The understanding of the thermal decomposition chemistry of chemical warfare nerve agents is largely limited by the scarcity of kinetic data. Because of the high toxicity of these molecules, experimental determination of their chemical properties is very difficult. In the present work, a comprehensive detailed kinetic model for the decomposition of sarin and some simulants, i.e. di-isopropyl methyl phosphonate (DIMP), diethyl methylphosphonate (DEMP), and triethyl phosphate (TEP) were developed, containing possible molecular and radical pathways. The importance of unimolecular pericyclic decomposition led to evaluate precisely the rate constants of these reactions with high level theoretical calculations. The QCISD(T)/cc-PV∞QZ//B2PLYPD3/6–311+G(2d,d,p) level of theory was selected after a benchmark. The contribution of hindered rotors was included with the 1D-HR-U approach. Tunneling was taken into account for H-atom transfer. Transition state theory was used to calculate high-pressure limit rate constants and pressure dependent rate constants were calculated using Master Equation modeling. The model was validated against experimental pyrolysis and oxidation experimental data available in literature. Flux analyses showed that whatever the conditions are, the first step of decomposition of the studied phosphorus compounds are pericyclic eliminations leading to successive decompositions, whereas bond-breaking or H-atom abstraction remain negligible, even at high temperature.

对化学战神经毒剂的热分解化学的理解在很大程度上受到动力学数据缺乏的限制。由于这些分子的高毒性，很难对其化学性质进行实验确定。在目前的工作中，沙林和一些模拟物，即磷酸二异丙酯（DIMP），甲基膦酸二乙酯（DEMP）和磷酸三乙酯（TEP）的分解的综合详细动力学模型被开发出来，其中包含可能的分子和自由基途径。单分子周环分解的重要性导致可以通过高级理论计算精确评估这些反应的速率常数。QCISD（T）/cc-PV∞QZ// B2PLYPD3 / 6–311 + G在基准测试后选择（2d，d，p）级理论。1D-HR-U方法包括了受阻转子的作用。H原子转移考虑了隧穿。过渡状态理论用于计算高压极限速率常数，而压力依赖性速率常数则使用Master Equation模型进行计算。该模型针对文献中提供的实验热解和氧化实验数据进行了验证。助焊剂分析表明，无论条件如何，所研究的磷化合物的分解第一步都是周环消除，从而导致连续分解，而即使在高温下，键断裂或H原子抽象也可忽略不计。