The reaction of ammonia and ethanol or related compounds towards pyridines over high‐silica zeolites with medium pore size

Abstract

Abstract. Pyridine bases were formed by the reaction of ethanol and ammonia over zeolite Nu-10 in the presence of oxygen, which was shown to play an essential role. The use of different proton-introduction procedures resulted in different activities and selectivities of the catalyst. H-Nu-10 and H-ZSMJ showed substantially higher pyridine selectivity than H-mordenite. In order to clarify the reaction mechanism of the title reaction, several other small amines and oxygenates were tested in the presence/absence of oxygen with respect to their selectivity towards pyridines. Zeolitic acid sites were shown to catalyse the dehydrogenation of ethanol, together with condensation, cyclization and aromatization, while structural defects probably produced oxidation products such as acetaldehyde and formaldehyde which are thought to play an important role in the reaction. The use of methylamine instead of ammonia greatly enhanced the pyridine selectivity.Introduction *