Vanadium phosphorus oxides with P/V=2 used as oxidation and ammoxidation catalysts

摘要: Abstract Vanadium polyphosphates with a molar ratio of P/V=2 (α-VO(PO3)2, β-VO(PO3)2 and amorphous as well partly crystalline VO(PO3)2) NH4VP2O7 were synthesized, characterized by chemical thermal analysis, X-ray diffraction FTIR spectroscopy used catalysts in the oxidation n-butane to maleic anhydride (MA) ammoxidation toluene benzonitrile. The results are compared catalytic properties V(PO3)3 (P/V=3), (NH4)2(VO)3(P2O7)2 (P/V=4/3) (VO)2P2O7 (P/V=1). MA selectivities VO(PO3)2 α- comparable one another, whereas specific rate per area formation strongly differs from rates solids. catalyst reveals similar that catalyst, but lower selectivity. Contrary other studies, only traces furan found total products CO CO2 detected on all at very low conversion. Surprisingly, exhibits remarkable activity show benzonitrile selectivity reaches value ≈85%. Noticeable benzaldehyde amounts could be detected, especially conversion rates, proving its role reaction intermediate.