Comparison of Extractability of Oxalic Acid from Dilute Aqueous Solutions Using Dioctylamine and Trioctylphosphine Oxide

In this investigation, the reactive extraction of oxalic acid from its dilute solutions using trioctylphosphine oxide (TOPO) or dioctylamine (DOA) mixed with several solvents was studied to examine the most proper extractant mixture. The organic-phase combinations were prepared by merging either TOPO or DOA with n-octane, 1-butanol, 1-decanol, methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), and diethyl sebacate (DES), respectively. The distribution coefficient, loading factor, and the extraction yield data were calculated for the interpretation of the results. It is found that in comparison with the physical extraction experiments performed with pure solvents oxalic acid extraction from aqueous solutions can be improved significantly by introducing TOPO or DOA to the extractant composition. According to the results, the maximum oxalic acid extraction is obtained with an extraction efficiency of 98.74% and a distribution coefficient of 78.125 if 1.652 mol·kg–1 of DOA dissolved in MIBK is used as t...