G. B. Manelis

THERMAL DECOMPOSITION OF AMMONIUM DINITRAMIDE AND MECHANISM OF ANOMALOUS DECAY OF DINITRAMIDE SALTS

Thermal decomposition of ammonium dinitramide proceedsvia homolytic rupture of the N−NO2 bond and partially by the proton transfer reaction. The monomolecular decay of the anion to N2O and NO3− in the solid state at 60 °C occurs with higher rates than those in the melt. This is related to a change in the reactivity of the anion due to the violation of its symmetry on going to the solid state. The absence of hydrogen bonds between the anion and cations or water molecules is an additional condition for the fast decay.

Phase state stabilization of ammonium nitrate for creating an oxidizing agent for smokeless gas-generating formulations yielding no toxic combustion products

Methods for phase stabilization of ammonium nitrate were sought for in order to considerably expand the application area of this oxidizing agent in various-purpose self-combustible formulations, including that in a new generation of gas-generating formulations for automobile air bags. New methods for stabilization of ammonium nitrate were studied and, in particular, a search was made for organic compounds that can stabilize ammonium nitrate even at their low content. The mechanism of phase state stabilization of ammonium nitrate by compounds of this kind was examined.

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.

Retardation of monomolecular reactions in the solid phase

The rate constants of initial monomolecular stages of thermal decomposition in the solid phase were measured for 22 organic compounds. The ratio of rate constants of decomposition in the melt and solid state, characterizing the reaction retardation in the crystal lattice, was determined. The retardation effect was compared to the physical properties of the crystal.

Thermal decomposition of ?-(difluoroamino)polynitroalkanes

The compounds RC(NO2)2NF2 differ little from their nitro analogs, RC(NO2)3, in stability. They decompose in the gas and liquid phases at identical rates and the decomposition is controlled by cleavage of a C-NO2 bond. For R=NO2, F, and Me the Arrhenius parameters, E (kJ mol−1) and log (A/s), are: 161.3 and 16.00; 180.2 and 16.20; 168.4 and 16.00, respectively.

Kinetics of Oxidation of Organic Acids by Ammonium Nitrate

Kinetics of oxidation of some organic acids by ammonium nitrate was studied. Temperature dependences of the rate constants of acid oxidation were determined.

Kinetic regularities of the heat release during the reactions of aliphatic hydrocarbons with aqueous HNO3

The kinetics of the heat release during the reactions of aqueous HNO3 withn-heptane andn-octadecane was studied. The kinetic regularities of the reactions of hydrocarbons C7H16−C18H38 with HNO3 and the heats of the reactions were described. At all stages, except initial, the hydrocarbon reacts with NO2 and nitric acid reproduces NO2 in the reaction with NO. The accumulation of NO2 results in the acceleration of the process. When the pressure of the hydrocarbon vapor is equilibrium, its reaction with NO2 can also proceed in the gas phase. The contribution of this reaction to the total heat release was estimated. The additives of aromatic and unsaturated hydrocarbons to aliphatic hydrocarbons increase strongly the initial rate of the heat release and changes slightly the subsequent stages of the process. Naphthenic hydrocarbons have almost no effect on the kinetic parameters of the process.

Kinetics of heat release during the reaction ofn-decane with nitrogen dioxide in the liquid phase

The rates of heat release in the nitrogen dioxide—n-decane system at a molar ratio of nitrogen oxides ton-decane (β) from 2.4·10−3 to 3.1 and gaseous volumes per mole ofn-decane (V(g)) equal to 0.05–4.5 were studied in the 55.2–92.8 °C temperature range. The initial rate of the process is determined by the interaction of NO2 withn-decane. The equilibrium constants of dissociation of N2O4 inn-decane and Henrys constants of NO2 and N2O4 in ann-decane solution were determined by complex analysis of the thermodynamic equilibrium in the NO2—n-decane system and dependences of the initial rates onV(g) and β. The experimentally observed self-acceleration of the process in the region of high β and lowT values was suggested to be due to the reaction of N2O4 with intermediate oxidation products. The rate constants of the reaction of NO2 withn-decane were compared with analogous values determined in its mixtures with HNO3 solutions.

Control over phase transformations in the crystal lattice of ammonium nitrate by modification of the system of intermolecular interactions via addition of organic substances

Methods for phase stabilization of ammonium nitrate were sought for to substantially extend the application fields of this oxidizing agent in self-combustible formulations for various purposes, including the new generation of gas-generating formulations for automobile safety bags. The phase state of ammonium nitrate alloys with minor additions of organic substances with crystallographic parameters close to those of ammonium nitrate was studied.

Influence of γ-irradiation on the kinetics of heat release during the interaction of an aqueous solution of HNO3 with aliphatic hydrocarbons

The influence of preliminary γ-irradiation and γ-irradiation during hte oxidation process on the kinetics of heat release in the systemsn-decane—aqueous solution of HNO3 and a solution of tributyl phosphate in a kerosene—aqueous solution of HNO3 was studied. The preliminary γ-irradiation of the system at 43°C increases the initial rate of the process (k1). The increase is proportional to the irradiation dose at doses up to 150kGy, then the increase ink1 is retarded, and the further course of the process becomes practically independent of the irradiation dose. The effect of γ-irradiation during the oxidation depends on the temperature of the system: at temperatures lower than 80 °C, γ-irradiation increases the rate of heat release, whereas at higher temperatures, γ-irradiation decreases the rate of heat release. The effects observed were explained by the competition of NO2 accumulation due to the radiolysis of nitric acid and processes of the addition of NO2 to unsaturated hydrocarbons produced by the radiolysis of the organic phase.