Thermodynamic Control on the Redox Fate of Nitroaromatic and Cylic Nitramine Explosives

Nitroaromatic and cyclic nitramine compounds are frequently encountered as energetic residues in live-fire military training ranges. Careful assessment on the redox fate of current and emerging explosives will allow accurate assessment of potential site risks and remediation strategies to protect the warfighter. This study employed the naturally-occurring reductant ferrous iron to investigate the factors controlling the rate and extent of electron transfer processes between the energetic residues and the environmental media. Reliable experimental and theoretical techniques were first established to accurately determine the one-electron reduction potentials of explosives, a thermodynamic measure indicative of the “reducibility” of a given explosive. Experimental studies employing ferrous iron and various iron-coordinating ligands suggested that kinetic factors such as the coordination environment of the metal ion reductant and surface catalysis must be considered, in addition to the thermodynamic parameter, to accurately predict the fate of energetic residues.