Predicting Solubility of Military, Homemade, and Green Explosives in Pure and Saline Water using COSMO‐RS

Abstract

AbstractThe conductor‐like screening model for real solvents (COSMO‐RS) has previously been shown to give accurate aqueous solubilities for a range of organic compounds using only quantum chemical simulation data. Application of this method for solid organic explosives, however, faces two difficulties; it requires correction for the free energy of fusion (a generally unknown quantity for these compounds) and it shows considerable error for common explosive classes such as nitramines. Herein we introduce a correction factor for COSMO‐RS that is applicable to a wide range of explosives, and requires no data beyond a quantum chemistry calculation. This modification allows COSMO‐RS to be used as a predictive tool for new proposed explosives or for systems lacking experimental data. We use this method to predict the temperature‐dependent solubility of solid explosives in pure and saline water to an average accuracy of approximately 0.25 log units at ambient temperature. Setschenow (salting‐out) coefficients predicted by this method show considerable improvement over previous COSMO‐RS results, but are still slightly overestimated compared to the limited experimental data available. We apply this method to a range of military, homemade, and “green” explosives that lack experimental seawater solubility data, an important property for environmental fate and transport modeling.