基于改进ReaxFF力场的全氟己酮热分解机理研究

Study on thermal decomposition mechanism of perfluorohexanone based on improved ReaxFF force field

采用基于密度泛函的紧束缚模型(DFTB)和改进的反作用力场(ReaxFF)对全氟己酮的热分解机理进行反应分子动力学仿真研究,分析了热分解的初始反应路径、微观反应过程以及体系内气体的生成机理,探讨了温度对全氟己酮热分解的影响,建立了以仿真数据为基础的一级动力学方程并对热分解过程进行一级动力学评估。结果表明,全氟己酮热分解的起始反应为:全氟己酮→全氟异戊烷+一氧化碳,全氟己酮热分解的主要产物为一氧化碳、四氟甲烷、六氟丙烯、全氟异丁烯、十氟丁烷、全氟异戊烷及大量活性基团。经一级动力学评估得到指前因子和表观活化能分别为5.0217×1014s-1和1771.96 kJ/mol。

A molecular dynamics simulation study on the thermal decomposition mechanism of perfluorohexanone using the tight functional model based on density functional model(DFTB)and the improved reaction force field(ReaxFF)was condcted.The initial reaction path of thermal decomposition,the microscopic reaction process and the gas generation mechanism in the system was analyzed.The effect of temperature on the thermal decomposition of perfluorohexanone was discussed.The first-order kinetic equation based on simulation data was established and the first-order kinetic evaluation of the thermal decomposition process was carried out.The results showed that the initial reaction of thermal decomposition of perfluorohexanone is:perfluorohexanone→perfluoroisopentane+carbon monoxide.The main products of thermal decomposition of perfluorohexanone are carbon monoxide,tetrafluoromethane,hexafluoropropylene,perfluoroisobutylene,decafluorobutane,perfluoroisopentane and a large number of active groups.The firstorder kinetic evaluation showed that the pre-finger factor and the apparent activation energy were 5.0217×1014 s-1 and 1771.96 kJ/mol,respectively.