Silicon-bridged transition metal compounds
AssigneeExxon Chemical Patents Inc.
InventorHoward C. Welborn, Jr.
Life of this patent
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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.
Claims6
A process for polymerizing .alpha.-olefins, which comprises contacting alpha-olefins having two or more carbon atoms under polymerization conditions with a catalyst system;
- comprising:
- (a) a transition metal compound represented by formula:
- ##STR6## wherein M' is a Group IV-B transition metal;
- X' and X" are the same or different hydride, halogen, 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;
- and
- (b) an organoaluminum component.
A process for producing poly alpha olefin which comprises contacting alpha-olefins having two or more carbon atoms under polymerization conditions with a catalyst system containing
- (a) a chiral transition metal compound represented by the formula:
- ##STR7## 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 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;
- and
- (b) an organoaluminum component.
A process for producing stereo regular polyalpha-olefins under polymerization conditions comprising contacting alpha-olefins having two or more carbon atoms with:
- (a) a transition metal compound represented by the formula:
- ##STR8## wherein M' is a Group IV-B transition metal;
- X' and X" are the same or different hydride, halogen, 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 and
- (b) an organoaluminum component.
A process for polymerizing .alpha.-olefins which comprises contacting alpha-olefins containing two or more carbon atoms under polymerization conditions with a catalyst system comprising a transition metal compound represented by the following formula as a component:
- ##STR9## wherein M' is a Group IV-B transition metal;
- X' and X" are the same or different hydride, halogen, 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.
A process for polymerizing .alpha.-olefins which comprises contacting alpha-olefins containing two or more carbon atoms under polymerization conditions with a catalyst system, at least one component of which is on an inert support, comprising a transition metal compound represented by the following formula as a component:
- ##STR10## wherein M' is a Group IV-B transition metal;
- X' and X" are the same or different hydride, halogen, 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.
Dependencies are inferred from the claim text.