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首页> 外文期刊>Polymers for advanced technologies >Synthesis of highly reactive polyisobutylene by selective polymerization with o-cresol/AlCl_3 initiating system
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Synthesis of highly reactive polyisobutylene by selective polymerization with o-cresol/AlCl_3 initiating system

机译：邻甲酚/ AlCl_3引发体系选择性聚合合成高反应性聚异丁烯

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摘要

Highly reactive polyisobutylenes (HRPIBs) with very large proportion (up to 95 mol%) of exo-double bond end groups and number average molecular weight (Mn) 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℃. 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 b-proton abstraction from -CH_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.
机译：高活性聚异丁烯（HRPIBs）的选择性阳离子聚合可以成功地合成高比例（高达95 mol％）的外双键端基和数均分子量（Mn）为5400-8500道尔顿（Da）的高反应性聚异丁烯。以邻甲酚/ AlCl_3为引发体系，在-20℃下从混合的C_4馏分进料中得到异丁烯（IB）。提出了阳离子聚合过程的可能机理。繁殖物种中较大的弱配位抗衡阴离子的存在可能导致通过碳正离子排列发生侧转移反应的可能性降低。该邻甲酚/ AlCl_3引发体系在混合的C_4馏分进料中显示出对IB聚合的极高选择性，并具有良好的性能，可用于在增长的聚异丁烯（PIBs）链端从-CH_3快速提取b质子。在混合的C_4馏分进料中制备的HRPIBs中高度的α-双键端基可以与在惰性溶剂（例如己烷）中通过IB阳离子聚合而商业生产的HRPIB中的α-双键端基相当。据我们所知，这是第一个通过将基于C_4混合进料的IB与基于AlCl_3的引发系统完全选择性聚合形成IB来获得HRPIBs的例子，为它的简单性和低成本提供了潜在的实用方法。

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