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Vanadium-phosphorus-oxygen industrial catalysts for C/sub 4/ hydrocarbon selective oxidation to maleic anhydride

Technical Report ·
OSTI ID:6421400

The selective oxidation of n-butane to maleic anhydride by vanadium-phosphorus-oxygen (V-P-O) industrial catalysts varying in P-to-V ratio has been studied in a fixed bed integral reactor system. Catalyst characterization studies including x-ray diffraction, laser Raman spectroscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, x-ray energy dispersive spectroscopy, and BET surface area measurements were used. A strong effect of P-to-V synthesis ratio on catalyst structure, catalyst morphology, vanadium oxidation state, and reactivity in n-butane selective oxidation was observed. A slight ''excess'' of catalyst phosphorus (P/V = 1.1 catalyst) was found to stabilize an active and selective (VO)/sub 2/P/sub 2/O/sub 7/ phase. The mechanism of n-butane selective oxidation to maleic anhydride was studied by in situ infrared spectroscopy using n-butane, 1-butene, 1,3-butadiene, crotyl alcohol, maleic acid, crotonic acid, and maleic anhydride feeds. During paraffin selective oxidation, highly reactive olefin species and maleic acid were observed on the surfaces of V-P-O catalysts. Further evidence in support of conjugated or possibly strained olefin and maleic acid reaction intermediates in n-butane and 1-butene partial oxidation to maleic anhydride was gathered.

Research Organization:
Ames Lab., IA (USA)
DOE Contract Number:
W-7405-ENG-82
OSTI ID:
6421400
Report Number(s):
IS-T-1313; ON: DE87010937
Country of Publication:
United States
Language:
English