AP对HATO热分解影响的机制

为详细了解高氯酸铵(AP)对5,5'-联四唑-1,1'-二氧二羟铵(HATO)热分解影响的机制,采用热重-质谱-傅里叶红外光谱(TG-MS-FTIR)联用技术、差示扫描量热法(DSC)、傅里叶红外光谱(FTIR)方法,对HATO和HATO/AP共混物的热分解特性、气体产物以及凝聚相变化进行了研究。结果表明,HATO具有两个连续热分解阶段,HATO/AP共混物则有3个热分解阶段;HATO、AP共混后,HATO使得AP熔融峰消失,AP可使HATO的热分解初始温度提前,热分解时间延长且不影响分解完全性;HATO热分解气体产物有CO_2、N_2O、HCN、NH_3、NO、N_2、H_2O,而HATO/AP共混物热分解产生气体主要有N_2、CO_2、N_2O、HCN、NH_3、H_2O、HCN、NO、HCl、NOCl;另外,采用等转化率法计算HATO和HATO/AP共混物四唑环基团的活化能分别为53.38 kJ·mol~(-1)和60.69 kJ·mol~(-1);通过对比HATO和HATO/AP共混物热分解特性以及凝聚相特征基团的变化,阐释了AP使HATO热分解温度提前的机理很可能是:AP的铵根离子与HATO之间发生了质子转移;推测AP导致HATO热分解时间延长的原因为:HATO/AP共混物产生的NH_3与热分解中间体1,1'-二羟基-5,5-联四唑(BTO)反应生成5,5'-联四唑-1,1'-二氧铵盐(ABTOX)。

Effect of AP on the Thermal Decomposition Mechanism of HATO

To systematically understand the effect of ammonium perchlorate (AP) on the thermal decomposition mechanism of 5,5''-bitetrazole-1,1''-dioxadihydroxyammonium(HATO), the thermal decomposition characteristics, gas products and condensed phase change of HATO and HATO/AP blends were analyzed by combination of thermogravimetry-mass spectrometry-Fourier transform infrared spectroscopy (TG-MS-FTIR), differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy (FTIR). HATO had two consecutive thermal decomposition stages,while HATO/AP blends had three. For HATO/AP blends, the melting profile of AP disappeared; the thermal decomposition of HATO showed an advanced initial temperature, prolonged decomposition time and unchanged completeness of HATO decomposition. The gas products from the thermal decomposition of HATO were CO₂, N₂O, HCN, NH₃, NO, N₂ and H₂O; whereas CO₂, N₂O, HCN, NH₃, NO, N₂, H₂O, HCl and NOCl were detected for HATO/AP blends. The activation energy of HATO and HATO/AP blends tetrazole ring, which was calculated by equal conversion rate method was 53.38kJ·mol^-1 and 60.69 kJ·mol^-1,respectively. By comparing the thermal decomposition process of HATO and HATO/AP blends and the change of characteristic groups of condensed phase, the advancement of thermal decomposition temperature of HATO can be attributed to the proton transfer between the ammonium ion of AP and HATO. The prolonged decomposition time for HATO/AP blends might be explained by following mechanism: NH₃ was produced from the HATO and AP, which further reacted with the thermal decomposition intermediate 1,1''-dihydroxy-5,5''-tetrazolium (BTO) to form Diammonium 5,5''-bistetrazole-1,1''-diolate (ABTOX).