Investigation of solute-solvent interactions in binary and quaternary solutions containing lithium perchlorate, propylene carbonate, and the deep eutectic solvent (choline chloride/ethylene glycol) at T=(288.15 to 318.15) K

Abstract

Deep eutectic solvents (DES) based on choline chloride have been used for numerous applications due to their relatively inexpensive and readily available nature. The goal of this work is to study the effect of a deep eutectic solvent {DES)choline chloride/ethylene glycol with the ratio of 1: 2(} on thermodynamic and transport properties of the solution of lithium perchlorate (LiClO4) in propylene carbonate (PC). In this regard, the density (d), speed of sound (u) and viscosity (η) were measured for the binary solution of (LiClO4 + PC) and quaternary solution of (LiClO4 + PC + DES) at T = (288.15 to 318.15) K under ambient pressure. Using this data, the values of standard partial molar volume (Vφ0), partial molar isentropic compressibility (κφ0) and viscosity B-coefficient were calculated. These quantities were applied to explain the influence of DES on the solute-solvent interactions in the studied system. The results indicate that the addition of DES on the solution of (LiClO4 + PC) lead to enhancement of the solute-solvent interactions. This work also reports a density functional theory study for DES with PC and LiClO4 to rationalize interactions. The interaction energies (Eint) between DES and PC or LiClO4 have been investigated using the B3LYP density functional theory. The DFT results revealed that the interactions between the studied DES and LiClO4 are stronger than those between LiClO4 and PC and DES-PC, which may be a reasonable explanation for the enhancement of solute-solvent interaction as a result of adding the DES.