助剂对二甲基二氯硅烷Wurtz聚合反应的影响

Effects of additives on Wurtz polymerization of dimethyldicholorosilane.

以二甲基二氯硅烷为反应单体、甲苯为溶剂 ,在超声波下 ,通过Wurtz法合成了聚硅烷。研究了助剂种类对该聚合反应的影响。结果表明 ,在甲苯溶剂中加入冠醚、二乙二醇二甲醚、六甲基磷酰三胺、聚醚等助剂可使该聚合反应在 80℃的较低温度下快速进行 ,从而降低了该聚合反应的危险性 ;冠醚、二乙二醇二甲醚、聚醚、六甲基磷酰三胺等对该聚合反应的促进作用 ,证明该反应活性中间体是阴离子活性体 ,该反应机理更倾向于阴离子聚合 ;冠醚的加入可极大地加快二甲基二氯硅烷的聚合反应 ;二甲基二氯硅烷加入后 ,反应立即进行 ,并放出大量的热 ,可根据反应温度的变化控制单体的滴加速率 ,防止爆聚现象出现 。

The effect of different additives in toluene under ultrasonic on Wurtz-type reductive coupling reaction of dimethyldichlorosilane was studied.The result showed that adding crown ether,diglyme,HMPA or polyether,would accelerate the rate of polymerization greatly at lower temperature of 80 ℃,thus decreased the danger of the polyreaction.The additives of crown ether,diglyme,HMPA and polyether would accelerate the rate of polymerization,which proved that the active monomer was anion active mass,the reaction mechanism was inclined to anion polymerization.The addition of crown ether accelerated the rate of polymerization greatly.The reaction carried out immediately and released great amount of heat when adding dimethyldichlorosilane.The drop feed rate could be in charge by temperature control,which avoided the implosion,and provided advantageous foundation for commercial synthesis of ceramics precursor polysilane.