The reactive distillation of lactic acid using solid catalyzed reaction was investigated. To study the reactive distillation, the esterification of lactic acid with methanol and the hydrolysis of methyl lactate were carried out. Both reactions were catalyzed by acidic cation exchange resins.
The reaction rate equation for the esterification and the hydrolysis reaction included the adsorption coefficient of alcohol and water. The adsorption coefficients were determined experimentally.
In the experiments of the reactive distillation, the reaction products of the esterification were distilled simultaneously with the hydrolysis reaction. The feed concentration of lactic acid, the molar ratio of the esterification reactants and the concentration of catalyst in both reactions were varied in the experiments. Another alcohol was used to react with lactic acid. The lactic acid solution obtained from the fermentation was used in experiments
As the feed concentration and the molar ratio of esterification reactants were decreased, the temperature of esterification mixture was increased and then the yield of purified lactic acid was increased. The yield was increased with the concentration of catalyst. But above 1.5 wt% of catalyst concentration, the concentration of catalyst had no influence on the yield. In experiments, the alcohol with low boiling temperature exhibited good yield.