Catalyst system for high activity and stereoselectivity in the homopolymerization and copolymerization of olefins
The present invention is directed to a novel composition, and to a method of making the composition, the composition being useful in catalyst systems for the homopolymerization and/or copolymerization of olefins, wherein such catalyst systems display a higher level of activity and stereoselectivity than previously reported. The present invention is also directed to novel polymeric compositions made with such catalyst systems, such as a novel syndiotactic polypropylene that melts at temperatures higher than previously reported.
1. An organometallic complex having the formula: R 2 Si(η n -C 29 H 36 )(η 1 -N—R′)M′X 2 .L, where (a) R is selected from the group consisting of alkyl groups, aryl groups, and combinations thereof; (b) n is selected from the group consisting of 1 and 5; (c) R′ is selected from the group consisting of alkyl groups, aryl groups and combinations thereof; (d) M′ is a transition metal; (e) X is selected from the group consisting of halides, alkyl groups, aryl groups, and combinations thereof; (f) L is an optional adduct; and (g) η n -C 29 H 36 is octamethyloctahydrodibenzofluorenylidene.
2. The organometallic complex of claim 1 , wherein M′ is selected from the group consisting of Zr, Hf, and Ti.
3. The organometallic complex of claim 1 , wherein X is selected from the group consisting of F, Cl, Br, I, and combinations thereof.
4. The organometallic complex of claim 1 , wherein R is a methyl (Me) group.
5. The organometallic complex of claim 1 , wherein R′ is a tert-butyl ( t Bu) group.
6. The organometallic complex of claim 1 , wherein L is an ether.
7. The organometallic complex of claim 1 , wherein L is selected from the group consisting of Et 2 O, THF, and CH 3 CN.
8. The organometallic complex of claim 1 , wherein the organometallic complex is a trigonal bipyramidal species having a formula selected from the group consisting of Me 2 Si(η 1 -C 29 H 36 )(η 1 -N- t Bu)ZrBr 2 .OEt 2 , Me 2 Si(η 1 -C 29 H 36 )(η 1 -N- t Bu)ZrCl 2 .OEt 2 , Me 2 Si(η 1 -C 29 H 36 )(η 1 -N- t Bu)HfBr 2 .OEt 2 , and Me 2 Si(η 1 -C 29 H 36 )(η 1 -N- t Bu)ZrMe 2 .THF.
9. A method for olefin polymerization comprising a step of catalyzing said polymerization using the organometallic complex of claim 1 .
10. The method of claim 9 , wherein the organometallic serves as a precatalyst for olefin polymerization.
11. A catalyst system comprising:
(a) a quantity of the organometallic complex of claim 1 ; and
(b) a co-catalyst.
12. The catalyst system of claim 11 , wherein the co-catalyst is selected from the group consisting of alkylaluminoxanes, boron-based Lewis acids, borate-based salts, amine salts, and combinations thereof.
13. The catalyst system of claim 11 , wherein the co-catalyst is selected from the group consisting of MAO (methylaluminoxane), B(C 6 F 5 ) 3 , (C 6 H 5 ) 3 C + B(C 6 F 5 ) 4 − , HMe 2 N(C 6 H 5 ) 30 B(C 6 F 5 ) 4 − , and combinations thereof.
14. A method for olefin polymerization comprising a step of contacting propylene with the catalyst system of claim 11 , to form syndiotactic polypropylene, wherein said syndiotactic polypropylene has an un-annealed melting temperature above 157° C.
15. A method for olefin polymerization comprising a step of contacting monomer with the catalyst system of claim 11 , to form a homopolymer, wherein said monomer is selected from the group consisting of ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene.
16. A method for olefin polymerization comprising a step of contacting monomers with the catalyst system of claim 11 , to form a copolymer, monomers are selected from the group consisting of ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene.
17. A method for olefin polymerization comprising a step of contacting monomers with the catalyst system of claim 11 , to form a terpolymer, wherein said monomers are selected from the group consisting of ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene.
18. A method for olefin polymerization comprising a step of contacting ethylene with the catalyst system of claim 11 , to form a polymer, wherein said polymer comprises branches selected from the group consisting of long-chain branches, short-chain branches, and combinations thereof.
19. The method of claim 16 , wherein said copolymer comprises branches selected from the group consisting of long-chain branches, short-chain branches, and combinations thereof.
20. The method of claim 17 , wherein said terpolymer comprises branches selected from the group consisting of long-chain branches, short-chain branches, and combinations thereof.
21. A method for making the organometallic complex of claim 1 , the method comprising the steps of:
(a) forming an OctM (C 29 H 37 M) species generated from C29H38 (octamethyloctahydrodibenzofluorene) and an alkali alkyl species, where M is an alkali metal;
(b) combining a hydrocarbon-based slurry of OctM with an excess of a Cl 2 Si(R) 2 species to form a first reaction product, wherein R is selected from the group consisting of alkyl groups, aryl groups, and combinations thereof;
(c) adding an metal alkyl amide species M″NHR′ species to the first reaction product to form a second reaction product, wherein M″ is an alkali metal and R′ is selected from the group consisting of alkyl groups, aryl groups, and combinations thereof;
(d) adding an alkali alkyl species to the second reaction product to doubly deprotonate the second reaction product and form third reaction product, a dialkali salt; and
(e) combining the dialkali salt with a M′X 4 species and reacting in the presence of a species L to form a product R 2 Si(η n -C 29 H 36 )(η 1 -N—R′)M′X 2 .L; wherein M′ is a transition metal; X is selected from the group consisting of halides, alkyl groups, aryl groups, and combinations thereof; and L is an optional adduct in the product.
22. The method of claim 21 , wherein the alkali alkyl species is selected from the group consisting of alkyllithium species, alkylsodium species, alkylpotassium species, and combinations thereof.
23. The method of claim 21 , wherein the alkali alkyl species is n-butyllithium.
24. The method of claim 21 , wherein the hydrocarbon-based slurry comprises an ethereal solvent.
25. The method of claim 21 , wherein OctM is OctLi.
26. The method of claim 21 , wherein the Cl 2 Si(R) 2 species is dichlorodimethylsilane (Cl 2 Si(CH 3 ) 2 ).
27. The method of claim 21 , wherein the metal alkyl amide species M″NHR′ species is lithium tert-butyl amide (LiNHC(CH 3 ) 3 ).
28. The method of claim 21 , wherein the dialkali salt is LiNC(CH 3 ) 3 Si(CH 3 ) 2 (C 29 H 36 Li).
29. The method of claim 21 , wherein L is Et 2 .
30. The method of claim 21 , further comprising a step of reacting the product R 2 Si(η n -C 29 H 36 )(η 1 -N—R′) M′R″ 2 .L with a species M′″R′ to form a variant product R 2 Si (η n -C 29 H 36 )(η 1 —N—R′) M′R″ 2 .L, where M′″ is selected from the group consisting of an alkali metal and a magnesium halide, and R″ is selected from the group consisting of an alkyl group differing from X and an aryl group differing from X.
31. Syndiotactic polypropylene made by the catalyst system of claim 11 , wherein the syndiotactic polypropylene has an un-annealed melting temperature above 157° C.
32. The syndiotactic polypropylene of claim 31 , wherein the stereochemical pentad fraction [rrrr] is greater than 99%.