Ammonium based deep eutectic solvents (DESs) on extraction of benzothiophene from iso-octane: experiment and COSMO-RS model

Densities of pure benzothiophene (BT), iso-octane (ISO), and tetra butyl ammonium bromide decanoic acid {[TBAB][DA]} as deep eutectic solvent and their binary mixtures of [BT] + [ISO], [BT] + {[TBAB][DA]} and {[TBAB][DA]} + [ISO] over the entire mole fractions were measured at different temperatures 303.15 K–353.15 K at 1 atm. From this measured density data, the solution thermodynamic properties such as excess molar volume, partial molar volume, excess partial molar volumes, apparent molar volume, isobaric expansivity, and excess isobaric expansivity were calculated. Further, this calculated excess molar volume data were correlated by Redlich-Kister polynomial fit equation. Subsequently, liquid–liquid extraction (LLE) experiment were conducted for the removal of BT from ISO using {[TBAB + DA]} at 298.15 K and 1 atm. This LLE process was characterized in terms of distribution coefficient and selectivity and thermodynamic consistency test were done by Othmer-Tobias and Hand Equations. Finally, the sigma (σ) profile and sigma (σ) potential of all the studied species were generated and analyzed using COSMO-RS model.