原位红外光谱法研究HMX炸药的热分解过程

原位红外光谱法是一种新兴的动态研究方法.该方法具有原位实时监控和红外光谱精确分析物质化学结构的优点,能够实时跟踪材料在不同温度下的化学变化,测定材料的微观结构与温度的关系.文章采用原位红外光谱研究了炸药1,3,5,7-四硝基-1,3,5,7-四氮杂环辛烷(HMX)在5℃·min-1升温条件下的热分解过程.研究结果表明:HMX在205℃发生C-N键和N-N键的断裂,随着温度的升高,C-N键的断裂速率远高于N-N键的断裂速率,表明C-N键的断裂是HMX的主要断键方式,在C-N键的断裂中伴随着N-N键的断裂.同时环的张力增大,表明断键的HMX产生分子内重新结合.检测到HMX的分解所释放出的CO2,N2O,CO,NO,HCHO,HONO,NO2和HCN等八种气体.根据HMX分解中凝聚相结构的变化和气相产物,推出HMX的分解机理:HMX产生C-N键的断裂,会释放出HCHO和N2O以及HONO和HCN;N-N键的断裂会释放出NO2.

Study on Thermal Decomposition of HMX Energetic Materials by In-situ FTIR Spectroscopy

In-situ FTIR spectroscopy is a rising and dynamic technique. This technique, which combines the advantages of investigation in-situ and accurate structure analysis by FTIR spectsoscopy, can detect the chemical change of materials in different temperature with real time and obtain the relationship between micromechanism of materials and temperature. In the present paper, thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) heated with 5 degrees C x min(-1) was investigated by in-situ FTIR spectroscopy. The results demonstrate that C-N bond cleavage and N-N bond cleavage of HMX occur at 205 degrees C. With increasing temperature, the rupture rate of C-N bond is faster than that of N-N bond, which verifies that the cleavage of C-N bond is the dominant rupture form. The augment in tension of HMX cyclic confirms that intramolecular cyclization occurs in breakage of HMX. Eight kinds of gaseous products such as CO2, N2O, CO, NO, HCHO, HONO, NO2 and HCN were determined. According to the structure change in condensed state and gaseous products, the decomposition mechanism was deduced that HCHO, N2O, HONO and HCN were released due to the cleavage of C-N bond, and NO2 was released due to the cleavage of N-N bond.