Can. J. Chem. 57.2464 ( 1979.Infrared spectra of the surfaces of vanadium pentoxide and vanadium pentoxide containing 9.09 m o l z caesium and potassium, as sulphates, have been determined after exposure to 2-propanol for various times. Interpretation of the spectra leads to the proposal that the principal source of catalyst activity may be associated with surface hydrogen and hydroxyl groups on V5+ and V4+ sites. The "stability" of the catalysts towards reduction by the alcohol was consistent with the activity series derived from kinetic measurements: V 2 0 5 (pure) < V 2 0 5 (Cs) < V,05 (K). The degree of sample reduction has also been assessed qualitatively by measurements of the ratio of surface area before to that after reaction and the same catalyst sequence was established. The trend in surface area ratios was similar to that shown by the surface "Tammann" temperatures of vanadium pentoxide and alkali metal sulphates which has been taken to imply that the ease and (or) extent with which the sulphates enter into inter-solid reactions with the oxide in the preparation stage may exert influence on the subsequent reducibility of the individual members of the catalyst series.

Can. J. Chem. 56.3078 ( 1978). The oxygen exchange reaction between 0, C"0, and the surfaces of vanadium pentoxide and promoted vanadium pentoxide catalysts has been studied in a circulation system using a quartz differential reactor. Isotopic compositions here analysed lvith an in-line mass spectrometer. Alkali metal sulphates, Li to Cs, were added to the pentoxide as individual promoters a t a concentration level of 9 n i o l z and the effect of variation of promoter concentration n a s examined with melts containing potassiurn sulphate at additional levels of 1, 2, and 5 n~o l z . The structures of the solids were studied by X-ray diffraction and by A T R and transniission infrared spectroscopy. The latter results have been used to explain the two activity series for the exchange rates: (i) V 2 0 , < Na i Li < K < R b < Cs (melts) and ( O n a etudie la structure des solides en utilisant la diffraction des rayons X, ainsi que la spectroxopie infrarouge par trans~nission et par RTA. Les vitesses d'echange ont conduit au classement dc l'activite des systemes selon les series suivantes: (i) V 2 0 s < N a < Li < K < R b < Cs et iii) V Z O~ < I m o l z < 2 n i o l z < 5 nmolz < 9 i n o l z (K). Les resultats des methodes enumerees ci-dessus ont permis de relier ces deus series aux effets conjugues de l'abondance et de la force relatives des liens vanadium oxygene se trouvant sur la surface des catalyseurs.[Traduit par le journal]

Calorimetric heats of adsorption have been determined for sulfur dioxide adsorbed at 298, 323, 373, and 423 K on both Californian and Quebec chrysotiles. Adsorption isotherms have been measured and some differential molar entropies calculated. Thermal desorption of surface species resulting from the adsorption of sulfur dioxide on Californian chrysotile at 298 K have been studied from 25 to 450 °C. Sulfurous and carbonic acids, in addition to sulfites and other trace species, have been shown to result from the adsorbent–adsorbate interactions. A mechanism for sulfur dioxide adsorption on chrysotile has been prepared which accounts for the observed high heats of adsorption measured at low surface coverages.