Investigation of active and selective oxygen in vanadium phosphorus oxide catalysts for n-butane conversion to maleic anhydride.

摘要

The role of lattice oxygens in two model catalysts, (beta)-VOPO(sub 4) and (VO)(sub 2)P(sub 2)O(sub 7), was investigated for the selective and nonselective oxidation of C(sub 4) hydrocarbons to maleic anhydride and combustion products. Specific catalytic oxygen sites in each model catalyst were labeled with specific amounts of (sup 18)O. Labeled sites were identified by laser Raman spectroscopy and Fourier transform infrared spectroscopy. The level of (sup 18)O enrichment in each site was estimated from the laser Raman spectra and the stoichiometry of reactions involved in the synthesis of the labeled catalysts. Products of the anaerobic C(sub 4) hydrocarbon oxidation and, in the case of (VO)(sub 2)P(sub 2)O(sub 7), alternating pulses of oxygen with pulses of hydrocarbon, over labeled catalysts were monitored by quadrupole mass spectrometry. 146 refs., 51 figs., 7 tabs. (ERA citation 15:035197)