Fast flow synthesis of highly reactive polyisobutylene co-initiated by an AlCl3/isopropyl ether complex

摘要

In this work, with AlCl _(3) addition in the range from 4 to 10 mmol L ~(?1) and enough isopropyl ether ( ~(i) Pr _(2) O) addition, we successfully synthesized highly reactive polyisobutylene (HRPIB) using a microflow system within 12 s or less. The temperature window was extended from ?20 °C to 50 °C, and the molecular weight ( M _(n) ) was adjustable between 500 and 15?000. The evolutions of HRPIBs and the effects of reaction conditions were carefully investigated, revealing multiple effects of an excess of ~(i) Pr _(2) O over AlCl _(3) including: (1) decreasing the intensive isomerization co-initiated by free AlCl _(3) ; (2) inhibiting the chain termination to present chain transfer dominated kinetics; (3) weakening the temperature sensitivity of M _(n) as a restriction on temperature elevation; (4) retarding the chain propagation to slow the reaction and increase the probability of isomerization. Key access to fast synthesis of high quality HRPIB is proposed to make a compromise of these effects by properly selecting ~(i) Pr _(2) O?:?AlCl _(3) .