Vanadium in cationic and anionic positions as a promoter of 12‐molybdophosphoric‐acid‐based catalysts

Derivatives of 12-molybdophosphoric acid (H3PMo12O40), containing vanadium in the form of a vanadyl cation or substituted as addenda in Keggin anions, have been synthesized and characterized by IR, LRS, XPS, NMR, and DTA/DTG. Their catalytic behavior in the oxidation of methanol, butane and pentane has been determined. Both catalysts exhibit strong acidity, due to hydrolysis of the secondary structure in the case of the salt. The vanadium atom performs its role as the active site for the activation of hydrocarbon molecules irrespective of whether it is present as a cation or incorporated in Keggin anions.