Properties of Methanol-Water Mixtures in a Coarse-Grained Model

Abstract

Methanol and water rank among the most important liquids in modern world due to their versatile use. As water, methanol and their mixture exhibit numerous anomalous properties, their description is challenging. Amphiphilic nature of methanol causes its aqueous solutions to have negative excess volume and enthalpy across entire composition range. Simple isotropic water model and its coarse-grained extension were used to study properties of methanol and water-methanol mixtures. Using Monte Carlo simulations, we showed that the model correctly describes the thermodynamic properties of methanol, ordering of water and methanol in mixtures, density dependence upon temperature and composition, and excess properties of mixtures. Although no conscious effort was made to fine-tune the potential, the results are remarkably close to experimental data.