In this article, multi-objective optimization technique was applied to improve the performance of simulated moving bed reactor (SMBR) and its modification, Varicol process for hydrolysis of methyl acetate. The optimization problems of interest considered are simultaneous maximization of purity and yield of acetic acid and methanol, respectively, in the raffinate and extract streams. The effect of distributed feed flow rate on the performance of SMBR and the applicability of reactive Varicol systems were also investigated. The non-dominated sorting genetic algorithm (NSGA) was used in obtaining Pareto optimal solutions. It was observed that reactive Varicol performs better than SMBR due to non-synchronous switching and its increased flexibility in distributing columns in various sections. (c) 2005 Elsevier B.V. All rights reserved.