Abstract

--- - Vapor-liquid equilibrium (VLE) and surface tension (ST) for the hexane + ethanol + cyclopentyl methyl ether mixture have been measured and modeled. VLE determinations are carried out in a dynamic Guillespie type cell at the isobaric condition of 94 kPa, whereas the dependence of ST on concentration is measured in a maximum differential bubble pressure tensiometer at atmospheric pressure and 298.15 K. - The thermodynamical consistent VLE data exhibit positive deviation from ideal behavior without ternary azeotropy and are well correlated by Redlich-Kister expansion and predicted by the binary nonrandom two-liquid, Wilson and universal quasichemical activity coefficient models. The ST data exhibit negative deviation from the linear behavior and are smoothed using the Myers-Scott expansion, showing no ternary aneotropic behavior. - The experimental data of VLE and ST are accurately characterized by applying the square gradient theory to the Peng-Robinson Stryjek-Vera equation of state (EoS) appropriately extended to mixtures employing the modified Huron-Vidal mixing rule. This theoretical framework shows that experimental VLE and ST data can be fully predicted by only using binary contributions within a global average absolute deviation of 1.25% for VLE and 6.1% for ST. The theoretical approach also provides a route to explore the concentration distribution of species in the interfacial region, where it is possible to conclude that hexane exhibits both adsorption and desorption; ethanol displays strong positive adsorption whereas CPME does not exhibit surface activity.