异丙苯过氧化物的热解反应及联枯的生成

Thermal decomposition of cumene peroxides and formation of bicummyl

在密闭隔氧环境下研究了异丙苯、过氧化氢异丙苯(CHP)和过氧化二异丙苯(DCP)体系的热分解行为,分析了体系热解产物,探讨了热解反应的机理及相关动力学,并考察了苯酚对DCP热解反应的影响规律。实验结果表明,异丙苯过氧化物的热解反应主要沿自由基路径进行,过氧化物受热产生异丙苯氧自由基,再进一步通过β碎裂、链转移和自由基结合等反应得到α,α-二甲基苄醇、苯乙酮及2,3-二甲基-2,3-二苯基丁烷(联枯)等产物;DCP分解速率符合一级反应动力学特征,活化能为127 kJ/mol;体系中苯酚的存在不会影响DCP分解的速率,但会显著改变热解产物的组成,特别是抑制联枯的生成。

The thermal decomposition in the system of cumene-cumene hydroperoxide(CHP)-dicumyl peroxide(DCP)was investigated in the closed and anoxic atmosphere.The formed products were analyzed,the mechanism and the kinetics of the thermal decomposition were discussed,and the effects on the thermal decomposition of DCP were investigated.The experimental results indicated that the thermal decomposition of CHP and DCP mainly proceeds in the free radical path.The peroxides were heated and formed the cumyl-oxy radical,then the products includingα,α-dimethyl phenylcarbinol,acetophenone and 2,3-dimethyl-2,3-diphenylbutane(bicummyl)were obtained through the reactions ofβ-scission,chains transfer and recombination of radicals.The decomposition rate of DCP can be described as first-order kinetic with the active energy of 127 kJ/mol.The existence of phenol will not affect the decomposition of DCP,but change the composition of products remarkably,especially inhibit the formation of bicummyl.