An infrared study on the MoO3/SiO2 catalytic system employed in toluene nitration Original Research Article

The 15% MoO3/SiO2 catalyst obtained by calcination of the (NH4)6Mo7O24·4H2O/SiO2 system at various temperatures, as well as upon its use in the reaction of toluene nitration using 65 or 100% HNO3, was studied by IR spectroscopy. The calcination process conducted at 240, 300, or 550 °C proceeds first through the formation of the Keggin structures, silicomolybdic acid, then, of molybdenum trioxide. All the molybdenum phases on the silica support obtained were found to be active in the toluene nitration process.