Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The activity coefficients at infinite dilution (gammai(infinity)), gas-liquid partition coefficients (KL) of organic solutes (n-alkanes, alkenes, alkyl benzenes, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, chloromethanes, alcohols and 1,4-dioxane) in the ionic liquid 1-Hexyl-2,3-dimethylimidazolium tetrafluoroborate ([HMMIM][BF4]) have been measured using the gas-liquid chromatographic method (GLC) at five temperatures: 313.15 K, 323.15 K, 333.15 K, 343.15 K, 353.15 K. The density of [HMMIM][BF4], as a function of temperature, was determined in atmosphere. The values of the partial molar excess enthalpies at infinite dilution (H-iE,(infinity)) were derived from the temperature dependence of the In gammai(infinity) values. The entropies (TrefS-iE,(infinity)) and Gibbs energies (G-iE,(infinity)) of organic solutes in [HMMIM][BF4] at a reference temperature Tref = 298.15 K were calculated from the gammai(infinity) values. The Hildebrand's solubility parameters of the IL [HMMIM][BF4] were determined by the regular solution theory (RST) combined with Flory ''combinatorial'' equation. Selectivity (Sij(infinity)) and capacity (kj(infinity)) at infinite dilution at 323.15 K have been determined for n-hexane (i)/benzene (j), cyclohexane (i)/benzene (j). The results were analyzed in comparison to literature data for alkylimidazolium ionic liquids (ILs) with [BF4]-. The interaction between the IL and the individual solutes can be disclosed by the linear free energy relationship (LFER) analysis.