高压下固相硝基甲烷分解的分子动力学计算

基于ReaxFF, 采用NVT系综和Berendsen方法对0–7 GPa时和2500 K时固相硝基甲烷的 分解过程进行分子动力学计算, 通过分析硝基甲烷发生分解反应生成的碎片数量随时间的变化, 对不同压强下硝基甲烷的分解机理进行研究. 计算结果表明在0–3 GPa时, 初始分解路径为C–N键断裂和硝基甲烷的异构化; 在4–7 GPa 时, 初始分解路径为分子间质子转移和C–N, N–O键的断裂; 在硝基甲烷的第二阶段反应中存在H₂O, NO, NO₂, HONO, 硝基甲烷分子自身的催化反应. 硝基甲烷在高温高压下发生热分解反应生成碳团簇, 且团簇中碳原子的数量和碳团簇的空间构型随着压强的变化而变化.关键词：ReaxFF 分子动力学热分解压强效应碳团簇

The effect of pressure on thermal decomposition of solid nitromethane via MD simulation

The thermal decomposition of solid nitromethane (NM) is studied by ReaxFF molecular dynamics simulations to obtain the time evolution of the mechanism of NM under high temperature and pressure. It is determined that the initial decomposition mechanism of NM is dependent on pressure effect. In the 0–3 GPa pressure regime, the initial reactions is the C–N bond dissociation and the unimolecular rearrangement connecting between NM and methyl nitrite isomers; in the 4–7 GPa, the initial pathways of NM are the intermolecular proton transfer and C–N, C–O bond rupture. In the secondary reactions step, several fragments, like H₂O, NO, NO₂, HONO, play a role of catalysis. The product decomposition of NM contains many different structures of carbon clusters, and the configuration of cluster is dependent on pressure.
Keywords：ReaxFF molecular dynamicsthermal decompositioneffect of pressurecarbon clusters