Studies on polymerizations initiated by syncatalytic systems based on aluminium organic compounds, 5. Copolymerization of isobutene and isoprene catalyzed by diethylaluminium chloride and chlorine

An extensive investigation of the main parameters regulating the copolymerization of isobutene and isoprene, initiated by the catalyst system diethylaluminium chloride + chlorine in methyl chloride, was carried out. The influence of the concentration of the catalyst components, of the monomers, of 1‐butene, and of the polymerization temperature on the yield, the molecular weight and the composition of the copolymer was studied. The reactivity ratio of isobutene with respect to isoprene is 2,5 ± 0,5 at −35°C. The activation energy M is −23,9 ± 3 kJ/mol and −18,0 ± 2 kJ/mol (−5,7 ± 0.7 and −4,3 ± 0,5 kcal/mol) for the copolymer with a mole fraction of 0,013 and 0,019, respectively, of isoprene, and −24,3 ± 2 kJ/mol (−5,8 ± 0,4 kcal/mol) for polyisobutylene. The results are compared with similar data obtained for the system diethylaluminium chloride + tert‐butyl chloride and diethylaluminium chloride + hydrogen chloride. The influence of water on the activity of the catalyst was investigated briefly and discussed. Some technological data obtained with typical copolymers are also reported.