Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Information on the interactions between ionic liquids and molecular solvents are essential for the understanding of the function of ionic liquids in related procedures, and excess properties are sensitive probe for these interactions. In this work, excess molar volume and excess logarithmic viscosity for the binary mixtures of 1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4]) with butanone, ethyl acetate, butylamine, and tetrahydrofuran have been determined from density and viscosity measurements in the whole composition range at the temperature of 298.15 K. It is found that for the studied systems, the values of excess molar volume are negative but those of excess logarithmic viscosity are positive in the whole concentration range. The excess molar volume values show their minimum at the ionic liquid mole fraction of 0.3, and excess logarithmic viscosity values exhibit a maximum at the same composition. The absolute values of excess molar volume follow the sequence: tetrahydrofuran greater than butanone greater than ethyl acetate greater than butylamine for the binary systems, whereas the values of excess logarithmic viscosity decrease in the order: tetrahydrofuran greater than butylamine greater than ethyl acetate greater than butanone. The results have been analyzed through the ion-dipole interaction, the hydrogen bonding, the packing efficiency and the ion-pairs exist in the ionic liquid.