NPT-MC simulations of enhanced solubility of RDX in polar-modified supercritical CO2

Isothermal-isobaric Monte Carlo (NPT-MC) simulations and the Widom test particle method were used to explore the degree of enhancement of solubility of the explosive 1,3,5-trinitro-s-triazine (RDX) in supercritical CO2 in the presence of small amounts of polar modifiers. Solubilities of RDX in supercritical CO2 mixtures containing DMSO, CH3CN or CH3OH were calculated and compared to results of RDX solubilities in pure supercritical CO2. The effect of dipole moment, concentration, temperature, pressure, RDX–modifier interaction strength, and effective size of the modifiers on the degree of solubility enhancement were explored. Results suggest that solubility is sensitive to the combined effects of dipole moment, concentration of the modifier, RDX–modifier interaction strength and effective size.