Study On Thermal Hazard Of Synthesis Process Of N-Methylmorpholine-N-Oxide Based On Calorimetry

This paper uses calorimetric equipment to study the thermal hazardrisks of the synthesis process of N-Methylmorpholine-N-oxide.The main work and research results are as follows:In this paper,a synchronous thermal analyzer（Q600）was used to study the self-decomposition characteristics of N-methylmorpholine-N-oxide with different heating rates under nitrogen atmosphere.The results showed that N-methyl morpholine began to decompose at 180℃.The thermodynamic parameters of N-methylmorpholine-N-oxide was obtained using Advanced Kinetics and Technology Solutions（AKTS）,such as The maximum reaction activation energy with 161.56 k J/mol,N-methylmorpholine-N-oxide T_D24 with 149.5℃and the adiabatic temperature riseΔT_adwas 166.5℃..Preliminary research results indacated that the risk grade of the self-decomposition reaction of N-methyl morpholine was second order.When the cooling system is out of control,it will cause short-term damage to the factory.Adiabatic Reaction Calorimeter（ARC）was used to analyze the thermal decomposition characteristics of hydrogen peroxide,N-methyl morpholine,and methyl morpholine-oxide.It showed that N-methyl morpholine was stable as the decomposition temperature of N-methyl morpholine was above 400℃.The decomposition temperature of hydrogen peroxide and N-methylmorpholine-N-oxide are 45℃and 150℃,and theoverallheat is 593.32 J/g and 411.53 J/g respectively.According to the estimation of decomposition heat,both of the self-decomposition process of hydrogen peroxide and N-methylmorpholine-N-oxide were the second order with the potential explosion risk.Due to the coupling effect of hydrogen peroxide and N-methylmorpholine-N-oxide in reaction products,the decomposition temperature of hydrogen peroxide increased slightly,while the decomposition temperature of N-methylmorpholine-N-oxide decreased by about 30°C.Reaction Calorimeter was used to study the thermal risk of the synthesis process of N-methylmorpholine-N-oxide.The study showed that the active energy was 95-115 KJ/mol,the adiabatic temperature rise was112.52-133.28℃,and the reaction MTSR was at 64.39-78.53℃.According to the Stoessel criticality diagram(T_p<MTSR<T_D24<MTT),the reaction level of thermal runaway was level two..It was verified by microreaction calorimeter（C80）that the reaction heat of adding hydrogen peroxide at one time was higher than that of adding drops,which increased the risk of the reaction.Therefore,the rate of feed of hydrogen peroxide should be controlled in the process of producing N-methylmorpholine-N-oxide to decrease the thermal hazard.