Experimental Investigation of The Separation of 4-Hydroxybenzoic Acid Employing Natural and Conventional Solvents

Abstract

4-hydroxybenzoic acid (4-HBA) has a wide range of applications in various chemicals, cosmetics, pharmaceuticals, wines and the polymer industries. In the present study, 4-HBA was extracted from the aqueous phase utilizing natural and conventional solvents (NACS) at a constant temperature of 298 K. The natural solvents used were corn oil and cottonseed oil, while the conventional solvents used were isoamyl alcohol, ethyl acetate and diethyl carbonate. Five different concentrations, 0.005 to 0.035 mol/liter, were prepared and applied in the batch experiment. Various extraction parameters were investigated, including the distribution coefficient (K_DHBA), extraction efficiency (%E_HBA), partition coefficient (P) and dimerization coefficient (D). The experimental results revealed the attractive association between the solute and solvent based on their various physicochemical properties. The highest extraction efficiency was obtained for isoamyl alcohol (58.98%) and the lowest for corn oil (39.48%). The order of distribution coefficients was experimentally obtained as follows: isoamyl alcohol (1.438) > ethyl acetate (0.986) > diethyl carbonate (0.961) > cottonseed oil (0.677) > corn oil (0.652). Natural solvents have the potential to avoid toxicity and could be explored for large-scale applications.