Activity coefficients at infinite dilution for various organic solutes in the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium hexafluorophosphate

Abstract

Activity coefficients at infinite dilution (γi∞) for a variety of polar and non-polar organic solutes (alkanes, cycloalkanes, alkenes, alkyl benzenes, alcohols, 1,4-dioxane, acetone, acetonitrile, tetrahydrofuran, chloroform and dichloromethane) in the ionic liquid (IL) 1-(2-hydroxyethyl)-3-methylimidazolium hexafluorophosphate ([C2OHmim][PF6]) have been determined by gas-liquid chromatography using the IL as the stationary phase. The measurements were conducted over the temperature range of 303–353 K. The partial molar excess Gibbs energies (ΔGiE,∞), enthalpies (ΔHiE,∞) and entropies (ΔSiE,∞) at infinite dilution of the 29 solutes in the IL have been calculated from the experimental γi∞ values obtained over the temperature range. The selectivity sij∞ and capacity kj∞ at T = 323.15 K for aliphatic/aromatic hydrocarbons and aliphatic/alcohol separation problems were calculated from the γi∞ and compared to the reported literature data for other [C2OHmim] based ILs.