Process for producing stereospecific polymers
US5158920A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 3, 1991 |
| Grant date | Oct 27, 1992 |
| Priority date | — |
| Expiry date | Jul 3, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/943
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Process for the preparation of bridged metallocene catalysts. A substituted or unsubstituted cyclopentadiene is deprotonated in a polar solvent to form a solution of the corresponding anion species. The solution is then cooled to a temperature within the range of about -10.degree. to -30.degree. C. A minor amount of a solution of substituted fulvene in a polar solvent is added to a major quantity of the solution of anionic substituted or unsubstituted cyclopentadiene. The substituted fulvene is present in the solvent to provide a concentration of less than 2 molal. The substituted fulvene is disubstituted on the terminal (6) carbon atom and may be substituted or unsubstituted on the cyclopentadienyl ring. The resulting mixture is warmed to a temperature within the range of about 0.degree. to 25.degree. C. (room temperature) to produce a bridged cyclopentadienyl ligand. The bridged ligand is then recovered and contacted with a transition metal halide or hydrocarbon compound under reaction conditions sufficient to complex the bridged ligand to produce a bridged metallocene. In the preparation of syndiospecific metallocene catalysts one cyclopentadienyl group is a substituted or unsub…
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