The effect of loading of vanadia on silica in the oxidation of butane

Journal Article · Mon Nov 01 00:00:00 EST 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1324· OSTI ID:5041631

Owens, L; Kung, H H ^[1]

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1. Northwestern Univ., Evanston, IL (United States)

The effect of vanadium loading on the structure and the catalytic behavior of silica-supported vanadium oxide catalysts in the selective oxidation of butane was investigated in a continuous flow reaction system using catalysts containing loadings of 0.53, 0.58, or 6.4 wt% vanadium supported on Davison or Cabosil silica. The lower loading samples were found to be more selective for oxidative dehydrogenation. At 520[degrees]C, with a feed of He/O[sub 2]C[sub 4]H[sub 10] = 88/8/4 at a total flow rate of 100 ml/min, the total dehydrogenation selectivity on the 0.58 wt% V sample was 65 and 50% at butane conversions of 5 and 20%, respectively, whereas they were 42 and 5% on the 6.4 and 50% at butane conversions of 5 and 20%, respectively, whereas they were 42 and 5% on the 6.4 wt% V samples. The activation energies for the oxidation of butane were about 110 kJ/mol for the lower loading samples and 164 kJ/mol for the higher loading samples. At 520[degrees]C, the activity per vanadium was comparable for the different samples. Laser Raman spectra of fresh catalysts indicated that only a well-dispersed vanadia species existed on the 0.58 wt% V sample, while crystalline V[sub 2]O[sub 5] was also formed on the 6.4 wt% V samples. The ratio of well-dispersed to crystalline vanadia species on the fresh catalysts was higher for the Cabosil silica-supported sample than the Davison silica-supported sample. After reaction, the spectra of the 0.58 wt% V samples did not indicate any changes. However, significantly more crystalline V[sub 2]O[sub 5] was found on the 6.4 wt% V samples on both silica supports, indicating that aggregation of vanadia had occurred during reaction. The higher total dehydrogenation selectivity on the 0.58 wt% V samples was attributed to the presence of the well-dispersed vanadia, while the presence of crystalline V[sub 2]O[sub 5] species on the higher loading samples contributed to the production of total oxidation products. 40 refs., 6 figs., 3 tabs.

• OSTI ID: 5041631
• Journal Information: Journal of Catalysis; (United States), Vol. 144:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
10 SYNTHETIC FUELS
BUTANE
DEHYDROGENATION
VANADIUM OXIDES
CATALYTIC EFFECTS
ACTIVATION ENERGY
RAMAN SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
ALKANES
CHALCOGENIDES
CHEMICAL REACTIONS
ENERGY
HYDROCARBONS
LASER SPECTROSCOPY
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
400201* - Chemical & Physicochemical Properties
100200 - Synthetic Fuels- Production- (1990-)