Thermal Stability and Detonation Properties of Potassium 4,4'-Bis(dinitromethyl)-3,3'-azofurazanate, an Environmentally Friendly Energetic Three-Dimensional Metal-Organic Framework.

Abstract

Environmentally acceptable alternatives to toxic lead-based primary explosives have become increasingly demanding for energetic materials (EMs) because of environmental concerns. Recent experiments suggested that energetic three-dimensional (3D) metal-organic frameworks (MOFs) are promising candidates for the next generation of environmentally friendly primary explosives. A new energetic 3D MOF, denoted as potassium 4,4'-bis(dinitromethyl)-3,3'-azofurazanate, was synthesized and suggested as an excellent candidate for green primary explosives. To achieve an atomistic-level understanding of the thermal stability and detonation properties of this material, we carried out quantum mechanics simulations to examine its initial decomposition mechanism and the Chapman-Jouguet state for sustainable detonation. We find that the initial decomposition reaction of potassium 4,4'-bis(dinitromethyl)-3,3'-azofurazanate is to break the C2N2O five-member ring in which K+ ions play a significant role in stabilizing the molecule structure, leading to an excellent thermal stability. Furthermore, this MOF system has a higher detonation velocity than that of lead azide, a comparable detonation pressure and temperature, and no toxic gases are produced at detonation. The combination of these detonation properties makes it a promising candidate for green EMs. Our results suggest that synthesizing 3D MOFs is an effective approach to develop environmentally acceptable alternatives to toxic EMs with enhanced thermal stability.