BiphasicSystems That Consist of Hydrophilic IonicLiquid, Water, and Ethyl Acetate: The Effects of Interactions on thePhase Behavior.

Thedesign of a biphasic system is important for the developmentof liquid–liquid extraction and biphasic catalysis. In thiswork, we report a series of ternary biphasic systems that consistof hydrophilic ionic liquid (IL), water, and ethyl acetate. The effectsof the structure of the ILs (cation, anion, and substituent group),IL/water ratio, and temperature on the phase equilibrium of thesebiphasic systems were investigated. The mutual solubility was lowerin the IL/water–ethyl acetate biphasic system than in the water–ethylacetate system when ILs with strong hydration ability were introduced,such as [EMIm]OAc, [EMIm]Cl, [EMIm]NO3, [EMIm]EtSO4, and [HOEMIm]Cl. In addition, the hydrogen-bonding basicityof the IL-containing phase could be tuned by changing the IL structureor IL/water ratio. These novel IL/water-ethyl acetate biphasic systemsmay present another option in addition to hydrophobic IL–waterand aqueous biphasic systems for liquid–liquid extraction. [ABSTRACT FROM AUTHOR]