Energetic Materials Frontiers最新文献

The thermal decomposition of a number of analogues of hexanitrohexaazaisowurtzitan (CL-20), in where one or more N-nitro groups have been replaced by another explosophoric unit (diverse N-alkylnitramine groups or N- trinitroethyl), has been studied by methods of isothermal and non-isothermal kinetics. It was found that replacing the N-nitro group with even a more thermally stable substituent leads to a decrease in the stability of the nitrated hexaazaisowurtzitane framework. It was suggested that the substituent distorts the symmetry of the strained hexaazaisowurtzitane cage, which affects the strength of the N–NO₂ bond. When a substituent less stable than the N-nitro group in the parent CL-20 is installed, the initial stage of degradation is determined by the decomposition kinetics of this substituent. One of the objects of this study, 4,10-dinitro-2,6,8,12-tetrakis (2,2,2-trinitroethyl) −2,4,6,8,10,12-hexaazaisowurtzitane (8), was synthesized for the first time; it was fully characterized and also confirmed by X-ray structural data.

Constructing heat-resistant fused heterocyclic compounds is increasingly fascinating in the field of energetic materials due to their excellent energy, high thermal stability, and low sensitivity, as well as high density in general. This study synthesized a novel heat-resistant explosive based on the imidazo [1,2-b]pyridazine fused ring，3,7-dinitroimidazo [1,2-b]pyridazine-6,8-diamine (5)，using a three-step facile method. This compound exhibited a high density (1.856 g cm⁻³) and low mechanical sensitivities (IS = 40 J, FS = 350 N). Meanwhile, it displayed a higher thermal decomposition temperature of 324 °C compared to conventional heat-resistant explosive HNS (T_d = 318 °C). In addition, it demonstrated significantly higher detonation performance (D = 8336 m s⁻¹, p = 27.25 GPa) than both TNT (D = 6881 m s⁻¹, p = 19.5 GPa) and HNS (D = 7612 m s⁻¹, p = 24.3 GPa). Theoretical analysis shows that the intramolecular hydrogen bonding interactions of NH₂–NO₂–NH₂ might be the main reason for the heat resistance of energetic materials based on the imidazo [1,2-b]pyridazine fused ring. The results of this study suggest that compound 5 is a promising building block and a candidate for heat-resistant energetic materials.

In the field of energetic materials, prime attention has been given to the synthesis of environmentally compatible energetic materials having an adequate balance between energy and stability. For this purpose, nitrogen-rich heterocyclic rings have contributed as pivotal frameworks. Nitro-functionalized 1,2,4-triazoles have been profusely used as a constituent for synthesizing high-performing energetic materials (EMs) due to their high nitrogen content, good thermal stability, and modifiable sites via functionalization. Combination with a different energetic scaffold may provide an opportunity for accessible tailoring. In this work, in an effort to investigate the potential of 3-nitrotriazoles, its N-acetonitrile derivative 2 was synthesized, which was further converted to various explosophores. N-methylene-C bridged asymmetrically connected tetrazole (3) and 1,2,4-oxadiazole (9 and 10) based EMs have been synthesized. Further tuning of energetic properties via salt formation strategy was employed for the synthesis of compounds 4–7, 11 and 12. 1,2,4-oxadiazole-based compound 9 was also confirmed via X-ray diffraction analysis, and 10 was analyzed with ¹⁵N NMR spectroscopy. Compounds 3, 4, 5, 7 and 9 exhibited high thermal stabilities and were found to be insensitive towards impact and friction. Compounds 5, 6, and 10 exhibited detonation performance comparable to the conventional insensitive explosive TATB.