CATALYSIS OF ALKALI ADDED Cu(II)-NaZ ZEOLITES IN BENZYL ALCOHOL OXIDATION

Abstract

The oxidation activities of alkali metal added Cu(II)-NaZSM-5 (Cu(II)-NaZ) zeolites in the gas-phase catalytic oxidation of benzyl alcohol were studied. The main products were benzaldehyde and carbon oxides (carbon dioxide + carbon monoxide). The partial oxidation activity was found to markedly increase using an alkali metal added Cu(II)-NaZ in comparison with the Cu(II)-NaZ zeolite itself. On the other hand, the degree of the increase in yield of deep oxidation products (CO2 + CO) catalyzed by the alkali added Cu(II)-NaZ was rather low. The alkali added to the Cu(II)-NaZ zeolite was tnus found to selectively promote the catalytic activity for the partial oxidation of benzyl alcohol. An alkali oxide such as Na2O, rather than the alkali salt itself, was suggested to substantially function as an active promoter for the oxidation activity for benzyl alcohol. The added alkali was found to more effectively act as a promoter for the oxidation when alkali and Cu(II) ion were accessible to each other, thereby the alkali was suggested to directly interact with the Cu(II)ion to virtually promote the oxidation of benzyl alcohol rather than as a separate function of the alkali itself. One of the roles of the alkali added to the Cu(II)-NaZ zeolite was suggested to promote the dissociation of the oxygen molecule based on the results of the exchange reaction of the oxygen molecule.