Reactive Extraction of Gluconic Acid Using Trioctylamine in Different Diluents

Reactive extraction of gluconic acid (GA) from aqueous solutions was investigated using trioctylamine (TOA) as extractant in the presence of benzyl alcohol (BA) and 1-decanol (DE) as diluents. Physical extraction of GA with pure diluents in the absence of TOA was found to be poor. Reactive extraction with an amine-diluent mixture enhanced the separation process. Higher extraction efficiencies and distribution coefficients were achieved in the presence of BA as compared to DE. Further optimization studies were carried out to determine the synergistic effect of amine/diluent ratio. Loading ratios higher than 0.5 suggested 3:1 complex formation of GA with the amine. A reactive extraction mechanism of GA in TOA was proposed, and the equilibrium complexation constant was determined.