Extraction of gluconic acid with organic solutions of Alamine 336

Abstract

Gluconic acid is used for a large number of different industrial applications due to some exceptionally useful properties. It is normally obtained in its pure state by extraction processes using amines. The aim of this study is to investigate the extraction of gluconic acid from aqueous solutions by Alamine 336 dissolved in a variety of diluents in a wide range of amine concentrations (0.23 - 1.72 mol L-1). Diluting solvents used in this study are hexane, cyclohexane, toluene, methyl isobutyl ketone (MIBK), and propanol. Using Bizek's approach, two acid: Amine complexes, (HO) : (R3N) and (HO) : (R3N)(2), are assumed to exist in the organic phase in the case of proton - donating diluents, while the complexes (HO) : (R3N) and (HO)(2) : (R3N)(3) are suggested in the case of non-proton-donating diluents. As a result of batch extraction experiments, valuable engineering data, such as distribution coefficients (D), loading factors (Z), and overall extraction constants (K-11, K-12 K-23) are calculated. No similar data were published previously for the investigated systems.