Estimation of transport properties and phase equilibrium of water or ethanol binary mixtures with ionic liquids

Abstract

Density and viscosity of two trifluoromethanesulfonate-based ionic liquids: 1-ethylimidazolium trifluoromethanesulfonate, [Eim][Triflate], and 1-ethylpyridinium trifluoromethanesulfonate, [Epy][Triflate], as well as binary mixtures of these ILs with water or ethanol were measured within the temperature range of 293.15–333.15 K. Measured density data were used to calculate the excess molar volume and the component partial molar volume and the obtained values were fitted using the Redlich-Kister expansion. Variation of viscosity with the binary mixture composition and temperature was modeled using the Jouyban-Acree model. Data on the vapor − liquid equilibrium (VLE) of the respective ionic liquids with water and ethanol were estimated at atmospheric pressure over a wide range of IL concentrations (up to 70 mol% of IL). For the boiling point temperature measurement of four respective binaries, an adapted Siwoloboff procedure was used. To describe VLE of these binary mixtures, ideal vapor phase and real liquid phase behavior were assumed; experimental isobaric t–x data were correlated with the NRTL model.