A green, reusable and highly efficient solid acid catalyst for the oxidation of aldehydes to the corresponding carboxylic acids using H2O2 and KMnO4:H5PV2Mo10O40 (10-molybdo-2-vanadophosphoric heteropolyacid)

H5PV7Mo10O40-catalyzed oxidation of aromatic aldehydes to the corresponding carboxylic acids using hydrogen peroxide and KMnO4 as oxidants under mild conditions is reported. This system provides an efficient, convenient and practical method for the oxidation of aromatic aldehydes. In this work, differences between Keggin and Well-Dawson type polyoxometalates are addressed in term of relative stability, hardness and acidity.