高温下气相CL-20热分解反应的分子动力学计算

ReaxFF reactive molecular dynamics simulations on the density-dependent thermal decomposition mechanisms of gas phase CL-20 at high temperature

研究气相CL-20炸药的反应机理及能量释放规律,有助于认识极端条件下含能材料的冲击点火和爆轰等过程.采用反应分子动力学计算方法,研究不同密度和温度下,气相CL-20热分解反应过程.结果表明气相状态时,其初始反应路径为CL-20单分子的N-NO2键断裂生成硝基自由基;第二阶段反应路径为C-C键、C-N键和N-N键等的断裂与生成,发生了质子转移和开环、闭环等基元反应,形成HCN、N2O2、HONO、NO等中间产物;第三阶段反应路径为N2,CO_(2),H2O和CO等最终稳定产物生成,且生成中间产物的基元反应数量远大于N2、H2O等最终产物生成的基元反应数量.此外,密度和温度还影响了高温下产物的反应速率常数.

The study on the reaction mechanism and energy release law of CL-20 gas phase, is helpful for people to understand the transient process of energetic materials shock ignition and detonation under extreme conditions. In this paper, ReaxFF molecular dynamics simulations were used to study the thermal decomposition reaction process of non-condensed phase ε phase CL-20 with density less than 1 g·cm-3. In the low-density state, the first stage reaction pathway of CL-20 is N-NO2 bonds cleavage to form nitro radicals. In the second stage, C-C bonds, C-N bonds, and N-N bonds are broken and formed by the proton transfer, ring opening reactions and ring closing reactions pathways. In the third stage, the final products like N2, CO_(2), H2O and CO are formed. The intermediate products such as HCN, N2O2, HONO, NO are generated, and the number of reaction pathways of intermediate products are much larger than that the number of final products such as N2 and H2O reactions pathways.