Dynamic properties of methanol–water mixtures at the temperatures up to 476.2 K and at high pressures via molecular dynamics simulation

Abstract

Viscosities and self-diffusion coefficients of methanol–water mixtures were calculated via molecular dynamics simulation from 298.2 to 476.2 K and at pressures up to 40 MPa. The periodic perturbation method (non-equilibrium molecular dynamics) and the Green-Kubo method with three-site flexible potential models were adopted for evaluating the viscosities and the diffusion coefficients, respectively. The calculated viscosities and diffusion coefficients of methanol–water mixtures agreed qualitatively with literature experimental values. The three-site flexible potential models used in this study provided similar performance to the previous studies that used rigid models. Results correlated with the Stokes–Einstein relation show the possibility that the effective hydrodynamic radii were approximately constant for the studied condition and might be little affected by the clathrate-type structure at lower methanol compositions.