Active centers of TiCl3 catalysts for propene polymerization

Abstract

Publications reporting numbers of active centers in TiCl3 propylene polymerization catalysts are very contradictory. Experimental data from the beginning of the sixties are reevaluated by the author. It is concluded that TiCl3-catalysts from the Hoechst type (and probably from the Stauffer AA-type) have, after an initial period of polymerization, numbers of active centers in the range of percentage of total TiCl3. This value increases with temperature. By cooling during polymerization some metal polymer bonds, probably active centers, disappear.