Fast flow synthesis of highly reactive polyisobutylene co-initiated by an AlCl₃/isopropyl ether complex
2016
Zhu, S. | Lu, Y. C. | Wang, K. | Luo, G. S.
In this work, with AlCl₃ addition in the range from 4 to 10 mmol L⁻¹ and enough isopropyl ether (ⁱPr₂O) 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 (Mₙ) 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 ⁱPr₂O over AlCl₃ including: (1) decreasing the intensive isomerization co-initiated by free AlCl₃; (2) inhibiting the chain termination to present chain transfer dominated kinetics; (3) weakening the temperature sensitivity of Mₙ 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 ⁱPr₂O : AlCl₃.
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