Hydroformylation by supported aqueous-phase catalysis: a new class of heterogeneous catalysts

Abstract

HOMOGENEOUS catalysts typically operate at relatively mild temperatures and exhibit high activities and selectivities1. However, it has long been recognized that many homogeneous reactions are not commercially viable because of problems of catalyst recovery. Thus, significant efforts have centred around the immobilization of the organometallic species responsible for catalysis2. At best, the performance of such heterogeneous catalysts only approximate those of their homogeneous counterparts. Here we describe a novel family of heterogeneous catalysts, denoted supported aqueousphase catalysts (SAPCs), designed to facilitate chemical reactions at the interface of two liquids. These catalysts consist of a watersoluble organometallic complex dissolved in a film of water which is supported on a high-surface-area hydrophilic solid. Reactions of liquid-phase organic reactants take place at the water–organic interface. Heterogeneous hydroformylation of alkenes by SAPCs containing water-soluble organometallic rhodium complexes is used to illustrate the efficacy of these new catalysts.