Synthesis And Properties Of Azobistetrazole Energetic Compounds

As a special and important material,energetic materials are widely used.To find energetic materials with high energy,low sensitivity,good stability,and environmental protection,researchers have conducted a lot of research.Nitrogen-rich intermediate compounds 1,1'-dihydroxy-5,5'-azobistetrazole?H₂AzTO?have the advantages of good oxygen balance,high enthalpy of formation,and environmental protection,which have attracted the attention of scientific researchers.Its practice proves that ionic salts and metal organic complexes have good adjustability and can reduce sensitivity.Therefore,in this paper,seven energetic ionic salts and co-crystals were synthesized by reacting H₂AzTO as a precursor with nitrogen-rich bases.Four energetic metal-organic complexes were prepared by hydrothermal reaction with Co²⁺,Cd²⁺,Ni²⁺,and Cu²⁺metal ions.The main research work is divided into the following two parts:?1?Ionic salts 2-7 and co-crystal 8 were synthesized by reacting H₂AzTO?1?with aminoguanidine,1,3-diaminoguanidine,imidazole,pyrazole,metformin,triaminoguanidine,and 2-methylimidazole,respectively.FT-IR,¹H NMR,¹³C NMR and elemental analysis were used to characterize the structures of compounds 2-8 in combination with X-ray single crystal diffraction.Differential scanning calorimetry and thermal weight loss analysis were used to test the thermal stability of compounds 2-8.The results showed that the decomposition temperatures of the seven products were between 155?and 265?.Except for ionic salts 3and 7,the thermal decomposition temperature of other ionic salts and co-crystal is better than RDX?205??.Their standard molar formation enthalpies are calculated by isodesmic reactions and Born-Haber cycle calculation,and the seven compounds are calculated using empirical Kamlet-Jacobs.Detonation velocities were between 7048 m·s^-19590 m·s^-1,and the detonation pressures were between 20.4 GPa³9.1 GPa.The mechanical sensitivity test shows that the impact sensitivities were between 7 J⁴0 J,and the friction sensitivity were between 24 N³60N.In summary,the ionic salt 7 exhibits excellent detonation performance(D=9590 m·s^-1,P=39.1 GPa).The impact sensitivity was 7 J and the friction sensitivity was24 N.Therefore,the ionic salt 7 has an application prospect as an explosive agent.?2?Four energetic metal-organic complexes 9-12 were prepared by reacting H₂AzTO?1?with Co²⁺,Cd²⁺,Ni²⁺and Cu²⁺ions,respectively.The structure of compound 9-12 was characterized by XRD,FT-IR,elemental analysis,and X-ray single crystal diffraction.The thermal stabilities of compound 9-12 were tested by differential scanning calorimetry and thermal weight loss analysis.The results show that the decomposition temperatures of the four complexes were between174°C²24°C.Except for complex 12,the thermal decomposition temperatures of other complexes were higher than the raw material H₂AzTO?175°C?.The detonation heat is calculated using the detonation equation,and the detonation performance was calculated using the improved Kamlet-Jacobs formula.Among them,the detonation velocities were between 8556 m·s^-1 to 9344 m·s^-11 and detonation pressures were between 34.7GPa⁴2.0 GPa.The mechanical sensitivity test shows that the impact sensitivities were between 35 J⁴0 J and the friction sensitivities were between 288 N³60N.The results show that the four energetic metal-organic complexes all exhibit high energy and low sensation.The effect of Cu-AzTO 10 wt%on the thermal decomposition of AP was studied by DTA.The results showed that the HTD decomposition peak of AP was 122 K earlier,the thermal decomposition was more violent,and the exothermic heat of the reaction was greatly improved than pure AP.The HTD activation energy E of mixed AP with 10 wt%Cu-AzTO was 165.4kJ·mol^-1 by using Kissinger,which was 50.6 kJ·mol^-1 lower than that of pure AP(216.0kJ·mol^-1).The results show that Cu-AzTO has a better catalytic effect on the thermal decomposition of AP and is expected to be used as a high-energy catalyst for the thermal decomposition of AP.