Nitro and dinitroamino N-oxides of octaazaanthracene as high energy materials

Abstract

The present study undertook the design of nitro and dinitroamino compounds from the skeleton of isomeric N-oxides of octaazanaphthalene, using computational methods to predict their degradation and explosive characteristics. The atom equivalent method was employed to evaluate the gas phase heats of formation of the designed species. Condensed phase heats of formation were also determined and found to be in the range of 220-286 kcal mol(-1). Crystal densities of all the designed molecules were calculated and found to be in the range of 1.91-1.98 g cm(-3). Detonation pressure (P) and detonation velocity (D) determined using the Kamlet-Jacobs equation showed that the performance of nitro-substituted compounds was comparable to that of RDX while that of dinitroamino compounds (P ≈ 43.4-43.7 GPa; D ≈ 9.6-9.7 km s(-1)) showed their superiority over HMX (P ≈ 39.3 GPa and D ≈ 9.10 km s(-1)). Impact sensitivity (h 50) of the designed molecules was compared with nitro- and nitramino-based commercial explosives on the basis of the available free space (∆V) per molecule in their crystal lattice estimated using wave function analysis. The study showed that dinitroamino compounds were more sensitive compared to their nitro analogs. Reactivity or chemical stability of the designed molecules were measured in terms of charge distribution, molecular electrostatic potential and frontier molecular orbital energy. The nitro compounds of N-oxides of octaazaanthracene were found to be more stable than their dinitroamino analogs.