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Synthesis of highly reactive polyisobutylene by selective polymerization with o ‐cresol/AlCl 3 initiating system
Author(s) -
Zhang L. B.,
Wu Y. X.,
Zhou P.,
Xu R. W.
Publication year - 2012
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1908
Subject(s) - cationic polymerization , isobutylene , polymerization , polymer chemistry , chain transfer , double bond , chemistry , materials science , organic chemistry , radical polymerization , copolymer , polymer
Highly reactive polyisobutylenes (HRPIBs) with very large proportion (up to 95 mol%) of exo ‐double bond end groups and number average molecular weight ( M n ) of 5400–8500 Dalton (Da) could be successfully synthesized by the selective cationic polymerization of isobutylene (IB) from the mixed C 4 fraction feed using o ‐cresol/AlCl 3 as initiating system at −20°C. A possible mechanism was proposed for the cationic polymerization process. The presence of large weakly coordinating counteranion in propagating species could lead to decreasing the possibility of the side transfer reactions via carbenium ion arrangements. This o ‐cresol/AlCl 3 initiating system exhibited extremely high selectivity toward IB polymerization in the mixed C 4 fraction feed and a good property for rapid β ‐proton abstraction from C H 3 in the growing polyisobutylenes (PIBs) chain ends. High extent of α ‐double bond end groups in HRPIBs prepared in the mixed C 4 fraction feed could be comparable to that in those commercially produced by cationic polymerization of IB in inert solvent (e.g. hexane). To our knowledge, this is the first example to achieve HRPIBs via completely selective polymerization of IB from C 4 mixed feed with AlCl 3 ‐based initiating system, providing a potentially practical process for its simplicity and low costs. Copyright © 2011 John Wiley & Sons, Ltd.