Catalyst composition and method for preparing polyethylene

1. A catalyst composition for polymerizing olefins, the catalyst composition comprising:

a) a first metallocene compound having the formula:

(X 1 )(X 2 )(X 3 )(X 4 )M 1 , wherein

M 1 is zirconium;

X 1 is an indenyl ligand which is substituted at the 1-position with a group selected independently from

X 2 is [1] an unsubstituted cyclopentadienyl ligand or an unsubstituted indenyl ligand, [2] a cyclopentadienyl ligand which is substituted with at least one hydrocarbyl substituent selected independently from a C 1 -C 12 alkyl or a C 2 -C 12 alkenyl, or [3] an indenyl ligand which is substituted at the 1-position with a group having the formula

 wherein X 1 and X 2 are unbridged; and

X 3 and X 4 are each a chloride;

b) optionally, a co-catalyst comprising an organoaluminum compound, an organoboron compound, an organozinc compound, an organomagnesium compound, an organolithium compound, or any combination thereof; and

c) an activator comprising a solid oxide treated with an electron-withdrawing anion (activator-support), an organoboron compound, an organoborate compound, an ionizing ionic compound, an aluminoxane compound, or any combination thereof.

2. The catalyst composition according to claim 1 , wherein the first metallocene compound is selected from:

wherein R 1 is C 6 F 5 (IE-1) or R 1 is H (IE-3);

wherein R 2 is H and R 3 is H (IE-4), R 2 is CH 2 CH 2 CH═CH 2 and R 3 is H (IE-5); R 2 is CH 2 CH 2 CH═CH 2 and R 3 is CH 3 (IE-6); R 2 is CH 2 CH═CH 2 and R 3 is H (IE-7), or R 2 is CH 2 CH═CH 2 and R 3 is CH 3 (IE-8);

or

any combination thereof.

3. The catalyst composition according to claim 1 , wherein the catalyst composition further comprises:

d) a second metallocene compound having the formula:

(X 5 )(X 6 )(X 7 )(X 8 )M 2 , wherein

M 2 is titanium, zirconium, or hafnium;

X 5 is an optionally substituted cyclopentadienyl, indenyl, or fluorenyl ligand, wherein the substituent is selected independently from a C 1 -C 12 hydrocarbyl group;

X 6 is an optionally substituted indenyl or fluorenyl ligand, wherein the substituent is selected independently from a C 1 -C 12 hydrocarbyl group or a C 1 -C 12 heterohydrocarbyl group;

wherein X 5 and X 6 are bridged by a bridging group selected from (>ER B 2 ) x or >BR B , wherein x is an integer from 1 to 3, E in each occurrence is selected independently from a carbon atom or a silicon atom, R B in each occurrence is selected independently from H or a C 1 -C 12 hydrocarbyl group, and wherein optionally, two R B moieties form a C 3 -C 6 cyclic group; and

X 7 and X 8 are independently selected from a halide, hydride, a C 1 -C 20 hydrocarbyl group, a C 1 -C 20 heterohydrocarbyl group, tetrahydroborate, or OBR A 2 or OSO 2 R A wherein R A is independently a C 1 -C 12 hydrocarbyl group.

4. The catalyst composition according to claim 3 , wherein

X 5 is unsubstituted or substituted with a C 1 -C 6 alkyl or C 2 -C 8 alkenyl group, and X 6 is substituted with two substituents selected independently from a C 1 -C 12 hydrocarbyl group; and

R B , in each occurrence, is selected independently from a C 1 -C 6 alkyl or C 2 -C 8 alkenyl group.

5. The catalyst composition according to claim 3 , wherein (>ER B 2 ) x is selected from (—CR B 2 CR B 2 —), (—SiR B 2 SiR B 2 —), (—CR B 2 SiR B 2 —), (—CR B 2 CR B 2 CR B 2 —), (—SiR B 2 CR B 2 CR B 2 —), (—CR B 2 SiR B 2 CR B 2 —), (—SiR B 2 CR B 2 SiR B 2 —), (—SiR B 2 SiR B 2 CR B 2 —), or (—SiR B 2 SiR B 2 SiR B 2 —).

6. A catalyst composition according to claim 3 , wherein (>ER B 2 ) x or >BR B is selected from >CMe 2 , >CPh 2 , >CHMe, >CHPh, >CH(tolyl), >CMeEt, >CMe(CH 2 CH 2 CH 3 ), >CMe(CH 2 CH 2 CH 2 CH 3 ), >CH(CH 2 CH 2 CH═CH 2 ), >CMe(CH 2 CH 2 CH═CH 2 ), >CEt(CH 2 CH 2 CH═CH 2 ), >CPh(CH 2 CH 2 CH═CH 2 ), >SiMe 2 , >SiPh 2 , >SiEt 2 , >Si(tolyD 2 , (—CH 2 CH 2 —), (—CMe 2 CMe 2 -), (—CH 2 CH 2 CH 2 —), (—CH 2 SiMe 2 CH 2 —), (—CH 2 SiPh 2 CH 2 —), (—SiMe 2 SiMe 2 -), >BMe, >BEt, >BPh, or >B(tolyl).

7. A catalyst composition according to claim 3 , wherein the second metallocene is selected from a compound having the formula:

wherein:

M 4 is zirconium or hafnium;

X 5 in each occurrence is independently F, Cl, Br, I, H, methyl, benzyl, phenyl, or methoxy;

R D in each occurrence is selected independently from H, C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 6 -C 10 aryl, C 7 -C 12 aralkyl, or C 1 -C 12 hydrocarbyloxide;

E 1 is C or Si;

R E in each occurrence is selected independently from H, C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 6 -C 10 aryl, or C 7 -C 12 aralkyl; and

R F is selected from H, C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 6 -C 10 aryl, or C 7 -C 12 aralkyl.

8. A catalyst composition according to claim 3 , wherein the second metallocene is selected from a compound having the formula:

wherein:

M 4 is zirconium or hafnium;

X 5 in each occurrence is independently Cl, Br, methyl, or benzyl;

R D in each occurrence is selected independently from H or t-butyl;

E 1 is C;

R E in a first occurrence is methyl or phenyl, and R E in a second occurrence is methyl, phenyl, or CH 2 CH 2 CH═CH 2 ; and

R F is H or CH 2 CH 2 CH 2 CH═CH 2 .

9. A catalyst composition according to claim 3 , wherein the second metallocene is selected from a compound having the formula:

10. The catalyst composition according to claim 1 , wherein the activator comprises a solid oxide treated with an electron-withdrawing anion, and wherein:

the solid oxide comprises silica, alumina, titania, zirconia, magnesia, boria, calcia, zinc oxide, silica-alumina, silica-coated alumina, silica-titania, silica-zirconia, silica-magnesia, alumina-titania, alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria, aluminum phosphate, aluminophosphate, aluminophosphate-silica, magnesium aluminate, titania-zirconia, mullite, boehmite, heteropolytungstates, or any combination thereof; and

the electron-withdrawing anion comprises fluoride, chloride, bromide, iodide, sulfate, bisulfate, fluorosulfate, phosphate, fluorophosphate, triflate, mesylate, tosylate, thiosulfate, C 1 -C 10 , C 6 -C 14 aryl sulfonate, trifluoroacetate, fluoroborate, fluorozirconate, fluorotitanate, or any combination thereof.

11. A catalyst composition according to claim 1 , wherein the activator comprises a solid oxide treated with an electron-withdrawing anion selected from fluorided alumina, chlorided alumina, bromided alumina, sulfated alumina, phosphated alumina, fluorided silica-alumina, chlorided silica-alumina, bromided silica-alumina, sulfated silica-alumina, phosphated silica-alumina, fluorided silica-zirconia, chlorided silica-zirconia, bromided silica-zirconia, sulfated silica-zirconia, phosphated silica-zirconia, fluorided mullite, chlorided mullite, bromided mullite, sulfated mullite, phosphated mullite, fluorided silica-coated alumina, chlorided silica-coated alumina, bromided silica-coated alumina, sulfated silica-coated alumina, phosphated silica-coated alumina, or any combination thereof.

12. A catalyst composition according to claim 1 , wherein:

a) the optional co-catalyst has a general formula:

i) M 3 (X 10 ) n (X 11 ) 3-n , wherein M 3 is boron or aluminum and n is from 1 to 3 inclusive;

ii) M 4 (X 10 ) n (X 11 ) 2-n , wherein M 4 is magnesium or zinc and n is from 1 to 2 inclusive; or

iii) M 5 X 10 , wherein M 5 is Li;

b) X 10 is independently hydride or a C 1 to C 20 hydrocarbyl; and

c) X 11 is independently a halide, a hydride, a C 1 to C 20 hydrocarbyl, or a C 1 to C 20 hydrocarbyloxide.

13. A catalyst composition according to claim 1 , wherein the optional co-catalyst comprises trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminum chloride, or any combination thereof.

14. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

15. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

16. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

17. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

18. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

19. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

20. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

21. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

22. The catalyst composition according to claim 1 , wherein the first metallocene compound has the formula:

23. A process for polymerizing olefins, the process comprising contacting at least one olefin monomer and the catalyst composition according to claim 1 under polymerization conditions to form an olefin polymer, wherein the at least one olefin monomer comprises ethylene or ethylene in combination with an olefin co-monomer selected from propylene, butene, pentene, hexene, heptene, octene, styrene, or a combination thereof.