Borohydride Catalysis of Nitramine Thermal Decomposition and Combustion. 3.Literature Review and Wrap-Up Discussion of Possible Chemical Mechanisms

摘要

This report is a summary of observations and possible chemical mechanisms forcatalysis of the decomposition and combustion of the nitramines HMX and RDX, and of propellants derived from them, by salts containing these anions is reviewed, as is available information on the effects of these salts on decomposition and combustion of HMX and RDX. The emphasis is on thermal decomposition and on salts with alkali metal anions. The pure salts appear stable under vacuum or inert gas to about 700-800 C, but there is a report of H2 evolution lower temperatures (ca 300-600 C, depending on the nature of the salt) is observed. When the salts are heated together with RDX, considerable enhancement of the decomposition rate of RDX is observed; this begins at the melting temperature of pure RDX and becomes intense, leading to a lower, mush sharper decomposition exotherm. These observations seem consistent with a catalysis mechanism involving attack of the B-H hydrogens of the catalyst on the nitramine, but it is difficult to evaluate the role of other processes, and of reaction of the catalyst with products. Keywords: RDX, HMX, Nitramines, Borohydrides, Boron hydrides, Catalysis mechanisms, Catalysis, Propellants, Explosives, Thermal decomposition, Gun propellants, VHBR Propellants. (jes)