Catalysis by Multimetallics. Catalyzed Homogeneous Oxidation of Alcohols and Ketones with Molecular Oxygen in the Presence of Hexarhodium Hexadecacarbonyl and Dirhenium Decacarbonyl

Article abstract of DOI:10.1021/ja00537a020

The compounds Rh6(CO)16 and Re2(CO)10 are effective catalysts for the conversion of ketones and cyclic alcohols to carboxylic acids.Cyclohexanol is converted to adipic acid via cyclohexanone as intermediate.Temperature, solvent, and pressure effects are reported and discussed.Increased acid yield with Rh6(CO)16 under conditions of increased CO and decreased oxygen pressure are interpreted on the basis of a lower nuclearity rhodium carbonyl being the reactive intermediate.The catalytic effect of the metal carbonyl is a consequence of the accelerated decomposition of the preformed peroxide intermediates.The side product ε-caprolactone is formed in the oxidation of cyclohexanone, but the yield is decreased in the presence of Rh6(CO)16 because of the catalyzed decomposition of its precursor peracid.The metal carbonyls catalyze the decomposition of hydrogen peroxide, but unlike ferrous ion (Fenton's reagent) do not enhance its function as an organic oxidant.