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Isomerization Polymerizations with Coordination Catalysts

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  P220-221

2026-01-21

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Isomerization Polymerizations with Coordination Catalysts

Polymerizations of many internal olefins, like 2-butene, 2-pentene, 3-heptene, 4-methyl-2-pentene, 4 phenyl-2-butene and others, with Ziegler–Natta catalysts are accompanied by monomer rearrangements. The isomerizations take place before insertions into the chains [311–318]:

The double bonds migrate from the internal to the α-positions:

The products consist exclusively of poly(1-olefin) units. Polymerizations of 2, 3 and 4 octenes with TiCl3/Al(C₂H₅)₃ at 80C for instance, result in the same high molecular weight homopolymer, poly (1-octene) [319]. Also, it was reported that addition of some transition metal compounds of Group VIII to Ziegler–Natta catalysts enhances isomerization of 2-olefins. When nickel compounds are added to TiCl₃–(C₂H₅)₃Al they react and form TiCl₃–NiX₂–(C₂H₅)₃Al. X can be a chloride, an acetylacetonate, or a dimethyl glyoximate [328]. The product is an efficient isomerization catalyst.