摘要
通过六氢吡啶与聚异丁烯链端作用的紫外光谱分析 ,证明了亲核试剂六氢吡啶既能捕获质子 ,又能稳定增长的碳正离子。采用计算机分子模拟技术研究了亲核试剂与质子和碳正离子之间的作用 ,通过聚异丁烯增长活性中心与亲核试剂的反应活化能以及在亲核试剂作用下聚异丁烯活性链端的电量变化 ,进一步证明了在聚异丁烯阳离子聚合反应中六氢吡啶是一种适宜的亲核试剂。六氢吡啶与质子反应的活化能为 - 16 7.5 4kJ·mol-1,而2 ,6 -二叔丁基吡啶与质子反应的活化能为 - 12 6 .15kJ·mol-1。
It was determined that nucleophiles hexpyridine have two effects both trapping proton and stabilizing carbocation growing center, through UV spectra between hexpyridine and the ends of PIB. Effect of Nucleophiles on proton and carbocation are studied in IB carbocationic polymerization using molecular simulation in computer. It was showed further that the hexpyridine is a suitable nucleophiles on IB carbocationic polymerization by activation energy and changes of net carbocationic charge of the growing species of isobutylene reacting with nucleophilic reagent. The activation energy of hexpyridine with proton is -167.54 kJ·mol -1 , while the activation energy of 2,6-Diter-butyl pyridine is -126.15 kJ·mol -1 that is conventionally employed. The mechanism of effect of nucleophiles on IB carbocationic polymerization was proposed.
出处
《石油化工高等学校学报》
CAS
2002年第1期1-6,共6页
Journal of Petrochemical Universities
基金
国家自然科学基金资助项目 (2 970 4 0 0 2 )
