Cationic polymerization by aromatic initiating systems. IV. Synthesis and characterization of α‐ω‐diphenylpolyisobutylene

Abstract

SynopsisThe polymerization of isobutylene using +&l coinitiator and the tertiary chlorides tert.-butyl chloride (t-BuC1) and 2,6-dichloro-2,6-dimethylheptane (Clf-R-Clf) initiators has been studied. Polymerization rates with the t-BuCl/&Al and Clt-R-Clt/+3Al initiating systems were high in the -20 to -7OOC range. Yields and molecular weights increased with decreasing temperature. As predicted by model experiments the extent of phenylation increases with decreasing temperatures. According to spectroscopic evidence the polyisobutylenes carry phenyl end groups.* A preliminary report concerning this research has appeared

End-Quenching of TiCl4-Catalyzed Quasiliving Polyisobutylene with Alkoxybenzenes for Direct Chain End Functionalization

“…When Russell et al [51][52][53][54][55][56] conducted SnCl 4 -catalyzed isobutylene polymerizations in ethyl chloride at -78.5 °C with phenol and substituted phenols as cocatalysts (initiators), they found evidence of phenolic end groups; however, proton expulsion was also a significant chain breaking event, leading to terminal unsaturation. 57 The first attempts at controlled termination of carbocationic polymerizations with an arene were reported by Kennedy et al [58][59][60][61] when they used a triphenylaluminum/tert-alkyl chloride initiating system. The arylaluminum acted as both a catalyst and chain terminating agent, yielding R,ω-diphenyl PIBs with 0.7-1.7 phenyl groups per chain.…”

“…The first attempts at controlled termination of carbocationic polymerizations with an arene were reported by Kennedy et al − when they used a triphenylaluminum/ tert -alkyl chloride initiating system. The arylaluminum acted as both a catalyst and chain terminating agent, yielding α,ω-diphenyl PIBs with 0.7−1.7 phenyl groups per chain.…”