Yu-ichiro Izato,* [a] Atsumi Miyake, [a] and Shingo Date [b] burning rates. Heat characteristic examinations found a similar trend. The burning rate of AN/AC mixed with CuO as a combustion catalyst deteriorated faster than an additivefree one. From the DSC result, AN/AC/CuO had a higher onset temperature and a lower heat of reaction than AN/ AC. These results suggested that, in the combustion wave of AN/C, a thermal decomposition zone is formed on the burning surface, and combustion performance was affected by the thermal decomposition of AN/C.

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The thermal decomposition of ammonium nitrate (AN) and potassium chloride (KCl) mixtures was investigated. The thermal properties were studied using differential scanning calorimetry (DSC), and the evolved gas was analyzed using thermogravimetry with mass spectrometry and pressurized DSC coupled with mass spectrometry (TG-DTA-MS and PDSC-MS). DSC measurements of AN/KCl mixtures in sealed and sealedseparated sample pans showed a sharp exothermic decomposition and lower onset temperature than pure AN, whereas AN/KCl in an open pan exhibited an endothermic reaction. In the sealed-separated pan, a separator with a pinhole divided the KCl and AN physically and the evolved gas could interact with both AN and KCl. TG-DTA-MS results revealed that HCl gas was evolved from AN/KCl, which indicated that the reaction of KCl with HNO 3 dissociated from AN formed HCl, and subsequent destabilization of AN. However, the TG-DTA-MS results did not indicate the violent exothermic reaction due to using an open pan and ordinary pressure conditions. PDSC-MS was used to observe two exothermic reactions of AN/KCl and analyze the evolved gases from the reactions. A violent first exothermic reaction was accompanied by a large amount of N 2 and N 2 O gases without H 2 O, and a second exothermic reaction accompanied by H 2 O, N 2 O, and other gases occurred subsequently. The reactions are HCl þ HNO 3 ! NO 2 Cl þ H 2 O ! Cl þ NO 2 þ H 2 O, which have a lower energy barrier by 103 kJ mol -1 than the energy barrier that is needed for HNO 3 homolysis cleavage, which is triggered by pure AN decomposition, HNO 3 ! OH þ NO 2 . We therefore concluded that AN reacts with KCl to produce Cl radicals via HCl and NO 2 Cl, and the Cl radical triggers a radical chain reaction of AN.

This work analyzed the thermal decomposition of ammonium nitrate (AN) in the liquid phase, using computations based on quantum mechanics to confirm the identity of the products observed in past experimental studies. During these ab initio calculations, the CBS-QB3//ωB97XD/6-311++G(d,p) method was employed. It was found that one of the most reasonable reaction pathways is HNO 3 + NH 4 + → NH 3 NO 2 + + H 2 O followed by NH 3 NO 2 + + NO 3 -→ NH 2 NO 2 + HNO 3 . In the case in which HNO 3 accumulates in the molten AN, alternate reactions producing NH 2 NO 2 are HNO 3 + HNO 3 → N 2 O 5 + H 2 O and subsequently N 2 O 5 + NH 4 + → NH 2 NO 2 + H 2 O. In both scenarios, HNO 3 plays the role of a catalyst and the overall reaction can be written as NH 4 + + NO 3 -(AN) → NH 2 NO 2 + H 2 O. Although the unimolecular decomposition of NH 2 NO 2 is thermodynamically unfavorable, water and bases both promote the decomposition of this molecule to N 2 O and H 2 O. Thus AN thermal decomposition in the liquid phase can be summarized as NH 4 + + NO 3 -(AN) → N 2 O