Molecular Simulation and Theory of Reactions in Supercritical Fluid Mixtures: Ionic Association in Supercritical Aqueous Solutions

Molecular simulation is a powerful tool for understanding and predicting thermophysical properties in systems both at equilibrium and away from equilibrium and composed of molecules ranging in complexity from spherically symmetric monatomic molecules to polymers. In recent years, our research group has applied molecular simulation to the study of supercritical aqueous solutions with the goal of understanding the molecular mechanisms underlying their thermophysical properties, including the ionic association equilibrium. In this paper, we review our work in this area and present new results on the reaction rates for ionic association and dissociation. In addition, we describe a new formalism for understanding the state dependence of reaction equilibria in supercritical fluid mixtures. This is an extension of our formalism for understanding and predicting the thermodynamic properties of supercritical fluid mixtures.