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Activity, stereospecificity, and structure of Ziegler-Natta catalysts.

1987; Volume: 30; Issue: 6 Linguagem: Inglês

10.1627/jpi1958.30.359

0582-4664

Kazuo Soga,

Organometallic Complex Synthesis and Catalysis

This paper summarizes some of our recent fundamental studies of isotactic polymerization of propylene. Based on the results of propylene polymerization with several kinds of one-component catalysts, the origin of polymerization activity is first discussed. The correlation between the oxidation states of titanium and polymerization activities for various olefins is clarified reasonably well from a detailed study of homo- and copolymerizations using a simplified catalyst. The role of MgCl2 on the enhancement of polymerization activity is also discussed in detail. The effect of internal and external donors in improving catalyst stereospecificity is then discussed; where are also presented the results of propylene polymerization using new types of highly active and isospecific catalysts originally found by Hercules Inc. and modified in our laboratory. A plausible model of isospecific catalytic center is finally proposed on the basis of these results.