Abstract: Catalyst compositions that are highly tolerant of catalyst poisons comprising a cationic or zwitterionic Group 4 metal complex of the constrained geometry type and an organoaluminum hydrocarbyloxide compound according to the formula R.sup.1.sub.2 Al(OR.sup.2),wherein R.sup.1 and R.sup.2 independently each ocurrence are C.sub.1-30 hydrocarbyl,the molar ratio of complex to organoaluminum hydrocarbyloxide compound being from 1:0.1 to 1:100.

Abstract: A supported catalyst composition comprising a complex of a Group 4 metal cyclopentadienyl derivative reacted with silica treated with an aluminoxane demonstrates improved reactivity, especially for incorporating long chain alpha-olefins and also shows improved resistance to catalyst poisoning. The supported catalyst composition is adapted to produce homogeneous polymers, copolymers, terpolymers, etc., for example, homogeneous polyethylene, homogeneous poly(ethylene-octene) copolymers and the like. The invention further includes the process of preparing the supported catalyst compositions and a process for preparing olefinic polymers using these catalyst compositions.

Abstract: An addition polymerization catalyst comprising a cationic complex of a Group 4 metal cyclopentadienyl derivative and an alumoxane shows improved resistance to catalyst poisons.