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Catalyst Parameters Determining Activity and Selectivity of Supported Gold Nanoparticles for the Aerobic Oxidation of Alcohols: The Molecular Reaction Mechanism
Author(s) -
Abad Alberto,
Corma Avelino,
García Hermenegildo
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701263
Subject(s) - alcohol oxidation , catalysis , chemistry , toluene , colloidal gold , metal , particle size , particle (ecology) , inorganic chemistry , oxygen , hydride , selectivity , nanoparticle , chemical engineering , organic chemistry , oceanography , engineering , geology
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 MH oxidation has been proposed that explains all experimental results.