ERDC/EL TR-07-16, Photochemical Degradation of Composition B and Its Components

Products of photodecomposition of 2,4,6-trinitrotoluene (TNT) have been observed as a coating on TNT particles and as a fine powdered residue surrounding TNT particles on ranges receiving limited rainfall. The significance of photolysis of explosive formulations on training ranges is unknown. Therefore, photolysis of a common explosive formulation, Composition B, and its components in a soil matrix were evaluated. Objectives included determination of photolysis rates, effects of light intensity and duration, effects of moisture on photolysis, and identification of photolysis products. Irradiations were performed in laboratory microcosms under controlled conditions. Solutions, solids, and both solutions and solid explosives spiked into soils were irradiated. Two approaches were used to characterize products: liquid chromatography/mass spectrometry and a combination of solid and liquid state 13C and 15N nuclear magnetic resonance (NMR), and liquid state 1H NMR. Irradiation of TNT in the aqueous phase generated dramatically more photolysis products than were previously reported. The most prominent nitrogen-containing functional groups, exclusive of unreacted nitro groups, were azoxy, amide, nitrile, and azo nitrogens. Results suggest that Composition B photolysis, particularly the TNT component, generates a dynamic mixture of products and ions beginning on the solid surfaces before dissolution, and increasing once in solution phase. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/EL TR-07-16 iii