Thermal decomposition of ammonium perchlorate

This review represents an attempt to summarize literature data on thermal decomposition of ammonium perchlorate. The mechanism of thermal decomposition and various factors which influence on the thermal decomposition of ammonium perchlorate are discussed.     

Thermal decomposition of methylammonium perchlorate

The thermal decomposition of methylammonium perchlorate (MAP) has been studied under isothermal and non-isothermal conditions. Differential thermal analysis of MAP showed, in addition to the exotherm due to decomposition, another exotherm at 408° which was observed for the first time. Chemical analysis and the infrared spectrum of the residue left behind after the decomposition proved it to contain NH₄ClO₄. The results have been explained on the basis of a methyl group transfer in addition to proton transfer in the decomposition process.     

Kinetics of ammonium perchlorate decomposition

The kinetic law of ammonium perchlorate decomposition in the presence and absence of metal oxides has been studied. Sublimation has also been considered from the kinetic point of view.

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Effect of tetramethylammonium perchlorate on ammonium perchlorate and propellant decomposition

The thermal decomposition of ammonium perchlorate (AP) is considerably modified when it is cocrystallized or mixed with small amounts of tetramethyl- ammonium perchlorate. The decomposition is sensitized when tetramethylphosphonium perchlorate is added to AP. The effect on the isothermal decomposition of AP when it is mixed with tetramethylammonium perchlorate, appears to be similar to that of AP-based composite propellant having the same mixed AP composition.     

Thermal decomposition of doped ammonium perchlorate

Isothermal decomposition of orthorhombic ammonium perchlorate (AP) has been studied as a function of concentration of the dopants, SO ₄ ^2– and PO ₄ ^3– . In either case, the rate of decomposition passes through a maximum as the dopant concentration increases. Activation energy of the decomposition process remains unaltered by doping. The results are interpreted in terms of electron transfer mechanism.

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Zusammenfassung Die isotherme Zersetzung von orthorhombischen Ammoniumperchlorat (AP) wurde in Abhängigkeit von der Konzentration der Dopanten SO ₄ ^2– und PO ₄ ^3– untersucht. In jedem Falle geht die Geschwindigkeit der Zersetzung mit steigender Dopantenkonzentration durch ein Maximum. Die Aktivierungsenergie des Zersetzungsprozesses wird durch dopen nicht verändert. Die Ergebnisse werden auf einem Elektronentransfer-Mechanismus basierend interpretiert.

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The author is thankful to Dr. V. R. Pai Verneker of Indian Institute of Science, Bangalore, for stimulating discussions.     

Ferrocene-modified dendrimers as support of copper nanoparticles: evaluation of the catalytic activity for the decomposition of ammonium perchlorate

Ferrocene (Fc)-based systems are frequently used as burning rate catalysts in the decomposition of ammonium perchlorate (AP)-based propellants. However, small Fc derivatives migrate to the surface of the propellant resulting in undesirable changes in the designed burning parameters and unstable combustion. To retard the migration and to increase the combustion rate of AP, fourth-generation polyamidoamine (PAMAM) dendrimers modified with Fc (PAMAM generation 4 [G4]-Fc) were synthetized and used as support for the obtention of copper nanoparticles (CuNPs). PAMAM G4 produced smaller nanoparticles (1–2 nm) with lower aggregation than PAMAM G4-Fc (12–14 nm). X-ray photoelectron spectroscopy (XPS) characterization confirmed the superior stabilizing and protecting effect against oxidation of CuNPs by PAMAM G4 in comparison to PAMAM G4-Fc, whereas molecular dynamics simulations have shown less flexibility and lower presence of stabilizing sites for nanoparticles in PAMAM G4-Fc. Antimigration tests confirmed the negligible migration of PAMAM G4-Fc compared with Fc, whereas PAMAM G4-Fc|CuNP affected the high-temperature decomposition of AP positively, decreasing the decomposition temperature in 87 °C owing to a synergistic effect between CuNPs and Fc. PAMAM G4-Fc can act both as an effective antimigration system of Fc and as a stabilizing framework of metal nanoparticles with application as catalysts of AP.     

The thermal decomposition of doped ammonium perchlorate

The thermal decomposition of ammonium perchlorate doped with Cu²⁺, Mn²⁺, Co²⁺ and Fe³⁺ (with and without H⁺) was studied using DTA and TG. Small concentrations of these ions inhibit the decomposition by eliminating the first exothermic peak. At higher concentrations, a catalyzed decomposition is observed. Either the influence of the doping ions on the mechanism of the thermal decomposition is different from that of added oxides or a modification of the electron transfer mechanism is needed.     

Thermal decomposition of ammonium perchlorate single crystals

The thermal decomposition of large single crystals of pure ammonium perchlorate and ammonium perchlorate doped with Ba2⁺ or SO^2?₄ ions has been investigated over the temperature range 220–290°C. Comparative studies were also made with compressed pellets of the pure powder and with small single crystals containing macroscopic flaws. The kinetic results were analyzed using a computer technique which permits a very detailed examination of various kinetic models. This reveals that the “induction period” (α < ～ 0.01) is very complex and comprises a desorption step, a linear process, an exponential process, and the beginnings of an Avrami process. The latter three processes are identified with (i) the inward growth of rapidly formed surface nuclei, (ii) “branching” of surface nuclei, and (iii) nucleation in the bulk crystal. Kinetic parameters are obtained for these three processes and also for the growth of nuclei in the bulk crystal. This model fits the kinetic data over the complete range of α(0–1), or 1 × 10^?5 < α < 1 if the desorption step is not included. The mechanism of the reaction and possible effects on this of Ba²⁺ and SO^2?₄ doping are discussed briefly.     

Effect of electric field on ammonium perchlorate decomposition

A novel method of detecting the charge-carrying species in inorganic decomposable salts is described. In ammonium perchlorate it is observed that the charge-carrying species at temperatures 150 and 230°C are oppositely charged; i.e., they are negatively charged (ClO^?₄ ions) at 230°C and positively charged (H⁺ or NH⁺₄) at 150°C.     

Thermal decomposition of cerium(III) perchlorate

Thermal decomposition of Ce(ClO₄)₃ ? 9H₂O and Ce(ClO₄)₃ to give cerium(IV) dioxide in the temperature range 240–460°C was studied by DSC–TGA, X-ray powder diffraction, IR and mass spectroscopy. The thermolysis of these salts was shown to proceed through the stage of formation of intermediate product supposedly cerium oxoperchlorate. The thermal decomposition of cerium(III) perchlorate hydrate at 460°C leads to formation of nanocrystalline cerium dioxide with particle size of 13 nm.     

CuO nanocrystals in thermal decomposition of ammonium perchlorate

CuO nanocrystals of different surface areas were prepared. All samples were characterized by X-ray diffraction, transition electron microscope, thermogravimetry, Brunauer-Emmett-Teller technique, Fourier transform infrared spectroscopy, and Raman spectroscopy. CuO nanocrystals showed a stable monoclinic structure. With increasing surface areas, the surface hydration became significant, which is followed by shifts in infrared frequencies and Raman phonon modes. CuO nanocrystals were explored as an additive to catalytic decomposition of ammonium perchlorate (AP). AP decomposition underwent a two-stage process. Addition of CuO nanocrystals led to a downshift of high-temperature stage towards lower temperatures.     

Radiation effects on thermal decomposition of ammonium perchlorate

Thermal decomposition of -irradiated (dose: 0–3.6 MGy) ammonium perchlorate was followed. The dynamic heating (range: 100–220 °C) and IR spectral measurements were carried out simultaneously. Temperature and dose brought a lowering in peak intensity of NH ₄ ⁺ and C10 ₄ ^– ions. Radiolytic products C10₃ and NH₃ are considered to initiate the decomposition process.     

Insight into the catalytic thermal decomposition mechanism of ammonium perchlorate

Journal of Thermal Analysis and Calorimetry -     

Effects of different additives on the thermal decomposition of ammonium perchlorate

IR spectral investigations on ammonium perchlorate (AP) in the presence of varying amounts of ammonium permanganate (APm) and 2% by weight of different rare earth oxide additives were made over the temperature range 25–290°. Heating and spectral scanning were done simultaneously and the peak intensity was presumed to be proportional to the amount of undecomposed AP. Presence of 10% APm lowered the temperature of AP decomposition from 200 to 110° and increased the rate by several folds. Mixed oxide produced as a result of deflagration of APm are considered catalyzing the process. In the presence of rare earth oxides additives, the NH ₄ ⁺ stretching peak intensity decreased considerably, the extent followed the trend Gd₂O₃ > MnO₂ > Nd₂O₃ > Pr₂O₃ > Dy₂O₃ > Y₂O₃ > La₂O₃ > virgin AP. An electron transfer mechanism is envisaged to explain the results.     

Thermal decomposition of ammonium perchlorate in the presence of bimetallic additives

The catalytic activity of the thermolysis products of double complex compounds in the decomposition reaction of ammonium perchlorate was studied. The products used are C_1.4N_1.6H₃CoFe (I), C₆N₈Co₄Fe₃ (II), O₁₁Co₄Fe₃ (III), O_8.5(CN)_0.3Cu₃Fe₂ (IV), and reactive CuO. All active phases decrease the temperature of complete decomposition of NH₄ClO₄, and the order of temperature decreasing is the following: I ≈ II (120 °C) > IV > III (80 °C) ? CuO.