N-甲基氧化吗啉热分解动力学分析

Thermal kinetics of N-methylmorpholine-N-oxide in the decomposition process

对在纤维素溶剂中具有广泛应用的N-甲基氧化吗啉(NMMO)热分解动力学进行研究。首先利用绝热加速量热仪(ARC)开展绝热分解实验,得到NMMO在绝热条件下的初始分解温度为119.87℃,通过动力学计算得到反应活化能为219.7 kJ·mol^(-1),为自分解一级反应。其次通过差示扫描量热仪(DSC)对NMMO进行非等温分解实验,并利用Friedman法、Flynn-Wall-Ozawa法和ASTM E698法3种动力学模型进行分解动力学计算。研究结果显示NMMO的初始分解温度为161.07~186.40℃,反应活化能分别为81~134、75.81~100.34和101.92 kJ·mol^(-1)。最后利用风险矩阵法定量评估NMMO热分解危险等级为Ⅲ级。该研究结果为降低NMMO生产、储存和运输中发生分解反应的风险提供了理论依据。

N-methylmorpholine-N-oxide(NMMO)is widely used in cellulose solvents.In this paper,the thermal kinetics of NMMO was studied.First,the adiabatic decomposition experiment was carried out u-sing the accelerating rate calorimeter(ARC),and the initial decomposition temperature of NMMO under adiabatic mode was 119.87℃.The apparent activation energy was 219.7 kJ·mol^(-1) and the reaction or-der was 1 by kinetic calculation.Second,differential scanning calorimetry(DSC)was used to investigate the decomposition process at different heating rates,and the thermal kinetics parameters of NMMO were obtained by Friedman method,Flynn-Wall-Ozawa method and ASTM E698 method software AKTS.The initial decomposition temperature was 161.07—186.40℃,and the apparent activation energy of the three models were 81—134 kJ·mol^(-1),75.81—100.34 kJ·mol^(-1) and 101.92 kJ·mol^(-1),respectively,which were lower than those of the ARC experimental results.Finally,the risk level of NMMO thermal decomposition was three grade by the risk matrix method.The results provide theoretical basis for reduc-ing risk in NMMO production,storage and transportation.