The effect of Preparation Methods and Activation Strategies upon the Catalytic behavior of the Vanadium Phosphorus oxides

EDUARDO LOMBARDO, CARLOS SÁNCHEZ , LAURA CORNAGLIA

CATALYSIS TODAY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1992 vol. 15 p. 404 - 418

0920-5861

The catalyst precursors for the oxidation of n-butane to maleic anhydride were prepared using vanadium pentoxide and orthophosphoric acid.The former was reduced using different agents (HCl and benzyl alcohol) and solvents (water, isobutyl and isopropyl alcohols). The precursors were activated applying different strategies which were selected and adapted from the liter$ure. The changes occurring in the solid were followed using XRD, XPS and P MAS NMR techniques. The catalytic  performance was evaluated using a flow reactor system. The equilibrated catalysts obtained after lOO- 400 hours on stream contained vanadyl pyrophosphate as the only crystallinephase o(RD). The XPS data showed significant phosphorus surface enrichment and the existence of only V(W) on the surface. The solvent used and the activation strategy strongly influenced the catalytic performance which could be traced through 31 P NMR to the presence of small amounts of V(v) containing phases. The results are discussed in terms of the current literature.