Role Of Additives In The Thermal-Decomposition Of Ammonium-Perchlorate And Evidence Supporting The Identification Of Nitryl Perchlorate As The Essential Reaction Intermediate

NO 2 ClO 4 was identified as the essential reaction intermediate in a recent study of the thermal decomposition of ammonium perchlorate (AP) (A.K. Galwey and M.A. Mohamed, Proc. R. Soc. London, Ser. A, 396 (1984) 425). Here, we report further measurements of the influences of selected additives on the same reaction; all the observations are consistent with, and provide support for, the earlier mechanistic conclusion. Attempts to introduce synthetic NO 2 ClO 4 directly on to the AP reactant resulted in no marked acceleration of reaction, an observation readily explained by the instability of the additive at reaction temperature (ca. 5 s lifetime) and its sensitivity to hydrolysis. In addition, the reaction rate of AP prepared with a low water content was greater than that of salt recrystallized from water, which can be explained by a lessening of the extent of hydrolysis of NO 2 ClO 4 . The effects of finely divided platinum metal and of lattice-incorporated CrO 2− 4 in promoting AP decomposition are identified with the abilities of these additives to oxidize ammonia. Lattice-incorporated sulphate and phosphate ions exhibited little or no influence on the AP decomposition rate.