Extraction equilibria of glycolic and glyoxylic acids with trialkylphosphine oxide and trioctylamine as extractant

Extraction of glycolic acid and glyoxylic acid from aqueous solution by trialkylphosphine oxide in methyl isobutyl ketone and trioctylamine in 1-octanol was studied under various extractant and acid concentrations. Glycolic acid can be extracted into the organic phase better by trialkylphosphine oxide than glyoxylic acid, whereas glyoxylic acid can be extracted into the organic phase better by trioctylamine than glycolic acid. Trialkylphosphine oxide could be used to remove glycolic acid from the mixture of glycolic acid and glyoxylic acid. A mathematical model was developed to describe the above liquid-liquid equilibrium. The reactive extraction mechanism of glycolic and glyoxylic acids with trialkylphosphine oxide and trioctylamine is also discussed.