Supported aqueous phase catalysis

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Virginia Polytechnic Institute and State University

This work describes a novel family of catalysts denoted Supported Aqueous Phase Catalysts (S.A.P.C.). These catalysts consist of a water-soluble organometallic complex supported in a thin film of water residing on a high surface area hydrophilic solid; the reaction takes place at the water-organic interface where the organic contains the reactants and products.

This novel type of catalysis is demonstrated by liquid phase hydroformylation. The support chosen is CPG-240, a porous glass with a narrow pore volume distribution. The catalytic species, HRh(CO)[m-P(PhSO₃Na)₃]₃ was synthesized from Rh(CO)₂(acac) by a new synthetic route and the complex was characterized by ³¹P solution NMR, ¹H solid-state NMR, and FTIR. After dissolving the catalytic species in water, it was impregnated into CPG-240. The hydroformylation of oleyl alcohol (OLOH) was accomplished at l00°C and 725 psig of H₂/CO = 1:1 using 0.002g Rh/g OLOH. As an example, after 5.5 h of contact time, 96.6% conversion was achieved. Evidence of no leaching of Rh was obtained by filtering away the supported catalyst and attempting both the hydroformylation of additional OLOH and the hydrogenation of added 1-hexene. The absence of conversion in both cases indicated that Rh was not leached into the organic phase. Because: (1) OLOH is not water soluble, (2) its double bond is internal and (3) the Rh does not leach into the organic phase, the concept of SAPC, which is to perform catalysis at an interface, is proven.