Study on the phase behaviour and thermodynamic properties of ionic liquids containing imidazolium cation with ethanol at several temperatures

Experimental densities, speeds of sound and refractive indices of the binary mixtures of ethanol with MMIM MeSO₄ (1,3-dimethylimidazolium methyl sulfate), BMIM MeSO₄ (1-butyl-3-methylimidazolium methyl sulfate), BMIM PF₆ (1-butyl-3-methylimidazolium hexafluorophosphate), HMIM PF₆ (1-hexyl-3-methylimidazolium hexafluorophosphate) and OMIM PF₆ (1-methyl-3-octylimidazolium hexafluorophosphate) were determined from T = (293.15 to 303.15) K. Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems were calculated. The (liquid + liquid) equilibrium (LLE) data of (IL + ethanol) were carried out experimentally and the NRTL and UNIQUAC correlative equation was applied to these mixtures.