Transition Metal Complex Catalyzed Hydroformylation in Biphasic Reaction Media

The industrial hydroformylation of alkenes is one of the most important examples of a homogeneously catalyzed process, implying that reactants, products and catalyst are all dissolved in the same liquid. This homogeneity often leads to separation problems, which may be surmounted by immobolization of the catalytically active complex on a solid support, however often leading to poorer activity and selectivity. A different way to oppose the separation problems might involve the "immobilization" of the catalyst in a mobille phase, i.e. the catalyst should be made soluble in water, and the catalytic hydroformylation should be accomplished as a biphasic liquid process, with reactants and products in an organic phase and with the catalyst in an aqueous phase, easily separable from the organic phase, so that the catalystcould be quantitatively recycled.
This process concept will be tested by kinetic investigation of the alkene hydroformylation catalyzed by water soluble rhodium complexes, prepared by sulfonation of the "non-participative" ligands in the catalytically active complexes. For this purpose we have synthesized 3,4-dimethyl-2,5,6-triphenyl-
1-phosphanorborna-2,5-dien (DMTPPNOR) and initiated kinetic examination of the propene hydroformylation in a plug flow reactor containing a fixed bed of a supported liquid phase catalyst based on Rh-DMTPPNOR. Future work includes sulfonation of DMTPPNOR (leading to NORBOS-Na), and preparation of a supported aqueous phase catalyst, which will also be tested against propene hydroformylation in a fixed bed plug flow reactor.