Reactive Extraction of Caproic Acid Using Tri-n-butyl Phosphate in Hexanol, Octanol, and Decanol

Abstract

Reactive extraction is an alternative method for recovery of caproic acid as compared to other processes such as distillation, membrane, dialysis, electrodialysis, and so forth. The profound success of reactive extraction has been noted in the recovery of carboxylic acids from dilute solutions. In present paper, reactive extraction of caproic acid using tri-n-butyl phosphate (TBP) (extractant), an organophosphorous compound, in hexanol, octanol, and decanol (diluents) has been studied. Results were presented in terms of distribution coefficients, loading ratio, degree of extraction, and equilibrium complexation constants. Four different models, relative basicity, mass action law, Langmuir, and linear solvation energy relationship (LSER) models, were used to represent the reactive extraction equilibrium for caproic acid−TBP−diluent. The data obtained are useful in understanding the equilibrium characteristics and efficient design of reactive extraction process for the recovery of caproic acid.