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  • Catalyst Parameters Determi...
    Abad, Alberto; Corma, Avelino; García, Hermenegildo

    Chemistry : a European journal, 01/2008, Letnik: 14, Številka: 1
    Journal Article

    As previously reported for for solventless reactions, gold nanoparticles supported on ceria are also excellent general heterogeneous catalysts for the aerobic oxidations of alcohols in organic solvents. Among organic solvents it was found that toluene is a convenient one. A systematic study on the influence of the particle size and gold content on the support has established that the activity correlates linearly with the total number of external gold atoms, and with the surface coverage of the support. Amongst catalysts with different supports, but similar gold particle size and content, gold on ceria exhibits the highest activity. By means of a kinetic study (influence of σ+ parameter, kinetic isotopic effect, temperature, alcohol concentration and oxygen pressure) a mechanistic proposal consisting of the formation of metal–alcoholate, β‐hydride shift from carbon to metal and MH oxidation has been proposed that explains all experimental results. Even nanoparticles need gold: The mechanism of alcohol oxidation by gold nanoparticles supported on nanoparticulated ceria, a general catalyst for aerobic alcohol oxidation (see scheme), has hydride transfer as the rate‐determining step.