Volumetric and compressibility properties for aqueous solutions of choline chloride based deep eutectic solvents and Prigogine–Flory–Patterson theory to correlate of excess molar volumes at T = (293.15 to 308.15) K

Abstract

The thermodynamic properties of deep eutectic solvents (DESs) as neoteric and green solvents are needed to develop and design processes and understand molecular interactions in these type of systems. In this regard, the density (ρ) and speed of sound (u) were measured for aqueous solutions of the DESs based on choline chloride (ChCl) as hydrogen bond acceptor (HBA) with some hydrogen bond donors (HBDs) ethylene glycol (EG), oxalic acid (OA), and malonic acid (MA). On the basis of this data, the excess and deviation molar properties were calculated. In the whole concentration range, the values obtained for excess molar volumes, VE, and isentropic compressibilites deviations, Δκs are negative and that they are increased with increasing the temperature indicating strong interactions between DESs and water. To better undestanding molecular interactions, properties such as excess isobaric thermal expansion (αp, mE), apparent molar volume (Vϕ, 1), and limiting apparent molar expansibility (ϕE, 10) were also calculated. Some equations such as Redlich-Kister and Hwang et al. were used to correlate these properties. Finally, the Prigogine–Flory–Patterson (PFP) theory was used to correlate the excess molar volumes values.