Determination of Dimethyl, Diethyl, and Dibutyl Phthalates in Small Arms Double-Base Propellants by Gas Chromatography

Abstract

Abstract : Rapid and accurate methods are proposed for the determination of dimethyl, diethyl, and dibutyl phthalates in small arms double-base propellants by gas chromatography. The phthalates are extracted from the propellant with methylene chloride and an aliquot is passed through a silicone rubber SE-30 column at a temperature of 200C for dimethyl and diethyl phthalates and 230C for dibutyl phthalate. Triacetin is used as the internal standard in the determination of dimethyl and diethyl phthalates, while dimethyl sebacate is used as the internal standard in the determination of dibutyl phthalate. None of the compounds found in ordinary small arms propellants interferes with the methods. Diphenylamine produces a peak that would interfere. However, it was found that the nitroglycerin usually present in small-arms propellants containing phthalates decomposes in the injector and the column and nitrates the diphenylamine and in this manner eliminates the interference from diphenylamine. (Author)