The hydrolysis of n-butyl acetate with aqueous sodium hydroxide was studied in the batch mode as well as in the continuous mode in a micro-reactor. The progress of the reaction was analyzed both with and without a phase transfer catalyst. The concentration of the unreacted sodium hydroxide in the aqueous phase was determined by titration with hydrochloric acid to monitor the progress of the reaction. The performance of the two systems is studied for different operating conditions, i.e. concentrations of reactants, stirring speeds (in batch mode) and flow rates (in continuous mode). Conditions are identified when the performance of the micro-reactor system is superior to that of the batch system. To understand this better the performance of a 1. mm channel and a 0.4. mm channel are compared with that of the batch reactor. © 2010 Elsevier B.V.