The Study Of Energetic Salts Salts Based On [1,2,4] Triazole [4,3-b][1,2,4] Triazole

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.High energy,low sensitivity,green environmental has been one of the goals of this field.Unfortunately,high energy and low sensitivity is usually a contradition.Recently,there is increasing evidence that nitrogen-rich heterocyclic energetic salts can effectively solve the contradiction,which is becoming the focus of research.Nitrogen-rich heterocyclic energetic compounds possess higher density,high electron delocalization and positive enthalpy of formation.In addition,nitrogen-rich heterocyclic energetic salts has more modification sites,and groups with higher energy density?NO₂?-NH-NO₂?-O-NO₂?-C?NO₃?₃,etc.?can be introduced to make it have better detonation performance.Most of the triazole and triazole energetic materials reported focus on their cations,and the oxygen balance?OB?is very low.In this paper,the energy-containing anion?OB=-8.3%?of triazole was designed and synthesized:3,6,7-trinitramine-7H-[1,2,4]triazole[4,3-b][1,2,4]triazole?referred to as triazole?was prepared from guanidine hydrochloride and hydrazine hydrate through a three-step reaction of substitution,ring closure and nitrification,with a yield of 60%,The experiment operation process is simple and convenient.And through the acid and alkali neutralization reaction,its derived 6 energetic salts.The single crystal of compound 5,6 and 7 were obtained by solvent volatilization method,and the crystal structures were further conformed by single-crystal X-ray diffraction.Among the anions of the three salts,the nitro group in the nitrosamine segment was almost in the plane of the thick ring,and the Angle between the nitro group in the nitrosamine segment and the plane of ring was 77.18°-87.45°.The resonance structure of carbonitramine without losing hydrogen proton in anion forms corresponding intramolecular hydrogen bond,the bond length is between 2.104-2.173?.In compound 5,all the guanidinium cations are roughly coplanar with the corresponding fused-triazole backbones,with the largest dihedral angle of 12.39°.the packing structure of anionic was built up and linked to a 2D double layer.The distances between adjacent layers are 2.977?and 3.216?.In compound 6,the dihedral angles between the triazole ring and the two aminoguanidinium cations are 12.07°and 62.79°,respectively.In compound 7,The dihedral angles between the backbone and the two cations are 6.93°,and 33.35°,respectively.Compound 6 and 7 exhibits wave-like stacking,the layer distance are 3.153?and 3.196?,respectively.The dihedral angle of compound 7 between two neighbour anions?67.73°?in the same layer is slightly larger than in compound 6?62.56°?.In this paper,six kinds energetic salts were then fully characterized using ¹H/¹³C NMR,IR and DSC.Compound 5,6 and 7 salts were further conformed by single-crystal X-ray diffraction.All the energetic compounds exhibitgood thermal stabilities with decomposition temperatures ranging from 151 to 235°C.The measured densities of the energetic salts ranged between 1.65 to 1.89 g cm^-3,andthe oxygen balance ranged from-42.8%to-11.3%.The heats of formation of these compounds were calculated to be in the range of 382.5 to 869.9 kJ mol^?11 by Gaussiansoftware.Their impact sensitivity and friction sensitivity were tested respectively.The sensitivity was improved after salting,and 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 8519 to 9518 m s^?1,and 27.6 to 41.1 GPa.All new salts show good thermal stabilities?>170°C?except compound 3.Most of them have acceptable sensitivities and attractive detonation properties to compete positively with RDX.The detonation performance and sensitivity of diammonium compound 2(v_D=9292 m s^-1,P=36.9 GPa,IS=8 J,FS=192 N)are superior to those of RDX.Dihydroxyamine compound 3exhibits acceptable sensitivity?IS=5 J,FS=108 N?and excellent detonation performance(v_D=9518 m s^-1,P=41.1 GPa)which is superior to that of HMX.These advantages suggest that these materials may well have promising applications as high-energy-density materials.