Theoretical Study of the Primary Processes in the Thermal Decomposition of Hydrazinium Nitroformate

Abstract

The primary reactions of the thermal decomposition of hydrazinium nitroformate (HNF) as well as ammonium nitroformate (ANF) were investigated theoretically using the G3 multilevel procedure. Calculations were performed for the reactions in the gas phase and in the melt using a simplified model of the latter. The influence of the melt on the reaction barriers was taken into account by calculation of the solvation free energies using a PCM model. In contrast with many other energetic salts, the ionic salt structures of the HNF and ANF were found to be minima on the PES. However, the most energetically favorable structures of the HNF and ANF in the gas phase are H-bonded complexes. In the melt, on the contrary, the ionic structure is lowest in free energy because of solvation effects. In both the gas phase and melt, the HNF decomposes preferably to nitroform and hydrazine. This fact agrees well with the experimentally observed absence of HNF among the gas-phase decomposition products. Thermolysis of HNF occurs mainly through the intermediacy of nitroform; computations do not support the suggestion that the aci-nitroform is an important intermediate of HNF thermolysis. The primary dissociation reactions of ANF resemble those of the HNF.

Accurate Thermochemistry of Novel Energetic Fused Tricyclic 1,2,3,4-Tetrazine Nitro Derivatives from Local Coupled Cluster Methods

“…Both methodologies are prone to error accumulation upon the increase of the system size. Even for the medium-sized species (10–20 non-H atoms), the uncertainties of the calculated values might exceed 10 kcal mol –1 . ,− …”

Enthalpy of Formation of N2H4 (Hydrazine) Revisited

“…Table contains the experimental values discussed earlier, together with a wider list of selected theoretical literature values for the enthalpy of formation of hydrazine. − ,− ,,,,,− Ignoring the negative B3LYP enthalpy of formation, one can find a low Δ f H °(0 K) of 99.85 kJ/mol and a high of 115.4 ± 2.0 kJ/mol. The ATcT ver.…”

“…The value of ΣD 0 was taken from Table of this paper (1694.0 kJ/mol). It was converted to a 0 K enthalpy of formation using a sum of atomic enthalpies = 1805.28 kJ/mol. g Kiselev and Gristan h Klopper, Bachorz, Hättig, and Tew .…”

pH-Sensitive C–ON Bond Homolysis of Alkoxyamines of Imidazoline Series: A Theoretical Study

“…First, in accordance with the VTST, the Gibbs free energy of reaction Δ r 0 G is the lower estimate of the Gibbs free energy of activation Δ ‡ G 0 . Moreover, the Δ r 0 G values of monomolecular decomposition reactions are typically profoundly lower , than the corresponding reaction enthalpies Δ r 0 H due to higher contributions of translational degrees of freedom into the entropy of products. Apart from this, the activation energies from Table were estimated using the only value of the rate constant at a fixed temperature.…”