Recovery of dilute acetic acid through esterification in a reactive distillation column

The recovery of acetic acid from its dilute aqueous solutions is a major pr oblem in both petrochemical and fine chemical industries. The conventional methods of recovery are azeotropic distillation, simple distillation and li quid-liquid extraction. Physical separations such as distillation and extra ction suffer from several drawbacks. The esterification of an aqueous solut ion (30%) of acetic acid with n-butanol/iso-amyl alcohol is a reversible re action. As excess of water is present in the reaction mixture, the conversi on is greatly restricted by the equilibrium limitations. The eaters of acet ic acid, namely, n-butyl acetate and iso-amyl acetate, have a wide range of applications. In view of the appreciable value of these esters, the presen t work was directed towards recovery of 30% acetic acid by reaction with n- butanol and iso-amyl alcohol in a reactive distillation column (RDC) using macroporous ion-exchange resin, Indion 130, as a catalyst bed, confined in stainless steel wire cages. Experiments were conducted in order to achieve an optimum column configuration for the synthesis of n-butyl acetate/iso-am yl acetate in an RDC, The effect of various parameters, e.,g. total feed fl owrate, length of catalytic section, reflux ratio, mole ratio of the reacta nts. location of feed points and effect of recycle of water were studied. ( C) 2000 Elsevier Science B.V. All rights reserved.