Diisopropyl methylphosphonate (DIMP) is a chemical weapon agent surrogate. Quantifying the rates of thermal decomposition of such compounds is important to enable predictions of spread of respective toxic vapors in different scenarios. An experimental setup is designed and built to quantify the rate of decomposition of DIMP at temperatures of 200–350 °C. Liquid DIMP is fed from a brass evaporator heated to 140 °C and vented with argon. It is mixed with a pre-heated carrier gas (air or nitrogen) in a steel flow reactor. The gas is sampled from the reactor after a certain residence time and sent to a Fourier transform infrared (FTIR) analyzer. Under 350 °C, the thermal decomposition of DIMP in air occurs much faster than in nitrogen. In air, the decomposition of DIMP can be described as the first order reaction with the rate constant kTs-1=107.4±2.5·exp-21.4±6.6kcal/molRT. Despite measuring substantial reduction in the DIMP concentration due to its thermal decomposition, present measurements could not detect the presence of propene and other decomposition products.

中文翻译：

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甲基膦酸二异丙酯（DIMP）低温热分解的实验表征


甲基膦酸二异丙酯 (DIMP) 是一种化学武器制剂替代品。量化此类化合物的热分解速率对于预测不同情况下各自有毒蒸气的扩散非常重要。设计并构建了一个实验装置来量化 DIMP 在 200–350 °C 温度下的分解速率。液体 DIMP 由加热至 140 °C 并通入氩气的黄铜蒸发器供给。它在钢流反应器中与预热的载气（空气或氮气）混合。经过一定的停留时间后，从反应器中对气体进行采样，并将其发送至傅里叶变换红外（FTIR）分析仪。在 350 °C 下，DIMP 在空气中的热分解速度比在氮气中快得多。在空气中，DIMP的分解可描述为一级反应，速率常数kTs-1=107.4±2.5·exp-21.4±6.6kcal/molRT。尽管测量到 DIMP 浓度由于其热分解而大幅降低，但目前的测量无法检测到丙烯和其他分解产物的存在。