Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/04—Monomers containing three or four carbon atoms
  • C08F110/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
  • C08F4/62—Refractory metals or compounds thereof
  • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
  • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
  • C08F4/65908—Component covered by group C08F4/64 containing a transition metal-carbon bond in combination with an ionising compound other than alumoxane, e.g. (C6F5)4B-X+
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
  • C08F4/62—Refractory metals or compounds thereof
  • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
  • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
  • C08F4/6592—Component covered by group C08F4/64 containing a transition metal-carbon bond containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring

Definitions

• This invention relates to an ionic catalytic process for the production of poly- -olefin resins which process permits improved control over tacticity, molecular weight and molecular weight distribution.
• Such poly- ⁇ -olefins are produced to the desired tactic configurations by polymerization of ⁇ -olefin monomers in the presence of a catalyst system comprising an ionic reaction product of a cyclopentadienyl Group 4 metal compound (hereafter a "metallocene”) of specific structure and an activator compound comprising a cation which is capable of reacting with a non-cyclopentadienyl ligand of the metallocene and an anion which is compatible with and non-coordinating to the metallocene cation generated upon reaction of the metallocene with said activator compound.
• a catalyst system comprising an ionic reaction product of a cyclopentadienyl Group 4 metal compound (hereafter a "metallocene”) of specific structure
• the catalyst system can be tailored to the production of the desired wight average molecular weight (M w ) poly- -olefins with end group functionalization and select tacticity type and level such as isotactic, syndiotactic or hemiisotactic configurations.
• M w wight average molecular weight
• Polymers comprised of ⁇ -olefin monomers have hydrocarbyl groups pendent from the polymer backbone chain. Relative to the polymer backbone chain, the pendent hydrocarbyl groups may be arranged in different stereochemical configurations which are denominated as atactic, isotactic, or syndiotactic pendent group configuration.
• the degree and type of tacticity of a polyolefin molecule is a critical determinant of the physical properties which a resin composed of such polymer molecules will exhibit.
• the weight average molecular weight (M w ) of a poly- ⁇ -olefin is an important physical property determinant of the practical uses to which such polymer can be put.
• the M w of such a resin must generally be in excess of 100,000.
• the poly- -olefin resin must generally have a high degree of crystallinity.
• the degree of crystallinity which a poly- ⁇ -olefin is capable of obtaining is, in major part, determined by the stereochemical regularity of the hydrocarbyl groups which are pendent to the polymer molecule backbone, i.e., the tacticity of the polymer.
• tacticity Five types have been described in poly- ⁇ -olefins: atactic, normal isotactic, isotactic stereoblock, syndiotactic, and hemiisotactic. Although all of these tacticity configurations have been primarily demonstrated in the case of polypropylene, in theory each is equally possible for polymer comprised of any ⁇ -olefin, cyclic olefin or internal olefin.
• the final resin properties and its suitability for particular applications depend on the type of tacticity, (stereoregularity) the melting point, the average molecular weight, the molecular weight distribution, the type and level of monomer and comonomer, the sequence distribution, and the presence or absence of head or end group functionality.
• the catalyst system by which such a stereoregular poly- ⁇ -olefin resin is to be produced should, desirably, be versatile in terms of M w , MWD, tacticity type and level, and comonomer choice. Further, the catalyst system should be capable of producing these polymers with or without head and/or end group functionality, such as olefinic unsaturation.
• Such catalyst system must be capable, as a commercially practical constraint, of producing such resins at an acceptable production rate.
• the catalyst system should be one which, at its productivity rate, provides a resin product which does not require a subsequent treatment to remove catalyst residue to a level which is acceptable for the resin in the end use application desired.
• an important feature of a commercial catalyst system is its adaptability to a variety of processes and conditions.
• Conventional titanium based Ziegler-Natta catalysts for the preparation of isotactic polymers are well known in the art. These commercial catalysts are well suited for the production of highly crystalline, high molecular weight materials. The systems are, however, limited in terms of molecular weight, molecular weight distribution, and tacticity control. The fact that the conventional catalysts contain several types of active sites further limits their ability to control the composition distribution in copolymerization.
• U.S. Patent No. 4,794,096 discloses a chiral, stereorigid metallocene catalyst which is activated by an alumoxane cocatalyst which is reported to polymerize olefins to isotactic polyolefin forms.
• Alumoxane cocatalyzed metallocene structures which have been reported to polymerize stereoregularly are the ethylene-bridged bis(tetrahydroindenyl) titanium and -zirconium (IV) catalyst. Wild et al, in J. Organomet. Chem.
• metallocene-alumoxane produced isotactic poly- ⁇ -olefin resins generally have a higher than desired catalyst residue content.
• Syndiotactic polyolefins were first disclosed by Natta et al. in U.S. Patent No. 3,258,455. As reported, Natta obtained syndiotactic polypropylene by using a catalyst prepared from titanium trichloride and diethyl aluminum monochloride. A later patent to Natta et al., U.S. Patent No. 3,305,538, discloses the use of vanadium triacetylacetonate or halogenated vanadium compounds in combinations with organic aluminum compounds for production of syndiotactic polypropylene.
• U.S. Patent No. 4,892,851 describes catalyst systems consisting of a bridged metallocene having at least two differently substituted cyclopentadienyl ring ligands which, when cocatalyzed with an alumoxane, is stated to be capable of production of syndiotactic polypropylene. Again, in commercial production to obtain a sufficient productivity level with such catalyst system, the content of alumoxane is undesirably high and consequently the catalyst residue in the resin so produced is undesirable.
• Ionically activated catalyst systems are becoming more desirable to minimize or avoid difficulties encountered with alumoxane activated systems.
• the first of various publications regarding ionic activators was by Turner et al. in EPA 277,004 and EPA 277,003.
• EPA 277,004 and 277,003 describe bis- cylopentadienyl metallocene catalyts for the production of homo-or co ⁇ polymers of polyolefins, including polypropylene.
• PCT application WO 92/05208 describes bis-cyclopentadienyl, ionically activated moieties useful for the production of syndiotactic polypropylene.
• Dow Corporation has several publications which describe mono-cyclopentadienyl, ionically activated moieties useful for the production of polyolefins, however the teachings of the publications are to polyethylene, not stereoregular polypropylene or polymers having stereoregular characteristics.
• the invention comprises a highly versatile process and catalyst system for the production of stereoregular polyolefins, particularly useful for the production of controlled tacticity poly- ⁇ -olefins with variable molecular weight, molecular weight distribution, stereoregularity and end group functionalization.
• the process comprises contacting ⁇ -olefin monomer and comonomers in a suitable solvent at a temperature of from about -10° C to about 300° C with an ionic catalyst to produce a polymer.
• the ionic catalyst comprises a cationic cyclopentadienyl derivative of the Group 4 metals, said derivatives containing at least one cyclopentadienyl (Cp) ligand, electrochemically balanced by one or more non-coordinating anions.
• the cyclopentadienyl Group 4 metal component (hereafter referred to as a "metallocene”) selected for the ionic catalyst is a chiral racemic compound
• a poly- ⁇ - olefin which is predominantly of an isotactic stereochemical configuration
• the metallocene selected for the ionic catalyst is a bridged stereorigid compound composed of one Cp ligand and a heteroatom ligand, there may also be produced a poly- ⁇ -olefin which is predominantly of the syndiotactic stereochemical configuration.
• the ionic catalyst system of this invention derivated from a particular metallocene complex will produce a polymer having the same type of tacticity which would be produced using methylalumoxane as the activating reagent.
• the ionic catalyst system allows new levels of control of the polymer properties (M w , MWD, tacticity level, end groups, comonomer content, etc.) for a single metallocene precursor by use of various non-coordinating anions as well as by the addition of third components such as Lewis bases and chiral Lewis bases. It has been discovered that the structure of the non- coordinating anion in the ionic catalyst species has a dramatic effect on the activity, molecular weight, comonomer incorporation, and end group unsaturation.
• This versatility is important in the use of metallocene catalysts to produce a broad family of polyolefins (e.g., PE, LLDPE, EP, PP etc.) but it is particularly important for the production of tacticity controlled poly- ⁇ -olefins (e.g., syndiotactic, isotactic) because 1) the preparation of new bridged metallocene structures is synthetically difficult 2) adjusting process parameters such as temperature or monomer concentration to adjust the molecular weight of the product also affects the level of tacticity and the melting point, and 3) use of chain transfer agents such as H2 to lower the molecular weight causes loss of end-group unsaturation which is a desirable and unique feature of poly- ⁇ -olefins produced using metallocene-based catalysts.
• tacticity controlled poly- ⁇ -olefins e.g., syndiotactic, isotactic
• Advantages of employing monocyclopentadienyl-heteroatom mettallocene catalyst activated by ionic systems include: (1) greater ability than bis (cyclopentadienyl) metalloanes to incoporation larger alpja olefins; (2) the ability to produce high molecular weight polymers, especially when using Ti based metallocenes.
• the invention provides a method for producing a poly- ⁇ -olefin of a desired stereochemical configuration.
• the poly- ⁇ -olefin polymers may be produced to a weight average molecular weight (M w ) which suits it to high strength applications, and the so produced resin contains minimal catalyst residue which does not require deashing of the resin to render it suitable for desired end use applications.
• M w weight average molecular weight
• the ionic catalysts used in this invention to produce stereoregular poly- -olefins can be represented by one of the following general formulae:
• (C5H5.y. x S x ) is a cyclopentadienyl ring substituted with from zero to five S radicals; x is from 1 to 5 denoting the degree of substitution;
• M is titanium, zirconium or hafnium; is a neutral Lewis base;
• A' is a bridging group, which group may serve to restrict rotation of the Cp and Cp* rings;
• Xl is a hydride radical, hydrocarbyl radical, substituted-hydrocarbyl radical, hydrocarbyl-substituted organometalloid radical or halocarbyl- substituted organometalloid radical;
• X5 is a hydride radical, hydrocarbyl radical or substituted-hydrocarbyl radical, halocarbyl radical or substituted halocarbyl radical, hydrocarbyl- substituted organometalloid radical or halocarbyl-substituted organometalloid radical, which radical may optionally be covalently bonded to both M and L';
• J is an element from Group 15 of the Periodic Table of Elements with a coordination number of 3 or an element from Group 16 with a coordination number of 2;
• S' is a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl-substituted organometalloid, or halocarbyl- substituted organometalloid; and
• z is the coordination number of the element J;
• y is O or l;
• w is an integer from 0 to 3;
• B' is a chemically stable, non-nucleophilic anionic complex preferrably having a molecular diameter about or greater than 4 angstroms; and d is an integer representing the charge of B ⁇
• the improved catalysts are preferably prepared by combining at least two components.
• the first component is a cyclopentadienyl derivative of a Group 4 metal compound containing at least one ligand which will combine with the second component or at least a portion thereof such as a cation portion thereof.
• the second component is an ion-exchange compound comprising a cation which will irreversibly react with at least one ligand contained in said Group 4 metal compound (first component) and a non- coordinating anion which is either a single coordination complex comprising a plurality of lipophilic radicals covalently coordinated to and shielding a central formally charge-bearing metal or metalloid atom or an anion comprising a plurality of boron atoms such as polyhedral boranes, carboranes and metallacarboranes.
• the cation portion of the second component may comprise Bronsted acids such as protons or protonated Lewis bases or may comprise reducible Lewis acids such as ferricinum, troplium, triphenylcarbenium or silver cations.
• suitable anions for the second component may be any stable and bulky anionic complex having the following attributes: 1) the anion should have a molecular diameter greater than 4 angstroms; 2) the anion should form stable ammonium salts; 3) the negative charge on the anion should be delocalized over the framework of the anion or be localized within the core of the anion; 4) the anion should be a relatively poor nucleophile; and 5) the anion should not be a powerful reducing or oxidizing agent.
• Anions meeting these criterias such as polynuclear boranes, carboranes, metallacarboranes, polyoxoanions and anionic coordination complexes are well described in the chemical literature.
• the cation of the second component reacts with one of the ligands of the first component, thereby generating an anion pair consisting of a Group 4 metal cation and the aforementioned anion, which anion is compatible with and noncoordinating towards the Group 4 metal cation formed from the first component.
• the anion of the second compound must be capable of stabilizing the Group 4 metal cation without interfering with the Group 4 metal cation's ability to function as a catalyst and must be sufficiently labile to permit displacement by an olefin, diolefin or an acetylenically unsaturated monomer during polymerization.
• the Group 4 metal compounds i.e., titanium zirconium and hafnium metallocene compounds, useful as first compounds in the preparation of the improved catalyst of this invention are cyclopentadienyl derivatives of titanium, zirconium and hafnium.
• useful complexes may be represented by the following general formula:
• the Group 4 metal compounds useful as the first component in ionic catalyst system for the production of crystalline poly- ⁇ -olefins are cyclopentadienyl derivatives of titanium, zirconium or hafnium which compounds are either chiral racemic compounds, or are non-chiral bridged stereorigid compounds composed of two differently substituted ligands.
• Such metallocene compounds are represented by the general formula set forth in equation 1-3, wherein M, Xi , X2 and L are defined as in Equations 1-2 and (1)
• A' is a divalent hydrocarbyl or silahydrocarbyl radical which structurally bridges together the cyclopentadienyl ring and the J ligand group to impart stereorigidity to the Group 4 metal compound such that the Group 4 metal compound is a chiral compound either in its pure L or pure D optical isomer form or a racemic mixture thereof; or
• A' is a divalent hydrocarbyl or silahydrocarbon radical which structurally bridges ligands having distinctly different chemical structures.
• Preferable metallocene precursors for producing poly- ⁇ -olefins having enhanced isotactic character are those where S and S' are chosen such that the metallocene framework has no plane of symmetry containing the metal center.
• Preferable metallocene precursors for the production of poly- ⁇ -olefins having enhanced syndiotactic character are also those where S and S' are chosen such that the ligands are coordinated with the transition metal and have substantially different steric bulk.
• S and S' are chosen such that the ligands are coordinated with the transition metal and have substantially different steric bulk.
• the pattern of the groups substituted on the Cp-ring is important.
• stereo difference or “sterically different” as used herein, it is intended to imply a difference between the steric characteristics of the Cp ring and heteroatom ligand that renders each to be symmetrical with respect to the A' bridging group but different with respect to each other that controls the approach of each successive monomer unit that is added to the polymer chain.
• the steric difference between the Cp ring and the heteroatom ligand acts to block the approaching monomer from a random approach such that the monomer is added to the polymer chain in the syndiotactic configuration.
• Preferable metallocene precursors for the production of syndiotactic polymers are those where S and S' are chosen such that the steric difference between the Cp and heteroatom ligand is maximized.
• the chiral and non-chiral bridged metallocene precursors for the formation of the ionic catalysts of this invention may be prepared by methods known in the art.
• the synthesis process generally comprises the steps of 1) preparing the ligand, 2) deprotonating the acidic protons of the ligand (using BuLi, KH or other strong bases), 3) reacting the deprotonated ligand with the halide of the transition metal, 4) purifying the metallocene halide complex, and 5) reacting the metallocene dihalide with MeLi or a hydride source to give the final product.
• a method of preparing these compounds is by reacting a cyclopentadienyl lithium compound with a dihalo compound whereupon a lithium halide salt is liberated and a monohalo substituent is covalently bound to the cyclopentadiene.
• the substituted cyclopentadiene is then reacted with a lithium salt of the heteroatom (for the sake of illustration, a lithium amide) whereupon the halide is eliminated from the monohalo substituent group, forming thereby a lithium halide salt with the heteroatom group, preferably an amide, covalently bonded to the substituent of the cyclopentadienyl reaction product.
• a lithium salt of the heteroatom for the sake of illustration, a lithium amide
• the resulting cyclopentadienyl derivative is then reacted with a base, preferably an alkyllithium, to remove the labile hydrogen atoms on the heteroatom and on the cyclopentadienyl ring.
• the cyclopentadienyl dianion is reacted with a Group 4 metal compound, preferably a tetrahalide.
• a Group 4 metal compound preferably a tetrahalide.
• the dichloride complex is then converted into the appropriate hydrocarbyl derivative using a Grignard, hthium, sodium, or potassium salt of the hydrocarbyl ligand.
• the procedure is analogous to that used to derivatize known bis(cyclopentadienyl) complexes according to EPA 277,004.
• Preferred heteroatom groups (JS') are amides such as t-butylamide, cyclododecylamide, and mesitylamide.
• Preferred complexes of this type are those in which the bridging (A') group is a dialkyi, diaryl, or alkylaryl silylene or methylene, 1,1-ethylene, or 2,2-propylene. Most preferred bridging groups are dimethylsilylene, diethylsilylene, diphenylsilylene, and methylphenlsilylene.
• Unbridged species can be prepared from a monocyclopentadienyl Group 4 trihalide complex and the lithium salt of a heteroatom moiety (amide, alkoxide, aryloxide, etc.).
• Suitable Group 4 metal compounds illustrative of these unbridged species include (pentamethylcyclopentadienyl) (di-t-butylphosphido) hafnium dimethyl, pentamethylcyclopentadienyl) bis(trimethyl-silyl amido) hafnium dimethyl, and (pentamethylcyclopentadienyl) (t-butoxy) titanium dimethyl.
• a subclass of monocyclopentadienyl complexes, those with fluorenyl groups, have been found to produce syndiotactic polypropylene when used in accord with this invention.
• Lewis acids such as, but not limited to, trialkylaluminums may be added to the catalyst system to modify the stereospecificity of the catalyst.
• the Lewis acid may also be tethered to the transition-metal component of the catalyst through the substituent group on the heteroatom ligand, thus adding chirality to the catalyst system.
• the cyclopentadienyl ligand may not require substituent groups in order to produce poly- ⁇ -olefins or polymers with blocks of isotacticity.
• Compounds useful as an activator component in the preparation of the ionic catalyst systems used in the process of this invention comprise a cation, which is a Bronsted acid capable of reacting with a ligand of the metallocene or first component, and a compatible non-coordinating anion represented by the formula: wherein: M' is a metal or metalloid selected from Groups V-B, VI-B, VII-B,
• VIE I-B, ⁇ -B, II-A rV-A, and V-A of the Periodic Table of Elements
• the anion is relatively large (bulky), capable of stabilizing the active catalyst species (the Group 4 cation) which is formed when the two compounds are combined and said anion is sufficiently labile to be displaced by olefinic diolfinic and acetylenically unsaturated substrates or other neutral Lewis bases such as ethers, nitriles and the like.
• active catalyst species the Group 4 cation
• anion is sufficiently labile to be displaced by olefinic diolfinic and acetylenically unsaturated substrates or other neutral Lewis bases such as ethers, nitriles and the like.
• Two classes of compatible non- coordinating anions have been described in EPA 277,003, EPA 277,004, and U.S.
• activator compounds containing single anionic coordination complexes which are useful in this invention may be represented by the following general formula:
• H is a hydrocarbon atom
• [L'-H] is a Bronsted acid
• M' is a metal or metalloid
• Ql to Q n are, independently, hydride radicals, hydrocarbyl and substituted-hydrocarbyl radicals, halocarbyl and substituted-halocarbyl radicals and hydrocarbyl- and halocarbyl-substituted organometalloid radicals, disubstituted pnictogen radicals, substituted chalcogen radical and any one, but not more than one, of Qi to Q n may be halogen radical; m is an integer representing the valence charge of M'; and n is the total number of ligands Q.
• any metal or metalloid capable of forming an anionic complex which is stable in water may be used or contained in the anion of the second compound.
• Suitable metals include, but are not limited to, aluminum, gold, platinum and the like.
• Suitable metalloids include, but are not limited to, boron, phosphorus, silicon and the like.
• Compounds containing anions which comprise coordination complexes containing a single metal or metalloid atom are, of course, well known and many, particularly such compounds containing a single boron atom in the anion portion, are available commerically. In light of this, salts containing anions comprising a coordination complex containing a single boron atom are preferred.
• the preferred activator compounds comprising boron may be represented by the following general formula:
• Ari and A ⁇ 2 are the same or different aromatic or substituted- aromatic hydrocarbon radicals containing from about 6 to about 20 carbon atoms and may be linked to each other through a stable bridging group; and X3 and X4 are, independently, hydride radicals, hydrocarbyl and substituted-hydrocarbyl radicals, halocarbyl and substituted-halocarbyl radicals, hydrocarbyl- and halocarbyl-substituted organometalloid radicals, disubstituted pnictogen radicals, substituted chalcogen radicals and halide radicals such that X3 and X4 will not be halide at the same time.
• Ari and Ar2 may, independently, be any aromatic or substituted-aromatic hydrocarbon radical.
• Suitable aromatic radicals include, but are not limited to, phenyl, naphthyl and anthracenyl radicals.
• Suitable substituents on the substituted-aromatic hydrocarbon radicals include, but are not necessarily limited to, hydrocarbyl radicals, organometalloid radicals, alkoxy and aryloxy radicals, alkylamido radicals, fluorocarbyl and fluorohydrocarbyl radicals and the Hke such as those useful as X3 and X4.
• the substituent may be ortho, meta or para, relative to the carbon atoms bonded to the boron atom.
• each may be the same or a different aromatic or substituted-aromatic radical as are Ari an d r2, or the same may be a straight or branched alkyl, alkenyl or alkynyl radical, a cyclic hydrocarbon radical or an alkyl-substituted cyclic hydrocarbon radical.
• X3 and X4 may also, independently be alkoxy or dialkylamido radicals wherein the alkyl portion of said alkoxy and dialkylamido radicals, hydrocarbyl radicals and organometalloid radicals and the hke.
• Ari an d Ar2 could be linked to either X3 and X4.
• X3 and X4 may also be linked to each other through a suitable bridging group.
• boron and other metal and metalloid compounds which may be used as an activator component in the preparation of the improved catalyst of this invention are described in EPA 277,004.
• suitable activators as described in EPA 277,004 is not intended to be exhaustive and other useful boron compounds as well as useful compounds containing other metals or metalloids would be readily apparent to those skilled in the art from the foregoing general equations.
• the most preferred activator compounds comprising boron may be represented by the following formula: 6. [L' -H] + [B(C 6 F 5 ) 3 Q]- wherein:
• F is flourine
• C is carbon
• B, L', and Q are defined above.
• Polymeric Q substituents on the most preferred anion offer the advantage of providing a highly soluble ion-exchange activator component and final ionic catalyst.
• Soluble catalysts and/or precursors are often preferred over insoluble waxes, oils, phases, or solids because they can be diluted to a desired concentration and can be transfered easily using simple equipment in commercial processes.
• Activator components based on anions which contain a plurality of boron atoms, as described in EPA 277,003 may be represented by the following general formulae:
• [L'-H] is either H + or a Bronsted acid derived from the protonation of a neutral Lewis base
• X, X', X", X , X ⁇ and Xg are, independently , hydride radicals, halide radicals, hydrocarbyl radicals, substituted-hydrocarbyl radicals, halocarbyl radicals, substituted-halocarbyl radicals, or hydrocarbyl- or halocarbyl substituted organometalloid radicals;
• Preferred anions of this invention comprising a plurality of boron atoms comprise:
• Illustrative, but not limiting, examples of second components which can be used in preparing catalyst systems utilized in the process of this invention wherein the anion of the second component contains a plurality of boron atoms are mono-, di-, trialkylammonium and phosphonium and dialkylarylammonium and -phosphonium salts as described in EPA 277,003.
• List of representative phosphonium compounds can be recited as illustrative second compounds, but it is simply noted that the phosphonium and substituted-phosphonium salts corresponding to the noted ammonium and substituted-ammonium salts found in EPA 277,003 may also be used as second compounds in the present invention.
• metallocene components identified above may be combined with most activator components above to produce an active olefin polymerization catalyst, it is important for continuity of the polymerization operations that either the metal cation initially formed from the metallocene component or a decomposition product thereof be a relatively stable catalyst. It is also important that the anion of the activitator compound be chemically stable and bulky. Further, when the cation of the activator component is a Bronsted acid it is important that the reactivity (i.e., acidity) of the activator component be sufficient, relative to the metallocene component, to facilitate the needed charge (e.g., proton) transfer.
• metallocenes in which the non-cyclopentadienyl and non heteroaton ligands can be hydrolyzed by aqueous solutions can be considered suitable metallocenes for forming the catalysts described herein, because water (the reference Bronsted acid) is a weaker acid than the ammonium ions used as the cation component in the preferred ion-exchange reagents.
• water the reference Bronsted acid
• ammonium ions used as the cation component in the preferred ion-exchange reagents.
• the ionic catalyst compositions used by the process of the present invention will, preferably, be prepared in a suitable solvent or diluent.
• suitable solvents or diluents include any of the solvents known in the art to be useful as solvents in the polymerization of olefins, diolefins and acetylenically unsaturated monomers.
• Suitable solvents include but are not necessarily limited to, straight and branched-chain hydrocarbons such as isobutane, butane, pentane, hexane, heptane, octane and the like; cyclic and alicyclic hydrocarbons such as cyclohexane, cycloheptane, methylcyclohexane, methylcycloheptane and the like and aromatic and alkyl- substituted aromatic compounds such as benzene, toluene, xylene, and the like.
• straight and branched-chain hydrocarbons such as isobutane, butane, pentane, hexane, heptane, octane and the like
• cyclic and alicyclic hydrocarbons such as cyclohexane, cycloheptane, methylcyclohexane, methylcycloheptane and the like and aromatic and alkyl- substituted aromatic
• Suitable solvents also include liquid olefins which may act as monomers or comonomers including propylene, 1-butene, 1-hexene, 3-methyl-l- pentene, 4-methyl-l-pentene, 1,4-hexadiene, 1-octene, 1-decene and the like.
• Suitable solvents further include basic solvents which are not generally useful as polymerization solvents when conventional Ziegler-Natta type polymerization catalysts are used such as chlorobenzene.
• the active catalyst species of the ionic catalyst systems used by the process of this invention is relatively stable and is not subject to the ion equilibrium deactivation as are alumoxane cocatalyzed metallocene catalyst systems.
• metallocene-alumoxane catalyst systems wherein, to obtain a practical level of catalyst productivity it is generally required to use an amount of alumoxane, measured as aluminum atom, to provide a ratio of Aktransition metal well in excess of 1000:1; the ionic catalyst systems used in the process of this invention which are highly productive may be prepared at ratios of metallocene to activator of 10:1 to about 1:1, preferably about 3:1 to 1:1.
• catalyst species depend on such factors as (1) the metallocene used and the degree to which the cyclopentadienyl Ugand of such metallocenes are substituted; (2) the nature of the anion moiety compound and the degree and type of substitution on such anions; (3) the nature of the cation moiety of the second compound, particularly in the case where the counter ion is a proton donor, the molecular size of neutral Lewis base which is liberated from such cation upon loss threrefrom of a proton; and (4) the ratios at which the metallocene and activator compound are employed.
• the two compounds combined for preparation of the active catalyst must be selected so as to avoid transfer of a fragment of the anion, particularly an aryl group, to the metallocene metal cation, thereby forming a catalytically inactive species.
• anions consisting of hydrocarbyl anions there are several means of preventing anion degradation and formation of inactive species.
• One method is to carry out the protonolysis process in the presence of small Lewis bases such as tetrahydrofuran. Discrete complexes can be isolated from these reactions, but the Lewis base is insufficiently labile to be displaced readily by ⁇ -olefin monomers, resulting in, at best, catalysts of very low activity.
• Another method of avoiding deleterious anion degradation is by steric hindrance.
• Anions of the second component which contain aryl groups can be made more resistant to degradation by introducing substituents in the ortho positions of the phenyl rings.
• active metallocene polymerization catalysts can be generated by this method, the complex reaction chemistry often prevents characterization of the catalytically active species.
• Steric hindrance can also result from substitutions on the cyclopentadienyl ring of the metallocene component.
• the high degree of substitution on the cyclopentadienyl ring creates sufficient bulkiness that not only cannot the Lewis base generated by the protonolysis reaction coordinate to the metal but also polyarylborate anions without substituents on the aryl rings do not transfer aryl fragments to generate catalytically inactive species.
• a third means of rendering the anion of the activator compound more resistant to degradation is afforded by fluorine substitution, especially perfluoro substitution, in the anion thereof.
• fluorine substitution especially perfluoro substitution
• One class of suitable non- coordinating anions can be represented by the formula [B(C6F5)3Q] " where Q is a monoanionic non-bridging radical as described above.
• tetra(pentafh ⁇ orophenyl)boron hereafter referred to for convenience by the notation [B(C6F5)4] " ([B(pfp)4]-) is virtually impervious to degradation and can be used with a much wider range of metallocene cations, including those without substitution on the cyclopentadienyl rings, than anions comprising hydrocarbyl radicals.
• the tetra(pentafluorophenyl)boron anion is illustrated below:
• the anion has little or no ability to coordinate to the metallocene cation and is not degraded by the metallocene cation
• structures of the ion-pair metallocene catalyst using the [B(pfp)4J- anion depend on steric hindrance of substituents on the cyclopentadienyl ring of metallocene, the nature of the cation of the activator component, the Lewis base liberated from the protonolysis reaction, and the ratio at which the metallocene and activator component are combined.
• non-coordinating anion contains a plurality of boron atoms as described in general formulae 7 and 8
• more effective catalysts are obtained with activator compounds containing larger anions, such as those encompassed by general formula 8 and those having larger m values in general formula 7.
• a + b + c 2
• Seconds compounds in which a + b + c even-numbered integers of 4 or more have acidic B-H-B moieties which can react further with the metallocene metal cation formed, leading to catalytically inactive compounds.
• the structure of the stable non-coordinating anion has an effect on the polymerization properties of a particular catalyst cation. It has been discovered that even simple changes to the structure of the non-coordinating anion can lead to significant and surprising changes in the polymerization properties of the catalytically active metallocene cation.
• the selected ionic catalyst system for controlled tacticity polyolefin production may be used to produce such poly- ⁇ -olefin by slurry polymerization using the olefin monomer as the polymerization diluent in which the selected catalyst is dissolved in an amount sufficient to yield the type of polymer desired.
• the polymerization process is carried out with a pressure of from about 10 to about 1000 psi (68.9 KPa - 6890 KPa), most preferably from about 40 to 600 5 psi (276 KPa - 4134 KPa).
• the polymerization diluent is maintained at a temperature of from about -10° C to about 150° C, preferably from about 20° C to about 100° C, and most preferably from about 30° C to about 90° C.
• the catalyst systems used by the process of this invention may also be employed in a high temperature/pressure polymerization process. In such, 0 the pressure can be in the range of 5,000-40,000 psi and the temperature in the range of 120-300° C.
• the polymerization may be carried out as a batchwise slurry polymerization or as a continuous process slurry polymerization.
• the procedure of continuous process slurry polymerization is preferred, in which 5 event ⁇ -olefin and catalyst are continuously supplied to the reaction zone in amounts equal to the ⁇ -olefin and catalyst removed from the reaction zone with the polymer in the product stream.
• the catalyst system described herein may optionally be placed on a support medium and employed in such polymerization processes as gas phase polymerization. Additionally, o scavenging agents may be employed during polymerization of olefins.
• anionic complexes of the form [B(pfp)3Q] " can be prepared by the addition of the lithium or Grignard reagents Li[Q] or o MgBr[Q] to B(pfp)3 in ether from which reaction Li[B(pfp)3Q]- is isolated in high yield as an etherate.
• the lithium salt can be converted into the final ammonium salt by treatment with R3NH + C1 " in methylene chloride.
• the insoluble hthium chloride is removed by filtration and the excess ammonium chloride is removed by washing the methylene chloride solution with water. 5
• the methylene chloride solution is dried using Na2S ⁇ 4, filtered and concentrated to the point of crystallization.
• Addition of a counter solvent such as pentene can be used to precipitate [R3NH][B( f )3Q].
• the hthium chloride was removed by filitration, and the resulting methylene chloride solution was washed with water (3 times using 50 ml), dried over Na2S ⁇ 4, filtered and evaporated to dryness.
• the resulting glassy solid (6.5 grams) was characterized by carbon and proton NMR.
• lithiated substituted cyclopentadienyl compounds are typically prepared from the corresponding cyclopentadienyl ligand and n-BuLi or MeLi, or by reaction of MeLi with the proper fulvene.
• ⁇ CI4 was typically used in its etherate form. The etherate can be prepared by simply adding ⁇ CI4 to ether and filtering off the solid product which is then vacuum dried.
• ⁇ CI4, ZrC.14, HfCl4, amines, silanes, substituted and unsubstituted cyclopentadienyl compounds or precursors, and lithium reagents were purchased from Aldrich Chemical Company, Cerac or Petrarch Systems.
• Methylalumoxane was supplied by either Schering or Ethyl Corporation.
• the initial preparative route chosen typically involved the isolation of intermediate products. Ease of preparation and a significant increase in yield could be obtained if one limits the number of isolated intermediates, however, when making new compounds, intermediates were commonly isolated to verify formation and to control stoichimetry in subsequent steps. When intermediate products were not isolated, samples were taken and characterized by 1 H NMR prior to proceeding to the next step of the reaction.
• Me2SiCl2 (150 ml, 1.24 mol) was diluted with -200 ml of ether. Li(Ci3H9)- Et2 ⁇ (lithiated fluorene etherate, 28.2 g, 0.11 mol) was slowly added. The reaction was allowed to stir for 1 hour prior to removing the solvent via vacuum. Toluene was added and the mixture was filtered through Celite to remove the LiCl. The solvent was removed from the filtrate, leaving behind the off-white solid, Me2Si(Ci3H9)Cl (25.4 g, 0.096 mol).
• Me2Si(Ci3H8) (N-Mes)ZrMe2 was prepared as in Example 2 using Li2[Me 2 Si(C 3H8) (N-Mes)] • Et 2 0.
• Li2[Me2Si(Ci3H8) (N-Mes)] ' £20 was prepared as in Example 1 using LiHNMes in place of LiHN-t-Bu.
• Me2Si(C5Me4H) (NHC12H23) (11.9 g, 0.033 mol) was diluted with -150 ml of ether. MeLi (1.4 M, 47 ml, 0.066 mol) was slowly added. The mixture was allowed to stir for 2 hours after the final addition of MeLi. The ether was reduced in volume prior to filtering off the product. The product, [Me2Si(C5Me4) ( Ci2H23)]Li2, was washed with several small portions of ether, then vacuum dried to yield 11.1 g (0.030 mol) of product.
• Me2Si(Ci3H 8 ) (N-t-Bu)ZrMe 2 (0.020 g)(.020 g) and [PhMe2NH][B(pfp)4] (0.010 g) were combined in 2 mis of toluene.
• Example 14 (Comparitive Example. Preparation of Isotactic Polypropylene Using Bis-tetrahydroindenyl Metallocene)
• propylene was polymerized in liquid propylene by adding under a nitrogen atmosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen, 25 ml of a toluene solution containing a rac- dimethylsilyl-bis(tetrahydroindenyl) zirconium dimethyl (18 mg) and N,N- dimethylanilinium tetrakis(pentafluorophenyl)boron (4 mg).
• Propylene (400 ml) was added and the autoclave stirred at 40° C for 40 minutes.
• the autoclave was cooled and vented and the contents dried in a vacuum oven.
• the yield of isotactic polypropylene was 22 g.
• the weight-average molecular weight of this polymer was 31,000 and the molecular weight distribution was 2.16.
• the polymer had a melting point of 143° C.
• Example 15 (Comparitive Example. Preparation of Isotactic Polypropylene Using Bis-tetrahydroindenyl Metallocene)
• propylene was polymerized in liquid propylene by adding under a nitrogen atmosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen, 25 ml of a toluene solution containing rac- dimethylsilyl-bis(tetrahydroindenyl) zirconium dimethyl (50 mg) and N,N- dimethylanilinium tris(pentafluorophenyl) (polystyrene)boron (50 mg, as prepared above).
• Propylene (400 ml) was added and the autoclave stirred at 40° C for 60 minutes.
• the autoclave was cooled and vented and the contents dried in a vacuum oven.
• the yield of isotactic polypropylene was 8.0 g.
• the weight-average molecular weight of this polymer was 7,800 and the molecular weight distribution was 2.66.
• the polymer had a melting point of 137° C.
• Example 16 (Comparitive Example. Preparation of Isotactic Polypropylene Using Bis-tetrahydroindenyl Metallocene)
• propylene was polymerized in liquid propylene by adding under a nitrogen atomosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen, 24 ml of a toluene solution containing rac- dimethylsilyl-bis(tetrahydroindenyl) zirconium dimethyl (19 mg) and N,N- dimethylanilinium tris(pentafluorophenyl) (methyl)boron (6 mg).
• Propylene (400 ml) was added and the autoclave stirred at 40° C for 30 minutes. The autoclave was cooled and vented and the contents dried in a vacuum oven.
• the yield of isotactic polypropylene was 1 g.
• the weight-average molecular weight of this polymer was 3400 and the molecular weight distribution was 2.2.
• the yield of isotactic polypropylene was 7.8 g.
• the weight-average molecular weight of this polymer was 555,000 and the molecular weight distribution was 1.86.
• the polymer had a melting point of 139° C. Analysis by 13 C NMR spectroscopy indicated that the polymer was about 95% isotactic.
• Example 18 (Comparitive Example. Preparation of Isotactic Polypropylene Using Bis-tetrahydroindenyl Metallocene)
• propylenef was polymerized in liquid propylene by adding under a nitrogen atmosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen, 10 ml of a toluene solution containing rac- dimethylsilyl-bis(tetrahydroindenyl) hafnium dimethyl (6 mg) and N, N- dimethylamlinium tetrakis (pentaflourophenyl) boron (10 mg).
• Propylene (300 ml) was added and the autoclave stirred at 60° C for 1 hour. The autoclave was cooled and vented and the contents dried in a nitrogen stream.
• the yield of isotactic polypropylene was 51.5 g.
• the weight-average molecular weight of this polymer was 106,000 and the molecular weight distribution was 2.59.
• the polymer had a melting point of 141.9° C.
• Example 19 (Comparitive Example. Preparation of Isotactic Polypropylene Using Bis-tetrahydroindenyl Metallocene and Metallocarborane Anion)
• propylene was polymerized in a hexane diluent by adding under a nitrogen atmosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen and containing 200 ml of dry, deoxygenated hexane, 3 ml of a toluene solution containing rac- dimethylsilylbis(tetrahydroindenyl) zirconium dimethyl (38 mg) and N,N- dimethylanilinium bis(7,8-dicarbaundecaborato) cobaltate (III) (12 mg).
• Propylene (200 ml) was added and the autoclave stirred at 50° C for 68 minutes.
• the autoclave was cooled and vented and the solid product (1 g) isolated.
• the product had a weight average molecular weight of 1700 and a melting point of 111.5° C.
• Example 20 (Comparitive Example. Preparation of Isotactic Poly-1-butene Using Bis-Indenyl Metallocene)
• 1-butene was polymerized in a hexane diluent by adding under a nitrogen atmosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen and containing 300 ml dry deoxygentated hexane, 20 ml of a toluene solution containing rac-dimethylsilyl-bis(idenyl) hafnium dimethyl (30 mg) and N,N-dimethylanilinium tetrakis (pentafluorophenyl) boron (10 mg).
• Example 21 (Comparitive Example. Preparation of Syndiotactic Polypropylene Using
• propylene was polymerized in a hexane diluent by adding under a nitrogen atmosphere to a 1 L stainless-steel autoclave, previously flushed with nitrogen and containing 100 ml dry deoxygentated hexane, 2 ml of a toluene solution containing 2- ⁇ yclopentadienyl-2-fluorenyl- propane zirconium dimethyl (30 mg) and N,N-dimethylanilinium tetrakis (pentafluorophenyl) boron (30 mg). Propylene (400 ml) was added and the autoclave stirred at 50° C for 50 minutes.
• the autoclave was cooled and vented and the contents dried in a nitrogen stream.
• the yield of syndiotactic polypropylene was 7 g.
• the number-average molecular weight of this polymer was 25,000 and the molecular weight distribution was 2.
• the polymer had a melting point of 122° C.

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