ABSTRACT: A novel methodology was developed for the preparation of isospecific metallocene catalysts for olefin polymerization that are tethered on silica surfaces with covalent bonds. A racemic ansa-zirconocene complex that has a SiCl moiety on its bridge was immobilized on SiO2 by the reaction of the SiCl anchor with SiOH on the solid surface. The prepared solid catalyst was found to be effective for isospecific propene polymerization (catalyst A). Pretreatment of silica surfaces with Me3SiCl improved the catalyst performance (catalyst B). An ansa-zirconocene complex with a BH group reacted with vinyl-coated silica gel to afford another immobilized catalysts (catalyst C). This catalyst achieved satisfactorily high catalytic activity and high isotacticity in its produced polypropene.
First publ. in: Applied Catalysis A 224 (2002), pp. 63-75.