A. I. Kazakov

Kinetics of the thermal decomposition of dinitramide 3.* Kinetics of the heat release during the thermal decomposition of dinitramide ammonium salt in the liquid phase

The kinetic regularities of the heat release during the thermal decomposition of liquid NH4N(NO2)2 at 102.4–138.9 °C were studied. Kinetic data for decomposition of different forms of dinitramide and the influence of water on the rate of decomposition of NH4N(NO2)2 show that the contributions of the decomposition of N(NO2)2− and HN(NO2)2 to the initial decomposition rate of the reaction at temperatures about 100 °C are approximately equal. The decomposition has an autocatalytic character. The analysis of the effect of additives of HNO3 solutions and the dependence of the autocatalytic reaction rate constant on the gas volume in the system shows that the self-acceleration is due to an increase in the acidity of the NH4N(NO2)2 melt owing to the accumulation of HNO3 and the corresponding increase in the contribution of the HN(NO2)2 decomposition to the overall rate. The self-acceleration ceases due to the accumulation of NO3− ions decreasing the equilibrium concentration of HN(NO2)2 in the melt.

KINETICS OF THERMAL DECOMPOSITION OF DINITRAMIDE. 1. DECOMPOSITION OF DIFFERENT FORMS OF DINITRAMIDE

Kinetic regularities of thermal decomposition of dinitramide in aqueous and sulfuric acid solutions were studied in a wide temperature range. The rate of the thermal decomposition of dinitramide was established to be determined by the rates of decomposition of different forms of dinitramide as the acidity of the medium increases: first, N(NO2)− anions, then HN(NO2)2 molecules, and finally, protonated H2N(NO2)2+ cations. The temperature dependences of the rate constants of the decomposition of N(NO2)− (kan) and HN(NO2)2 (k′ac) and the equilibrium constant of dissociation of HN(NO2)2 (Ka) were determined:kan=1.7·1017 exp(−20.5·103/T), s−1,k′ac=7.9·1016 exp(−16.1·103/T), s−1, andKa=1.4·10 exp(−2.6·103/T). The temperature dependences of the decomposition rate constant of H2N(NO2)2+ (kd) and the equilibrium constant of the dissociation of H2N(NO2)2+ (Kd) were estimated:kd=1012 exp(−7.9·103/T), s−1 andKd=1.1 exp(6.4·103/T). The kinetic and thermodynamic constants obtained make it possible to calculate the decomposition rate of dinitramide solutions in a wide range of temperatures and acidities of the medium.

Kinetics of the thermal decomposition of dinitramide

The kinetic regularities of the thermal decomposition of dinitramide in aqueous solutions of HNO3, in anhydrous acetic acid, and in several other organic solvents were studied. The rate of the decomposition of dinitramide in aqueous HNO3 is determined by the decomposition of mixed anhydride of dinitramide and nitric acid (N4O6) formed in the solution in the reversible reaction. The decomposition of the anhydride is a reason for an increase in the decomposition rates of dinitramide in solutions of HNO3 as compared to those in solutions in H2SO4 and the self-acceleration of the process in concentrated aqueous solutions of dinitramide. The increase in the decomposition rate of nondissociated dinitramide compared to the decomposition rate of the N(NO2)2− anion is explained by a decrease in the order of the N−NO2 bond. The increase in the rate constant of the decomposition of the protonated form of dinitramide compared to the corresponding value for neutral molecules is due to the dehydration mechanism of the reaction.

Influence of the supramolecular structure of the liquid reaction medium on the kinetics of acetone oxidation with aqueous solutions of nitric acid

Refined kinetic characteristics for the initial stage of acetone oxidation using purified nitric acid were obtained by dynamic calorimetry and NMR spectroscopy. The differences of obtained characteristics from the literature data are significant. The dependences of the 17O NMR spectra in the HNO3-H2O binary system and 1H NMR spectra in the ternary system with acetone on the reactant concentration were studied in detail. The character of the supramolecular structure of the reaction medium and its influence on the initial rate of acetone oxidation are discussed.

Kinetics and mechanism of thermal decomposition of ammonium nitrate and sulfate mixtures

Fundamental kinetic aspects of the decomposition of mixtures and double salts of ammonium nitrate and ammonium sulfate were studied. The effect of water and sulfuric acid additives on the thermal decomposition rate of ammonium nitrate and sulfate mixtures was examined. The constant of proton exchange between nitric acid and the sulfate anion in molten ammonium nitrate was estimated.

Energetic properties and impact sensitivity of crystalline explosives

The impact sensitivity of some groups of nitrates and cubane derivatives has been correlated with their heat of explosion and chemical structure. These correlations show the ways of reducing explosion hazard in handling these compounds. It is currently impossible to construct a reference series of compounds that would allow explosives with preset sensitivity to be synthesized on the basis of a preliminary energetic prediction. New opportunities to enhance safety in handling explosives can be provided by investigating their detonation ability.

Structure and properties of cocrystals of trinitrotoluene and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane

Crystals containing 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane and trinitrotoluene molecules in a 1: 1 ratio were obtained. The crystal structure was determined, and DSC thermograms, thermal stability, and the standard enthalpy of formation were investigated. An analysis of the crystal structure shows that interactions between the oxygen and nitrogen atoms of the nitro groups ON=O…NO2 of adjacent molecules are among the structure-forming intermolecular interactions in the crystals of polynitroamine compounds.

Synthesis and thermal decomposition of ditetrazol-5-ylamine

Ditetrazol-5-ylamine (DTA) was synthesized from cyanuric chloride in four steps. The thermal decomposition of DTA in the solid state was studied by thermogravimetry, volumetry, mass spectrometry, IR spectroscopy, and calorimetry. Under isothermal conditions at 200–242 °C, thermal decomposition obeys the first order autocatalytic kinetics. The kinetic and activation parameters of DTA decomposition were determined. The composition of gaseous reaction products and the structure of condensed residue were studied. The thermal effect of thermal DTA decomposition is 281.4 kJ mol−1. The nitrogen content in a mixture of gaseous products formed by the reaction in a temperature interval of 200–242 °C exceeds 97 vol.%.

Kinetics of heat release during decomposition of cellulose

The kinetic behavior and temperature dependences of the rate constants for thermal decomposition are determined for cellulose of different biological origins and forms. The possibility of thermal decomposition of cellulose in a combustion regime without oxygen is analyzed.

Slow large-scale supramolecular structuring as a cause of kinetic anomalies in the liquid-phase oxidation with nitric acid

Isothermal calorimetry, static and dynamic light scattering, and NMR spectroscopy studies provided evidence for slow formation of large associates of solvates in aqueous solutions of nitric acid, which makes it possible to attribute the anomalous kinetic features in the oxidation of acetone to the supramolecular mechanism of the reaction.