Reactive Extraction of Gallic Acid Using Trioctylamine and Tributyl Phosphate with Natural Oils

Experimental and theoretical perspectives of reactive extraction of gallic acid (GA) from aqueous solutions using tri-n-butyl phosphate (TBP) and tri-n-octylamine (TOA) as extractant dissolved in three nontoxic natural oils, namely, rice bran oil, sunflower oil, and soybean oil, are investigated. The solvent's extractability is observed in an order of sunflower oil > rice bran oil > soybean oil and rice bran oil > sunflower oil > soybean oil with TOA and TBP, respectively. The theoretical insights of reaction mechanisms for the extraction of GA are estimated in the form of overall equilibrium constants (K_E), stoichiometric coefficients (m), individual equilibrium constants (K₁₁, K₁₂, K₂₁), and concentrations (C₁₁, C₁₂, and C₂₁) of various complexes formed between extractant and acid.