Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Densities and electrical conductances of amino acids, glycine, l-alanine and l-valine in aqueous ionic liquid, 1-hexyl-3-methylimidazolium bromide ([HMIm]Br) solutions have been measured at 298.15 K. These data have been used to calculate the apparent molar volumes, infinite dilution apparent molar volumes, and the standard partial molar volumes of transfer of the amino acids from water to the aqueous ionic liquid solutions. It has been observed that both the infinite dilution apparent molar volume and the standard partial molar volumes of transfer in the glycine + [HMIm]Br +H2O system increases with increasing ionic liquid concentrations and decrease in the cases l-alanine and l-valine systems. The contribution of the charged end groups (NH3+, COO-), CH2 group and other alkyl chain of the amino acids was estimated using infinite dilution apparent molar volume values. Molar conductivities of [HMIm]Br in aqueous amino acids solutions have been applied for determination of association constants and limiting molar conductivies, using the low concentration chemical model (lcCM) of conductance equation.