Abstract
In order to elucidate the effect of XnOm on the catalytic activity and selectivity, vapor phase oxidation of butadiene and isomerization of 1-butene were carried out in air over a series of Mo-P-X (1:0.2:0.1 atomic ratio) oxide catalysts in which component X was varied over a wide range. Oxidation and isomerization activities were compared with the dehydration activity on isopropyl alcohol that was used as a measure of acidity of the catalysts. A good proportional relationship was obtained between dehydration activity and oxidation activity as well as isomerization activity. The change in the reaction-order of butadiene oxidation was also interpreted in terms of the acidic property of the catalyst. The selectivity of butadiene to maleic anhydride increased clearly by the addition of a third component, but the relationship between selectivity and acidic property was not clear.
