Efficient Synthesis of a Superior Heat-Resistant Energetic Material Based on Fused Pyrazolotriazine Ring

Abstract

Fused-ring energetic materials are considered to be promising energetic materials. However, their practical applications are usually hindered due to the tedious synthetic routes. In this work, 4-amino-3,8-dinitropyrazolo­[5,1-c]­[1,2,4]­triazin-7-ol (4) was easily prepared within three straightforward steps starting from commercially available ethyl cyanoglyoxylate 2-oxime (1). Compound 4 is a promising heat-resistant explosive, with remarkable thermal stability (decomposition temperature 332 °C) and thermal sensitivity (burst point 380 °C at 5 s). In addition, it demonstrates high density (1.88 g cm–3), good detonation velocity (8538 m s–1), and low impact and friction sensitivities (IS > 40 J; FS > 360 N). Optimized conditions for the synthesis of 4 have also been investigated, and a scale of 10 g could be prepared over one-batch reaction using the modified synthetic path with a high overall yield (46%). The advanced performance and scalable production of 4 make it a bright prospect for industrial production.

Achieving heat-resistant energetic compounds via silver-catalyzed one-pot cycloaddition of ethyl 2-isocyanoacetate and nitrogen-rich diazonium

“…In order to further study the heat resistances of these two compounds ( 4c and 5c ), the thermal sensitivities of both compounds were measured by using the five-second (5 s) delay bursting point at high temperatures. 26 Compound 4c or 5c (50 mg) was added to an aluminum tube and then placed in Wood's alloy. The corresponding calculation formula for the 5 s delay time ( τ ) is as follows (3):ln τ = E / RT + ln c τ is the value of delayed time (s); c is a constant; R is the molar gas constant (8.314 J (mol K) −1 ); E is the isosurface activation energy of the sample (J mol −1 ); and T is the bursting temperature (K).…”

“…In order to further study the heat resistances of these two compounds (4c and 5c), the thermal sensitivities of both compounds were measured by using the ve-second (5 s) delay bursting point at high temperatures. 26 Compound 4c or 5c (50 mg) was added to an aluminum tube and then placed in Wood's alloy. The corresponding calculation formula for the 5 s delay time (s) is as follows (3):…”

A π-stacking highly stable insensitive energetic inner salt and its insensitive energetic salts

“…For some acidic ligands, their ammonium salts, hydroxylamine salts, and diammonium salts have good detonation performance and safety and have been widely studied. 33–35 Therefore, we synthesized three energetic salts, namely, ammonium salt, hydroxylamine salt, and diammonium salt, using TzTO as the acidic parent. Single-crystal X-ray diffraction tests showed that weak interactions such as π–π stacking and hydrogen bonding in the structures of these energetic salts contributed greatly to the enhanced thermal stability and reduced mechanical sensitivity.…”

Studies on the Synthesis and Properties of High-Energy Low-Sensitivity Compounds Based on 3-Amino-1,2,4-triazole

“…The last 20 years have experienced great effort on promising high-energy low-sensitivity compounds. The nitrogen-rich heterocycles, such as pyrazole, − 1,2,3-triazole, , 1,2,4-triazole, , tetrazole, − pyrimidine, 1,3,5-triazine, , and 1,2,4-triazine, have all been used as the backbone in the construction of high-energy low-sensitivity compounds. However, it is still a big challenge to obtain a qualified compound considering the natural contradiction between energy and safety and the difficulty to scale up for practical applications.…”

“…In addition to molecular design, crystal engineering was verified as an effective way to improve the performance of new energetic compounds. ,− The crystal data offer a micro-perspective into the molecule, which displays the molecular arrangement directly. To date, five stacking models including face-to-face, wavelike, mixing, and 3D-cube have been reported (Figure a).…”