CA2063090C - Cyclopentadienyl group 6b metal alpha-olefin polymerization catalysts and process for polymerizing alpha-olefin - Google Patents

Abstract

Disclosed is a catalyst system for the homopolymerization and copolymerization of alpha-olefins having 2-8 carbon atoms, said catalyst system comprising a cyclopentadienyl Group 6b metal hydrocarbyl compound in which the metal has an oxidation state of +3, said Group 6b metal compound being supported on an inorganic support. The catalyst system may also contain a Group 2 or Group 3 metal alkyl compound.

Description

O1 CYCLOPENTADIENYL GROUP 6b METAL ALPHA-OLEFIN POLYMERIZATION

06 The present invention relates to catalyst systems for 07 polymerizing alpha-olefins and processes for polymerizing 08 alpha-olefins using such catalysts.

BACKGROUND OF THE INVENTION

12 Chromium based catalysts are used in the commercial 13 polymerization of small alpha-olefins such as ethylene and 14 propylene. One such catalyst is prepared by depositing chromocene (bis(cyclopentadienyl) chromium (II)) on an 16 inorganic metal oxide support, as disclosed in British 17 Patent No. 1,253,063 to Karapinka. U.S. Patent 18 No. 4,015,059, issued March 29, 1977 to Karol, describes the 19 use of bis(indenyl)- and bis(flourenyl)-chromium (II) compounds supported on activated inorganic oxide supports as 21 catalysts for the polymerization of ethylene.

23 Recently, new synthetic methods have been described for 24 preparing Cr+' organometallic compounds. Theopold, J. Am.
Chem. Soc. (1988), 110, 5902 entitled "Cationic Chromium 26 (III) Alkyls as Olefin Polymerization Catalysts", Theopold,

2~ Acc. Chem. Res. (1990), 23, 263 entitled "Organochromium 28 (III) Chemistry: A Neglected Oxidation State" and Thomas 29 et al., J. Amer. Chem. Soc., 113 (1991), p. 893 et seq.
disclose that certain pentamethylcyclopentadienyl chromium 31 (III) alkyls can be prepared, and that they can be used for 32 making polyethylene homogeneously in CHZC12. However, these 33 homogeneous Cr (III) polymerization catalysts have several ~os~o~o 01 deficiencies. These include low polymer productivity, rapid 02 deactivation, and the need to use polar, non-coordinating 03 solvents. Additionally, since they are homogeneous 04 catalysts, they are unsuitable for gas phase olefin 05 polymerizations.

07 U.S. Patent No. 4,530,914, issued July 23,1985 to Ewen 08 et al., discloses a catalyst system for the polymerization O9 of alpha-olefins which comprises two or more metallocenes, l0 each having different propagation and termination rate 11 constants, and aluminoxane. The metallocenes are 12 cyclopentadienyl derivatives of a transition metal of 13 Group 4b, 5b, and 6b metals of the Periodic Table. They are 14 described by the formulas (CSR'm)PR",(CSR'm)MeQ3_P and 15 R~~~(CSR~~)ZMeQ' where (CSR'm) is a cyclopentadienyl or 16 substituted cyclopentadienyl, each R' is hydrogen or a 1~ hydrocarbyl radical, R" is an alkylene radical, a dialkyl 18 germanium or silicon or an alkyl phosphine or amine radical i9 bridging two (CSR'm) rings, Q is a hydrocarbon radical, Me 20 is a Group 4b, 5b, or 6b metal, s is 0 or 1, p is 0, 1, 21 or 2; when p=0, s=0; m is 4 when s is 1 and m is 5 when s 22 is 0.

2~ U.S. Patent No. 4,939,217, issued July 3, 1990 to Stricklen, 25 also discloses a process for polymerizing olefins where the 26 polymerization is conducted in the presence of hydrogen, and 2~ a catalyst system is used which contains aluminoxane and at 28 least two metallocenes, each having different olefin 29 polymerization termination rate constants. The metallocenes 30 disclosed are similar to those described in aforementioned 31 U.S. Patent No. 4,530,914.

33 U.S. Patent No. 4,975,403, issued December 4, 1990 to Ewen,

3~ discloses a catalyst system for use in the polymerization of '., olefins. The catalyst system includes at least two different chiral, stereo-rigid metallocene catalysts of the formula R" (CS (R' )4) 2MeQP (where Me is a Group 4b, 5b or 6b metal and (CS(R')d) is a cyclopentadienyl or substituted cyclopentadienyl ring) and an aluminum compound.
Canadian Patent Application No. 2,000,567, published April 13, 1990, discloses a process for producing polyethylene using a composite catalyst made up of a solid catalyst component typified by a selected chromium compound, a modified aluminum compound typified by a trialkylaluminum, and an alkylaluminum alkoxide compound. The chromium compound may be chromium oxide, and the modified aluminum compound may be the reaction product of an organoaluminum compound and water.
It has now been discovered that when cyclopentadienyl Group 6b metal hydrocarbyl compounds, in which the Group 6b metal is in an oxidation state of +3, are supported on inorganic metal oxide or inorganic metal phosphate supports, high productivity alpha-olefin polymerization catalysts are produced, and that the use of a co-catalyst improves the productivity of many of these compounds.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a catalyst system for the homopolymerization and copolymerization of alpha-olefins having 2-8 carbon atoms, said catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the metal has an oxidation state of +3, said chromium compound being supported on an inorganic support.

"'-. -4 -There is also provided in accordance with the present invention a catalyst system for the homopolymerization and copolymerization of alpha-olefins having 2-8 carbon atoms) said catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the chromium has an oxidation state of +3, said chromium compound being supported on an inorganic support, and a Group 2 or 3 metal alkyl compound.
Further provided in accordance with the present invention is a process for the homopolymerization or copolymerization of alpha-olefins having 2-8 carbon atoms comprising polymerizing said alpha-olefin, or copolymerizing two or more alpha-olefins in the presence of a catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the crrarium has an oxidation state of +3, said chromium compound being supported on an inorganic support.
The present invention alsd provides a process for the homopolymerization or copolymerization of alpha-olefins comprising polymerizing said alpha-olefin, or copolymerizing two or more alpha-olefins in the presence of a catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the chromium has an oxidation state of +3, said chromium compound being supported on an inorganic support, and a Group 2 or 3 metal alkyl compound.
In the above catalyst systems and processes, chromium is a preferred Group 6b metal, silica, aluminum phosphate and alumina aluminum phosphate are preferred supports, and aluminoxanes and trialkylaluminum compounds are preferred Group 2 or 3 metal alkyl compounds.

ro- -5-Ol BRIEF DESCRIPTION OF THE FIGURES

03 Figures 1, 2 and 3 each show scanning electron micrographs 04 of polyethylene samples.

0$ The present invention provides catalyst systems for use in 09 the polymerization (either homopolymerization or copolymerization) of alpha-olefins, including ethylene, 11 propylene, 1-butene, 1-hexene and 4-methyl-1-pentene.

13 It has quite surprisingly been found that, even though the 14 productivity of many cyclopentadienyl Group 6b metal hydrocarbyl compounds is quite low when employed as catalyst 16 in the homogeneous polymerization of alpha-olefins, when 17 these compounds are supported on an inorganic metal oxide or i8 inorganic phosphate solid support, their productivity i9 increases dramatically, especially when co-catalysts are used. While the catalyst systems of the present invention 21 can be used to polymerize a variety of alpha-olefins, they 22 are especially useful in the polymerization of ethylene.
23 These catalysts produce polyethylene in high yield, and the 24 polymers produced have remarkably uniform particle size and highly desirable morphology (i.e., substantially spherical) 26 that is suitable for gas phase polymerizations. In 27 addition, the catalyst systems of this invention produce 28 polyethylene with a variety of molecular weight 29 distributions, depending on the support used.
31 Referring now to the Figures, Figure 1 shows a scanning 32 electron micrograph (SEM) at X10 magnification of a 33 polyethylene sample produced by homogeneous polymerization 34 using [Cp*Cr (THF) iCH3] + [BPh4]- (where Cp* represents 206~0~0 01 pentamethylcyclopentadienyl, THF is tetrahydrofuran, and Ph 02 is phenyl). As can be seen, this sample is characterized by 03 very small, irregularly shaped particles. These particles 04 are typically less than 20-50 ~.m (microns) in diameter.
OS Figure 2 shows an SEM at X10 magnification of a polyethylene 06 sample produced by the method of the present invention using Cp*Cr(CH3)2(THF) on a silica support. As can be seen, this 08 sample has particles of much larger size (about 1 mm in O9 diameter) than those in Figure 1. The particle size is quite suitable for gas phase polymerization applications.
11 Figure 3 shows a SEM of a polyethylene sample produced by 12 the method of this invention using Cp*Cr(CH3)z(THF) on a 13 A1203~2A1P04 support. As can be seen, the particles are 14 quite uniform in size, and primarily spherical in nature.
Again, the particle size and spherical nature of the polymer 16 makes this system attractive for gas phase polymerization 1~ applications.
i8 i9 Activities for the catalyst systems of the present invention are greater than 3,000 grams of polymer per gram of chromium 21 metal per hour ("g/g Cr/hr"), preferably greater than 22 30,000 g/g Cr/hr, and more preferably greater than 23 200,000 g/g Cr/hr.

The term molecular weight distribution ("MWD"), as used 26 herein, is the weight average molecular weight ("Mw") 2~ divided by the number average molecular weight ("Mo"), i.e., 28 Mw/Mo. The polymers produced in accordance with the present 29 invention using silica supported catalysts have a MWD
greater than 10, preferably greater than 15, and more 31 preferably greater than 20. These polymers, which have high 32 ~D~s, have improved ease of processing, better melt 33 behavior, and other desirable properties such as impact ~o~~o~o 01 resistance and environmental stress crack resistance. Large 02 blow molded products are superior when made with high MWD
03 polymers. Additionally, film is more puncture resistant 0~ when made from polymer with a high MWD. The polymers made OS in accordance with this invention using alumina aluminum 06 phosphate supported catalysts possess high molecular weight 0~ and a more narrow MWD, making them useful in such O8 applications as injection molding.

The catalyst systems of the present invention comprise at 11 least one cyclopentadienyl Group 6b metal hydrocarbyl 12 compound in which the Group 6b metal is in an oxidation 13 state of +3, and which is catalytically active when 14 deposited on an inorganic metal oxide or inorganic metal phosphate support. As used herein, the term 16 "cyclopentadienyl" refers to unsubstituted cyclopentadienyl 1~ as well as substituted derivatives of cyclopentadienyl in i8 which the cyclopentadienyl ring contains one or more 19 substituents which do not interfere with the Group 6b metal compound's ability to function as an alpha-olefin 21 polymerization catalyst. Examples of substituted 22 cyclopentadienyl include pentamethylcyclopentadienyl, 23 methylcyclopentadienyl, t-butylcyclopentadienyl, and 2~ pentaphenylcyclopentadienyl, as well as compounds where the substituent forms a multi-cyclic ring with the 26 cyclopentadienyl ring. Examples of these multi-cyclic rings 2~ include indenyl and fluorenyl rings. For the sake of 28 simplicity, the abbreviation "Cp" will be used herein to 29 refer to unsubstituted cyclopentadienyl, and the abbreviation "Cp*" will be used to refer to 31 pentamethylcyclopentadienyl. Cp* is a preferred 32 cyclopentadienyl group as it stabilizes the organometallic 33 compound of this invention.

~0630~Q
_8-01 The Group 6b metal compounds useful in the present invention 02 include compounds wherein the metal is chromium, molybdenum 03 or tungsten. Compounds in which the metal is chromium are 04 preferred. The Group 6b metal atom in the compound has an 05 oxidation state of +3.

07 These Group 6b metal compounds have, in addition to one 08 cyclopentadienyl group, at least one hydrocarbyl group 09 bonded to the metal atom. As used herein, the term "hydrocarbyl" refers to alkyl, alkenyl, aryl, aralkyl and 11 alkaryl radicals and the like. Exemplary hydrocarbyl 12 radicals include, but are not limited to, methyl, ethyl, 13 propyl, butyl, amyl, isoamyl, hexyl, neopentyl, isobutyl, 14 heptyl, octyl, nonyl, decyl, cetyl, phenyl, benzyl and other similar groups. Additionally, organosilyl groups, such as 16 trimethylsilyl methyl, i.e., (CH3)3SiCHz-, and the like can 1~ be used. If more than one hydrocarbyl group is bonded to 18 the metal atom, they can be independent or linked, i.e., 19 they can form a 3-, 4-, 5-, 6-, or 7-membered metallocycle.
preferably, the hydrocarbyl group is sigma bonded to the 21 Group 6b metal.

23 In addition to the cyclopentadienyl and hydrocarbyl groups, 24 the Group 6b metal compounds of the present invention may also contain one or more sigma donor stabilizing ligands.
26 These ligands contain an atom, such as oxygen, nitrogen, 2~ phosphorous or sulfur, which has a nonbonded electron pair.
28 Examples of these ligands include, but are not limited to, 29 ethers, amines, phosphines and thioethers. Ethers such as tetrahydrofuran (THF) and amines such as pyridine are 31 preferred. Compounds with pyridine are most preferred and 32 give catalysts with high activity and stability.

2063~~~
_g_ 01 Examples of the Group 6b metal compounds useful in this 02 invention include, but are not limited to, compounds having 03 the following general formulas:

0 5 ( Cs ( R' ) s ) ,MXbL ( I ) 06 ((Cs(R')5)aMXb~c (II) Or 07 ((~s(R')s).MXb(L)~l+ (Al (III) O9 wherein M is a Group 6b metal such as chromium, molybdenum and tungsten;

12 (Cs(R~)s) is a cyclopentadienyl or substituted 13 cyclopentadienyl ring;

R~ is at each independent occurrence hydrogen, a hydrocarbyl 16 radical having 1-20 carbon atoms, or adjacent R' groups may 17 together form one or more rings;

i9 X is a hydrocarbyl radical having 1-20 carbon atoms (for example, a monovalent saturated aliphatic or alicyclic 21 radical or a monovalent aromatic radical, or combinations 22 thereof);

2 4 a = 1 or 2 , b = 1 or 2 where a+b = 3 ;
26 c = 1 or 2 with the proviso that when c = 2 then X is alkyl;

28 L is at each independent occurrence a sigma donor 29 stabilizing ligand;
31 m = 1 to 2 inclusive; and 33 A is an anion.
3~

-10- ~ ~ a z Examples of compounds having Formula (I) above include, but are not limited to, Cp*Cr(CH3)2(THF), Cp*Cr(Bzyl)2(THF), Cp*Cr (Bzyl)z(Pyr) , Cp*Cr(CH3)z(Pyr) , Cp*Cr(TMSM)Z(Pyr) and Cp*Cr(TMSM)2 where Bzyl is benzyl, Pyr is pyridine and TMSM
is trimethylsilylmethyl.
Further examples of the Group 6b compounds of this invention include monomeric Group 6b metal compounds, dimeric Group 6b metal compounds, and cationic Group 6b metal compounds. A
preferred monomeric Group 6b metal compound is Cp*Cr(Bzyl)Z(THF), [Cp*Cr(CH3)2]2 is a preferred dimeric compound, and a preferred cationic compound is [Cp*CrCH3(THF)2]+[BPh4]'. An especially preferred compound is Cp*Cr (CH3) z (Pyr) .
In part, the choice of Group 6b metal compound is based on the thermal stability of the compound and its ease of preparation. Of the Group 6b metal compounds useful in this invention, the organochromium compounds are preferred.
_Theopold, J. Am. Chem. Soc. (1988), 110, 5902 entitled "Cationic Chromium (III) Alkyls as Olefin Polymerization Catalysts", Theopold, Acc. Chem. Res. (1990), 23, 263 entitled "Organochromium (III) Chemistry: A Neglected Oxidation State", and Thomas et al., J. Amer. Chem. Soc., 113 (1991) , p. 893 et seq, describes syntheses useful in r~.aking~
some of the Group 6b metal compounds of this invention.
Similar procedures can be used to make related compounds.
In the catalyst systems of the present invention, the Group 6b metal compound is deposited on an inorganic support. Suitable inorganic metal oxide supports include ~d~3~~'~

01 silica, alumina, silica-alumina mixtures, thoria, zirconia, 02 magnesium oxide and similar oxides. Suitable inorganic 03 metal phosphates include aluminum phosphate, zirconium 04 phosphate, magnesium-containing alumina phosphate and OS alumina aluminum phosphate. Silicas, aluminum phosphates 06 and alumina aluminum phosphates are preferred. Suitable silica supports include Davison 952, Davison 955, Crosfield 08 EP-10 and Crosfield EP17MS. Further examples of useful 09 supports are the following: alumina aluminum phosphates with aluminum to phosphorus ratios of about 5:1 to 1:1 as 11 disclosed in U.S. Patents Nos. 4,080,311 and 4,219,444;
12 magnesia-alumina-aluminum phosphates as described in U.S.
13 patent No. 4,210,560; zinc oxide-cadmium oxide-alumina-I4 aluminum phosphates such as those disclosed in U.S. Patent No. 4,367,067; and the calcium, barium, and/or strontium 16 oxide-alumina-aluminum phosphates described in U.S. Patent 17 Nos. 4,382,877 and 4,382,878. The acidity of these supports 18 can be adjusted by judicious inclusion of basic metals such 19 as alkali and alkaline earth metals (Ca, Be, Mg, K, Li) to counteract excessive acidity. Other useful supports include 21 magnesium halides, particularly magnesium chloride, such as 22 those described in "Transition Metals and Organometallics as 23 Catalysts for Olefin Polymerization" (1988, Springer-Verlag) 2~! edited by W. Kaminsky and H. Sinn and "Transition Metal Catalyzed Polymerizations-Ziegler-Natta and Metathesis 26 Polymerizations" (1988, Cambridge University Press) edited 27 by R. Quirk.

29 The supports useful in this invention should have a high surface area. In general, these supports should have the 31 characteristics listed in the following table:
32 Property Broad Ranqe Preferred Range 33 Surface area 25-600 m2/g 100-370 m2/g 01 Pore volume 0.25-4 cm3/g 0.7-3 cm3/g Mean particle 30-200 microns 60-140 microns 03 diameter 0~
05 preferably, the pore size distribution is broad, with a 06 significant percentage of the pores in the macropore range 0~ (>500 Angstroms). Preferably, at least 50% of the pores are 0a macropores. It is also desirable that the support be O9 substantially anhydrous before the Group 6b metal compound is deposited on it. Thus, it is desirable to calcine the 11 support prior to deposition of the Group 6b metal compound.

13 The supported catalysts of this invention are readily 14 prepared by techniques well known in the art. For example, a solution of the Group 6b metal compound in aliphatic, 16 aromatic or cycloaliphatic hydrocarbons, or ethers such as 1~ diethyl ether or tetrahydrofuran can be stirred with the i8 support until the Group 6b metal compound is adsorbed on or 19 reacted with the support. The amount of Group 6b metal compound relative to the amount of support will vary 21 considerably depending upon such factors as the particle 22 size of the support, its pore size and surface area, the 23 solubility of the Group 6b metal compound in the solvent 24 employed, and the amount of Group 6b metal compound which is to be deposited on the support. However, in general the 26 amount of Group 6b metal compound used is adjusted so that 2~ the final metal content (calculated as the element), 28 relative to the support, is in the range of from about 0.01 29 to about 10 weight percent. In most cases, the most desirable level is in the range of about 0.1 to about 31 5 weight percent.

33 It has been found that the activity of many of the supported 3~ Group 6b metal compounds of this invention is significantly 20~3a~p 01 increased when they are employed in conjunction with a 02 co-catalyst. The co-catalysts useful in the practice of the 03 present invention are Group 2 and Group 3 metal alkyls. As 04 used herein, the term "Group 2 and Group 3 metal alkyls"
05 refers to compounds containing a metal from Group 2 or 06 Group 3 of the Periodic Table (such as Mg, Zn, B, or A1) to 0~ which is bonded at least one alkyl group, preferably a C, to O8 Cg alkyl group. Suitable Group 2 and Group 3 metal alkyls O9 include dialkyl magnesium, dialkyl zinc, trialkylboranes, and aluminum alkyls. Suitable aluminum alkyls include 11 trialkylaluminums (such as trimethylaluminum, 12 triethylaluminum, triisobutylaluminum and trioctylaluminum).
13 Trialkylaluminums with alkyl groups of four carbons or 1! greater are preferred. Other aluminum alkyls useful in the practice of the present invention include alkylaluminum 16 alkoxides (such as diethylaluminum ethoxide and 1~ ethylaluminum diethoxide), and alkylaluminum halides (such 18 as diethylaluminum chloride, diethylaluminum bromide, 19 diethylaluminum iodide, diethylaluminum fluoride, ethyl aluminum dichloride, ethyl aluminum dibromide, ethyl 21 aluminum diiodide, ethyl aluminum difluoride, and ethyl 22 aluminum sesquichloride).

2! Other suitable aluminum alkyls are aluminoxanes, including those represented by the general formula (R-A1-O)o for the 26 cyclic form and R(R-A1-O)o-A1R2 for the linear form. In 2~ these formulas, R is, at each independent occurrence, an 28 alkyl group (such as methyl, butyl, isobutyl and the like) 29 preferably with more than two carbon atoms, more preferably with 3-5 carbon atoms, and n is an integer, preferably from 31 1 to about 20. Most preferably, R is an isobutyl group.
32 Mixtures of linear and cyclic aluminoxanes may also be used.
33 Examples of aluminoxanes useful in this invention include, 3!

~~~o~o but are not limited to, ethyl aluminoxane, isobutyl aluminoxane, and methyl aluminoxane. Aluminoxanes (also known as "alumoxanes") suitable for use in this invention are described in Pasynkiewicz, "Alumoxanes: Synthesis, Structure, Complexes and Reactions," Polyhedron 9, p. 429 (1990) The preferred Group 2 and Group 3 metal alkyls are the aluminoxanes and the trialkylaluminums.
When used, the Group 2 and Group 3 metal alkyls are used in a Group 2 or 3 metal alkyl to Group 6b metal compound mole ratio of from about 1:1 to about 1000:1. The preferred mole ratio is from about 10:1 to about 200:1.
The catalyst systems of the present invention may be used in either slurry or gas phase polymerization processes. After the catalysts have been formed, the polymerization reaction is conducted by contacting the monomer charge with a catalytic amount of the catalyst at a temperature and at a =pressure sufficient to initiate the polymerization reaction.
If desired, an organic solvent may be used as a diluent and to facilitate materials handling. The polymerization reaction is carried out at temperatures of from about 30°C
or less up to about 200°C or more, depending to a great extent on the operating pressure, the pressure of the entire monomer charge, the particular catalyst being used, and its concentration. Preferably, the temperature is from about 30°C to about 125°C. The pressure can be any pressure sufficient to initiate the polymerization of the monomer charge, and can be from atmospheric up to about 1000 psig.
As a general rule, a pressure of about 20 to about 800 psig is preferred.

~~~3~90 01 When the catalyst is used in a slurry-type process, an inert 02 solvent medium is used. The solvent should be one which is 03 inert to all other components and products of the reaction 04 system, and be stable at the reaction conditions being used.
05 It is not necessary, however, that the inert organic solvent 06 medium-also serve as a solvent for the polymer produced.
07 The inert organic solvents which may be used include 08 saturated aliphatic hydrocarbons (such as hexane, heptane, O9 pentane, isopentane, isooctane, purified kerosene and the like), saturated cycloaliphatic hydrocarbons (such as 11 cyclohexane, cyclopentane, dimethylcyclopentane, 12 methylcyclopentane and the like), aromatic hydrocarbons 13 (such as benzene, toluene, xylene and the like), and 14 chlorinated hydrocarbons (such as chlorobenzene, tetrachloroethylene, o-dichlorobenzene and the like).
16 Particularly preferred solvents are cyclohexane, pentane, 17 isopentane, hexane and heptane.

19 When the catalyst is used in a gas phase process, it is suspended in a fluidized bed with, e.g., ethylene.
21 Temperature, pressure and ethylene flow rates are adjusted 22 so that to maintain acceptable fluidization of the catalyst 23 particles and resultant polymer particles. Further 24 descriptions of such a fluidized bed may be found in British Patent No. 1,253,063, to Karapinka, which is incorporated by 26 reference herein.

28 The following examples are intended to further illustrate 29 the present invention.

2~63~9~

06 Silica supports were purchased from W. R. Grace & Co., and included Davison 952 and Davison 955 silicas. These silicas 0a have the following properties:

Property Davison 952 Davison 955 11 Surface area 340 mz/g 300 m2/g 13 Pore volume 1.68 cm3/g 1.60 cm3/g 14 Mean particle 110 microns 40 microns diameter 1~ The alumina aluminum phosphate supports used in the 18 following examples were prepared by the procedure of 19 Example 1 in U.S. Patent No. 4,080,311, issued March 21, 1978 to Kehl, which patent is incorporated by reference 21 herein. The product had an A1203 to A1P04 ratio of 1:2.

In the preparation of the following catalysts, all 26 manipulations were performed under argon using glove box or 2~ Schlenk techniques. All solvents were thoroughly dried over 28 Na/benzophenone or calcium hydride and distilled prior to 29 use.

20~3Q~~0 Ol EXAMPLE 2 02 [Cp*Cr(CH3)z]z 04 The organochromium compound [CP*Cr(CH3)z]z was prepared by 05 the procedure described in Theopold, Acc. Chem. Res., 23 06 (1990), p. 264.

O9 SUPPORTED [Cp*Cr(CH3)z]z ii The organochromium compound [Cp*Cr(CH3)z]z (0.040 g, 12 9,2 x 10-s mole), prepared as described in Example 2, was 13 dissolved in 10 ml of pentane, giving a dark brown solution 14 to which was added Davison 952 silica (1.00 g). The resulting mixture was stirred for 15 minutes, giving a dark 16 brown solid and a clear supernatant. The resulting solid 17 catalyst was washed with pentane, and dried to a i8 free-flowing powder.

21 SUPPORTED Cp*Cr (CH3) z (THF) 23 [Cp*Cr(CH3)z]z (0.040 g, 9.2 x 10-5 mole) was added to 20 ml 24 of tetrahydrofuran ("THF") and stirred for 0.5 hour, generating a green colored solution containing 26 Cp*Cr(CH3)z(THF} . A1z03~2A1P04 (1.0 g) solid support was 27 added all at once to this solution, and the resulting 28 mixture was stirred for several minutes. All of the 29 organochromium compound reacted with the solid support yielding a deep purple catalyst and a clear supernatant.
31 The resulting catalyst slurry was filtered and the purple 32 solid was washed twice with 10 ml of THF and dried under 33 vacuum to a free flowing powder.

~o~~o~o -lg-02 [ Cp*CrCH3 (THF) 2] + [ BPh4]' 04 This compound was prepared by the method described in Thomas 05 et al., J. Amer. Chem. Soc., 113 (1990), p. 900.
06 preparation No. 13, method B was used to prepare compound 07 number 14 in that paper, i.a., [Cp*CrCH3(THF)2]+[BPh4]~

SUPPORTED [ Cp*CrCH3 ( THF) 2 ] + [ BPh4 ]
ii 12 [Cp*CrCH3(THF)2]+[BPh4]' (0.075 g, 1.1 x 10'° mole) was 13 dissolved in 20 ml of THF and treated all at once with 14 1.00 g of A1203~2A1P04. The resulting mixture was stirred for 15 minutes resulting in a dark blue solid and a clear 16 supernatant. The solid was washed with THF, and dried to a 1~ free-flowing powder.

i9 COMPARATIVE EXAMPLE A
ETHYLENE POLYMERIZATION USING AN UNSUPPORTED CATALYST

22 90.1 micromoles of [Cp*CrCH3(THF)Z]+[BPh4]' was dissolved in 23 25 ml methylene chloride in a 50 ml Fischer-Porter bottle, 24 and pressured to 50 psig with ethylene. The reactor was stirred at 25°C for 1.0 hour. Initially, the ethylene 26 uptake was rapid, but this rate decreased rapidly over the 2~ first half hour. The reaction was stopped by venting the 28 pressure. The polymer produced was washed with isopropanol 29 and then with acetone. The polymer was then dried under vacuum. The results of this polymerization are indicated in 31 Run 1 in Tables I and II.

~oo~o~o OS The procedure of Comparative Example A was repeated, except 06 that 71 molar equivalents of isobutyl aluminoxane (IBAO) was added to the reaction vessel prior to pressurization with O8 ethylene. The results of this polymerization are indicated 09 in Run 2 in Tables I and II.

14 Polymerization runs were conducted in 1 or 2 liter autoclave reactors under particle form (slurry) conditions using 16 between 300 and 500 ml heptane as diluent, and a weighed l~ amount of catalyst (typically 0.050 to 0.250 g). Run times 18 of 0.5 to 1.0 hour were normally employed. For example, in 19 a typical run, 0.100 g of the catalyst prepared in Example 4 (Cp*Cr (CH3) 2 (THF) adsorbed on A1203. 2A1P04) was charged to a 21 one-liter autoclave along with 300 ml of heptane.
22 polyisobutylaluminoxane (0.5 ml of a 1. OM heptane solution, 23 prepared by slow hydrolysis of triisobutylaluminum with 1.0 24 equivalents of H20 as in Example 3 of U.S. Patent No. 4,665,208, issued May 12, 1987 to Welborn et al., which 26 patent is incorporated by reference herein) was added to the stirred reactor as co-catalyst. The reactor temperature and 28 pressure were adjusted to 85° C. and 550 psi (with 29 ethylene), respectively. The ethylene was supplied on demand from a pressurized reservoir. After 0.5 hour, the 31 reaction was stopped by rapidly cooling the reactor and 32 venting the pressure. The polymer produced was washed with 33 isopropanol and acetone, and dried under vacuum to yield z O1 82.9 g of white, granular solid. The results of this 02 polymerization are indicated in Run 15 in Tables III and IV.

04 Polymerization runs similar to that described above were OS conducted using the catalysts and conditions shown in 06 Tables I, III, and V below. Analytical data for the 07 polyethylenes produced in these runs is shown in Tables II, 08 IV and VI below. All molecular weights in these tables were 09 determined by gel permeation chromatography.

14 The procedure of Example 7 is repeated in a 2 liter, stirred autoclave using the supported Cr+3 catalysts described 16 above, except that heptane is not added to the autoclave.
17 The reactor temperature and pressure are adjusted to 85°C
18 and 550 psi (with ethylene), respectively. A white, i9 granular polymer is produced.

2~6~~~~

TABLE I

03 POLYMERIZATION [Cp*CrMe(THF)2][sPh4]
DATA
FOR

04 Rua Support' ~CmolCo- Al:Cr"ClH4, Temp. Activity' Cr catalyst psig C

1 none 90.1 -- 0 50 25 510 2 none 90.1 IBAO 71:1 50 25 89 3 Davison 952 28.2 IBAO 71:1 50 25 6,690f 08 Silica O9 4 Davison 952 21.6 -- 0 550 80 0 Silica 5 Davison 952 27.0 IBAO 110:1 550 80 48,400 1 Silica 12 6 Davison 952 27.0 IBAO 71:1 550 85 50,600 13 silica 14 7 Davison 952 27.0 A1(CH3)3 71:1 550 85 3,700 Silica 8 A12032A1P04 15.0 IBAO 33:1 550 85 233,000 16 - : ., 'Precalcined at for hours.

dole ratio.

'g polymer/g Cr/hr.

HZC12, dperformed catalyst under homogeneous conditions in C

21 rapidly deactivated.

~IBAO
=
isobutylaluminoxane.

Polymerization performed for two hours.

II
__, _ DATA
FOR
POLYETHYLENES
PREPAR

WITH
[Cp*CrMe (THF) 2]
[aPh4]

Run Supports Tm) Density Mean Particle Mw~' MWD
C

05 g/cc Diameter, x la-3 Microns 1 --' 135.5 -- -- 125 5.8 5 Davison 952 138.8 -- 830 252 12.8 08 Silica O9 6 Davison 952 137.9 0.942 850 258 22.6 Silica 11 7 Davison 952 136.3 -- -- 236 34.2 Silica 8 A12032A1P04 138.0 0.927 -- j --14 gprecalcined at for hours.

sDetermined by GPC.

16 .performed under homogeneous conditions in CHzCl2.

iToo high to be measured by GPC, i.e., >_300,000.

... 2003090 TABLE III

DATA FOR
SUPPORTED
Cp*CrMe ~xx~~

04 Run Support' pmol Co- Al CZH4, Temp. Activity'"
:
Cri Cr c8talyst prig C

9 Davison 952 46.0 -- 0 550 80 0 06 Silica 07 10 Davison 952 46.0 EAO 44:1 550 80 15,200 Silica 11 Davison 952 46.0 IBAO 44:1 550 85 33,000 O9 Silica 12 Davison 955 46.0 IBAO 44:1 550 85 51,000 11 Silica 12 13 Davison 955 18.4 IBAO 54:1 550 85 55,900 Silica 13 14 A1203 2A1P0446. -- 0 550 85 5, 400 A1203 2A1P0418. IBAO 27 550 85 173, 000

4 :

16 A1203 2A1P0418.4 IBAO 54: 550 65 272, 000 17 A120g2A1P04 18.4 IBAO 27:1 550 65 169,000 18 A12032A1P04 18.4 IBAO 27:1 550 85 240,000 rPrecalcined at for hours.

'Moleratio.

'g lymer/g Cr/hr.
po "EAO = ethylaluminoxane.

IBAO = isobutylaluminoxane.

01 - ' --DATA POLYETHYLENES
PREPARED

WITH SUP PORTEDCp~CrMe(THF) Run Supports Tm,C Density Mw9 MWD

05 g/cc x 10'3 0 10 Davison 952 138.4 0.941 306 18.2 p' silica 11 Davison 952 139.6 -- 293 19.2 p8 Silica d9 12 Davison 955 138.3 -- 301 20.4 Silica 11 13 Davison 955 138.3 0.941 270 14.4 Silica 14 A12032A1P04 135.1 -- r --15 A1203 2A1P04134 -- r --.

16 A12032A1P04 136.6 0.927 r --17 AlzOg2A1P04 139.0 0.924 r --18 A12032A1P04 138.1 0.926 r --1' PCalcined 400C for 48 hours.
at i9 q~etermined by GPC.

'Too be measured by i.e., >-300,000.
high GPC, to 20~~090 O1 w -DATA [Cp*CrMe2~2 FOR

04 Run Support' umol Co- Al:Cr' CZHq)Temp. Activity"

Cr catalyst prig C

19 Davison 952 76.7 -- 0 550 85 15,200 06 silica 07 20 Davison 955 74.8 -- 0 550 85 16,000 Silica O9 21 A12032AlPOq 57.5 -- 0 550 85 2,900 'Calcined 48 hours.
at for 'Mole ratio.

polymer/g Cr/hr.

~~~6~Q90 VI

03 ~~YTICAL
DATA
FOR
POLYETHYLENES
PREPARED

WITH
SUPPORTED
[Cp*CrMe2)2 0~

Run Support" Tm,C Density Mean ParticleMwW MWD

05 g/cc Diameter, x i0'3 Microns 19 Davison 952 139.3 -- 910 252 23.5 0,~ Silica O8 20 Davison 955 140.6 -- -- 347 14.7 O9 silica 21 A12032A1P04 138.3 -- -- x --12 "Calcined at for hours.

13 wDetermined by GPC.

14 xToo high to be measured by GPC, i.e., >_300,000.

16 Looking, now, at Tables I
and II, it can be seen that the 1~ polymerization using the homogeneous cationic Cr+3 compound 18 has low activity (Run 1), and that adding triisobutyl-19 aluminoxane does not improve the activity, but rather reduces it (Run 2).
These runs were performed at so as 21 to avoid decomposition of the thermally labile homogeneous 22 catalyst.

2~ In contrast, Run shows an approximately ten-fold improvement in activity using a supported catalyst system of 26 this invention.

28 Runs 4-8 show the need for a co-catalyst when using this 29 cationic Cr+3 compound. The aluminoxane co-catalyst gives improved activity over the trimethylaluminum co-catalyst.
31 Additionally, higher molecular weights (Mw) and higher 32 molecular weight distributions (MWD = Mw/Mo) are obtained 33 with the catalyst system of the present invention (see ~0~3090 01 Table III). The activity of this catalyst system was 02 highest when the support was an alumina aluminum phosphate 03 support, and the polymer had higher molecular weight as 04 well.
OS
06 Looking, now, at Tables III and IV, a co-catalyst appears to 07 be necessary with the silica support and is advantageous 08 with the alumina aluminum phosphate support. Using the O9 aluminoxane with the longer alkyl groups (isobutyl vs.
ethyl) gives higher activities. Also, the Davison 955 11 silica, which has a substantially smaller average particle 12 size than the Davison 952 silica, gives higher activity 13 (compare Runs 10 and 11 with Runs 12 and 13).

Table III also shows that the catalyst systems of this 16 invention perform exceptionally well over the temperature 1~ range of 65°-85°C.

19 Looking, now, at Table V and VI, the catalyst system of this invention based on [Cp*Cr(CH3)z]Z dimer is also quite active, 21 and gives polymer with very attractive high molecular 22 weights and broad (high) MWD's.

Cp*Cr(TMSM)2 2~ 1.318 g of CrCl3(THF)3 was placed in a 100 ml Schlenk flask 28 along with a stirring bar and about 50-60 ml of THF.
29 0.500 g of Cp*Li was added to the resulting slurry producing a blue solution ([Cp*CrClz)2). This solution was allowed to 31 stir for at least three hours (preferably overnight). To 32 the stirring solution was slowly added 2 equivalents of 33 LiCH2Si(CH3)3. The solution changed from blue to purple.

206~~~~

01 The THF was then removed by rotoevaporation and the 02 resulting solid was dissolved in pentane yielding a red 03 brown solution which was filtered to remove LiCl. The 04 pentane was removed by rotoevaporation and the solid was OS redissolved in a minimum amount of pentane and crystallized 06 at -30°C. Yield 50-60%.

O8 It is important to note that this compound is thermally O9 unstable and decomposes at room temperature liberating tetramethylsilane.

13 SUPPORTED Cp*Cr(TMSM)2 Cp*Cr(TMSM)Z (0.075 g) was dissolved in 10 ml of pentane.
16 A1z03'ZA1P04 (1.00 g) was added all at once to the stirred 17 solution resulting in the formation of a purple solid and 18 clear supernatant after 15 minutes. The solid was i9 collected, washed twice with pentane, and dried in vacuo to a free-flowing powder.

24 The supported Cp*Cr(TMSM)Z prepared in Example 10 was used to polymerize ethylene by a procedure similar to that 26 described in Example 7, except that the polymerization was 27 performed at 8o°C and 550 psi total pressure (ethylene and 28 hydrogen). The results of these polymerization runs are 29 indicated in Table VII below, and analytical data for the polyethylenes produced are indicated in Table VIII below.

20fi~09~

TABLE VII

OZ

POLYMERIZATION SUPPORTED MSM)Z
DATA Cp*Cr(T
FOR

R C mol Cr Co-catalyst Al:Cri H (psi) Activity3 ' 04 un ~ Z

OS 22 31 None 0 0 2,500 06 23 16 IBAO 16:1 0 250,000 24 16 IBAO 32:1 0 341,000 25 16 IBAO 32:1 ~10 294,000 26 16 IBAO 32:1 25 340,000 27 16 IBAO 32:1 25 230,000 28 16 IBAO 32:1 50 227,000 13 29 16 IBAO 32:1 50 249,000 14 30 16 IBAO 32:1 100 194,000 31 16 IBAO 32:1 200 124,000 16 32 16 TEBS 32:16 0 "0 'Support for dehydrated all at runs.

for hours ZMoleratio.

'Expressed as g polymer/g Cr/hr.

4IBA0is isobutylaluminoxane.

STEB
is triethylboron.

6B:Crmole ratio.

2!

3!

2~63~9~

TABLE VIII

DATA FOR
POLYETHYLENES

PREPARED
WITH SUPPORTED
Cp*Cr(TMSM)Z

Run Tm, c MI' HLMIg Mvr9 MWD

0 x 10-3 23 139.1 0 0 1,124 2.02 24 139.4 0 0 891 7.61 25 139.9 0 0 -- --26 139.9 0 2.27 330 9.29 11 27 141.9 0 2.03 276 8.52 12 28 139.7 0 6.50 228 9.62 13 29 138.8 0 11.9 205.6 9.40 14 30 138.0 0 12.7 116.3 8.37 31 135.0 High High 55.8 7.10 17 'Melt Index (ASTM
D-1238, Condition E) 18 BHigh load melt index (ASTM
D-1238, Condition F) lg 9Determined by GPC.

22 Cp*Cr(Bzyl)2(THF) 24 To a slurry of CrCl3(THF)3 (2.00 g, 5.33 mmoles) in 50 ml of THF was added LiCp*
(0.76 g, 5.34 mmoles) slowly with 26 stirring to yield a deep blue solution.
This solution was 27 stirred for two hours.
Slow addition of benzyl magnesium 28 chloride (5.3 ml of 2.0 M solution) resulted in a deep 2g purple solution after complete addition.
Solvent was subsequently removed under vacuum to yield a sticky purple 31 residue.
Pentane (200 ml) was added and stirred overnight.

32 The pentane solution slowly became green-brown during this 33 time. The pentane solution was filtered to remove metal 34 halides, concentrated to ca.
75 ml and stored at -40C

01 overnight. The crystalline material that formed was 02 collected, washed with cold pentane, and dried under vacuum, 03 affording 680 mg (29%) of dark brown material.

06 HOMOGENEOUS POLYMERIZATION WITH Cp*Cr(Bzyl)2(THF) O8 Seventy-five milligrams of Cp*Cr(CHzPh)2(THF) was dissolved O9 in 50 ml of heptane and placed in a thick-walled glass vessel which was attached to a purified ethylene supply.
11 Ethylene was added to 50 psi at ca. 20°C. A mild exotherm 12 ensued with the generation of 0.70 g of beige polymer after 13 one hour. The catalyst was essentially inactive after one 14 hour as evidenced by the lack of ethylene uptake.

18 Cp*Cr (Bzyl ) 2 (THF) was supported on A1203 ~ 2A1P04 (which had 19 been dehydrated at 400°C for 48 hours) and used to polymerize ethylene using the procedure described in 21 Example il. The results of these polymerization runs are 22 indicated in Table IX below.

TABLE

DATA
FOR
Cp*Cr(Bzyl) ~xsg~

0~ Run ~ mol Cr Co-catalyst Al:Cr' HZ (psi) Activity"

OS 33 12 IBAO 25:1 0 444,000 06 34'2 12 IBAO 25:1 0 235,000 0~ 35'2 12 IBAO 25:1 0 230,000 Og 'Mole ratio.

"Expressed as g polymer/g Cr/hr.

11 'zPolymerization performed with argon/ethylene mixture 12 (250 psi/300 psi).

Cp *
Cr ( ) z ( Pyr ) 1~ This S.K.;
compound was prepared as described in Noh, ig Sendlinger, S.
C.;
Janiak, C.;
Theopold, K.
H.
J.
Am.
Chem ig Soc.
(1989), 111, 9127.

22 Cp*Cr(Bzyl)Z(Pyr) 2~ This compound was prepared as in Example 15 except that two equivalents of benzylmagnesium bromide were substituted for 26 methyllithium. A microcrystalline solid formed and was 27 dried under vacuum. Anal. Calc. for CZ9H~NCr: C,77.65;
2g H,7.64; N,3.12. Found: C,77.03; H,7.48; N,2.80.

~D~~a90 Ol 03 Cp*Cr(TMSM)z(Pyr) OS This compound was prepared as in Example 15 except that two 06 equivalents of trimethylsilylmethyllithium solution were added in place of methyllithium. Long, black needles formed 08 after cooling to -40 °C overnight. These were collected and 09 dried to yield 1.30 g (55%) of pure material. Anal. Calc.
for Cz3HazNSizCr: C, 62.67; H, 9.60; N, 3.17. Found: C, 11 62.36; H, 9.46; N, 2.84.

16 Cp*Cr(CH3)z(Pyr) , Cp*Cr(Bzyl)z(Pyr) , and Cp*Cr(TMSM)z(Pyr) were individually supported on dehydrated (400 °C) supports 18 as in Example 10 to give catalysts with ca 1.0 wt %
19 chromium. The supports used are listed in the following tables.

24 The supported catalysts of Example 18 were each in turn used to polymerize ethylene by a procedure similar to that 26 described in Example 11. The results of these 2~ polymerization runs are indicated in the following tables.

20~~0~0 03 Run Support' Cr Compound ~.cmol Co-cat Al:Cr Activity' Cr 04 36 A12032A1P04Cp'Cr(CH3)2(Pyr)d 15.7 IBAO 19 623,000 05 37 A1 O 2A1P0C 'Cr CH P r 15. IBAO 19 237, 000 2 3 4 a 7 p ( 3)2( y ) 38 A12032A1P04Cp'Cr(CHg)2(Pyr)d 8.4 IBAO 24 764,000 39 A1P0, Cp'Cr(CHg)2(Pyr)d 8.4 IBAO 24 1,488,000 40 A1P0, Cp Cr(CHg)2(Pyr)d 8.4 IBAO 24 1,600,000 41 EP-10~ Cp Cr(CHg) (Pyr)d 16.7 IBAO 18 410,000 42 EP-10 (Pyr)d 15.7 IBAO 19 356 Cp'Cr(CH 000 ) 1 g , 12 43 AlzOg2A1PO4Cp'Cr(Bzyl)2(Pyr)h 12.8 IBAO 24 750,000 13 44 A12032A1P04Cp'Cr(TMSM)2(Pyr)i 12.8 IBAO 24 722,000 17 ' ated at 400C 4 l runs.
Support for 2 hrs.
dehydr for al b Mole ratio 19 ' polymer/g Cr/hr.
Expressed as g d Pyr =
pyridine 21 ' IBAO
=
isobutyl aluminoxane 22 f psi/250 ethylene/argon Polymerization psi performed with 23 ratio 24 g ca support (similar to Davison 52) Crosfield 9 sili Bzyl =
benzyl 26 ' TMSM
=
trimethylsilylmethyl ~~~~~9~

Ol TABLE
XI

DATA
FOR POLYETHYLENES
PREPARED

CATALYSTS
OF
TABLE

Run # Tm, C MI' HLMIb 07 36 137.0 0 0 37 138.8 0 0 38 139.6 0 0 11 39 139.3 0 0 13 40 136.1 - ---17 43 141.4 0 44 137.6 0 23 ' Melt Index (ASTM D-1238, Condition E) 24 ° High Load Melt Index (ASTM D-1238, Condition F)

Claims (84)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A catalyst for the homopolymerization and copolymerization of alpha-olefins having 2-8 carbon atoms, said catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the chromium has an oxidation state of +3, said Group 6b metal compound being supported on an inorganic support.

2. The catalyst system of claim 1 wherein the hydrocarbyl is sigma bonded to the chromium.

3. The catalyst system of claim 1 or 2 wherein the chromium compound has the formula:
(C5(R')5)aCrX b(L) (I) [(C5(R')5)aCrX b]c (II) or L(C5(R')5)aCrX b(L)m]+[A] (III) wherein (C5(R')5) is a cyclopentadienyl or substituted cyclopentadienyl ring;
R' is at each independent occurrence hydrogen, a hydrocarbyl radical having 1-20 carbon atoms, or adjacent R' groups may together form one or more rings;
X is a hydrocarbyl radical having 1-20 carbon atoms;
a = 1 or 2, b = 1 or 2 wherein a+b = 3;

c = 1 or 2 with the proviso that when c = 2 then X is alkyl;
L is at each independent occurrence a sigma donor stabilizing ligand;
m = 1 to 2 inclusive; and A is an anion.

4. The catalyst system of Claim 3 wherein the chromium compound has the formula:
(Cs (R')5) CrX2L

5. The catalyst system of Claim 4 wherein (C5(R')5) is pentamethylcyclopentadienyl.

6. The catalyst system of Claim 4 wherein X is selected from the group consisting of methyl, benzyl and trimethylsilylmethyl, and L contains oxygen or nitrogen.

7. The catalyst system of Claim 4 wherein L is tetrahydrofuran or pyridine.

8. The catalyst system of Claim 3 wherein the chromium compound has the formula:
[C5(R')5)CrX2]6

9. The catalyst system of Claim 8 wherein (C5(R')5) is pentamethylcyclopentadienyl.

10. The catalyst system of Claim 8 wherein X is selected from the group consisting of methyl, benzyl and trimethylsilylmethyl.

11. The catalyst system of Claim 8 wherein c=2.

12 . The catalyst system of Claim 3 wherein the chromium compound has the formula:
[C5(R')5)CrXL2]+A'

13. The catalyst system of Claim 12 wherein (C5(R')5) is pentamethylcyclopentadienyl.

14. The catalyst system of Claim 12 wherein X is selected from methyl, benzyl and trimethylsilylmethyl.

15. The catalyst system of Claim 12 wherein L contains oxygen or nitrogen.

16. The catalyst system of Claim 15 wherein L is selected from tetrahydrofuran and pyridine.

The catalyst system of Claim 3 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+[BPh4]-Cp*Cr(Bzyl)2(THF) Cp*Cr(TMSM)2 Cp*Cr(CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)2(Pyr) where Cp* is pentamethylcyclopentadienyl, THF is tetrahydrofuran, Ph is phenyl, Bzyl is benzyl, TMSM is trimethylsilylmethyl and Pyr is pyridine.

18. The catalyst system of Claim 1 wherein the support is an inorganic metal oxide or inorganic metal phosphate.

19. The catalyst system of Claim 18 wherein the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate.

20. The catalyst system of Claim 19 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

21, The catalyst system of Claim 20 wherein the support is alumina aluminum phosphate.

22. The catalyst system of claim 17 wherein the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate.

23. The catalyst system of claim 22 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

24. The catalyst of claim 23 wherein the support is alumina aluminum phosphate.

25. A catalyst system for the homopolymerization and copolymerization of alpha-olefins having 2-8 carbon atoms, said catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the chromium has an oxidation state of +3, said chromium compound being supported on an inorganic support, and a Group 2 or 3 metal alkyl compound.

26. The catalyst system of claim 25 wherein the hydrocarbyl is sigma bonded to the chromium.

27. The catalyst system of claim 25 wherein the chromium compound has the formula:

(C5(R')5)aCrXb(L) (I) [(C5(R')5)aCrXb]c (II) or [(C5(R')5)aCrXb(L)m]+ [A] (III) wherein (C5(R')5) is a cyclopentadienyl or substituted cyclopentadienyl ring;

R' is at each independent occurrence hydrogen, a hydrocarbyl radical having 1-20 carbon atoms, or adjacent R' groups may together form one or more rings;
X is a hydrocarbyl radical having 1-20 carbon atoms;
a = 1 or 2 , b = 1 or 2 where a+b = 3;
c = 1 or 2 with the proviso that when c = 2 then X is alkyl;
L is at each independent occurrence a sigma donor stabilizing ligand;
m = 1 to 2 inclusive; and A is an anion.

28. The catalyst system of Claim 27 wherein the chromium compound has the formula:

(C5(R')5) CrX2L

29. The catalyst system of Claim 28 wherein (C5(R')5) is pentamethylcyclopentadienyl.

30. The catalyst system of Claim 28 wherein X is selected from the group consisting of methyl, benzyl and trimethylsilylmethyl, and L contains oxygen or nitrogen.

31 . The catalyst system of Claim 28 wherein L is tetrahydrofuran or pyridine.

32 . The catalyst system of Claim 27 wherein the chromium compound has the formula:

[C5(R')5)CrX2]c

33 . The catalyst system of Claim 32 wherein (C5(R')5) is pentamethylcyclopentadienyl.

34 . The catalyst system of Claim 32 wherein X is selected from the group consisting of methyl, benzyl and trimethylsilylmethyl.

35 . The catalyst system of Claim 32 wherein c=2.

36 . The catalyst system of Claim 27 wherein the chromium compound has the formula:

[(C5(R')5) CrXL2] +A-

37 . The catalyst system of Claim 36 wherein (C5(R')5) is pentamethylcyclopentadienyl.

38 . The catalyst system of Claim 36 wherein X is selected from methyl, benzyl and trimethylsilylmethyl.

39 . The catalyst system of Claim 36 wherein L contains oxygen or nitrogen.

40 . The catalyst system of Claim 39 wherein L is selected from tetrahydrofuran and pyridine.

41. The catalyst system of Claim 27 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+[BPh4]-Cp*Cr(Bzyl)2(THF) Cp*Cr(TMSM)2 Cp*Cr (CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)2(Pyr) where Cp* is pentamethylcyclopentadienyl, THF is tetrahydrofuran, Ph is phenyl, Bzyl is benzyl, TMSM is trimethylsilylmethyl, and Pyr is pyridine.

42. The catalyst system of Claim 25 wherein the support is an inorganic metal oxide or inorganic metal phosphate.

43. The catalyst system of Claim 42 wherein the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate.

44. The catalyst system of Claim 43 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

45. The catalyst system of Claim 44 wherein the support is alumina aluminum phosphate.

46. The catalyst system of Claim 25 wherein the Group 2 or Group 3 metal alkyl compound is an alkylaluminum compound.

47. The catalyst system of Claim 46 wherein the alkylaluminum compound is selected from the group consisting of trialkylaluminum compounds, alkylaluminum alkoxides, alkylaluminum halides and aluminoxanes.

48. The catalyst system of Claim 47 wherein the alkylaluminum compound is an aluminoxane or trialkylaluminum compound.

49. The catalyst system of Claim 25 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+ [BPh4]-Cp*Cr(Bzyl)2(THF) or Cp*Cr (TMSM)2, Cp*Cr(CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)~(Pyr) the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate, and the Group 2 or 3 metal alkyl compound is an alkylaluminum compound.

50. The catalyst system of Claim 49 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

51. The catalyst system of Claim 50 wherein the support is alumina aluminum phosphate.

52. The catalyst system of Claim 49 wherein the alkylaluminum compound is selected from the group consisting of trialkylaluminum compounds, alkylaluminum alkoxides, alkylaluminum halides and aluminoxanes.

53. The catalyst system of Claim 52 wherein the alkylaluminum compound is an aluminoxane or trialkylaluminum compound.

54. The catalyst system of Claim 25 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+ [BPh4]-Cp*Cr(Bzyl)2(THF) or Cp*Cr(TMSM)2, Cp*Cr(CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)2(Pyr) the support is silica or alumina aluminum phosphate, and the alkylaluminum compound is an aluminoxane or a trialkylaluminum compound.

55. The catalyst system of Claim 54 wherein the support is alumina aluminum phosphate.

56. A process for the homopolymerization or copolymerization of alpha-olefins having 2-8 carbon atoms comprising polymerizing said alpha-olefin, or copolymerizing two or more alpha-olefins in the presence of a catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the metal has an oxidation state of +3, said chromium compound being supported on an inorganic support.

57. The process of claim 56 wherein the hydrocarbyl is sigma bonded to the chromium.

58. The process of claim 56 wherein the chromium compound has the formula:

(C5(R')5)aCrXb(L) (I) [(C5(R')5)aCrXb]c (II) or [(C5(R')5)aCrXb(L)m]+[A]- (III) wherein (C5(R')5) is a cyclopentadienyl or substituted cyclopentadienyl ring;

R' is at each independent occurrence hydrogen, a hydrocarbyl radical having 1-20 carbon atoms, or adjacent R' groups may together form one or more rings;
X is a hydrocarbyl radical having 1-20 carbon atoms;
a = 1 or 2, b = 1 or 2 wherein a+b = 3;
c = 1 or 2 with the proviso that when c = 2 then X is alkyl;

L is at each independent occurrence a sigma donor stabilizing ligand;
m = 1 to 2 inclusive; and A is an anion.

59. The process of Claim 58 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+ [BPh4]-Cp*Cr(Bzyl)2(THF) Cp*Cr(TMSM)2 Cp*Cr(CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)2(Pyr) where Cp* is pentamethylcyclopentadienyl, THF is tetrahydrofuran, Ph is phenyl, Bzyl is benzyl, TMSM is trimethylsilylmethyl, and Pyr is pyridine.

60. The process of Claim 56 wherein the support is an inorganic metal oxide or inorganic metal phosphate.

61. The process of Claim 56 wherein the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate.

62. The process of Claim 61 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

63. The process of Claim 62 wherein the support is alumina aluminum phosphate.

64. The process of Claim 59 wherein the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate.

65. The process of Claim 64 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

66. The process of Claim 65 wherein the support is alumina aluminum phosphate.

67. A process for the homopolymerization or copolymerization of alpha-olefins comprising polymerizing said alpha-olefin, or copolymerizing two or more alpha-olefins in the presence of a catalyst system comprising a cyclopentadienyl chromium hydrocarbyl compound in which the chromium has an oxidation state of +3, said chromium 6b-metal compound being supported on an inorganic support, and a Group 2 or 3 metal alkyl compound.

68. The process of Claim 67 wherein the hydrocarbyl is sigma bonded to the chromium.

69. The process of claim 67 wherein the chromium compound has the formula:

(C5(R')5)aCrXb(L) (I) [(C5(R')5)aCrXb]c (II) or [(C5(R')5)aCrXb(L)m]+ [A] (III) wherein (C5(R')5) is a cyclopentadienyl or substituted cyclopentadienyl ring;
R' is at each independent occurrence hydrogen, a hydrocarbyl radical having 1-20 carbon atoms, or adjacent R' groups may together form one or more rings;
X is a hydrocarbyl radical having 1-20 carbon atoms;
a = 1 or 2, b = 1 or 2 wherein a+b = 3;
c = 1 or 2 with the proviso that when c = 2 then X is alkyl;
L is at each independent occurrence a sigma donor stabilizing ligand;
m = 1 to 2 inclusive; and A is an anion.

70. The process of Claim 69 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3J+ (BPh4]-Cp*Cr(Bzyl)2(THF) Cp*Cr(TMSM)2 Cp*Cr(CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)2(Pyr) where Cp* is pentamethylcyclopentadienyl, THF is tetrahydrofuran, Ph is phenyl, Bzyl is benzyl, TMSM is trimethylsilylmethyl, and Pyr is pyridine.

71. The process of Claim 67 wherein the support is an inorganic metal oxide or inorganic metal phosphate.

72. The process of Claim 71 wherein the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate.

73. The process of Claim 72 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

74. The process of Claim 73 wherein the support is alumina aluminum phosphate.

75. The process of Claim 67 wherein the Group 2 or Group 3 metal alkyl compound is an alkylaluminum compound.

76. The process of Claim 75 wherein the alkylaluminum compound is selected from the group consisting of trialkylaluminum compounds, alkylaluminum alkoxides, alkylaluminum halides and aluminoxanes.

77. The process of Claim 76 wherein the alkylaluminum compound is an aluminoxane or trialkylaluminum compound.

78. The process of Claim 67 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+[Bph4]-Cp*Cr(Bzyl)2(THF) or Cp*Cr(TMSM)2, Cp*Cr(CHj)2(Pyr) Cp*Cr(TMSM)2(Pyr) Cp*Cr(Bzyl)2(Pyr) the support is selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconium phosphate, and alumina aluminum phosphate, and the Group 2 or 3 metal alkyl compound is an alkylaluminum compound.

79. The process of Claim 78 wherein the support is selected from silica, aluminum phosphate and alumina aluminum phosphate.

80. The process of Claim 79 wherein the support is alumina aluminum phosphate.

81. The process of Claim 78 wherein the alkylaluminum compound is selected from the group consisting of trialkylaluminum compounds, alkylaluminum alkoxides, alkylaluminum halides and aluminoxanes.

82. The process of Claim 81 wherein the alkylaluminum compound is an aluminoxane or trialkylaluminum compound.

83. The process of Claim 78 wherein the chromium compound is selected from Cp*Cr(CH3)2(THF) [Cp*Cr(CH3)2]2 [Cp*Cr(THF)2CH3]+ [BPh4]-Cp*Cr(Bzyl)2(THF) Cp*Cr(TMSM)2 Cp*Cr(CH3)2(Pyr) Cp*Cr(TMSM)2(Pyr) and Cp*Cr(Bzyl)2(Pyr) the support is silica or alumina aluminum phosphate, and the alkylaluminum compound is an aluminoxane or a trialkylaluminum compound.

84. The process of Claim 83 wherein the support is alumina aluminum phosphate.