Synthesis and olefin polymerization using supported and non-supported geometry constrained titanium complexes

The synthesis of a constrained geometry titanium complex and its immobiliza tion on different supports have been studied for the catalytic polymerizati on of ethylene, propylene and styrene. The formation of higher molecular we ight polymers was found in the heterogeneous system as compared to the homo genous parent for polyethylene and polypropylene. Polymerization of propyle ne yielded atactic products with elastomeric properties due to long polymer chains. However, syndiotactic polymers were formed in the polymerization o f styrene. Catalytic activity was found to be dependent on MAO and titanium concentration; the higher the metal concentration the lower the activity o f the catalyst. The activity of the heterogeneous system was determined as a function of time, and a first-order deactivation pathway was found at roo m temperature. The type of solvent (toluene or CH2Cl2) also played an impor tant role in the polymerization of ethylene and styrene, although different tendencies were found for either monomers. (C) 1999 Elsevier Science S.A. All rights reserved.