Hydrophobic deep eutectic solvents as water-immiscible extractants

Hydrophobic deep eutectic solvents (DESs) are presented for the first time. They consist of decanoic acid and various quaternary ammonium salts. The effect of the alkyl chains on the hydrophobicity and the equilibrium of the two-phase DES–water system were investigated. These new DESs were successfully evaluated for the recovery of volatile fatty acids from diluted aqueous solutions.