取代基对硝基苯热分解机理影响的ReaxFF/lg模拟

ReaxFF/lg Simulation on the Substituent Effect upon the Thermal Decomposition Mechanism of Nitrobenzene Compounds

使用ReaxFF/lg反应分子动力学模拟,研究了1,3,5-三硝基苯(TNB)、2,4,6-三硝基甲苯(TNT)和2,4,6-三硝基苯胺(TNA)的初始分解反应,通过反应物分解趋势、初始分解路径、重要产物和团簇分析,阐明了甲基和氨基的引入对硝基苯化合物热分解的影响机制。结果表明,甲基和氨基的引入改变了硝基化合物的初始反应路径,促进了反应物的分解,提高硝基异构化反应和分子间H或O原子转移反应的频次,降低硝基直接解离反应的频次,其中TNT表现最为明显;引入取代基后,含氢产物(OH、HO_(2)N、H_(2)、H_(2)O和NH_(3))生成数量增多,ON和CO_(2)数量减少;由于氨基的引入,TNA分解生成更多的N_(2)分子。取代基的引入改变了含能分子的氧平衡,导致了硝基苯类化合物初始分解机理的差异。

The initial decomposition reactions of 1,3,5-trinitrobenzene(TNB),2,4,6-trinitrotoluene(TNT)and_(2),4,6-trinitroaniline(TNA)were studied using ReaxFF/lg molecular dynamics simulation.The effect of methyl and amino group on the thermal decomposition of nitrobenzene compounds was elucidated through the reactant decompostion trend,initial decomposition pathway,main products and cluster analysis.The results show that the introduction of methyl and amino group changes the initial decomposition path ways of nitro products,and promotes the decomposition of reactants,increases the frequency of nitro isomerization reaction and intermolecular H or O atom transfer reaction,and reduces the frequency of direct nitro dissociation reaction,among which TNT is the most obvious.After the introduction of substituents,the number of hydrogen-containing products(OH,HO_(2)N,H_(2),H_(2)O and NH_(3))increases,and the number of ON and CO_(2)decreases.Due to the introduction of amino groups,TNA produces more N_(2).The introduction of substituents alters the oxygen balance of energetic molecules,resulting in differences in the initial decomposition mechanism of nitrobenzenes.