(A) study on purification of lactic acid using esterification and batch reactive distillation

Abstract

Kinetics of esterification of lactic acid with methanol catalyzed by cation exchange resin and purification of lactic acid using batch reactive distillation was investigated. Pseudo-homogeneous model was developed to interpret the measured kinetic data. In the case that the mass transfer resistances are not controlling, the simulated results based on pseudo-homogeneous model agreed well with experimental data. In the reactive distillation experiment, the reaction products of the esterification were distilled to hydrolysis part to be recovered into pure lactic acid. The yield of lactic acid increased as catalyst loading in the esterification part increased and reactant mole ratio and feed lactic acid concentration decreased. Methanol as a reactant gave higher yield than other alcohols. The yield of lactic acid was closely related to the boiling temperature of the reaction mixture in the esterification part.