A study on the liquid-liquid equilibria of 1-alkyl-3-methylimidazolium hexafluorophosphate with ethanol and alkanes

This work demonstrates the ability of the 1-alkyl-3-methylimidazolium hexafluorophosphate to act as an extraction solvent in petrochemical processes for the removal of alkanes from their azeotropic mixture with ethanol. LLE (liquid-liquid equilibrium) of the ternary systems hexane + ethanol + 1-hexyl-3-methylinlidazolium hexafluorophosphate (HMIM PF6) or 1-octyl-3-methylimidazolium hexafluorophosphate (OMIM PF6) and heptane + ethanol + OMIM PF6, are carried out at 298.15 K and atmospheric pressure. Experimental liquid-liquid data are correlated by using different equations. The solute distribution ratio and the selectivity, determined from tie-line data, suggest the efficiency of the ILs used as solvents. A comparison with other IL, in terms of solvent capacity, is included. The liquid-liquid extraction process is simulated by using conventional software and the obtained results are shown. (C) 2008 Elsevier B.V. All rights reserved.