Thermodynamic parameters and infinite dilution activity coefficients for organic solutes in deep eutectic solvent: Choline Chloride + 1,5-Pentanediol

Abstract

A series of thermodynamic parameters related to choline chloride + 1,5-pentanediol deep eutectic solvent were studied through inverse gas chromatography at 303.15–343.15 K. The infinite dilution activity coefficient (γ12∞) was used to predict the solute separation ability and the intermolecular interaction strength of DES. The interaction between molecules was further described by partial molar excess properties (ΔH1E,∞,TΔS1E,∞, ΔG1E,∞). The value of γ12∞ was also used to compute the separation parameters for common separation problems benzene (1)/methanol (2), n-hexane (1)/benzene (2) and benzene (1)/thiophene (2). The miscibility of organic solutes and DES was evaluated using the Flory–Huggins interaction parameter, and the result showed alcohols were good solvents for the DES. Moreover, the Hildebrand solubility parameters (Î́2) of the DES were calculated, and the result revealed that the value showed a downward trend with the increase of temperature.