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

1994-01-11

Schofer, Joseph L.

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

526160, 526351, 502152, C08F 464

Patent

active

052782654

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 characterized by a cationic metallocene ligand having sterically dissimilar ring structures joined to a positively charged coordinating transition metal atom, and a stable noncoordinating counter anion for the metallocene cation. The ring structures are substituted cyclopentadienyl rings which are sterically different from one another at sufficiently low kinetic energy states induced by the substituents on the cyclopentadienyl groups to impart a stereorigid relationship relative to said coordinating metal atom to prevent rotation of the rings about their coordination axes at the polymerization temperature. The catalyst with a C3+ alpha olefin or ther ethylenically unsaturated compound in a polymerization reaction zone and maintained in contact with the catalyst in the reaction zone under low termperature polymerization conditions to produce a syndiotactic polymer.

REFERENCES:
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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 Polymerization by a Cationic Dicyclopentadienylzirconium(IV) Alkyl Complex", Journal of American Chemical Society, vol. 108, pp. 7410-7411, 1986.

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