Thermodynamic properties and activity coefficients at infinite dilution for different solutes in deep eutectic solvent: 1-butyl-3-methylimidazolium chloride + glycerol

Abstract

Activity coefficients for 33 solutes at infinite dilution were determined in deep eutectic solvent (1-butyl-3-methylimidazolium chloride + glycerol) prepared by a molar ratio of 2 [BMIM] [Cl]: 1 glycerol. The retention data of solutes in prepared deep eutectic solvent (DES) as an extracting solvent were obtained with the aid of gas liquid chromatography (g.l.c) operated at different temperatures, T = (313.15–343.15) K and at ambient pressure. The separation capacity and molecular interactions of solutes in DES were determined from the activity coefficient measurements. The intermolecular interactions were further expressed by calculating thermodynamic functions including partial molar enthalpies (∆H1E, ∞), Gibbs free energy (∆G1E, ∞), and entropy term (Tref∆S1E, ∞), at infinite dilution. These were calculated from the activity coefficients at infinite dilution data. The activity coefficient data was also used to compute the separation parameters (selectivity and capacity) for selected industrial extraction problems (hexane/benzene; cyclohexane/benzene; acetone/ethanol and cyclohexane/ethanol). Activity coefficients data are important as they can be used for pre-screening of separation solvents for industrial extraction processes.