Hydrophobic ionic liquid (IL)-molecular solvent composite extractant was developed for the removal of phenols from aqueous solution. The results showed that tetradecyltrihexylphosphonium bromide ([P66614]Br)-ethyl acetate mixtures could not only decrease the viscosity of extractant notably

but also have good affinity to phenols. The distribution coefficient of phenol in [P66614]Br-ethyl acetate-water biphasic system ([P66614]Br/ethyl acetate molar ratio 1:4) was 5.3 times higher than that using pure ethyl acetate as extractant

9—60 times higher than those using several common hydrophobic ILs and only 25.3% smaller than that using pure [P66614]Br. The viscosity of 20% (mol) [P66614]Br mixture was only 1% of pure [P66614]Br. The solvation interactions calculated by COSMO-RS indicated that there were strong hydrogen-bonding interaction between the phenol and [P66614]Br

which drove phenol into the [P66614]Br-rich phase. This mixture also showed good extraction abilities for phloroglucinol

4-chlorophenol and 2

5-dinitrophenol with distribution coefficients of 91

490 and 1492

respectively. These results provided a new opportunity for designing phenol-removing solvent with both good thermodynamic and kinetic properties.