Binks Fiona C, Cavalli Gabriel, Henningsen Michael, Howlin Brendan J, Hamerton Ian
Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey,Guildford GU2 7XH, Surrey, UK.
Intermediates Division, BASF AG, Carl-Bosch-Straße 38, 67056 Ludwigshafen, Germany.
Polymers (Basel). 2019 Apr 10;11(4):657. doi: 10.3390/polym11040657.
The reaction of phenyl glycidyl ether (PGE) with 1-ethyl-3-methylimidazolium acetateand 1-ethyl-3-methylimidazolium thiocyanate to initiate the polyetherification reaction wasexamined using thermal and spectral analysis techniques. The influence of the nucleophilicity of theanions on the deprotonation of the 1-ethyl-3-methylimidazolium cation determined the reactionpathway. The thermal degradation of the ionic liquid liberated the acetate ion and led, subsequently,to the deprotonation of the acidic proton in the imidazole ring. Thus, polymerisation of PGEoccurred via a carbene intermediate. The more nucleophilic thiocyanate anion was not sufficientlybasic to deprotonate the 1-ethyl-3-methylimidazolium cation, and thus proceeded through directreaction with the PGE, unless the temperature was elevated and a competing carbene mechanismensued.
采用热分析和光谱分析技术，研究了苯基缩水甘油醚（PGE）与乙酸1-乙基-3-甲基咪唑鎓和硫氰酸1-乙基-3-甲基咪唑鎓引发的聚醚化反应。阴离子亲核性对1-乙基-3-甲基咪唑鎓阳离子去质子化的影响决定了反应途径。离子液体的热降解释放出乙酸根离子，随后导致咪唑环中酸性质子的去质子化。因此，PGE的聚合通过卡宾中间体发生。亲核性更强的硫氰酸根阴离子碱性不足以使1-乙基-3-甲基咪唑鎓阳离子去质子化，因此通过与PGE直接反应进行，除非温度升高并引发竞争的卡宾机理。
