Synthesis of halogen-free polyisobutylene by in situ hydride transfer to living polyisobutylene from tributylsilane.

Abstract

Hydride transfer reaction between living polyisobutylene cation (PIB+) and tributylsilane in hexanes/methyl chloride 60/40 (v/v) solvent mixtures at -80, -70 and -60 °C was studied to synthesize halogen-free polyisobutylene (PIB). The hydride transfer reaction between tributylsilane and living PIB capped with 1,1-ditolylethylene (PIB-DTE+) have also been carried out under similar conditions at -80 °C. The rate of hydride transfer reaction increases with the increase of tributylsilane concentration for the reaction of both PIB+ and PIB-DTE+ with tributylsilane. Gel Permeation Chromatography and NMR Spectroscopy suggested practically complete capping of the polymeric cation and the absence of side reactions.