Recovery of Lactic Acid by Batch Distillation with Chemical Reactions Using Ion Exchange Resin

Abstract

Batch distillation of lactic acid with the simultaneous reactions was studied. Lactic acid was reacted with methanol, and methyl lactate was produced by the esterification reaction. The volatile methyl lactate was distilled simultaneously with the hydrolysis reaction into lactic acid. To recover pure lactic acid through two reactions and distillation, batch distillation system consisted of two condensers, feed vessel, and reboiler was studied. For both reactions of esterification and hydrolysis, the acidic cation exchange resin was used as a solid catalyst. As the concentration of catalyst increased, the yield of recovered lactic acid was increased. As the feed concentration of lactic acid and the reactant molar ratio in the esterification reaction decreased, the recovery yield of lactic acid was increased. The yield of recovered lactic acid was as high as 95%. When impure lactic acid solution obtained from bacterial fermentation was used as feed, highly pure lactic acid solution was obtained with yield of 92% in reboiler.