Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The goal of this work is to study thermodynamic and transport properties of cholinium aminoate ionic liquids ([Ch][AA] ILs) including of cholinium glycinate, cholinium valinate and cholinium prolinate as green and biocompatible extractants in water media at T = (288.15 to 318.15) K and in mixed solvent of water-polyethylene glycol di-methyl ether 250 (PEGDME250) with different mass fractions 0.025 to 0.750 at 298.15 K under atmospheric pressure ( 85 kPa). In this respect, density ( ), speed of sound (u), and viscosity ( ) of the studied aqueous solutions were experimentally measured. From the experimental density and acoustic studies, the limiting values for apparent molar volume ( V ), apparent molar isentropic compressibility ( ), and also the transfer molar volume (tran V ) and isentropic compressibility (tran ) of [Ch][AA] from water to aqueous PEGDME250 solutions were calculated. The measured viscosity data were correlated by the extended Jones-Dole equation for obtaining viscosity B-coefficient, the transfer viscosity B-coefficient (tranB) and the free energies of activation per mole of solvent ( 1 ) and solute ( 2 ). Finally, the solute-solvent interactions in these solutions were evaluated on the basis of changing the above thermodynamic and transport properties from aqueous binary to ternary solutions consist of the [Ch][AA] and PEGDME250. The results indicated that the IL-water interactions become more favorable in the presence of PEGDME250 compared to pure water in the order of: [Ch][Gly] greater than [Ch][L-Pro] greater than [Ch][L-Val]; and above critical concentrations these ternary solutions can be split into two-phases (i.e. PEGDME250-rich phase and [Ch][AA]-rich phase).