Synthesis and characterization of amphoteric salts and azo-bridged heat-resistant explosives with a 1,2,4-triazole framework

The formation of anions and cations from amphoteric compounds is an effective method to adjust the properties of amphoteric energetic materials, but there are few reports in the field of energetic materials. Based on the excellent properties and modifiability of 1,2,4-triazoles, this work provides a method for the synthesis of novel energetic materials by bridging triazole rings with carboxylic acid, ester and azo groups. Triazole cyclization of carboxylic acids gave the amphoteric compound 6,5-diamino-1′,4′-dihydro-4H,5′H-[3,3′-bis (1,2,4-triazole)]-5′-one ( 6 ) and formed the anionic hydroxylamine salt ( 8 ), which was not ideal in thermal stability ( T d = 161 °C). In order to further adjust the properties, 6 was reacted with nitric acid to form nitrate 7 . Cationic nitrate 7 has good thermal stability ( T d = 334 °C) and high detonation properties ( D v = 8337 m∙s −1 ) in high-energy nitrates. In addition, azo compound (5-nitro-1H, 2′H-[3,3′-bis (1,2,4-triazole)]-5′-yl) hydrazine ( 4 ) has low sensitivity ( IS = 20 J, FS = 240 N), good thermal stability ( T d = 287 °C) and detonation characteristics ( D v = 8602 m∙s −1 , P = 30.5 GPa) comparable to RDX ( D v = 8795 m∙s −1 ). Compounds 4 and 7 have good detonation properties and thermal stability, and have broad application prospects as heat-resistant insensitive explosives. Triazole cyclization of carboxylic acids produces the amphoteric compound 6,5-diamino-1′,4′-dihydro-4H, 5′H-[3,3′-bis (1,2,4-triazole)]-5′-one, and both anionic and cationic salts are formed to regulate its properties. Amphoteric compounds can form cationic salts and anionic salts simultaneously to adjust the properties, which provides a way to adjust the properties of new energetic materials. The all-triazole skeleton compound (5-nitro-1H, 2′H-[3,3′-bis (1,2,4-triazole)]-5′-yl) hydrazine was prepared by coupling. • The formation of cations and anions simultaneously through amphoteric molecules can improve the performance of energetic materials. • Compound 4 has comparable energy to RDX. • NCI, and Hirshfeld surfaces were performed to explore the relationship between structure and properties.