Liquid-liquid extraction of phenolic compounds from aqueous solution using hydrophobic deep eutectic solvents

This work evaluates the efficiency of extracting phenolic compounds (phenol, guaiacol, eugenol and pyro-catechol) from aqueous solution using Hydrophobic Deep Eutectic Solvents (HDESs). Four solvents were selected by screening HDESs database using the predictive model COSMO-RS (Conductor like Screening Model for Real Solvent): menthol: dodecanoic acid [2:1], decanoic acid: dodecanoic acid [2:1], octanoic acid: menthol [2:1] and thymol: menthol [1:1]. Experimental liquid-liquid equilibria of ternary systems {water - HDESs - phenolic compounds} measured at 298.15 K under atmospheric pressure were used to determine the distribution coefficient and selectivity values. Experimental data were used to determine the interaction parameters of the thermodynamic Non-Random Two-Liquid model (NRTL). NRTL model represents with good accuracy experimental data. COSMO-RS model predicts well the ternary systems containing phenolic compounds except those containing pyrocatechol. Finally, extraction of the four phe-nolic compounds from synthetic oil and kinetics study were performed. The extraction process using HDES: octanoic acid: menthol [2:1] exhibits the highest efficiency and more than 85 % of phenolic com-pounds are extracted after 5 min.(c) 2022 Published by Elsevier B.V.