Palladium Nanoparticle-Graphene Catalysts for Asymmetric Hydrogenation

We report for the first time the application of palladium nanoparticle-graphene (Pd/Gn) catalysts in the asymmetric hydrogenation of aliphatic alpha,beta-unsaturated carboxylic acids using cinchonidine as chiral modifier. Pd/Gns were prepared by deposition-precipitation from the aqueous phase over graphite oxide and subsequent simultaneous reduction of both the support and the metal precursor with NaBH4. The materials obtained were characterized by ICP optical emission spectroscopy, X-ray diffraction spectroscopy, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. We demonstrate that the Pd/Gns modified by cinchonidine can act as efficient catalysts in the asymmetric hydrogenation of alpha,beta-unsaturated carboxylic acids for producing optically enriched saturated carboxylic acids.