Study On The Synthesis And Performance Of Several Energetic Compounds Of Triazole And Oxadiazole

With the development of modern warfare,energetic materials are required to satisfy many requirements,such as high energy,high safety,low synthetic cost and good environmental compatibility.In order to meet the increasing requirements,the research of modern energetic materials not only needs to focus on the design of molecular structure,but also investigates the relationships between crystal structure and properties.High energy and insensitivity are two desirable properties in the development of energetic materials.It is a continuing task to achieve a perfect balance between energy and safety.In this thesis,triazole and oxadiazole with high density and high heat of formation is taken as the research object.The energetic compounds based on pyrimidine-triazole,pyrazine-triazole and pyrazine-oxadiazole were designed and synthesized respectively.They are 4,6-bis（3-nitramino-4-amino-1,2,4-triazole-5）-pyrimidine,2,5-bis（3-nitramino-4-amino-1,2,4-triazole-5）-pyrazine and 2-oxo-5-nitro-3-（5-nitroimino-1,3,4-oxadiazole-2-yl）-pyrazine.The structures and properties of the compounds were systematically studied by NMR,IR,elemental analysis,mass spectrometry,differential scanning calorimetry and single crystal diffraction.4,6-bis（3,4-diamino-1,2,4-triazole-5-yl）-pyrimidine was synthesized from pyrimidine-4,6-dicarboxylic acid,and 4,6-bis（3-nitramino-4-amino-1,2,4-triazole-5-yl）-pyrimidine was obtained by nitrification.The energetic salts were synthesized by using their derivatives as energetic cation and anion respectively.The densities of these salts ranging from 1.67 to 1.77 g?cm^-3.The Hirshfeld surfaces analyses demonstrate that extensive hydrogen bonds andπ–πinteractions result in good thermal stabilities of these salts.The highest decomposition temperature was observed in perchlorate with 278.1℃.Meanwhile,their impact and friction sensitivities were determined to be in ranges of 32-40 J and 207-360 N,respectively.Their detonation velocities and pressures were calculated to be in range of 7810-8484 m?s^-1and 26.65-32.14 GPa,respectively.2,5-bis（3,4-diamino-1,2,4-triazole-5-yl）-pyrazine was synthesized from pyrazine-2,5-dicarboxylic acid,and 2,5-bis（3-nitramino-4-amino-1,2,4-triazole-5-yl）-pyrazine was obtained by nitrification.The energetic salts were synthesized by using their derivatives as energetic cation and anion respectively.The densities of these salts ranging from 1.67 to1.77 g?cm^-3.The Hirshfeld surfaces analyses demonstrate that extensive hydrogen bonds andπ–πinteractions result in good thermal stabilities of these salts.The highest decomposition temperature was observed in perchlorate with 283.1℃.Meanwhile,their impact and friction sensitivities were determined to be in ranges of 34-40 J and 212-360 N,respectively.Their detonation velocities and pressures were calculated to be in range of7837-8502 m?s^-1and 27.10-32.98 GPa,respectively.2-oxo-5-nitro-3-（5-nitroimino-1,3,4-oxadiazole-2-yl）-pyrazine was synthesized from methyl 2-amino-pyrazine-3-carboxylate by a three-step reaction.The compound has a high density(ρ:1.77 g?cm^-3).The noncovalent interaction,Hirshfeld surfaces analyses the molecular electrostatic potentials demonstrate that extensive hydrogen bonds andπ–πinteractions result in good thermal stabilities of the compound.The thermal decomposition temperature reached 270°C.At the same time,it also shows low mechanical sensitivity,the impact sensitivity and friction sensitivity is 34 J and 360 N,respectively.The theoretical calculation results show that the detonation velocity of the compound is 8516 m·s^-1 and the detonation pressure is 31.85 GPa.