In pharmaceutical syntheses, the solvent choice generally represents a complex design step. Traditionally, this choice is operated according to criteria connected with the reaction step and without any consideration on the following separation steps. The purpose of this study is to highlight the benefits of a global approach of optimisation for the solvent determination. In this way, an optimisation framework dedicated to global synthesis is applied to a simple reaction-separation operation integrating a Beckmann rearrangement reaction, leading to interesting solvent choices. (C) 2003 Elsevier B.V. All rights reserved.