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

Methanol and water rank among the most important liquids in modern world due to their versatile use. As water, methanol and their mixtures exhibit numerous anomalous properties, their description is challenging. The amphiphilic nature of methanol causes its aqueous solutions to have negative excess volume and enthalpy across the entire composition range. A simple isotropic water model and its coarse-grained extension were used to study the properties of methanol and water-methanol mixtures. Using Monte Carlo simulations, we showed that the model correctly describes the thermodynamic properties of methanol, density dependence of water-methanol mixtures 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.