Synthesis And Properties Of Nitrogen Heterocyclic Energetic Salts

Development of modern high energy density materials?HEDMs?with improved performance and low sensitivity as well as environmental compatibility has been an urgent demand of modern military.Unfortunately,high energy and low sensitivity is usually a contradition.Thus,it is urgently required to synthesize novel explosive compounds with low sensitivity to improve the safety of explosives while maintaining their high energetic characteristics.Recently,there is increasing evidence that nitrogen-rich heterocyclic energetic salts can effectively solve the contradiction,which is becoming the focus of research.Salt-based energetic materials often possess advantages over nonionic molecules,because these salts tend to exhibit lower vapor pressures,higher positive heat of formation and higher themal stability.In addition,energetic salts have good adjustability,and through careful design of the anionic and cationic components,are expected to meet different application conditions.Nitroazole compounds contain large number of C-N,N-N and N-O band,which result in high heat of formation,high density and good oxygen balance.Energetic salts based on azole compounds are becoming an important aspect in energetic material research.In this thesis,C-N bridged 3,4-Dinitro-1-?1H-tetrazol-5-yl?-1H-pyrazol-5-amine?HANTP?and its ten nitrogen-rich energetic salts were design and synthesized successfully,which were then fully characterized using ¹H/¹³C NMR,IR and EA.HANTP?2.7?,its ammonium?2.9?and guanidinium?2.12?salts were further conformed by single-crystal X-ray diffraction.All the energetic compounds exhibit good thermal stabilities with decomposition temperatures ranging from 171 to 170?.The measured densities of the energetic salts ranged between 1.61-1.84 g cm^-3.The heats of formation of these compounds were calculated to be in the range of 729.1-1275.2 kJ mol^-1 by gaussian software based on the designed isodesmic reaction.HANTP and its salts are determined using a BAM Fallhammer apparatus and a BAM friction tester,respectivity.Some of the energetic salts exhibit insensitive.The detonation velocities and pressures of these energetic salts were calculated by EXPLO5?v6.01?to be between 8229-9295 m s^-1 and 25.4-38.3 GPa.Among them,hydroxylammonium salt?2.10?has high density(?=1.84 g cm^-3),good thermal stability?T_d=171??,low sensitivities?IS=35J,FS=216N?and excellent detonation performance(v_D=9295 m s^-1,P=38.3 GPa),which is compete with,or exceed the performance of those of HMX and make it a competitive candidate to replace HMX.Continuing our efforts in finding new eco-friendly primary explosives with good performance and stabilities,we present herein the preparation and characterization of potassium 5-?5-amino-3,4-dinitro-1H-pyrazol-1-yl?tetrazol-1-ide?KANTP,3.2?with a rare 2D energetic MOF structure,andsodium 5-?5-amino-3,4-dinitro-1H-pyrazol-1-yl?tetrazol-1-ide?NaANTP,3.3?with a rare 1D energetic MOF structure.The melting point and decomposition temperature of these energetic compounds were measured in the range of 253-269?,which possesse good thermal stabilities.The measured densities were 2.92 and 1.93g cm^-3.The niteogen contents were calculated between 45.15 and 47.91%.Their impact and friction sensitivities were determined to be 2-7 J and 144-160 N better than Pb?N₃?₂.The detonation velocity and pressure of new primary explosives were calculated using two methods?EXPLO5 and Kamlet formula?to be 8380-8430 m s^-1 and 31.4-34.0 GPa.From the comprehensive consideration of their physicochemical properties,KANTP is predicted to be suitable as green primary explosive.Additionally,high density energetic compounds?E?-1,2-bis?3,4-dinitro-1H-pyrazol-5-yl?diazene?4.1? and sodium 7,8-dinitro-2-oxido-4-oxo-4H-pyrazolo[5,1-d][1,2,3,5]tetrazin-6-ide?4.2?were synthesized and characterized by HR-MS and single-crystal X-ray diffraction.Two energetic compounds exhibit excellent thermal stabilities with decomposition temperatures?245 and 280??and high densities(1.88 and 1.95 g cm^-3).Impact and friction sensitivity has been determined by a BAM standard,for further reseach to explore the performance of explosive and obtain energetic salts with high energy and low sensitivity.