Catalysts based on supported 12-molybdophosphoric acid

Catalysts preparation by equilibrium adsorption of 12-molybdophosphoric aci d in water-ethanol solutions onto silica, titania, carbon and alumina is st udied. The solute/support interaction follows the decreasing order: alumina , carbon, silica and titania. It is observed that the molybdophosphoric aci d keeps its Keggin-type structure after being supported at room temperature on all supports. This species is stable up to 500 degrees C on silica, 400 degrees C on titania or carbon and 250 degrees C for alumina. The acidity of the supported heteropoly acid decreases in the following order: silica > titania > carbon > alumina.