Study On Process Of Synthesis Of NTO Via Reacting To With Nitric Acid

3-nitro-1,2,4-triazol-5-one?NTO?,as an insensitive high explosive,has been extensively studied and applied in recent years owing to its high performance but low cost.There have been many methods of NTO synthesis.Among them,the method of direct formation of NTO via reacting TO with nitric acid has advantages such as simplicity of the reaction,benefit to environmental protection,and so on.Thus,the synthesis process using this synthetic method is chosen as the research subject in this paper.Studies on kinetics,thermal analysis,reaction mechanism around the synthesis of NTO via reacting TO with nitric acid are performed.It is important to study around the synthesis process of an explosive in order to insure the safety of the production or optimize the process of production.The research results include:First,the influence of concentration of HNO₃ and TO and reaction temperature on the rate of synthesis of NTO from TO in nitric acid solution is investigated by using exponential model of kinetics.An exponential kinetic equation is established by data of experiments of nitration of TO in 60.4-76.2%HNO₃.Kinetic parameters such as apparent reaction orders of TO and HNO₃,activation energy and frequency factor for nitration of TO are determined.Data of experiments of nitration of TO with 60.0-96.7%HNO₃ are used for verification of this model.As a result,the values of nitration rate calculated are close to those measured.It shows this model can quantitatively and qualitatively describe the influence of concentration of reactants and reaction temperature on the rate of nitration TO.The reaction order of HNO₃ is 10;it demonstrates that the changes in the concentration of HNO₃ significantly influence the reaction rate.The mechanism of this influence is studied exploringly.The results show that there might be a X material.It reacts with TO through elementary reaction,which produces NTO.The concentration of this material is in exponential equilibrium with concentration of HNO₃,ultimately resulting in the reaction order of HNO₃ as 10.In addition,the application of the kinetic equation suggested in the actual production process is illustrated.Such as,the maximum reaction temprature is determined by this equation combined with the parameters of equipment and meterial.The allowed maximum mass of addition of TO is determined via this equation combined with the parameters of equipment and reaction temperature.The highest temperature of the circulating water in jacket is determined through this equation combined with the technological parameters.Secondly,five kinds of heat effects during the nitration process of TO in different concentrations of nitric acid along the main reaction path have been differentiated and determined in detail.They include the heat of process of dosing the sample of TO(?H_TO,dosing),dissolution heat of TO(?H_{TO,dissolution}),crystallization heat of NTO(?H_{NTO,crystallization}),the reaction heat??H_r?and the heat(?H_HNO3)caused by changes in concentration of nitric acid.It should be possible to use above five heat effects to estimate the thermal effect for a single subprocess,or provide estimation of the heat for a complex process or a total process along the main reaction path.The evaluation for the influence of these heat effects on synthesis process points out the following main results:?H_r has the dominant contribution to the total exothermic effect during manufacture process in various concentrations of HNO₃;the contribution ability rank of other four heat effects are different under various concentration of HNO₃ applied in the production process.Thirdly,the stability of NTO in nitric acid environment is studied using the thermal analysis and quantitative analysis of concentration of NTO.The results show that the NTO will reacts with nitric acid in nitric acid environment,accompanied by the generation of brown fumes typical for nitrogen oxides.The rate of reaction between NTO and nitric acid increases with increasing reaction temperature and HNO₃ concentration.There is a continuous exothermic effect after mixing NTO with nitric acid.The rate of heat release also increases with increasing reaction temperature and HNO₃ concentration.So it is supposed that the reaction between NTO and HNO₃ is an exothermic reaction.With the increase of temperature and HNO₃ concentration,the reaction rate increases,causing the increase of exothermic rate.The yield of NTO decreases with increasing the reaction time and holding temperature.Hence,in order to avoid the decrease of yield,it is necessary to apply appropriate reaction temperature and time,holding temperature and time.The most comprehensive and latest mian and side reaction pathes of NTO synthesis are updated.The side raction path?V?is added.Fourthly,the influence of temperature on the process of reaction of NTO formation between TO and 67.5%-98.6%HNO₃ is investigated by employing the method of thermal analysis.The changes of reaction process with the temperature of reaction increasing are exposed,including the changes of heat effects,mian and side reaction pathes and their degree of generation,yield of NTO,maximum rate of heat release,main reaction time and color of the reaction mixture.The heat of total process of NTO synthesis is analyzed according to the mian and side reaction mechanism.It is found that the thermal effects of the main reaction and side reactions?V?and?VI?can be distinguished from the total process heat.