N-甲基-N′-甲氧基偶氮-N-氧化物结构和性能的理论研究

Theoretical Study on Structure and Properties of N-Methyl-N′-methoxydiazene-N-oxide

基于密度泛函理论研究了N-甲基-N′-甲氧基偶氮-N-氧化物(MMDO)的结构、生成焓、密度和热分解机理,同时对其硝胺异构体二甲基硝胺(DMNA)进行了对比研究。结果表明:MMDO的Z式构型比E式构型稳定性更好,为主要存在形式;两种构型之间的异构化能垒高于热分解能垒,在热分解的条件下不会发生Z-E异构化反应;Z-MMDO的生成焓(42.50 kJ.mol-1)明显高于其硝胺异构体DMNA(-12.74 kJ.mol-1),热稳定性也好于DMNA,但密度(1.331 g.cm-3)略低于后者(1.363 g.cm-3);CH3O—N和CH3—O断裂为MMDO的两条竞争热分解途径。

The structure,enthalpy of formation,density and thermal decompostion mechanism of N-methyl-N′-methoxydiazene-N-oxide（MMDO） were studied based on density fuctional theory,and compared with its nitramino-isomer dimethylnitramine（DMNA）.Results show that Z-conformation of MMDO is more stable than that of E-conformation,and Z-conformation of MMDO is the main existence form.The energy barriers of isomerizations between Z and E forms are higher than that of thermal decomposition,accordingly the isomerizations do not occur in the conditions of thermal decomposition.The enthalpy of formation（42.50 kJ·mol^-1） and thermal stablily of Z-MMDO are higher than that of its nitramino-isomer DMNA（-12.74 kJ·mol^-1）.However the density（1.331 g·cm^-3） of Z-MMDO is slightly lower than that of DMNA（1.363 g·cm^-3）.CH3O—N and CH3—O dissociations are two competitive thermal decomposition ways of MMDO.