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 and mechanism of nitration of cellulose with the HNO3-CH2Cl2 mixture

Complexing in the HNO₃-CH₂Cl₂ system was confirmed tensimetrically. The kinetics of nitration of wood cellulose by the HNO₃-CH₂Cl₂ mixture were investigated. A large part of the cellulose is nitrated in a first fast reaction in comparison to the HNO₃-H₂SO₄ mixture with the same concentration of HNO₃. The rate of the process is determined by the rate of diffusion of the HNO₃, the rate of the process decreases more rapidly in the case of HNO₃-CH₂Cl₂ than in the HNO₃-H₂SO₄ mixture, which is probably due to the effect of CH₂Cl₂ on the diffusion coefficient of HNO₃.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2445–2450, November, 1989.     

Kinetics of the thermal decomposition of dinitramide

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. For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 395–401 March 1998.     

Method of delivery of methane from seafloor deposits of solid hydrates to the surface

A model of the process of methane delivery from seafloor deposits of solid hydrates to the surface has been developed and approved. The model considers methane delivery through a vertical pipe lowered from the sea surface to the seafloor deposit. The model allows to determine important characteristics of the flow through the pipe—the possibility of stationary self-sustained flow of the medium to the surface; the gushing character of the flow; medium velocity, pressure, and composition distribution along the pipe—and thus to optimize the process of gas production.     

Lower concentration limit of carbon filtration combustion

For mixtures of carbon materials and an inert filler, dependences of the characteristics of the filtration combustion wave on the gaseous oxidizer supply rate at a fuel content in the mixture of less than 7 wt % were obtained. The existence of a lower concentration limit for a steady-state filtration combustion wave was established. It was demonstrated that at a given intensity of heat loss, the concentration limits are determined by the reactivity of the carbon material and the oxidizer supply rate. At the effective coefficient of heat loss α = 8 W/(m² K), effective conductivity of mixture material λ = 2 W/(m K), and air supply rate G = 0.1 m/s, the lowest fraction of carbon in the mixture at which combustion is still possible was 4.5 wt % for carbon-carbon composite, 2.5 wt % for activated birch coal, and 2.0 wt % for birch coal, the most reactive kind of carbon.     

Chain and monomolecular decomposition of hexogen in solutions

The decomposition of hexogen dissolved in alkylaromatic hydrocarbons, alcohols, ketones, ethers, chloroform, and some other solvents occurs via the chain mechanism. This mechanism is supported by slowing down of the reaction when inhibitors are added, the solvent deuterium kinetic isotope effect, and the dependence of the rate on the reactivity of the C—H bond in solvents. The chain reaction propagates through the transfer of a free valence from the primary N-radicals formed by N—NO₂ bond dissociation to the C-centered radicals of the solvent. The solvents are inert when the N—H bond dissociation energy is >380 or <200 kJ mol^–1, and hexogen decomposition in such solvents is monomolecular.