The Effect of Molybdenum Component in the Vanadium-Molybdenum Oxide Catalyst on the Oxidation Activity

Abstract

The oxidation of butene and acetic acid as well as the isomerization of butene iR the presence of excess air were carried out over V20s-MoO3 catalysts contain1ng O.-v30 atom%e of Mo. Then, the activity for dehydration of isopropylalcohol (IPA) which was adopted as, a measure of acidity of the catalysts was also examined, in order to elucidate the addition effect of MoO3 on the catalyst activities. The activities for both the oxidation and isomerization of butene correlated fairly well with the IPA dehydration activity (Fig. 8) which inereased with increasing MoO3content, reached a maximum at Mo=15N20 atom%e (Fig. 1) and then decreased. The reaction order of the butene oxidation with respect to butene eoncentratien decreased from O.9 to O.5, with addition of 10.v20 atem% of Mo (Table 1). However, the activity for the decomposition of acetic acid remained constant (Fig. 6). lt is considered that at least in the case of partial oxidation of such electron-donoptype compounds as olefin, the main role of MoO3 added to V20ti is not an ativation of surface oxygen, but an increase of acidity which promotes the adsorption or activation of the reactant on the surface.