Phase Equilibria of the Azeotropic Mixture Hexane + Ethyl Acetate with Ionic Liquids at 298.15 K

This work reports the results of a study on the use of the two ionic liquids as an extraction solvent in the separation of the azeotropic mixture of hexane with ethyl acetate. Experimental densities, speeds of sound, and refractive indices of the binary mixtures of ethyl acetate + hexane or + 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIM PF 6 ) were determined from (293.15 to 303.15) K, since they are necessary to determine liquid−liquid equilibria. Excess molar volumes, changes of refractive index on mixing, and deviations in isentropic compressibility for the above systems were calculated. Liquid−liquid equilibria (LLE) were determined for the ternary systems hexane + ethyl acetate + HMIM PF 6 or 1-octyl-3-methylimidazolium hexafluorophosphate (OMIM PF 6 ) at 298.15 K and atmospheric pressure. The values of selectivity and distribution ratio were derived from the tie-line data. Experimental liquid−liquid equilibria data were correlated with the NRTL and UNIQUAC equations. These equations were verified to accurately correlate the experimental data.