八硝基立方烷高温热分解分子动力学模拟

Pyrolysis of Octanitrocubane via Molecular Dynamics Simulations

随着对高能量密度材料的性能要求不断提高,新型高能量密度材料成为近期研究热点,其中八硝基立方烷(ONC)由于其优越的性能成为其中典型的代表,然而关于八硝基立方烷热分解的动力学机理研究比较少。本文采用Reax FF反应力场模拟高温条件下凝聚相八硝基立方烷初始热分解过程。研究发现热分解过程中八硝基立方烷笼状骨架结构中C―C键最先发生断裂,并逐步破坏形成八硝基环辛烯等,随后出现NO_2和O等,计算结果表明笼状骨架结构的破坏存在三种不同路径。八硝基立方烷在高温条件下热分解的主要产物有NO_2、O_2、CO_2、N_2、NO_3、NO、CNO以及CO等,其中N_2和CO_2是终态产物,不同温度对产物均产生不同程度的影响。

As the requirements for the performance of high-energy-density materials increase, research to develop new types of high-energy-density materials has become highly heated recently. Octanitrocubane, by virtue of its superior performance, is one of the typical representatives of recently developed high-energy-density materials. However, there have been few studies on the thermal decomposition mechanism of octanitrocubane,even though they are essential to analyze the thermostability and sensitivity of octanitrocubane, as well as to achieve its efficient application. In this study, the initial pyrolysis process of condensed-phase octanitrocubane at high temperature was investigated using Reax FF reactive molecular dynamics simulation. The results showed that it is the C―C bond of the octanitrocubane cage skeleton structure that breaks first, and then octanitrocubane cage skeleton structure is gradually destroyed, and the small molecules such as NO2 and O occur afterwards.The simulation identified three different damage pathways of the cage skeleton. The main products of octanitrocubane thermal decomposition at high temperature are NO2, O2, CO2, N2, NO3, NO, CNO, and CO, of which N2 and CO2are the final products. The products that form depend on temperature.