Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Activity coefficients at infinite dilution (c1 i ) and (gas liquid) partition coefficients (KL) for organic compounds (alkanes, alkenes, alkyl benzenes, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, 1,4- dioxane, chloromethanes, and alcohols) and water in the ionic liquid (IL) 1-butyl-3-methylimidazolium perchlorate ([BMIM][ClO4]) have been measured by the (gas-liquid) chromatographic method in the temperature range of (303.15 353.15) K. Density, q as a function of temperature for [BMIM][ClO4] at pressure p = 101.3 kPa were measured. The values of the partial molar excess enthalpies at infinite dilution ( HE;1 i ) were derived from the temperature dependence of the c1 i values. The entropies (Tref SE;1 i ) and Gibbs free energies ( GE;1 i ) of organic solutes in [BMIM][ClO4] at a reference temperature Tref = 298.15 K were also calculated from the c1 i values. The Hildebrand s solubility parameters of the IL [BMIM][ClO4] were also determined by the regular solution theory (RST) combined with Flory combinatorial equation. Selectivity (S1 ij ) and capacity (k1 j ) at infinite dilution at 323.15 K have been determined for nhexane (i)/benzene (j), cyclohexane (i)/benzene (j)). The results were analyzed in comparison to literature values for 1-buthyl-3-methylimidazolium-based ionic liquids (ILs) for the same separation problems. For three isomeric xylenes separation problems, selectivity at 323.15 K were also obtained from the c1 i values.