Patent Application
20070254801
A detailed description will now be provided. Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims. Each of the inventions will now be described in greater detail below, including specific embodiments, versions and examples, but the inventions are not limited to these embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the inventions when the information in this patent is combined with available information and technology.
Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents. Further, unless otherwise specified, all compounds described herein may be substituted or unsubstituted and the listing of compounds includes derivatives thereof.
As used herein, the term “fluorinated support” refers to a support that includes fluorine or fluoride molecules (e.g., incorporated therein or on the support surface.)
The term “activity” refers to the weight of product produced per weight of the catalyst used in a process per hour of reaction at a standard set of conditions (e.g., grams product/gram catalyst/hr).
The term “commercial quantity” includes an amount sufficient to produce from about 1 ton/hr to about 5 tons/hour of a polyolefin or from about 1 ton to about 50 tons over a period of from about 5 days to about 2 years.
The term “open dish” refers to fast removal of volatile product.
The term “olefin” refers to a hydrocarbon with a carbon-carbon double bond.
The term “substituted” refers to an atom, radical or group replacing hydrogen in a chemical compound.
The term “tacticity” refers to the arrangement of pendant groups in a polymer. For example, a polymer is “atactic” when its pendant groups are arranged in a random fashion on both sides of the chain of the polymer. In contrast, a polymer is “isotactic” when all of its pendant groups are arranged on the same side of the chain and “syndiotactic” when its pendant groups alternate on opposite sides of the chain.
The term “bonding sequence” refers to an elements sequence, wherein each element is connected to another by sigma bonds, dative bonds, ionic bonds or combinations thereof.
Embodiments of the invention generally include supported catalyst compositions. The catalyst compositions generally include a support composition and a transition metal compound, which are described in greater detail below. In one or more embodiments, the support composition has a bonding sequence selected from Si—O—Al—F, F—Si—O—Al or F—Si—O—Al—F, for example.
Such catalyst compositions generally are formed by contacting a support composition with a fluorinating agent to form a fluorinated support and contacting the fluorinated support with a transition metal compound to form a supported catalyst system. As discussed in further detail below, the catalyst systems may be formed in a number of ways and sequences.
The support composition as used herein is an aluminum containing support material. For example, the support material may include an inorganic support composition. For example, the support material may include talc, inorganic oxides, clays and clay minerals, ion-exchanged layered compounds, diatomaceous earth compounds, zeolites or a resinous support material, such as a polyolefin, for example. Specific inorganic oxides include silica, alumina, magnesia, titania and zirconia, for example.
In one or more embodiments, the support composition is an aluminum containing silica support material. In one or more embodiments, the support composition is formed of spherical particles.
The aluminum containing silica support materials may have an average particle/pore size of from about 5 microns to 100 microns, or from about 15 microns to about 30 microns, or from about 10 microns to 100 microns or from about 10 microns to about 30 microns, a surface area of from 50 m2/g to 1,000 m2/g, or from about 80 m2/g to about 800 m2/g, or from 100 m2/g to 400 m2/g, or from about 200 m2/g to about 300 m2/g or from about 150 m2/g to about 300 m2/g and a pore volume of from about 0.1 cc/g to about 5 cc/g, or from about 0.5 cc/g to about 3.5 cc/g, or from about 0.5 cc/g to about 2.0 cc/g or from about 1.0 cc/g to about 1.5 cc/g, for example.
The aluminum containing silica support materials may further have an effective number or reactive hydroxyl groups, e.g., a number that is sufficient for binding the fluorinating agent to the support material. For example, the number of reactive hydroxyl groups may be in excess of the number needed to bind the fluorinating agent to the support material is minimized. For example, the support material may include from about 0.1 mmol OH−/g Si to about 5 mmol OH−/g Si.
The aluminum containing silica support materials are generally commercially available materials, such as P10 silica alumina that is commercially available from Fuji Sylisia Chemical LTD, for example (e.g., silica alumina having a surface area of 281 m2/g and a pore volume of 1.4 ml/g.)
The aluminum containing silica support materials may further have an alumina content of from about 0.5 wt. % to about 95 wt. %, of from about 0.1 wt. % to about 20 wt. %, or from about 0.1 wt. % to about 50 wt. %, or from about 1 wt. % to about 25 wt. % or from about 2 wt. % to about 8 wt. %, for example. The aluminum containing silica support materials may further have a silica to aluminum molar ratio of from about 0.01:1 to about 1000:1, for example.
Alternatively, the aluminum containing silica support materials may be formed by contacting a silica support material with a first aluminum containing compound. Such contact may occur at a reaction temperature of from about room temperature to about 150° C. The formation may further include calcining at a calcining temperature of from about 150° C. to about 600° C., or from about 200° C. to about 600° C. or from about 35° C. to about 500° C., for example. In one embodiment, the calcining occurs in the presence of an oxygen containing compound, for example.
In one or more embodiments, the support composition is prepared by a cogel method (e.g., a gel including both silica and alumina.) As used herein, the term “cogel method” refers to a preparation process including mixing a solution including the first aluminum containing compound into a gel of silica (e.g., Al2(SO4)+H2SO4+Na2O—SiO2.)
The first aluminum containing compound may include an organic aluminum containing compound. The organic aluminum containing compound may be represented by the formula AIR3, wherein each R is independently selected from alkyls, aryls and combinations thereof. The organic aluminum compound may include methyl alumoxane (MAO) or modified methyl alumoxane (MMAO), for example or, in a specific embodiment, triethyl aluminum (TEAl) or triisobutyl aluminum (TIBAl), for example.
The support composition is fluorinated by methods known to one skilled in the art. For example, the support composition may be contacted with a fluorinating agent to form the fluorinated support. The fluorination process may include contacting the support composition with the fluorine containing compound at a first temperature of from about 100° C. to about 200° C. for a first time of from about 1 hour to about 10 hours or from about 1 hour to about 5 hours, for example and then raising the temperature to a second temperature of from about 250° C. to about 550° C. or from about 400° C. to about 500° C. for a second time of from about 1 hour to about 10 hours, for example.
As described herein, the “support composition” may be impregnated with aluminum prior to contact with the fluorinating agent, after contact with the fluorinating agent or simultaneously as contact with the fluorinating agent. In one embodiment, the fluorinated support composition is formed by simultaneously forming SiO2 and Al2O3 and then contacting the with the fluorinating agent. In another embodiment, the fluorinated support composition is formed by contacting an aluminum containing silica support material with the fluorinating agent. In yet another embodiment, the fluorinated support composition is formed by contacting a silica support material with the fluorinating agent and then contacting the fluorided support with the first aluminum containing compound.
The fluorinating agent generally includes any fluorinating agent which can form fluorinated supports. Suitable fluorinating agents include, but are not limited to, hydrofluoric acid (HF), ammonium fluoride (NH4F), ammonium bifluoride (NH4HF2), ammonium fluoroborate (NH4BF4), ammonium silicofluoride ((NH4)2SiF6), ammonium fluorophosphates (NH4PF6), (NH4)2TaF7, NH4NbF4, (NH4)2GeF6, (NH4)2SmF6, (NH4)2TiF6, (NH4)ZrF6, MoF6, ReF6, SO2ClF, F2, SiF4, SF6, ClF3, ClF5, BrF5, IF7, NF3, HF, BF3, NHF2 and combinations thereof, for example. In one or more embodiments, the fluorinating agent an ammonium fluoride including a metalloid or nonmetal (e.g., (NH4)2PF6, (NH4)2BF4, (NH4)2SiF6).
In one or more embodiments, the molar ratio of fluorine to the first aluminum containing compound (F:Al1) is generally from about 0.5:1 to 6:1 or from about 0.5:1 to about 4:1, for example.
In one or more embodiments, the molar ratio of fluorine to the first aluminum containing compound (F:Al1) is generally from about 0.5:1 to 6:1, or from about 0.5:1 to about 4:1 or from about 2.5:1 to about 3.5:1, for example.
Embodiments of the invention generally include contacting the fluorinated support with a transition metal compound to form a supported catalyst composition. Such processes are generally known to ones skilled in the art and may include charging the transition metal compound in an inert solvent. Although the process is discussed below in terms of charging the transition metal compound in an inert solvent, the fluorinated support (either in combination with the transition metal compound or alternatively) may be mixed with the inert solvent to form a support slurry prior to contact with the transition metal compound. Methods for supporting transition metal catalysts are generally known in the art. (See, U.S. Pat. No. 5,643,847, U.S. Pat. Nos. 09,184,358 and 09,184,389, which are incorporated by reference herein.)
A variety of non-polar hydrocarbons can be used as the inert solvent, but any non-polar hydrocarbon selected should remain in liquid form at all relevant reaction temperatures and the ingredients used to form the supported catalyst composition should be at least partially soluble in the non-polar hydrocarbon. Accordingly, the non-polar hydrocarbon is considered to be a solvent herein, even though in certain embodiments the ingredients are only partially soluble in the hydrocarbon.
Suitable hydrocarbons include substituted and unsubstituted aliphatic hydrocarbons and substituted and unsubstituted aromatic hydrocarbons. For example, the inert solvent may include hexane, heptane, octane, decane, toluene, xylene, dichloromethane, chloroform, 1-chlorobutane or combinations thereof
The transition metal compound and the fluorinated support may be contacted at a reaction temperature of from about −60° C. to about 120° C. or from about −45° C. to about 112° C. or at a reaction temperature below about 90° C., e.g., from about 0° C. to about 50° C., or from about 20° C. to about 30° C. or at room temperature, for example, for a time of from about 10 minutes to about 5 hours or from about 30 minutes to about 120 minutes, for example.
In addition, and depending on the desired degree of substitution, the weight ratio of fluorine to transition metal (F:M) is from about 1 equivalent to about 20 equivalents or from about 1 to about 5 equivalents, for example. In one embodiment, the supported catalyst composition includes from about 0.1 wt. % to about 5 wt. % transition metal compound.
Upon completion of the reaction, the solvent, along with reaction by-products, may be removed from the mixture in a conventional manner, such as by evaporation or filtering, to obtain the dry, supported catalyst composition. For example, the supported catalyst composition may be dried in the presence of magnesium sulfate. The filtrate, which contains the supported catalyst composition in high purity and yield can, without further processing, be directly used in the polymerization of olefins if the solvent is a hydrocarbon. In such a process, the fluorinated support and the transition metal compound are contacted prior to subsequent polymerization (e.g., prior to entering a reaction vessel.) Alternatively, the process may include contacting the fluorinated support with the transition metal in proximity to contact with an olefin monomer (e.g., contact within a reaction vessel.)
In one specific embodiment, useful for producing the catalyst systems described herein in commercial quantities, the catalyst system is formed by contacting an alumina-silica support composition with ammonium bifluoride in the presence of water to form a first fluorinated support composition. The method then includes heating the first fluorinated support composition in an oxygen containing atmosphere to a temperature of from about 200° C. to about 600° C. to form a second fluorinated support composition, wherein the second fluorinated support composition includes a bonding sequence selected from Si—O—Al—F, F—Si—O—Al, F—Si—O—Al—F and combinations thereof and then contacting the second fluorinated support composition with a transition metal compound to form a supported catalyst system, wherein the transition metal compound is represented by the formula [L]mM[A]n; wherein L is a bulky ligand, A is a leaving group, M is a transition metal and m and n are such that a total ligand valency corresponds to the transition metal valency.
In one specific embodiment, the method includes contacting a commercial quantity of alumina-silica support composition with an aqueous fluorinating agent to form a first fluorinated support composition, heating the first fluorinated support composition in an oxygen containing atmosphere to a temperature of from about 200° C. to about 600° C. to form a second fluorinated support composition and contacting the second fluorinated support composition with the transition metal compound to form a supported catalyst system.
In another specific embodiment, the method includes contacting an alumina-silica support composition with a fluorinating agent in the presence of water within a muffle furnace to form a first fluorinated support composition, heating the first fluorinated support composition in an oxygen containing atmosphere to a temperature of from about 200° C. to about 600° C. to form a second fluorinated support composition and contacting the second fluorinated support composition with the transition metal compound to form a supported catalyst system.
The contact of the alumina-silica support composition with the fluorinating agent may occur in a single batch, in multiple batches, in an open dish or in a container with partial removal of the volatile product, for example.
In one specific embodiment, the fluorinating agent includes ammonium and a fluorine containing compound. For example, the fluorinating agent includes ammonium bifluoride.
In one embodiment, the first fluorinated support composition includes from about 1 wt. % to about 30 wt. % fluorinating agent, or from about 2 wt. % to about 25 wt. % or from about 5 wt. % to about 20 wt. %, for example.
In one embodiment, the alumina-silica includes from about 1 wt. % to about 30 wt. % alumina, or from about 2 wt. % to about 25 wt. % or from about 5 wt. % to about 20 wt. %, for example.
In one embodiment, the second fluorinated support composition includes from about 0.1 wt. % to about 15 wt. % fluorine or from about 1 wt. % to about 10 wt. %, for example.
In one embodiment, the second fluorinated support composition includes a molar ratio of aluminum to fluorine of from about 0.1 to about 10, or from about 1 to about 8 or of about 1 to 1, for example.
In one embodiment, the first fluorinated support composition is heated to a first temperature for a first time of from about 1 hour to about 4 hours or from about 2 hours to about 3 hours, for example, and then to a second temperature for a time of from about 1 hour to about 10 hours or from about 2 hours to about 6 hours, for example, wherein the second temperature is greater than the first temperature. For example, the first temperature may be from about 20° C. to about 200° C. or from about 50° C. to about 150° C. and the second temperature may be from about 200° C. to about 450° C. or from about 300° C. to about 400° C.
In one or more embodiments, the transition metal compound includes a metallocene catalyst, a late transition metal catalyst, a post metallocene catalyst or combinations thereof. Late transition metal catalysts may be characterized generally as transition metal catalysts including late transition metals, such as nickel, iron or palladium, for example. Post metallocene catalyst may be characterized generally as transition metal catalysts including Group IV, V or VI metals, for example.
Metallocene catalysts may be characterized generally as coordination compounds incorporating one or more cyclopentadienyl (Cp) groups (which may be substituted or unsubstituted, each substitution being the same or different) coordinated with a transition metal through π bonding.
The substituent groups on Cp may be linear, branched or cyclic hydrocarbyl radicals, for example. The cyclic hydrocarbyl radicals may further form other contiguous ring structures, including indenyl, azulenyl and fluorenyl groups, for example. These contiguous ring structures may also be substituted or unsubstituted by hydrocarbyl radicals, such as C1 to C20 hydrocarbyl radicals, for example.
A specific, non-limiting, example of a metallocene catalyst is a bulky ligand metallocene compound generally represented by the formula:
[L]mM[A]n;
wherein L is a bulky ligand, A is a leaving group, M is a transition metal and m and n are such that the total ligand valency corresponds to the transition metal valency. For example m may be from 1 to 3 and n may be from 1 to 3.
The metal atom “M” of the metallocene catalyst compound, as described throughout the specification and claims, may be selected from Groups 3 through 12 atoms and lanthanide Group atoms, or from Groups 3 through 10 atoms or from Sc, Ti, Zr, Hf. V, Nb, Ta, Mn, Re, Fe, Ru, Os, Co, Rh, Ir and Ni. The oxidation state of the metal atom “M” may range from 0 to +7 or is +1, +2, +3, +4 or +5, for example.
The bulky ligand generally includes a cyclopentadienyl group (Cp) or a derivative thereof. The Cp ligand(s) form at least one chemical bond with the metal atom M to form the “metallocene catalyst.” The Cp ligands are distinct from the leaving groups bound to the catalyst compound in that they are not highly susceptible to substitution/abstraction reactions.
Cp ligands may include ring(s) or ring system(s) including atoms selected from group 13 to 16 atoms, such as carbon, nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron, aluminum and combinations thereof, wherein carbon makes up at least 50% of the ring members. Non-limiting examples of the ring or ring systems include cyclopentadienyl, cyclopentaphenanthreneyl, indenyl, benzindenyl, fluorenyl, tetrahydroindenyl, octahydrofluorenyl, cyclooctatetraenyl, cyclopentacyclododecene, phenanthrindenyl, 3,4-benzofluorenyl, 9-phenylfluorenyl, 8-H-cyclopent[a]acenaphthylenyl, 7-H-dibenzofluorenyl, indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl, hydrogenated versions thereof (e.g., 4,5,6,7-tetrahydroindenyl or “H4Ind”), substituted versions thereof and heterocyclic versions thereof, for example.
Cp substituent groups may include hydrogen radicals, alkyls (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, luoromethyl, fluroethyl, difluroethyl, iodopropyl, bromohexyl, benzyl, phenyl, methylphenyl, tert-butylphenyl, chlorobenzyl, dimethylphosphine and methylphenylphosphine), alkenyls (e.g., 3-butenyl, 2-propenyl and 5-hexenyl), alkynyls, cycloalkyls (e.g., cyclopentyl and cyclohexyl), aryls (e.g., trimethylsilyl, trimethylgermyl, methyldiethylsilyl, acyls, aroyls, tris(trifluoromethyl)silyl, methylbis(difluoromethyl)silyl and bromomethyldimethylgermyl), alkoxys (e.g., methoxy, ethoxy, propoxy and phenoxy), aryloxys, alkylthiols, dialkylamines (e.g., dimethylamine and diphenylamine), alkylamidos, alkoxycarbonyls, aryloxycarbonyls, caromoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, organmetalloid, radicals (e.g. dimethylboron), Group 15 and Group 16 radicals (e.g., methylsulfide and ethylsulfide) and combinations thereof, for example. In one embodiment, at least two substituent groups, two adjacent substituent groups in one embodiment, are joined to form a ring structure.
Each leaving group “A” is independently selected and may include any ionic leaving group, such as halogens (e.g., chloride and fluoride), hydrides, C1 to C12 alkyls (e.g., methyl, ethyl, propyl, phenyl, cyclobutyl, cyclohexyl, heptyl, tolyl, trifluoromethyl, methylphenyl, dimethylphenyl and trimethylphenyl), C2 to C12 alkenyls (e.g., C2 to C6 fluoroalkenyls), C6 to C12 aryls (e.g., C7 to C20 alkylaryls), C1 to C12 alkoxys (e.g., phenoxy, methyoxy, ethyoxy, propoxy and benzoxy), C6 to C16 aryloxys, C7 to C18 alkylaryloxys and C1 to C12 heteroatom-containing hydrocarbons and substituted derivatives thereof, for example.
Other non-limiting examples of leaving groups include amines, phosphines, ethers, carboxylates (e.g., C1 to C6 alkylcarboxylates, C6 to C12 arylcarboxylates and C7 to C18 alkylarylcarboxylates), dienes, alkenes (e.g., tetramethylene, pentamethylene, methylidene), hydrocarbon radicals having from 1 to 20 carbon atoms (e.g., pentafluorophenyl) and combinations thereof, for example. In one embodiment, two or more leaving groups form a part of a fused ring or ring system.
In a specific embodiment, L and A may be bridged to one another to form a bridged metallocene catalyst. A bridged metallocene catalyst, for example, may be described by the general formula:
XCpACpBMAn;
wherein X is a structural bridge, CpA and CpB each denote a cyclopentadienyl group, each being the same or different and which may be either substituted or unsubstituted, M is a transition metal and A is an alkyl, hydrocarbyl or halogen group and n is an integer between 0 and 4, and either 1 or 2 in a particular embodiment.
Non-limiting examples of bridging groups “X” include divalent hydrocarbon groups containing at least one Group 13 to 16 atom, such as, but not limited to, at least one of a carbon, oxygen, nitrogen, silicon, aluminum, boron, germanium, tin and combinations thereof; wherein the heteroatom may also be a C1 to C12 alkyl or aryl group substituted to satisfy a neutral valency. The bridging group may also contain substituent groups as defined above including halogen radicals and iron. More particular non-limiting examples of bridging group are represented by C1 to C6 alkylenes, substituted C1 to C6 alkylenes, oxygen, sulfur, R2C=, R2Si=, —Si(R)2Si(R2)—, R2Ge=or RP=(wherein “=” represents two chemical bonds), where R is independently selected from hydrides, hydrocarbyls, halocarbyls, hydrocarbyl-substituted organometalloids, halocarbyl-substituted organometalloids, disubstituted boron atoms, disubstituted Group 15 atoms, substituted Group 16 atoms and halogen radicals, for example. In one embodiment, the bridged metallocene catalyst component has two or more bridging groups.
Other non-limiting examples of bridging groups include methylene, ethylene, ethylidene, propylidene, isopropylidene, diphenylmethylene, 1,2-dimethylethylene, 1,2-diphenylethylene, 1,1,2,2-tetramethylethylene, dimethylsilyl, diethylsilyl, methyl-ethylsilyl, trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di(n-butyl)silyl, di(n-propyl)silyl, di(i-propyl)silyl di(n-hexyl)silyl, dicyclohexylsilyl, diphenylsilyl, cyclohexylphenylsilyl, t-butylcyclohexylsilyl, di(t-butylphenyl)silyl, di(p-tolyl)silyl and the corresponding moieties, wherein the Si atom is replaced by a Ge or a C atom; dimethylsilyl, diethylsilyl, dimethylgermyl and/or diethylgermyl.
In another embodiment, the bridging group may also be cyclic and include 4 to 10 ring members or 5 to 7 ring members, for example. The ring members may be selected from the elements mentioned above and/or from one or more of boron, carbon, silicon, germanium, nitrogen and oxygen, for example. Non-limiting examples of ring structures which may be present as or part of the bridging moiety are cyclobutylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene, for example. The cyclic bridging groups may be saturated or unsaturated and/or carry one or more substituents and/or be fused to one or more other ring structures. The one or more Cp groups which the above cyclic bridging moieties may optionally be fused to may be saturated or unsaturated. Moreover, these ring structures may themselves be fused, such as, for example, in the case of a naphthyl group.
In one embodiment, the metallocene catalyst includes CpFlu Type catalysts (e.g., a metallocene catalyst wherein the ligand includes a Cp fluorenyl ligand structure) represented by the following formula:
X(CpR1nR2m)(FlR3p);
wherein Cp is a cyclopentadienyl group, Fl is a fluorenyl group, X is a structural bridge between Cp and Fl, R1 is a substituent on the Cp, n is 1 or 2, R2 is a substituent on the Cp at a position which is ortho to the bridge, m is 1 or 2, each R3 is the same or different and is a hydrocarbyl group having from 1 to 20 carbon atoms with at least one R3 being substituted in the para position on the fluorenyl group and at least one other R3 being substituted at an opposed para position on the fluorenyl group and p is 2 or 4.
In yet another aspect, the metallocene catalyst includes bridged mono-ligand metallocene compounds (e.g., mono cyclopentadienyl catalyst components). In this embodiment, the metallocene catalyst is a bridged “half-sandwich” metallocene catalyst. In yet another aspect of the invention, the at least one metallocene catalyst component is an unbridged “half sandwich” metallocene. (See, U.S. Pat. No. 6,069,213, U.S. Pat. No. 5,026,798, U.S. Pat. No. 5,703,187, U.S. Pat. No. 5,747,406, U.S. Pat. No. 5,026,798 and U.S. Pat. No. 6,069,213, which are incorporated by reference herein.)
Non-limiting examples of metallocene catalyst components consistent with the description herein include, for example:
In one or more embodiments, the transition metal compound includes cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl, CpFlu, alkyls, aryls, amides or combinations thereof. In one or more embodiments, the transition metal compound includes a transition metal dichloride, dimethyl or hydride. In one or more embodiments, the transition metal compound may have C1, Cs or C2 symmetry, for example. In one specific embodiment, the transition metal compound includes rac-dimethylsilanylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride.
One or more embodiments may further include contacting the fluorinated support with a plurality of catalyst compounds (e.g., a bimetallic catalyst.) As used herein, the term “bimetallic catalyst” means any composition, mixture or system that includes at least two different catalyst compounds, each having a different metal group. Each catalyst compound may reside on a single support particle so that the bimetallic catalyst is a supported bimetallic catalyst. However, the term bimetallic catalyst also broadly includes a system or mixture in which one of the catalysts resides on one collection of support particles and another catalyst resides on another collection of support particles. The plurality of catalyst components may include any catalyst component known to one skilled in the art, so long as at least one of those catalyst components includes a transition metal compound as described herein.
As demonstrated in the examples that follow, contacting the fluorinated support with the transition metal ligand via the methods described herein unexpectedly results in a supported catalyst composition that is active without alkylation processes (e.g., contact of the catalyst component with an organometallic compound, such as MAO.)
The absence of substances, such as MAO, generally results in lower polymer production costs as alumoxanes are expensive compounds. Further, alumoxanes are generally unstable compounds that are generally stored in cold storage. However, embodiments of the present invention unexpectedly result in a catalyst composition that may be stored at room temperature for periods of time (e.g., up to 2 months) and then used directly in polymerization reactions. Such storage ability further results in improved catalyst variability as a large batch of support material may be prepared and contacted with a variety of transition metal compounds (which may be formed in small amounts optimized based on the polymer to be formed.)
In addition, it is contemplated that polymerizations absent alumoxane activators result in minimal leaching/fouling in comparison with alumoxane based systems. However, embodiments of the invention generally provide processes wherein alumoxanes may be included without detriment.
Optionally, the fluorinated support and/or the transition metal compound may be contacted with a second aluminum containing compound prior to contact with one another. In one embodiment, the fluorinated support is contacted with the second aluminum containing compound prior to contact with the transition metal compound. Alternatively, the fluorinated support may be contacted with the transition metal compound in the presence of the second aluminum containing compound.
For example, the contact may occur by contacting the fluorinated support with the second aluminum containing compound at a reaction temperature of from about 0° C. to about 150° C. or from about 20° C. to about 100° C. for a time of from about 10 minutes hour to about 5 hours or from about 30 minutes to about 120 minutes, for example. reside on a single support particle so that the bimetallic catalyst is a supported bimetallic catalyst. However, the term bimetallic catalyst also broadly includes a system or mixture in which one of the catalysts resides on one collection of support particles and another catalyst resides on another collection of support particles. The plurality of catalyst components may include any catalyst component known to one skilled in the art, so long as at least one of those catalyst components includes a transition metal compound as described herein.
As demonstrated in the examples that follow, contacting the fluorinated support with the transition metal ligand via the methods described herein unexpectedly results in a supported catalyst composition that is active without alkylation processes (e.g., contact of the catalyst component with an organometallic compound, such as MAO.)
The absence of substances, such as MAO, generally results in lower polymer production costs as alumoxanes are expensive compounds. Further, alumoxanes are generally unstable compounds that are generally stored in cold storage. However, embodiments of the present invention unexpectedly result in a catalyst composition that may be stored at room temperature for periods of time (e.g., up to 2 months) and then used directly in polymerization reactions. Such storage ability further results in improved catalyst variability as a large batch of support material may be prepared and contacted with a variety of transition metal compounds (which may be formed in small amounts optimized based on the polymer to be formed.)
In addition, it is contemplated that polymerizations absent alumoxane activators result in minimal leaching/fouling in comparison with alumoxane based systems. However, embodiments of the invention generally provide processes wherein alumoxanes may be included without detriment.
Optionally, the fluorinated support and/or the transition metal compound may be contacted with a second aluminum containing compound prior to contact with one another. In one embodiment, the fluorinated support is contacted with the second aluminum containing compound prior to contact with the transition metal compound. Alternatively, the fluorinated support may be contacted with the transition metal compound in the presence of the second aluminum containing compound.
For example, the contact may occur by contacting the fluorinated support with the second aluminum containing compound at a reaction temperature of from about 0° C. to about 150° C. or from about 20° C. to about 100° C. for a time of from about 10 minutes hour to about 5 hours or from about 30 minutes to about 120 minutes, for example.
The second aluminum containing compound may include an organic aluminum compound. The organic aluminum compound may include TEAl, TIBAl, MAO or MMAO, for example. In one embodiment, the organic aluminum compound may be represented by the formula AlR3, wherein each R is independently selected from alkyls, aryls or combinations thereof.
In one embodiment, the weight ratio of the silica to the second aluminum containing compound (Si:Al2) is generally from about 0.01:1 to about 10:1, for example
While it has been observed that contacting the fluorinated support with the second aluminum containing compound results in a catalyst having increased activity, it is contemplated that the second aluminum containing compound may contact the transition metal compound. When the second aluminum containing compound contacts the transition metal compound, the weight ratio of the second aluminum containing compound to transition metal (Al2:M) is from about 0.1: to about 5000:1, for example.
Optionally, the fluorinated support may be contacted with one or more scavenging compounds prior to or during polymerization. The term “scavenging compounds” is meant to include those compounds effective for removing impurities (e.g., polar impurities) from the subsequent polymerization reaction environment. Impurities may be inadvertently introduced with any of the polymerization reaction components, particularly with solvent, monomer and catalyst feed, and adversely affect catalyst activity and stability. Such impurities may result in decreasing, or even elimination, of catalytic activity, for example. The polar impurities or catalyst poisons may include water, oxygen and metal impurities, for example.
The scavenging compound may include an excess of the first or second aluminum compounds described above, or may be additional known organometallic compounds, such as Group 13 organometallic compounds. For example, the scavenging compounds may include triethyl aluminum (TMA), triisobutyl aluminum (TIBAl), methylalumoxane (MAO), isobutyl aluminoxane and tri-n-octyl aluminum. In one specific embodiment, the scavenging compound is TIBAl.
In one embodiment, the amount of scavenging compound is minimized during polymerization to that amount effective to enhance activity and avoided altogether if the feeds and polymerization medium may be sufficiently free of impurities.
As indicated elsewhere herein, catalyst systems are used to form polyolefin compositions. Once the catalyst system is prepared, as described above and/or as known to one skilled in the art, a variety of processes may be carried out using that composition. The equipment, process conditions, reactants, additives and other materials used in polymerization processes will vary in a given process, depending on the desired composition and properties of the polymer being formed. Such processes may include solution phase, gas phase, slurry phase, bulk phase, high pressure processes or combinations thereof, for example. (See, U.S. Pat. No. 5,525,678, U.S. Pat. No. 6,420,580, U.S. Pat. No. 6,380,328, U.S. Pat. No. 6,359,072, U.S. Pat. No. 6,346,586, U.S. Pat. No. 6,340,730, U.S. Pat. No. 6,339,134, U.S. Pat. No. 6,300,436, U.S. Pat. No. 6,274,684, U.S. Pat. No. 6,271,323, U.S. Pat. No. 6,248,845, U.S. Pat. No. 6,245,868, U.S. Pat. No. 6,245,705, U.S. Pat. No. 6,242,545, U.S. Pat. No. 6,211,105, U.S. Pat. No. 6,207,606, U.S. Pat. No. 6,180,735 and U.S. Pat. No. 6,147,173, which are incorporated by reference herein.)
In certain embodiments, the processes described above generally include polymerizing olefin monomers to form polymers. The olefin monomers may include C2 to C30 olefin monomers, or C2 to C12 olefin monomers (e.g., ethylene, propylene, butene, pentene, methylpentene, hexene, octene and decene), for example. Other monomers include ethylenically unsaturated monomers, C4 to C18 diolefins, conjugated or nonconjugated dienes, polyenes, vinyl monomers and cyclic olefins, for example. Non-limiting examples of other monomers may include norbornene, nobomadiene, isobutylene, isoprene, vinylbenzocyclobutane, sytrene, alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene and cyclopentene, for example. The formed polymer may include homopolymers, copolymers or terpolymers, for example.
Examples of solution processes are described in U.S. Pat. No. 4,271,060, U.S. Pat. No. 5,001,205, U.S. Pat. No. 5,236,998 and U.S. Pat. No. 5,589,555, which are incorporated by reference herein.
One example of a gas phase polymerization process includes a continuous cycle system, wherein a cycling gas stream (otherwise known as a recycle stream or fluidizing medium) is heated in a reactor by heat of polymerization. The heat is removed from the cycling gas stream in another part of the cycle by a cooling system external to the reactor. The cycling gas stream containing one or more monomers may be continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. The cycling gas stream is generally withdrawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer product may be withdrawn from the reactor and fresh monomer may be added to replace the polymerized monomer. The reactor pressure in a gas phase process may vary from about 100 psig to about 500 psig, or from about 200 psig to about 400 psig or from about 250 psig to about 350 psig, for example. The reactor temperature in a gas phase process may vary from about 30° C. to about 120° C., or from about 60° C. to about 115° C., or from about 70° C. to about 110° C. or from about 70° C. to about 95° C., for example. (See, for example, U.S. Pat. No. 4,543,399, U.S. Pat. No. 4,588,790, U.S. Pat. No. 5,028,670, U.S. Pat. No. 5,317,036, U.S. Pat. No. 5,352,749, U.S. Pat. No. 5,405,922, U.S. Pat. No. 5,436,304, U.S. Pat. No. 5,456,471, U.S. Pat. No. 5,462,999, U.S. Pat. No. 5,616,661, U.S. Pat. No. 5,627,242, U.S. Pat. No. 5,665,818, U.S. Pat. No. 5,677,375 and U.S. Pat. No. 5,668,228, which are incorporated by reference herein.) In one embodiment, the polymerization process is a gas phase process and the transition metal compound used to form the supported catalyst composition is CpFlu.
Slurry phase processes generally include forming a suspension of solid, particulate polymer in a liquid polymerization medium, to which monomers and optionally hydrogen, along with catalyst, are added. The suspension (which may include diluents) may be intermittently or continuously removed from the reactor where the volatile components can be separated from the polymer and recycled, optionally after a distillation, to the reactor. The liquefied diluent employed in the polymerization medium may include a C3 to C7 alkane (e.g., hexane or isobutene), for example. The medium employed is generally liquid under the conditions of polymerization and relatively inert. A bulk phase process is similar to that of a slurry process. However, a process may be a bulk process, a slurry process or a bulk slurry process, for example.
In a specific embodiment, a slurry process or a bulk process may be carried out continuously in one or more loop reactors. The catalyst, as slurry or as a dry free flowing powder, may be injected regularly to the reactor loop, which can itself be filled with circulating slurry of growing polymer particles in a diluent, for example. Optionally, hydrogen may be added to the process, such as for molecular weight control of the resultant polymer. The loop reactor may be maintained at a pressure of from about 27 bar to about 45 bar and a temperature of from about 38° C. to about 121° C., for example. Reaction heat may be removed through the loop wall via any method known to one skilled in the art, such as via a double-jacketed pipe.
Alternatively, other types of polymerization processes may be used, such stirred reactors in series, parallel or combinations thereof, for example. Upon removal from the reactor, the polymer may be passed to a polymer recovery system for further processing, such as addition of additives and/or extrusion, for example.
The polymers (and blends thereof) formed via the processes described herein may include, but are not limited to, linear low density polyethylene, elastomers, plastomers, high density polyethylenes, low density polyethylenes, medium density polyethylenes, polypropylene (e.g., syndiotactic, atactic and isotactic) and polypropylene copolymers, for example.
In one embodiment, the polymer includes syndiotactic polypropylene. The syndiotactic polypropylene may be formed by a supported catalyst composition including CpFlu as the transition metal compound.
In one embodiment, the polymer includes isotactic polypropylene. The isotactic polypropylene may be formed by a supported catalyst composition including [m] as the transition metal compound.
In one embodiment, the polymer includes a bimodal molecular weight distribution. The bimodal molecular weight distribution polymer may be formed by a supported catalyst composition including a plurality of transition metal compounds.
In one or more embodiments, the polymer has a narrow molecular weight distribution (e.g., a molecular weight distribution of from about 2 to about 4.) In another embodiment, the polymer has a broad molecular weight distribution (e.g., a molecular weight distribution of from about 4 to about 25.)
The polymers and blends thereof are useful in applications known to one skilled in the art, such as forming operations (e.g., film, sheet, pipe and fiber extrusion and co-extrusion as well as blow molding, injection molding and rotary molding). Films include blown or cast films formed by co-extrusion or by lamination useful as shrink film, cling film, stretch film, sealing films, oriented films, snack packaging, heavy duty bags, grocery sacks, baked and frozen food packaging, medical packaging, industrial liners, and membranes, for example, in food-contact and non-food contact application. Fibers include melt spinning, solution spinning and melt blown fiber operations for use in woven or non-woven form to make filters, diaper fabrics, medical garments and geotextiles, for example. Extruded articles include medical tubing, wire and cable coatings, geomembranes and pond liners, for example. Molded articles include single and multi-layered constructions in the form of bottles, tanks, large hollow articles, rigid food containers and toys, for example.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof and the scope thereof is determined by the claims that follow.
As used in the examples, silica-alumina refers to silica alumina that was obtained from Fuji Sylisia Chemical LTD (Silica-Alumina 205 20 μm), such silica having a surface area of 260 m2/g, a pore volume of 1.30 mL/g, an aluminum content of 4.8 wt. %, an average particle size of 20.5 μn and a pH of 6.5.
Unless otherwise specified, the fluorination of the alumina-silica was accomplished by slurrying 5.0 g of alumina-silica in 15 mL of water at ambient temperature. 0.30 g of NHF.HF (in 10 mL of water) was added to the slurry. The resulting mixture was then placed under partial vacuum at 90° C. in a rotavap. Heat treatment profile 1 included heating the resulting dry solids in a muffle furnace at 400° C. for 3 hours. Heat treatment profile 2 included heating the resulting dry solids in a muffle furnace at 260° C. for 1 hour and then at 400° C. for 3 hours. The solids were left to cool to ambient temperature and placed under vacuum.
Unless otherwise specified, the first catalyst preparation method (“isolated method”) included mixing 1 g. of the fluorinated support in 6 mL of toluene with 4 g. of TIBAL (25.2 wt. % in heptane) at a 1:1 wt. ratio and stirring with a magnetic stir bar for 5 minutes at ambient temperature. 10 mg. of dimethylsilylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride was then added at ambient temperature. The mixture was then stirred for 1 hour and filtered. The resulting solids were washed with 6 mL of toluene, washed twice with 5 mL of hexane and dried under vacuum. The dried solids were then slurried in 12.3 g. of mineral oil and stored at −35° C. until use for polymerizations.
Unless otherwise specified, the second catalyst preparation method (“one pot”) included mixing 10 mg. of dimethylsilylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride with 4.0 g of TIBAL (25.2 wt. % in heptane) and stirring the mixture for about 15 minutes at ambient temperature. 1.0 g of the fluorinated support was then added as a dry powder and the mixture was stirred for another 15 minutes. 6 g. of mineral oil were then added and the resulting mixture was stirred for 5 minutes.
Propylene Polymerizations: The catalyst slurry was then contacted with propylene monomer to form polymer. The polymerization conditions and results of each polymerization follow in Tables 1, 2 and 3.
Unexpectedly, it was observed that both heat treatment profiles resulted in approximately the same catalytic activity and properties. Further, it was observed that the highest catalyst activity was observed for the catalyst prepared with 6 wt. % fluorinating agent. It was further observed that one-pot catalyst preparation resulted in higher catalyst activity than the isolated method. In addition, the one-pot method produced polymer having a higher molecular weight.
Ethylene/Propylene Polymerizations: The catalyst slurry was then contacted with propylene monomer to form polymer. The polymerization conditions and results of each polymerization follow in Tables 4 and 5.
Unexpectedly, it was observed that the fluorinated alumina-silica catalyst activity increased with an increase in the ethylene content of the feed. However, the activity of the MAO/SiO2 catalyst remained relatively constant. Further, the melt flow if the fluorinated alumina-silica decreased with an increase in ethylene content, while the melt flow of the comparison system did not change.
Effect of % fluorine: Several samples of prepared fluorinated supports were analyzed for the amount of fluoride content. The Small Glass
It was observed that the highest fluoride content was obtained when the fluorinating process was carried out under open glass dish heat treatments at 400° C. for 5 hours, which also resulted in the highest activity.
Stability: A 20-gram sample of NH4F.HF supported AlSiO2 was heat-treated using the small glass dish heat treatment method (method A1). The resulting F—AlSiO2 support was used to prepare catalyst using the insitu catalyst preparation method. The catalyst system was then tested for stability at 0° C. and at ambient temperature (25° C.).
Effect of Supporting Methods: Method A was achieved by slurrying 5.04 grams of alumina-silica in 10 mL of water at ambient temperature. To the silica/water slurry, a solution of 0.52 grams of NHF.HF in 15 mL of water was added at ambient temperature (25° C.). The resulting “wet” solids were then placed under partial vacuum (15 in. Hg) at 90° C. in a rotavap to remove the water.
Method B was a achieved adding about 3.15 L of water to a 3 gallon HDPE bucket that was equipped with a mechanical stirrer (4.5″L×3.5″ W anchor-type). About 1.0 Kg of alumina-silica were slowly added to the water while maintaining agitation at 60 rpm. To the thick slurry, a solution of 100 grams of NH4F.HF in 800 mL of water were slowly added while stirring at ambient temperature. The mixture was left to stir for 1 hour at ambient temperature.
Method 1 was achieved by adding to a 3.0-L, 1-neck ( 24/40), round bottom flask, the white slurry until the flask was about ⅔ full. The flask was attached to a rotavap that was equipped with a mineral oil bath and two-piece cold trap style condenser. The condenser was charged with ice and the flask was placed under full vacuum (760 mm mercury; dry vacuum pump). The flask was rotated at 60 rpm while the bath temperature increased from ambient temperature up to 95° C. The water was removed after 2 hours. The supported NH4F.HF on AlSiO2 was obtained as a semi-wet solid.
Method 2 was achieved by charging a vessel to about ¾ full with the water slurry of the supported NH4F.HF on AlSiO2. The flask was equipped with a stir shaft that contained 4 kneading propeller-type impellors. The flask was closed with a 3 ( 24/40) neck lid and placed in a mineral oil bath. The slurry was heated from ambient temperature to 115° C. under a slow nitrogen purge while stirring. After 3 hours, about 34 of the water evaporated and stirring was not possible. The stirrer and the oil bath were turned off and the slurry was left to slowly cool in the bath with a slow nitrogen flow overnight. The water evaporated overnight.
Heat treatment Method Al was achieved by placing 20 gram of the supported NH4F.HF on AlSiO2 solid mixture in a small glass dish. The dish was placed in a muffle furnace and heated at 400° C. for 3 hours. While still “hot” (about 250° C.), the solids were transferred into a “hot” (about 110° C.) schlenk round bottom flask. The flask was capped with a rubber septa and placed under vacuum while it cooled to ambient temperature. The solids were then stored under nitrogen.
Heat treatment Method A2 was achieved by charging a 3L round bottom flask (1-neck, 24/40) (⅔ full) with the supported ammonium bifluoride salt on AlSiO2. The 3L flask was then placed in a muffle furnace and heat-treated for 5 hours at 400° C. The flask was removed from the muffle furnace and cooled to about 250° C. The flask was then equipped with a coarse glass filter adapter and placed in a vacuum atmosphere's antechamber where it was then placed under vacuum and backfilled with nitrogen three times. The flask was then stored under nitrogen in a glove box.
Heat treatment Method A3 was achieved by transferring the contents from each 3L Flask into two medium (170 mm O.D.×90 mm Height) glass dishes and two large (190 mm O.D.×100 mm Height) glass dishes. The glass dishes were then placed in a muffle furnace at 350° C. After 1.0 hour, the temperature reached to 400° C. and left at this temperature for 5 hours. The dish was taken out of the muffle furnace and place in a hood to cool to about 250° C. (thermocouple). The solids were slowly transferred into a 2 gallon pressure/vacuum vessel (Alloy Products) that was equipped with a metal funnel. The process was repeated for the second dish. The vessel was placed under vacuum (−30 in. Hg) overnight. The vessel was transferred into a glove box and slowly filled with nitrogen. (1195-002). The catalysts were then exposed to polymerization.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11413791 | Apr 2006 | US |
| Child | 11529903 | US |
