Liquid-liquid equilibria for ternary mixtures of 1-alkyl-3-methyl imidazolium bis{(trifluoromethyl)sulfonyl}imides, n-hexane and organic compounds at 303.15 K and 0.1 MPa

Highlights: • LLE data of ternary systems involving an IL were determined at 303.15 K and 0.1 MPa. • The selectivity values decrease with an increase in the alkyl chain length of the cation of the IL. • The solute distribution ratio remains of the same magnitude order for the cations studied. • Experimental data were well correlated with the Non-Random Two-Liquid model. • ILs can be used in selective extraction such as in reactors of supported liquid membranes. - Abstract: Ternary liquid-liquid equilibria were experimentally determined for eight systems composed of an ionic liquid + n-hexane + an organic compound implicated in the racemic resolution of rac-2-pentanol (rac-2-pentanol, vinyl butyrate, rac-2-pentyl butyrate or butyric acid) at a temperature of 303.15 K and pressure of 0.1 MPa. The following ionic liquids were used: 1-ethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [emim⁺][NTf₂⁻], and 1-hexyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [hmim⁺][NTf₂⁻]. The binodal curves and the tie line of the conjugate phases compositions were determined through measurement of the refractive index for the ionic liquid-rich phase and by using gas chromatography for the hexane-rich phase, enabling their potential to be assessed for selective extraction of organic compounds from a mixture of ionic liquid reaction media for the resolution of rac-2-pentanol. Liquid phase activity coefficients were calculated using the Non-Random Two-Liquid equation and the tie line theoretical data calculated from the model are in good agreement with the experimental data. As yet, the literature contains no data for the systems studied in this paper.