Process and catalyst for producing syndiotactic polymers

Details Process and catalyst for producing syndiotactic polymers Process and catalyst for producing syndiotactic polymers

1993-05-25

1994-03-08

Schofer:, Joseph

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

502152, 526170, C08F 4642

Patent

active

052928381

ABSTRACT:
Syndiospecific catalysts and processes for the syndiotactic propagation of a polymer chain derived from an ethylenically unsaturated monomer which contains 3 or more carbon atoms or is a substituted vinyl compound. The catalysts comprise an unbalanced metallocene cation having sterically dissimilar ring structures joined to a positively charged coordinating transition metal atom and a stable noncoordinating counter anion for the metallocene cation. Both ring structures are substituted cyclopentadienyl rings and one is sterically different from the other. Both are in a stereorigid relationship to the coordinating transition metal atom to prevent rotation of the rings by direct stearic hindrence between the ring structures. The catalyst is contacted with a C3+ alpha olefin or other ehtyleically unsaturated compound in a polymerization reaction zone and maintained in contact with the catalyst in the reaction zone under polymerization conditions to produce a syndiotactic polymer.

REFERENCES:
patent: 3135809 (1964-06-01), Bosmajian
patent: 3305538 (1967-02-01), Natta et al.
patent: 3364190 (1968-01-01), Emrick
patent: 4658078 (1987-04-01), Staugh et al.
Zambelli, A. et al., "Isotactic Polymerization of Propene: Homogenous Catalysts Based on Group 4 Metallocenes Without Methylaluminoxane:", Macro-Molecule 1989, pp. 2186-2189 (pp. 18-19).
Jordan, Richard F. et al., "Reactive Cationic Dicyclopentadienylzirconium (IV) Complexes", Journal of American Chemical Society, vol. 108, pp. 1718-1719, 1986.
Jordan, Richard F. et al., "Ethylene Polymeriaation by a Cationic Dicyclopentadienylzirconium(IV Alkyl Complex", Journal of American Chemical Society, vol. 108, pp. 7410-7411, 1986.

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