Journal of Chemical Thermodynamics, Vol.55, 138-143, 2012
Ethanol extraction from its azeotropic mixture with hexane employing different ionic liquids as solvents
In this work, the ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMim] [NTf2], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, [BMim][NTf2], 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl) imide, [BMpy][NTf2], 1-butyl-3-methylpyridinium trifluoromethanesulfonate, [BMpy][TfO], have been investigated for their use as solvents in extraction processes for the ethanol removal from its azeotropic mixture with hexane. Therefore, the experimental determination of the liquid + liquid equilibrium for the ternary systems {hexane (1) + ethanol (2) + [EMim][NTf2] (3)}, {hexane (1) + ethanol (2) + [BMim][NTf2] (3)}, {hexane (1) + ethanol (2) + [BMpy][NTf2] (3)} and {hexane (1) + ethanol (2) + [BMpy][TfO] (3)} was carried out at T = 298.15 K and atmospheric pressure. Classical parameters such as selectivity and solute distribution ratio, derived from the tie-line data, were calculated and afterwards, the structural influence of the ionic liquids on the extraction process was analyzed. Finally, the experimental LLE data were correlated by means of the NRTL and UNIQUAC models. (C) 2012 Elsevier Ltd. All rights reserved.