Results are presented concerning the behavior of alumina-supported gold catalysts and the effects of addition of Li 2 O and CeO x on the oxidation, dehydrogenation and dehydration reactions of ethanol. Pure alumina mainly acts as an acidic catalyst and produces diethyl ether and ethylene. Gold particles play an important role in converting ethanol into ethylene oxide and acetaldehyde. Addition of Li 2 O influences the selectivity by suppressing the formation of diethyl ether and ethylene. With the Au/Li 2 O/Al 2 O 3 catalysts, a high selectivity toward ethylene oxide can be obtained. The influence of the oxygen concentration on the gas flow is investigated. It is suggested that at low concentrations, the role of oxygen is mainly to prevent coke formation on the catalytic surface.