USE OF WATER-SOLUBLE LIGANDS IN HOMOGENEOUS CATALYSIS

This chapter deals with the preparation of water soluble ligands and their use in the synthesis of water-soluble complexes as well as in catalysis. An important advantage over heterogeneous systems is that selectivity is achieved by a modulation of the coordination sphere of the metal. However, a recurrent problem is the separation of the organic products from the active catalyst. Their performances are, however, diminished by losses of the metal in solution, thereby preventing any application in commercially viable processes. A more attractive approach has been made using water-soluble ligands that are poorly soluble in organic media, allowing the catalysis to be carried out in a two-phase system. Moreover, the method can be applied either by contacting the organic phase containing the parent complex with the sulfonated ligand dissolved in water, or by mixing the complex and the ligand of interest in a solvent in which both are soluble. © 1992, Academic Press Inc.