STUDY OF CHROMIUM-DOPED CATALYSTS IN N-BUTANE OXIDATION TO MALEIC-ANHYDRIDE

In order to investigate the effect of additives on the active sites of VPO catalysts, chromium doped catalysts have been prepared in aqueous medium. The Cr/V atomic ratio was limited to 2.5%. XRD, IR, XPS, isop ropyl alcohol decomposition and n-butane oxidation tests were used for a comparative study of the bulk and surface properties of the catalys ts. XRD analysis reveals that (VO)(2)P2O7 and VOPO4 phases are poorly crystallized. The XPS results show a strong surface enrichment of chro mium in Cr-doped materials which is deleterious for the production of maleic anhydride (MA). At high conversion, catalyst deactivation occur red by surface coking.