Vapor-liquid interfacial properties of binary mixtures from molecular
simulation and density gradient theory
Abstract
Properties of the vapor-liquid interface of 16 binary mixtures were
studied using molecular dynamics simulations and density gradient theory
in combination with the PCP-SAFT equation of state. All binary
combinations of the heavy-boiling components (cyclohexane, toluene,
acetone, and carbon tetrachloride) with the light-boiling components
(methane, carbon dioxide, hydrogen chloride, and nitrogen) were
investigated at 0.7 times the critical temperature of the heavy-boiling
component in the whole composition range. Data on the surface tension,
the enrichment, the relative adsorption, and the interfacial thickness,
as well as for the vapor-liquid equilibrium and Henry’s law constant are
reported. The binary interaction parameters were fitted to experimental
data in a consistent way for all systems and both methods. Overall, the
results from both methods agree well for all investigated properties.
The interfacial properties of the different studied systems differ
strongly. We show that these differences are directly related to the
underlying phase equilibrium behavior.