Derivatives of 2-(3,4-dinitro-1H-pyrazol-1-yl) acetonitrile: Design strategy, syntheses, and properties of a series of new melt-cast explosives

Abstract

Melt-cast explosives, the most widely used energetic materials in military composite explosives, play an important role in improving the energy and safety performance of military composite explosives. In this work, a structural type for melt cast materials was designed by linking 3,4-dinitro-1H-pyrazole with tetrazole or 1,2,4-oxadiazole through a N-CH2-C bridge. All the compounds were thoroughly characterized by nuclear magnetic resonance, fourier transform infrared spectroscopy, elemental analysis. Compounds 4, 6 and 7 were unambiguously confirmed by X-ray single crystal diffraction analysis. The crystal densities of the three compounds were between 1.66 g·cm-3 and 1.81 g·cm-3. The impact and friction sensitivities were measured by standard BAM fall-hammer techniques, and their detonation performances were computed using the EXPLO5 v6.05.04 program. The melting points of 4 and 6 are 91.5 ℃ and 93 ℃, respectively. And they exhibited high thermal stabilities and were found to be insensitive towards impact and friction. Their overall properties are superior to traditional melt-cast explosives 2,4,6-Trinitrotoluene (TNT), dinitroanisole (DNAN) and 3,3'-Bi(1,2,4-oxadiazole)-5,5'-diylbis(methylene) dinitrate (BODN), which may have excellent potential applications in insensitive melt-cast explosives.