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US 5,017,714 AGranted
Silicon-bridged transition metal compounds
AssigneeExxon Chemical Patents Inc.
InventorHoward C. Welborn, Jr.
Life of this patent
Estimating the term…
Abstract
Silicon-bridged transition metal compounds and their use as .alpha.-olefin polymerization catalysts are disclosed. A chiral silicon-bridged metallocene catalyst polymerizes .alpha.-olefins to high isotacity with a minimum of inversions at high rates of catalyst activity. The catalyst is easily made in high yields and readily separated from atactic meso forms.
Claims13
A transition metal compound said compound having the formula:
- ##STR6## wherein M' is a Group I/B transition metal;
- X' and X" are the same or different hydride, halogen, or hydrocarbyl or halohydrocarbyl having up to about 6 carbon atoms;
- A' and A" are the same or different asymmetrical mononuclear or polynuclear hydrocarbyl or silahydrocarbyl moieties;
- and
- S' is a bridge of 1-4 atoms selected from the group consisting of silanylene, silaalkylene, oxasilanylene and oxasilaalkylene.
2 more elements
A chiral transition metal compound having the formula:
- ##STR8## wherein M' is titanium, zirconium or hafnium;
- X' and X" are the same or different hydride, chlorine, bromine, iodine, or 1-6 carbon-atom alkyl, haloalkyl, aryl or haloaryl;
- n and m are the same or different integers from 1 to 4;
- R' and R" are the same or different hydrocarbyl or silahydrocarbyl of 1-20 carbon atoms, and 0-2 silicon atoms, or taken together, two or more of R' or of R" are hydrocarbylene or silahydrocarbylene of 1-20 carbon atoms and 0-2 silicon atoms;
- and
- S' is a chain of 0-4 carbon atoms and 1-2 silicon atoms selected from the group consisting of silanylene, silaalkylene, oxasilanylene and oxasilaalkylene, in which each silicon atom is disubstituted with the same or different hydrocarbyl having 1 to 5 carbon atoms.
3 more elements
Racemic [1,1'-dimethylsilanylene-bis(4,5,6,7-tetrahydroindenyl)] zirconium dichloride.
Dependencies are inferred from the claim text.