Thermal decomposition of ammonium perchlorate

The methods of thermogravimetric analysis (TGA) and differential scanning calorimettry (DSC) have been used to study the thermal decomposition of ammonium perchlorate (AP). TGA curves obtained under both isothermal and nonisothermal conditions show a characteristic slowdown at the extents of conversion, α = 0.30−0.35. DSC demonstrates that in this region the process changes from an exothermic to an endothermic regime. The latter is ascribed to dissociative sublimation of AP. A new computational technique (advanced isoconversional method) has been used to determine the dependence of the effective activation energy (Eα) on α for isothermal and nonisothermal TGA data. At α > 0.1, the Eα dependencies obtained from isothermal and nonisothermal data are similar. By the completion of decomposition (α → 1) the activation energy for the isothermal and nonisothermal decomposition respectively rises to ∼110 and ∼130 kJ mol-1, which are assigned to the activation energy of sublimation. The initial decomposition (α → ...

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Kinetics of Thermal Decomposition of Cubic Ammonium Perchlorate

This volume brings together international scientists in the field of solid rocket propulsion. Thirty-nine papers present in-depth coverage on a wide range of topics including: advanced materials and non-traditional formulations; the chemical aspects of organic and inorganic components in relation to decomposition mechanisms, kinetics, combustion and modelling; safety issues, hazards and explosive characteristics; and experimental and computational interior ballistics research, including chemical information and the physics of the complex flow field.

Solid propellant chemistry, combustion, and motor interior ballistics

Mechanism of the decomposition of ammonium perchlorate

Development of metal-free and environmentally friendly catalysts is of great significance for thermal decomposition of ammonium perchlorate (AP). In the present study, graphitic carbon nitride (g-C3N4) has been demonstrated to possess intrinsic catalytic activity for thermal decomposition of AP. Adding 10 wt% g-C3N4 to AP decreases the decomposition temperature by 70 °C and the activation energy (Ea) by 119.8 kJ mol−1. Moreover, the apparent decomposition heat of AP in the presence of 10 wt% g-C3N4 reaches up to 1362.6 J g−1, which is much higher than that of the pure AP (574.2 J g−1). Furthermore, a possible catalytic mechanism for the thermal decomposition of AP with g-C3N4 has been proposed. The unique surface structure of g-C3N4 consisting of triazine units connected by planar amino groups can be favourable for the adsorption and diffusion of perchloric acid via Lewis acid–base interactions, which decreases the reaction activation energy of AP and facilitates the formation of superoxide radical anions (˙O2−) and holes (h+), leading to the oxidation reaction of ammonia more completely in the catalytic decomposition of AP.

Anthony Russell-Jones

Papers

Sublimation of ammonium perchlorate