To support assessment of the potential fate and effects of current and future energetic compounds, we have developed predictive models for their characteristic degradation pathways. We have reported our results on hydrolysis of nitroaromatic energetics (TNT and DNAN) previously. Here we summarize more recent results on reduction of aromatic nitro compounds, and oxidative polymerization of aromatic amines (formed by reduction of nitroaromatics). For the reduction pathway, a predictive model in the form of a free energy relationship (FER) based on the Marcus theory of outer-sphere electron transfer was developed. The FER relates the rate constant for NAC reduction to the free energy of the reaction, which was calculated from one-electron reduction potentials determined using molecular modeling. The FER accurately describes NAC reduction kinetics for non-energetic compounds. The model was found to accurately predict newly measured rate constants for TNT and 2,4-dinitrotoluene, although not for DNAN. For the oxidation of NAC reduction products (aromatic amines, AAs), we choose manganese oxide as the model oxidant. Rate constants for oxidation of model NACs by manganese dioxide were compiled from the literature, and new data for energetics-related AA’s were measured. Correlation analysis of these data was performed with descriptor data ranging from Hammett constants, to (calculated) pKa’s, to HOMO and one-electron oxidation potentials (both calculated and measured). The resulting correlations improve with increasing mechanistic specificity.

Prediction of environmental fate properties for novel munitions compounds

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.