Supported polyperoxometallates: Highly selective catalyst for oxidation of alcohols to aldehydes

A new highly selective heterogeneous catalyst is developed from phosphomolybdic acid for the oxidation of alcohols by supporting polyoxomolybdate anions on vanadium–aluminum mixed oxide. The Keggin anion was found to be stable on the surface of vanadium–aluminum mixed oxide unlike alumina. It was further observed to undergo degradation with peroxide, to form surface bound polyperoxomolybdate species. In order to examine its usefulness, the catalyst was screened for the oxidation of variety of alcohols, using hydrogen peroxide under solid–liquid–liquid phase transfer conditions to yield corresponding aldehydes with almost 100% selectivity. In all the substrates examined, no traceable amount of over oxidised product was detected.

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