Model Catalysts for Clarification of Active Site-Polymer Relationship in Heterogeneous Olefin Polymerization

摘要

Model catalysts having specially designed active species on support surfaces were employed to understand relationships between the structure/state of active sites and their catalytic performances for two classes of industrial olefin polymerization catalysts: Ziegler-Natta and Phillips catalysts. Propylene polymerization using a TiCl3/MgCl2 model Ziegler-Natta catalyst clarified an important role of the Ti dispersion state for the polymer stereo & chemical structures. Model Phillips catalysts having monochromate and dichromate structures on silica support imparted knowledge that dinuclear species is more responsible for the production of α-olefin comonomer in ethylene polymerization, thus giving more branched polyethylene.