Molecular simulation study of solvation structure in supercritical aqueous solutions

We report new molecular dynamics simulations of aqueous solutions that consist of various solutes (xenon, NaCl, benzene, toluene, and benzonitrile) at infinite dilution in supercritical water at two thermodynamic states: one at the critical density and at 5% above the critical temperature, the other at 50% above the critical density and along the critical isotherm. These new simulations complement our previous simulations of infinitely dilute supercritical aqueous solutions of argon, Na +, Cl −, and methanol at the same state points. The aim of this work is to determine the solvation structure around various solutes in supercritical water with the goal of developing a molecular understanding of the solubility of nonpolar noble gases, ionic fluids and organics in supercritical water. Such an understanding can provide important insight into fundamental aspects of supercritical water oxidation of organic wastes. In addition, we report thermodynamic properties and solute—solvent structural quantities for the various solutes.