Vanadium pentoxide/titanium dioxide system. Structural investigation and activity for the oxidation of butadiene
- Brunel Univ.
Catalyst samples were prepared from nine different anatase or rutile samples mixed with 1-60Vertical Bar3< vanadium pentoxide (V/sub 2/O/sub 5/) and heated in air to 450/sup 0/C for five hours or to 750/sup 0/C overnight, and characterized by differential thermal analysis, thermogravimetric analysis, ESR and IR spectroscopy, X-ray diffraction, catalytic activity tests for butadiene oxidation to maleic anhydride at 220/sup 0/-300/sup 0/C, and tests of reducibility with carbon monoxide. No interaction between V/sub 2/O/sub 5/ and TiO/sub 2/ occurred below 600/sup 0/C. Above the V/sub 2/O/sub 5/ melting point (690/sup 0/C), oxygen was evolved during reduction of vanadium(V) to (IV), and a V/sub 2/O/sub 5/-catalyzed transformation of anatase to rutile occurred simultaneously. With increasing V/sub 2/O/sub 5/ content, the oxygen loss went through a maximum at 10Vertical Bar3< V/sub 2/O/sub 5/, of which 2Vertical Bar3< apparently combined with impurities, and a maximum of 8Vertical Bar3< formed V/sub x/Ti/sub y/O/sub 2/ (x = 0.04, y = 0.96), in which tetravalent vanadium occupied substitutional rather than interstitial positions in the rutile lattice. The V/sub x/Ti/sub y/O/sub 2/ compound was less active but more selective in the butadiene conversion to maleic anhydride than V/sub 2/O/sub 5/. The selectivity apparently depended on the difficulty of removing lattice oxygens.
- OSTI ID:
- 6635300
- Journal Information:
- J. Catal.; (United States), Vol. 57:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BUTADIENE
OXIDATION
CATALYSTS
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
CRYSTAL LATTICES
PHASE TRANSFORMATIONS
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE EFFECTS
THERMODYNAMIC ACTIVITY
TITANIUM OXIDES
VANADIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DIENES
HYDROCARBONS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLYENES
SYNTHESIS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
400201* - Chemical & Physicochemical Properties
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)