A comparison of the results obtained from deterministic and stochastic model-based optimization approaches for the determination of the optimal open-loop operating policy for a semi-batch reaction system are presented. The commercial synthesis of an intermediate in the production of the hypertension agent Eprosartan is considered in this case study. Identification of the reaction mechanism and estimation of the kinetic model parameters from experimental data are carried out as part of the development of a detailed semi-batch reaction system model that is used with the optimization approaches. The results of this study indicate that conversion optimization of the operating conditions can provide a good approximation to the economic optimum in the case of high conversion operation. This study also indicates that the optimal operating policy for the catalyst and reactant are batch, with the catalyst addition occurring prior to the reactant. and that a reduction in the amount of reactant from current practice is possible. (C) 2004 Elsevier Ltd. All rights reserved.