Volumetric behavior and solution microstructure of methanol–water mixture in sub- and supercritical state via density measurement and MD simulation

Molecular Dynamics Simulation of Na+–Cl– Ion-Pair in Water–Methanol Mixtures under Supercritical and Ambient Conditions

“…The error bars in PMFs for all cases are found to be around 0.2–0.5 kJ/mol. We have used experimental densities of water–methanol binary mixtures. , The details of the chosen solvent mixtures are listed in Table and Table .…”

“…We have used experimental densities of water−methanol binary mixtures. 81,82 The details of the chosen solvent mixtures are listed in Table 1 and Table 2.…”

Insight into the Local Composition of the Wilson Equation at High Temperatures and Pressures through Molecular Simulations of Methanol–Water Mixtures

“…For example, ρ xm=0.2 is equal to 0.95 g•cm −3 at ambient, while ρ xm=0.2 is equal to 0.64 g•cm −3 at 300 °C−25 MPa and ρ xm=0.2 is equal to 0.48 g•cm −3 at 350 °C−25 MPa. 14,25,26 Therefore, we bring the following discussion assuming the Wilson parameters do not depend on pressure. First, the self-diffusion coefficients of methanol and water mixture were calculated from the time dependence of the mean square displacement using the Einstein relation 28 and compared with experimental data to confirm the reliability of our simulation results.…”

“…The temperature and pressure conditions in the simulation were three sets as ambient (25 °C–0.1 MPa), 300 °C–25 MPa, and 350 °C–25 MPa. The densities of the latter two conditions were evaluated from the measurement data in our group . Hence, the number densities ( N / V ) in the simulation were set to the experimentally determined densities to allow isobaric analysis at any given temperature. ,− Table shows the length of the box in this simulation.…”

“…In these decades, there have been many reports on the fundamental properties of subcritical and supercritical water and industrial applications. , Some experimental and theoretical approaches revealed the fact that hydrogen bonding still exists in sub- and supercritical water and methanol . Since the inhomogeneous structure attributed to hydrogen bonding is influenced by temperature and pressure, the solution structure of methanol–water mixtures is influenced by the effect of temperature and pressure, bringing about some unique features in physical properties of alcohol–water mixture at high temperature and pressure including sub- and supercritical conditions. − Our group has measured the density of the methanol–water mixture and performed MD simulations for understanding of the relationship between the macroscopic and microscopic properties at (300 to 400) °C, and at high pressures, and showed that volumetric behavior and solution structure changed dramatically with only the change of mole fraction at high temperatures. This interesting behavior is also related to the nonideality or inhomogeneity of a solution at high temperatures and pressures and induces a strong interest in how the inhomogeneous structure at high temperatures can be expressed in terms of local composition that is widely used in representing liquid phase nonideality.…”