The Oxidation Activity and Acid-base Properties of V2O5-K2SO4-H2SO4 Catalysts

The vapor-phase oxidation of 1-butene, butadiene, and acetic acid were carried out in the presence of excess air over two series of V2O5-K2SO4-H2SO4 catalysts, V2O5-K2SO4-H2SO4 (2-x-1, mole ratio) and V2O5-K2SO4-H2SO4 (2-1-y) where x and y were varied (X=0∼1.0, y=0∼3), and the relationship between catalytic behavior and acid-base properties of the catalysts was investigated. The acidity and basicity of V2O5-K2SO4-H2SO4 catalysts were obtained from the values of dehydration activity for isopropyl alcohol (IPA), rp, and the ratio of (dehydrogenation activity for IPA)/(dehydration activity for IPA), ra/rp, which were measured in the presence of excess air. It has been found that the acid-base properties of the catalysts are changed largely by the contents of K2SO4 and H2SO4, and that oxidation activity and selectivity can be interpreted in terms of the acid-base properties of the catalysts. It can be concluded that the acid-base conception in which the catalytic activities are governed by the acidbase properties between the catalyst and reactant is still effective in explaining the function of the K2SO4 and H2SO4 added to V2O5.