Insights into experimental and theoretical approach to physicochemical properties of aqueous PEGylated deep eutectic solvents at T=(293.15–323.15) K

Abstract

This paper demonstrates the excess molar properties: excess molar volumes VmE and excess isentropic compressibilities Ks,mE of aqueous binary mixtures of PEGylated DESs at T = (293.15 - 323.15) K and at atmospheric pressure. The DESs were prepared from combination of Tetrabutylammonium bromide/Benzyltributylammonium chloride as HBA with Polyethylene glycols of different average molar masses 200, 400, and 600 as HBD. The excess molar properties excess molar volumes VmE and excess isentropic compressibilities Ks,mE of DESs binary mixtures were obtained over the entire composition range from experimental values of the density and speed of sound of both pure and aqueous DES mixtures. The Redlich-Kister equation was used to estimate the standard deviation between experimental and calculated excess properties. The stronger interaction between water and components of studied DESs gave negative values for both excess molar properties. This behaviour of the investigated systems was assessed using Extended Real Associated Solution Model (ERAS) and Prigogine-Flory-Patterson theory (PFPT). The obtained results were interpreted in terms of interactions between the mixture components, temperature, structure of HBA and molecular mass of HBD.