硝酸羟胺的热稳定性评估及热分解机理研究

为评估氧化剂硝酸羟胺的热稳定性,使用标准液体铝皿于3K/min、4K/min、5K/min加热速率下进行热分析。借助非等温DSC曲线的参数值,应用Kissinger法和Ozawa法求得热分解反应的表观活化能和指前因子,根据Zhang-Hu-Xie-Li公式、Hu-Yang-Liang-Xie公式、Hu-Zhao-Gao公式以及Zhao-Hu-Gao公式,计算硝酸羟胺的自加速分解温度和热爆炸临界温度,并对热分解机理函数进行了研究。设计了7条热分解反应路径,采用密度泛函理论B3LYP/6-311++G(d,p)方法对硝酸羟胺的热分解进行了动力学和热力学计算。计算结果表明,硝酸羟胺热分解的自加速分解温度TSADT=370.05K,热爆炸临界温度Tbe0=388.68K,Tbp0=397.54K,热分解最可几机理函数的微分形式为f(α)=17×(1-α)18/17。硝酸羟胺热分解各路径中,动力学优先支持路径Path 6、Path 5、Path 4和Path 1生成NO和NO_2,其次是Path 2、Path 7和Path 3生成N2和N_2O。温度在373K以下时,Path 1′反应无法自发进行,硝酸羟胺无法进行自发的热分解。从热力学的角度来看,硝酸羟胺在370.05K以下储存是安全的。

Thermal Stability Evaluation and Thermal Decomposition Mechanism of Hydroxylamine Nitrate

To evaluate the thermal stability of oxidizer hydroxylamine nitrate (HAN),the standard aluminum crucibles for liquid was used,and DSC measurements of hydroxylamine nitrate were performed using simultaneous thermal analysis at heating rates of 3 K/min,4 K/min,5 K/min.With the help of parameter values from the non-isothermal DSC curves of HAN,the thermal decomposition activation energy and pre-exponential constant were obtained by Kissinger method and Ozawa method.The self-accelerating decomposition temperature and thermal explosion temperature were calculated by Zhang-Hu-Xie-Li formula,Hu-Yang-LiangXie formula,Hu-Zhao-Gao method and Zhao-Hu-Gao method.And the most probable mechanism was studied.To study thermal decomposition mechanism,seven different paths of the thermal decomposition mechanism of hydroxylamine nitrate were designed,and density functional theory (DFT) with B3LYP/6-311++G (d,p) methods was used to carry out the kinetic analysis and thermodynamic analysis.The calculation results showed that TsADT =370.05 K,Tbe0 =388.68 K,and Tbp0 =397.54 K.Differential form of the most probable mechanism is f (a) =17 × (1-a) 18/17.Path 6,Path 5,Path 4 and Path 1 which produce NO and NO2 were supported in priority,and Path 2,Path 7 and Path 3 which produce N2 and N2 O were supported in secondary place.When the temperature was below 373 K,the reaction of Path 1'could not occur spontaneously,and thermal decomposition of hydroxylamine nitrate could not be spontaneous.From the perspective of thermodynamics,it is safe for hydroxylamine nitrate storage at 370.05 K.