Effect of alkali metal added to supported La catalysts on the catalytic activity in the gas-phase catalytic oxidation of benzyl alcohol

Abstract

The oxidation activities of lanthanum (La) catalyst supported on both crystalline and amorphous oxides including NaZSM-5 zeolite and the alkali metal-added counterparts were studied using a gas-phase catalytic oxidation of benzyl alcohol. The main oxidation products were benzaldehyde and carbon dioxide, together with a trace amount of benzene and/or toluene under certain reaction conditions. The addition of alkali metal to the lanthanum catalysts supported on NaZSM-5 and SiO2 promoted the catalytic activity of the partial oxidation in the benzyl alcohol oxidation. The influences of the oxide supports, the amount of La supported on the catalyst, the added alkali metal/La atomic ratio, and the catalyst preparation on the catalytic activity in the benzyl alcohol oxidation were investigated. The amount of adsorbed ethanol on the La-supported catalyst, the O2 uptake amount, the transient response experiment of the oxidation reaction, together with the BET surface area and the X-ray powder diffraction (XRD) pattern of the catalysts, were measured in order to determine the crucial factors in the partial oxidation activity. A promotion scheme for the alkali metal added to the La/NaZSM-5 catalyst is proposed.