Synthesis Technology Of High Nitrogen Energetic Material H₄TTP Performance Study

H₄TTP（2,3,5,6-Tetrad（1H-tetrazole-5-yl）pyrazine）,as a new N-rich energetic material,has a nitrogen content of 71.58%,a detonation velocity of 8655 m·s^-1,a detonation pressure of28.0 Gpa,a density of about 1.88 g·cm^-3,a decomposition temperature of 259℃,and the H₅₀of 33.8 cm.With stable properties,low sensitivity,good stability and other characteristics,it is an ideal candidate for new high energy low sensitivity explosive.The preparation method of H₄TTP was proposed by Tomasz G.Witkowski in 2018,using 2,3-diamino-2-butene dinitrile（DAMN）as raw material for three-step reaction synthesis.The preparation method has low atomic utilization rate,difficult purification,and high toxicity and risk of some raw materials.Its synthesis technology and properties have not been studied at home and abroad.Therefore,it is of great significance to study the synthesis technology and properties of H₄TTP.In this study,N-rich energetic material H₄TTP was synthesized with DAMN as raw material,and the synthesis process conditions of H₄TTP were optimized.Besides,the thermal decomposition mechanism of H₄TTP at high temperature was studied,and its density and mechanical impact sensitivity were tested.（1）Synthesis of 2,3,5,6-pyrazine tetronitrile:2,3,5,6-pyrazine tetronitrile（TCP）was synthesized from DAMN through oxidative dehydrogenation and nucleophilic substitution of2,3-dichloro-5,6-dicyano-1,4-benzoquinone（DDQ）.The properties and structures of the products were characterized by purity analysis,infrared spectroscopy,nuclear magnetic resonance,mass spectrometry and elemental analysis.Single factor experiment and response surface experiment were used to optimize the process conditions.The optimized process conditions were:n（DAMN）:n（DDQ）=2.06:1,reaction temperature 79℃,reaction time 4.2 h,the yield of TCP 71.9%.（2）Synthesis process of H₄TTP:H₄TTP was obtained by[2+3]cycloaddition reaction using TCP as raw material.The properties and structures of the products were characterized by,purity analysis,infrared spectroscopy,nuclear magnetic resonance,mass spectrometry and and elemental analysis.Single factor experiment and response surface experiment were used to optimize the process conditions.The optimized process conditions are as follows:n（TCP）:n（Na N₃）=1:4.5,reaction temperature 127℃,reaction time 38 h,H₄TTP yield 84.2%.（3）Study on thermal decomposition mechanism:The thermal decomposition of H₄TTP at constant high temperatures of 2000 K,2250 K,2500 K,2750 K and 3000 K was studied by molecular dynamics simulation of Reax FF/lg reaction field.Through product analysis and TG-MS test combined with H₄TTP,it can be seen that the main product of H₄TTP decomposition is N₂,and the Arrhenius equation is used to fit the change curve of system potential energy during the thermal decomposition process to obtain the reaction kinetic parameters of H₄TTP,including chemical reaction rate constant,activation energy and pre-exponential factor.（4）Safety study:The physicochemical properties of H₄TTP were investigated by means of density measurement of energetic materials,TG-DSC,5s burst point,friction sensitivity and impact sensitivity.The results show that the decomposition temperature of H₄TTP is 259.51℃,the explosion point temperature is 293.22℃,the friction sensitivity and impact sensitivity explosion probability are 4%and 8%respectively,the H₅₀ is 33.8 cm,and the density of H₄TTP is about 1.88 g·cm^-3 at 25℃.