Reactive extraction of carboxylic acids using organic solvents and supercritical fluids: A review

A review of the current applications of organic compounds and supercritical fluids as solvents for separation of carboxylic acids from aqueous solutions by physical and reactive extraction is presented. A comparison of efficiencies of acetic, propionic, succinic, and citric acid extraction by using 1-octanol and supercritical CO2 performed in the batch mode and the semi-continuous mode is presented. Supercritical CO2 is a recommended solvent for use in the reactive extraction of carboxylic acids because of its environmentally benign, non-toxic, non-flammable, non-polluting and recoverable characteristics. It is concluded that the supercritical reactive extraction process is an efficient method of carboxylic acid separation from aqueous solutions with higher yield, simplicity, and competitiveness than the other separation methods.