C,N-二甲基-C-(3-吡啶基)硝酮的安全性及分解机理

The safety and decomposition mechanism of C,N-dimethyl-C-(3-pyridyl)nitrone

[目的]C,N-二甲基-C-(3-吡啶基)硝酮(简称硝酮)是一种非常重要的中间体,对其热稳定性、分解动力学和分解机理进行研究。[方法]采用差示扫描量热技术(DSC)测试了硝酮的热稳定性,研究了硝酮的分解动力学特性,采用热重-红外-质谱(STA-FTIR-MS)同步联合测试方法研究了硝酮的热分解机理。[结果]硝酮具有热敏性,升温速率在0.5~8.0℃/min之间时,起始分解温度范围为146.86~189.38℃,平均分解放热量为(808.05±17.88) J/g,分解活化能为86.59~92.93 kJ/mol;硝酮分解最大反应速率到达时间TMR_(ad)为24 h,对应的温度TD24为94.3℃,TD8为105.6℃;硝酮分解为多步复杂反应,分解产物包含3-乙酰基吡啶、N-甲基-1-(3-吡啶基)乙基-1-亚胺、氨气、水及二氧化碳。[结论]获取了硝酮的安全性数据,为安全生产奠定基础。

[Aims] C,N-dimethyl-C-(3-pyridyl)nitrone,short for nitrone,is a key intermediate.Its thermal stability,decomposition kinetics and mechanism were studied.[Methods] The thermal stability of nitrone was tested by differential scanning calorimetry(DSC),the decomposition kinetics and mechanism of nitrone was studied by simultaneous thermal analysis coupled with Fourier transform infrared and mass spectrometry(STA-FTIR-MS).[Results] The nitrone was heat-sensitive,its initial decomposition temperature was 146.86-189.38 ℃ when heating rate was between 0.5-8.0 ℃/min.The decomposition heat was(808.05±17.88)J/g and the decomposition activation energy was 86.59-92.93 kJ/mol.The maximum decomposition reaction rate arrival time TMRadwas 24 h,and the corresponding temperature(TD24)was 94.3 ℃,while the TD8 was 105.6 ℃.Nitrone decomposition was a complex multi-step reaction,with the decomposition products including 3-acetylpyridine,N-methyl-1-(3-pyridyl)ethyl-1-imine,ammonia,water and carbon dioxide.[Conclusions] Nitrone safety data obtained from this study will provide a base for chemical production safety.