THEORETICAL STUDY OF THE THERMODYNAMIC PROPERTIES OF NITROGEN- AND OXYGEN-CONTAINING HIGH-ENERGY MATERIALS

Different multi-level [G2, G3, G2M(CC5)] and DFT-based (B3LYP, MPW1B95, and MPWB1K) techniques were tested for the calculations of the gas-phase formation enthalpy of nitrometanes as well as C-N bond dissociation energies of these species. The calculated values of the formation and reaction enthalpies were compared with the experimental data if these data were available. It was found that only the G3 procedure gave accurate (within 1 kcal/mol) results. Two new hybrid meta-DFT methods proposed by Truhlar's group showed good results for the reaction enthalpies of the C-N bond dissociation. Using the G3 procedure, the accurate formation enthalpies of some nitro-alkanes with remarkably scattered experimental data were obtained. The gas-phase formation enthalpies of hydrazinium (HNF) and ammonium nitroformate (ANF) were calculated. These data gave an opportunity to predict the dominating vaporization pathway of these compounds. The standard-state enthalpy of formation of a new perspective high-energy compound, [1,2,5] oxadiazolo[3,4-e][1,2,3,4] tetrazine-4,6-di-N-dioxide (furazano-1,2,3,4tetrazine-1,3-dioxide), was computed using the theoretically calculated gasphase formation enthalpy and the experimentally measured sublimation enthalpy.