Thermophysical characterization of aqueous deep eutectic solvent (choline chloride/urea) solutions in full ranges of concentration at T = (293.15–323.15) K

Abstract

Deep eutectic solvents (DESs) as a novel generation of green solvents have been used in several processes in academia and technology in the recent years. In this study, it was measured some thermophysical properties of aqueous solutions of the deep eutectic solvents (choline chloride/urea) in full ranges concentration of DES at T=(293.15–323.15)K. The densities, speeds of sound, refractive indices, and viscosities of the investigated systems have been measured by precise methods and those results used to calculate various thermodynamic and transport properties including the excess molar volumes (VE), the partial molar volumes (V¯m,1 and V¯m,2), the excess isobaric thermal expansions (αpE), the excess molar isentropic compressibility (κs,mE), the viscosity deviations (Δη), and the deviation of molar refraction (ΔRD). These variations of properties were discussed in terms of solute-solvent interactions occurring between the components of the solutions. Eyring theory of vicos flow is used to calculate excess activation functions (ΔG#E), ΔH#E and ΔS#E of DES solutions.