| abstract |
Olefin polymerization is conducted using a catalyst system comprising an organo-aluminum compound and a solid catalyst product prepared by reacting an organo-tin compound of the formula SnR3Y wherein R is a hydrocarbon group having 1-14 carbon atoms and Y is a halogen or alkoxy, and a halide of a Group III element of the Periodic Table, with quadrivalent titanium compound, quadrivalent vanadium compound, pentavalent vanadium compound, or a mixture or reaction product thereof. In one embodiment, the reaction may be conducted in the presence of a titanium compound having a valency of lower than quadrivalent or a vanadium compound having a valency of lower than quadrivalent or pentavalent. |