Enrichment of Aromatic Compounds Using Ionic Liquid and Ionic Liquid-Based Aqueous Biphasic Systems

Both hydrophibic C₈mim]PF₆] and C₄mim]Cl/(K₂CO₃, K₂HPO₄ or K₃PO₄) aqueous biphasic system (ABS) were employed for the enrichment of aromatic compounds including nitrobenzene, 4-nitrophenol, phenol and aniline from aqueous solutions. In C₈mim]PF₆] enrichment system, the distribution ratio (D) of nitrobenzene and aniline increase with the increasing of pH values of aqueous phase from 2 to 8, but there is no obvious change for 4-nitrophenol and phenol. And the D values of the aromatic compounds decrease with the phase ratio change from 1/5 to 1/30 (IL phase volume/aqueous phase volume). In C₄mim]Cl/(K₂CO₃, K₂HPO₄ or K₃PO₄), the distribution ratio increase with the increasing of the salts concentrations. The distribution ratio order in C₈mim]PF₆] and C₄mim]Cl/kosmotropic salt ABS is nitrobenzene > phenol > aniline > 4-nitrophenol. It is expected that these results are promising for the removal of the aromatic compounds from water, especially for sample enrichment in analytical science.