Abstract: In the present work, we examined the catalytic oxidation activities of Dawson and Keggin structure molybdophosphoric acids and related the results with the structureal characteristics. The results show that Dawson structure heteropoly acids have higher activities to either oxidative dehydrogenation reaction or oxygen addition reaction.

Key words: Dawson structure molybdophosphoric acid, Keggin structure molybdophosphoric acid, Oxidation of isobutylaldehyde