was in excess of 80%.
EXAMPLE 56
Sequential Hydroformylation, Aldolization, Hydrogenation in Separate Steps
In a series of experiments, n-valeraldehyde was produced by the hydroformylation of 1-butene and separated from the i-isomer. A 20% methoxytriglycol solution of the n-valeraldehyde was then aldolized to provide the n,n-enal condensation product. It was observed that the aldolization was much slower in the absence of the hydroformylation catalyst system in the presence of it in the previous example. After 30 minutes reaction time, only a 1.2% conversion was reached. After 14 hours,the aldehyde conversion was 47.2%, i.e., the concentration of the n,n-enal in mole equivalents was 47.2%.
During the above experiment, and other experiments with KOH solutions in methoxytriglycol, yellow, then amber, then brown color formation was observed indicating potential instability. The addition of 2% KOH to methoxytriglycol resulted in an amber color even at room temperature. Therefore, the amount of KOH in the hydroformylation experiments was minimized.
To the reaction mixture from the above aldolization experiment, the hydroformylation catalyst of the previous example was added. Then the mixture as pressured to 570 psi (39 atm) and heated as usual to 120.degree. C. with a 20/1 mixture of H.sub.2 /CO. A high H.sub.2 /CO ratio was used to increase the hydrogenation rate of the n,n-enal to the n,n-anal.
The hydrogenation of the n,n-enal to the n,n-anal was followed by glc. During the first 90 minutes, the percentage conversion increased as follows: 6% (5 min.); 13% (20 min.); 21% (40 min.); 28% (60 min.); and 39%(90 min.). Under these conditions, no further significant aldolization of the n-C.sub.5 aldehyde occurred.
EXAMPLE 57
Combined Hydroformylation-Aldolization of 1-Butene with Various Tris-(AlkylDiphenyl Phosphine) Rhodium Carbonyl Hydride Complexes
The combined hydroformylation aldolization of 1-butene under the conditionsof Example 56 was also studied with the tris-(n-butyl diphenyl phosphine) and the tris-(n-hexyl diphenyl phosphine) complexes. The SEP complex was also used in this group of experiments under similar conditions but using a 1/1 rather than a 5/1 initial H.sub.2 /CO reactant ratio. The results are shown in Table XVII.
Overall, the data of the Table show that different alkyl diphenyl phosphinecomplexes are similar catalysts for combined hydroformylation adolization. The results also indicate that the provision of sufficient carbon monoxidefor hydroformylation is a key factor in avoiding olefin hydrogenation.
The first two experiments (Seq. Nos. 1 and 2) with the butyl diphenyl phosphine complex (A) show the effect of the KOH on the adolization. The results are similar to those obtained in comparative experiments using theSEP complex in a previous example (see Table I). The second pair (Seq. Nos.3 and 4) shows the effect of starting with a synthesis gas having a low, i.e., 1.5, H.sub.2 /CO ratio. Lower selectivities to the n-product are obtained but the reaction rates are increased and the by-product are obtained but the reaction rates are increased and the by-product n-butane formation is drastically reduced. The two different catalyst ligands used in these experiments, i.e., n-hexyl diphenyl phosphine (B) and trimethylsilylethyl phosphine (C), led to similar results.
TABLE XVII__________________________________________________________________________Combined Hydroformylation Aldolization of 1-Butene at 120.degree. C., C,in the Presence of Varioustris-Alkyl Diphenyl Phosphine) Rhodium Carbonyl Hydride ComplexesL = Ar.sub.2 PR; A:R = C.sub.4 H.sub.9 ; B:R = C.sub.6 H.sub.13 ; C:R =CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ; L/Rh = 140; Rh = 110 ppm; Pressure= 350 psi (26 atm) Approximate Selectivities Fraction to Aldehydes Selec- H.sub.2 /CO Reacted Reac- Mole % tivityRun Rate Con- tion C.sub.10 's % n to n-Seq. No. Ligand KOH H.sub.2 /CO Ratio Constant version Time C.sub.5 's n,n(i) n,n- n/i 100n ButaneNo 7132 Species % Initial Feed Final k, min.sup.-1 % Min. i- n anal enal Ratio n mole__________________________________________________________________________ %1 303 A Nil 5 1.5 20.1 0.058 15 4 4.9 95.1 19.6 95.1 80 34 4.4 95.6 21.9 95.6 13.02 290 A 0.1 5 1.5 21.0 0.043 15 5 10.7 16.8 7.3 65.2 15.1 93.8 80 42 6.7 24.5 21.9 46.9 24.1 96.0 13.73 299 B 0.1 1.5 1.5 11.6 0.151 15 2 18.5 75.2 7.3 4.8 82.8 80 12 14.1 63.1 6.7 16.0 7.7 88.5 1.94 293 C 0.1 1.5 1.5 6.8 0.088 15 3 18.0 75.7 6.3 4.9 83.1 80 20 16.0 73.6 0.9 9.5 5.9 88.5 109 120 19.0 12.8 34.4 33.8 7.5 88.2 2.1__________________________________________________________________________
EXAMPLE 58
Combined Hydroformylation Aldolization of 1-Butene at 145.degree. C. in thePresence of Tris-SEP and Tris-TPP Rhodium Carbonyl Hydride Complexes
The combined hydroformylation-aldolization of 1-butene was also studied under similar conditions at 145.degree. C. At this temperature, the known tris-TPP complex is unstable under the reaction conditions. In contrast, the novel tris-SEP complex is stable under the reaction conditions. In contrast, the novel tris-SEP complex is stable. The experimental conditions and results are shown in Table XVIII.
As it is shown by the table, in the first pair of experiments (Seq. Nos. 1 and 2), both the triphenyl phosphine (TPP) complex and the trimethylsilylethyl diphenyl phosphine (SEP) complex were employed as hydroformylation catalysts in methoxytriglycol in the absence of KOH. A comparison of the results showed that the rate of the SEP complex catalyzed reaction was higher. Even more significantly, the selectivity ofthe SEP complex to produce aldehydes of high n/i ratios was much higher (Seq. No. 1). At 80% conversion, the SEP catalyzed reaction had a 7.6 n/i ratio. The comparable ratio for the TPP system was 3.1 (Seq. No. 2). Most revealingly, the TPP reaction gave an n/i ration of 12.4 at 15% conversion. Apparently, during the further course of the experiment, the TPP catalyst system decomposed and led to species of much lower catalytic activity and selectivity.
In the second pair of experiments (Seq. Nos. 3 and 4), the same two catalyst systems were employed in the presence of KOH to effect hydroformylation and aldolization. KOH was found to be an effective a aldolization catalyst. Both complexes were also effective in catalyzing the hydrogenation of the aldol condensation products. However, the difference between the activity and selectivity of the two catalysts remained. The SEP complex plus KOH system produced a 6.6 n/i ratio of aldehydes at 80% conversion (Seq. No. 3). The comparative n/i ratio for the TPP complex plus base was only 4.2 (Seq. No. 4).
TABLE XVIII__________________________________________________________________________Combined Hydroformylation Aldolization of 1-Butene at 145.degree. C. and350 psi (.about.26 atm.) in thePresence of tris-SEP and tris-TPP Rhodium Carbonyl Hydride ComplexesSEP = Ph.sub.2 PCH.sub.2 CH.sub.2 Si(CH.sub.3).sub.3 ; TPP = Ph.sub.3 P;L/Rh = 140; Rh = 110 ppm Approximate Selectivities Fraction to Aldehydes Select- H.sub.2 /CO Reacted Re- Mole % ivityRun Rate Con- action C10's % n to n-Seq. No. Ligand KOH H.sub.2 /CO Ratio Constant version Time C5's n,n(i) n,n- n/i 100n ButaneNo 7132 Species % Initial Feed Final k, min.sup.-1 % Min. i- n anal enal Ratio n mole__________________________________________________________________________ %1 238 SEP Nil 5 1.17 2.7 0.174 79 18 11.6 88.4 7.6 88.6 12.02 TPP Nil 5 1.5 14.7 0.138 15 1 7.5 92.5 12.4 92.5 80 90 24.6 75.4 3.1 75.4 15.43 262 SEP 0.2 5 1.5 4.6 0.07 80 42 15.2 21.1 44.4 19.4 6.7 87.0 19.44 295 TPP 0.1 5 1.5 6.4 0.121 15 1.5 8.6 38.4 3.0 50.0 16.8 94.44 295 TPP 0.1 5 1.5 6.4 0.121 15 1.5 8.6 38.4 3.0 50.0 16.8 94.4 80 80 29.7 12.0 48.5 9.8 4.2 80.6 13.2__________________________________________________________________________
The above quantitative observations on the relative stability of the SEP and TPP based systems could be qualitatively predicted when observing the respective reaction mixtures after the reactions. The SEP systems without and with base were yellow and amber, respectively. The TPP systems with and without base became black.

Number	Name	Date
2850002	Huang et al.	Jul 1958
3067299	Fekete	Dec 1962
3122581	Pike	Feb 1964
3487112	Paulik et al.	Jun 1969
3501403	Jacques et al.	Mar 1970
3527809	Pruett et al.	Sep 1970
3726809	Allum et al.	Apr 1973
3832404	Allum et al.	Aug 1974
3856837	Chandra	Dec 1974
3907852	Oswald et al.	Sep 1975
4052461	Tinker et al.	Oct 1977
4083803	Oswald et al.	Apr 1978
4108905	Wilkinson	Aug 1978
4134906	Oswald et al.	Jan 1979
4151114	Oswald et al.	Apr 1979
4260828	Morrell et al.	Apr 1981
4270369	Harris et al.	Mar 1981
4283562	Billig et al.	Oct 1981
4287370	Harris et al.	Mar 1980
4298541	Oswald et al.	Nov 1981

Number	Date	Country
28378	May 1981	EPX
2062352	Jun 1971	DEX
925721	May 1963	GBX
1179242	Jul 1967	GBX
1182763	Mar 1970	GBX
1414662	Nov 1973	GBX
1342877	Jan 1974	GBX
1412257	Oct 1975	GBX
1419769	Dec 1975	GBX
1420928	Jan 1976	GBX
1421136	Jan 1976	GBX

Homogeneous hydroformylation catalysis with silyl substituted alkyl diaryl phosphine metal complexes

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