Effects of Electron Donors in Super High Activity Catalysts for Polypropylene

Abstract

Electron donors play a dominant role in determining the behavior of super high activity (MgCl2-supported) catalysts for polypropylene. This is particularly so in systems in which the internal donor is a phthalate ester and where an alkoxysilane or hindered amine is used as external donor. Fundamental questions pertaining to the mechanism of these catalysts are the respective roles of the internal and external donors in determining the activity and stereospecificity of the system and the relationship between the nature of the donor and the hydrogen activation effects commonly observed in propene polymerization with this type of catalyst.