Yuichi Hiraoka

Effects of various poisoning compounds on the activity and stereospecificity of heterogeneous Ziegler?Natta catalyst

Abstract A TiCl4/ethylbenzoate/MgCl2 Ziegler–Natta catalyst was pretreated with chemically different poisoning compounds to investigate their effects on the catalyst activity and stereospecificity for propylene polymerization. The poisoning power on the activity was in the order of methanol > acetone > ethyl acetate. A kinetic analysis using the stopped-flow method revealed that addition of the poisoning materials decreased the activity through the reduction of the number of active sites, whereas the catalyst isospecificity was hardly affected by these materials.

POISONING OF ACTIVE SITES ON ZIEGLER-NATTA CATALYST FOR PROPYLENE POLYMERIZATION

The effects of poisoning materials on catalytic activity and isospecificity of the supported Ziegler-Natta catalyst were investigated. A minor amount of simple structure of Lewis base, i.e., methanol, acetone, ethyl acetate, was introduced into the catalyst slurry for partial poisoning catalytic active centers. It was found that the variations in deactivation power were in the order of methanol > acetone > ethyl acetate. The kinetic investigation via stopped-flow polymerization showed that poisoning compounds caused a decrease in activity through the reduction of the number of active sites whereas no effect on the degree of isotacticity was observed.