Promotion Effect of Alkali Metal Added to Impregnated Cobalt Catalysts in the Gas-Phase Catalytic Oxidation of Benzyl Alcohol

Abstract

The effect of the addition of alkali metals on the catalytic activity of cobalt catalysts (Co/NaY, Co/SiO2, etc.) impregnated on inorganic oxides including NaY and SiO2 was studied using the gas-phase catalytic oxidation of benzyl alcohol. The partial oxidation activities, measured by the yield of benzaldehyde, of the supported Co catalysts were selectively promoted by adding alkali metal, with keeping the yield of CO2 low. The amount of added alkali metal under a constant amount of the impregnated cobalt had an optimal value for the catalytic activity of the benzaldehyde formation. The influences of the supporting method of Co, the inorganic oxide support, the amount of supported Co, and the kind of the added alkali metal on the partial oxidation activity were investigated to explore the supported Co catalysts for high catalytic activity. The sorpted oxygen species, rather than gaseous oxygen, were suggested to participate in the formation of benzaldehyde on the basis of a transient response experiment. ...