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Title: Vanadium pentoxide/titanium dioxide system. Structural investigation and activity for the oxidation of butadiene

Journal Article · · J. Catal.; (United States)

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