ZrCl4 as Catalyst for Olefins and Styrene Polymerization:  Effect of Ethereal Donors on the Activity and Stereospecificity

Complexes of ZrCl 4 incorporating neutral donors such as THF and Et 2 O activated by methylaluminoxane have been found to be active homogeneous catalytic systems for the polymerization of ethylene. They also promote the propylene and styrene polymerization with high degree of iso- and syndiotacticity, respectively. The different behaviors in propylene and styrene polymerization using methylalumoxane containing different amounts of Al(CH 3 ) 3 with respect to isotactic propylene and syndiotactic styrene polymerization of these compounds suggest that the presence of neutral Lewis bases on the metal center plays a crucial role on the stereoselectivity of polymerization reaction.