An infrared study on the MoO 3/SiO 2 catalytic system employed in toluene nitration

Abstract

The 15% MoO 3/SiO 2 catalyst obtained by calcination of the (NH 4) 6Mo 7O 24·4H 2O/SiO 2 system at various temperatures, as well as upon its use in the reaction of toluene nitration using 65 or 100% HNO 3, 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.