Polymerization of 3,5,5-trimethyl-1-hexene with Ziegler-Natta catalysts

Polymerization of 3,5,5-trimethyl-1-hexene (TM1H) with TiCI₃ and alkylaluminium catalysts was studied. TM1H can be polymerized, but the polymerization rate is quite low due to the bulky substituent of the side chain. During the polymerization of TM1H, the isomerization of TM1H to internal olefins was observed. The overall activation energy for polymerization of TM1H was estimated to be approx. 37 kJ/mol. By adding optically active L-menthol to the TiCI₃-(i-C₄H₉)₃AI catalyst, a stereoelective polymerization was induced. Monomer-isomerization copolymerization of TM1H and trans-2-butene took place, giving copolymers consisting of the corresponding 1-olefin units.