Lee YH  Kang JW  Hong YK  Kim KS

Vol. 20,  No. 4, pp. 349-353, Dec.  2014

Ionic liquid Imidazolium Aqueous two phase system Binodal curve Succinic acid

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Succinic acid is an important precursor in industries producing biopolymers, pharmaceutical and food additives and green solvents. However, due to the high price of petroleum and the global CO2 emission, the biological production of succinic acid from renewable biomass is a novel process due to the fixation of CO2 into succinate during fermentation. In this study, aqueous two phase systems based on imidazolium ionic liquids/K2HPO4 were used as an effective separation and concentration process for succinic acid. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of imidazolium ionic liquids to aqueous K2HPO4 solutions in the presence of succinic acid. It can be found that the ability of imidazolium ionic liquids for phase separation followed the order [HMIm][Br]≒[OMIm][Br]>[BMIm][Br]>[EMIm][Br]. The maximum value of extraction efficiency for succinic acid was about 90% and the amount of coextracted water into top phase is proportional to the chain length of cation in imidazolium ionic liquids. It was concluded that the aqueous two phase systems composed of imidazolium ionic liquids/K2HPO4 was effective for the selective extraction and concentration of succinic acid.