In this work, viscosities, densities, and speeds of sound of three binary mixtures containing the ionic liquids 1-ethyl-3methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][NTf 2 ], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim]-[NTf 2 ], and 1-hexyl-3-methylimidazo-lium bis(trifluoromethylsulfonyl)imide, [hmim][NTf 2 ], mixed with ethanol were measured at atmospheric pressure in the range of (278.15 to 338.15) K, covering the entire range of compositions. From these experimental data, the excess isentropic compressibility and molar isentropic compressibility of pure components and mixtures have been calculated. Additionally, excess properties, such as viscosity deviation, excess molar volume, excess isentropic compressibility, and excess molar isentropic compressibility, have been calculated and fitted with the Redlich−Kister polynomial equation.

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The heterogeneous azeotropic distillation process is widely used to separate nonideal binary mixtures into their constituent pure components. This method uses the addition of a third component, called an entrainer, to cause liquid−liquid phase separation over a broad range of compositions in the ternary phase diagram. Ethanol dehydration was used as a case study and diisopropyl ether and isobutyl alcohol were analyzed as possible entrainers in a heterogeneous azeotropic distillation. In this way, isobaric vapor−liquid−liquid equilibrium was measured for the ethanol + water + diisopropyl ether or + isobutyl alcohol ternary mixtures at 101.3 kPa. The data were correlated by the NRTL and UNIQUAC models, and a set of parameters for each model was obtained. A separation sequence for ethanol dehydration using diisopropyl ether was proposed. The simulation of the separation sequence was carried out satisfactorily by commercial software (Aspen Hysys) using the thermodynamic model UNIQUAC with the binary parameters obtained in this study.

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