Hydrophobic Deep Eutectic Solvents for the Recovery of Bio-Based Chemicals: Solid–Liquid Equilibria and Liquid–Liquid Extraction

The solid–liquid equilibrium (SLE) behavior and liquid–liquid extraction (LLX) abilities of deep eutectic solvents (DESs) containing (a) thymol L-menthol, (b) trioctylphosphine oxide (TOPO) L-menthol were evaluated. distribution coefficients (KD) determined for the solutes relevant two biorefinery cases, including formic acid, levulinic furfural, acetic propionic butyric L-lactic acid. Overall, both an increasing KD was observed DESs acids in size thus hydrophobicity. Furfural, being most hydrophobic, seen to extract highest (for DES 14.2 ± 2.2 4.1 0.3), lactic acid small, independent (DES 0.5 0.07 0.4 0.05). TOPO similar ranges as traditional TOPO-containing composite solvents, while thymol/L-menthol DES, absence Lewis base functionality, a smaller observed. selectivity separation different investigated because acid–base interaction phosphine group. selective towards (Sij = 9.3 0.10, FA 2.1 0.28).