Study On The Thermal Safety During The Process Of Synthesis Reaction Of DNP

3,4-Dinitropyrazole?DNP?could be a very promising energetic material as a cast explosive to replace TNT because of its high density,high energy and low sensitivity.There is a risk of thermal runaway in the synthesis of DNP because of a large amount of exothermic.The risk assessment of synthetic process were carried out by studying the thermal safety of synthesis reaction.It can be great significance to the production of chemical industry.Easymax HFCal was used to measure the exothermic regularity of three reaction processes.Some thermodynamic parameters of thermal runaway reactions such as adiabatic temperature(?T_ad)and maximum temperature of synthetic reaction?MTSR?were calculated here.Accelerating Rate Calorimeter?ARC?was used to study the secondary decomposition characterizations in adiabatic condition of the reaction solution.The relation of the time to maximum rate under adiabatic condition(TMR_ad)and temperature could be analyzed by ARC.The temperature when the TMR_adis 24h(T_D24)was obtained furthermore.When cooling failure completely,the risk assessment of thermal runaway reaction were carried out by two methods.The results showed that the thermal risk was acceptable and the risk was level 2during the synthesis of N-Nitropyrazole.The synthesis of 3-Nitropyrazole is an endothermic process,and the secondary reaction is almost impossible.The thermal risk level of the synthesis process of 3,4-Dinitropyrazole is unacceptable,and the reaction risk level is level 5.The reaction temperature of the existing process can be reduced from 100?to 60?70?to make the thermal risk level acceptable,and the reaction risk level can be reduced to level 2.Thermal stability of each reaction products was studied by ARC.On this basis,the thermal decomposition kinetic parameters were calculated and compared with the thermal stability of the reaction solution.The results show that the adiabatic decomposition of N-Nitropyrazole is divided into two stages and the second stage is the main thermal decomposition stage;the adiabatic decomposition of 3-Nitropyrazole into one stage;the adiabatic decomposition of 3,4-Dinitropyrazole is divided into three stages,of which the latter two stages are the main thermal decomposition stages.The thermal decomposition of N-Nitropyrazole,3-Nitropyrazole and 3,4-Dinitropyrazole had no strong autocatalytic effect and was relatively stable.The thermal decomposition of the reaction fluid is earlier than that of the solid,and the main exothermic stage is earlier,indicating that the thermal stability of the reaction fluid is poor.