Extraction of Caproic Acid Using Tri-n-butyl Phosphate in Benzene and Toluene at 301 K

The recovery of caproic acid from the aqueous stream is of practical relevance due to its market value and the stringent environmental standards. A number of techniques like distillation, membrane, dialysis, electrodialysis, and reactive extraction are available. The profound success of reactive extraction has been noted in the recovery of carboxylic acids from dilute solutions. In the present paper, reactive extraction equilibrium of caproic acid using tri-n-butyl phosphate (TBP, extractant), an organophosphorous compound, in benzene and toluene (diluents) has been studied. Equilibrium parameters such as distribution coefficients, loading ratio, degree of extraction, and equilibrium complexation constants have been presented. The data obtained are useful in understanding the equilibrium characteristics and efficient design of the reactive extraction process for the recovery of caproic acid.