The polymerization of isobutylene by AlCl3 in CH2Cl2 and the role of CH2Cl2 in the initiation reaction

Abstract

AbstractA solution of AlCl3 in CH2Cl2 prepared in advance was used 18 days after the mixing of the components as an initiation system in the polymerization of isobutylene performed in CH2Cl2 in the temperature range between −10 and −20°C. The 1H‐NMR analysis of polyisobutylene (PIB) samples synthesized to low and high conversion showed that it is the initiation reaction and not the transfer reaction to dichloromethane that is responsible for the CH2Cl endgroup in the polymer chain. In case of the transfer to monomer formation of PIB with internal terminal unsaturation [PIBCHC(CH3)2] is preferred to external unsaturation [PIBCH2(CH3)CCH2]. The solutions of AlCl3 in CH2Cl2 showed an absorption band at λmax = 302 nm.