A micro-channel with a guideline structure, with two inlets and two outlets was tested as a reactor for performing orgarnic-,aqueous two-phase reactions. Partition walls so-called guideline structure were designed at the middle of a micro-channel with adequate intervals in order to stabilize and to maintain a laminar two-phase flow. Toluene and water were selected as the test fluids. Flow conditions for a complete two-phase laminar flow were determined and a good phase separation was ensured. The hydrolysis reaction of benzoyl chloridedissobved in the organic phase with water in the aqueous phase was conducted. The results were compared with those of a batch reactor. (c) 2007 Elsevier Ltd. All rights reserved.