Process for producing stereospecific polymers

Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing

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502103, 502117, 556 43, 556 53, 556 58, C08F 464, C08F 468, C08F 469

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051589206

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 unsubstituted cyclopentadienyl ring and the other is a substituted cyclopentadienyl group sterically different from the first ring structure. Here, the cyclopentadienyl compound subjected to the protonation reaction can be a substituted or unsubstituted fluorenyl or indenyl group which is deprotonated and reacted with a 6, 6-dialkyl fulvene.

REFERENCES:
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patent: 4975403 (1990-12-01), Ewen
Jordan et al., JACS 1986, 108, 7410-11.
Jordan et al., JACS 1986, 108, 1718-19.
Zambelli et al., Macromolecules, 1989, 22, 2186-89.

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