Application of Prigogine–Flory–Patterson theory to correlate the thermodynamic properties of aqueous mixtures of some three-component deep eutectic solvents based on choline chloride and carboxylic acids at T = (288.15 to 318.15) K

Abstract

Thermodynamic properties of some neoteric three-component deep eutectic solvents (DESs) and their mixture with water are of great practical and fundamental importance in various fields of sciences. In this work the measurements of density and speed of sound data for neat four DESs (choline chloride/lactic acid/ethylene glycol, choline chloride/lactic acid/glycerol, choline chloride/oxalic acid/ethylene glycol and choline chloride/oxalic acid/glycerol) and their aqueous mixture were carried out over the entire composition range at T = (288.15 to 318.15) K. Some of the thermodynamic properties including the excess molar volumes (VE), the apparent molar volumes (Vφ,1 and Vφ,2), excess isobaric thermal expansion (αp, mE), the isentropic compressibility deviation (Δκs) and speed of sound deviation (Δu) were computed based on these data. These main properties were evaluated according to numerous solute-solvent interactions among the various components in the mixtures for all of the investigated systems. In addition, the properties were fitted by the Redlich–Kister and Hwang equations. Finally, the capability of Prigogine–Flory–Patterson (PFP) theory for reproducing the main experimentally observed properties of the investigated systems containing DESs. The binary interaction parameter χ12 of PFP theory are negative and these represent the stronger interactions between the components (DESs + water), as compared to the self-interactions among the pure components in the systems.