| Acetaldehyde is one of the most important aliphatic chemicals. It can be used as a raw material for the production of acetic, acetic anhydride, ethyl acetate and many other products. In this paper, Cu/SiO2 catalyst, which is based on Cu(NO3)2 and porous silica is used as a carrier, for a vapor phase synthesis of acetaldehyde from ethanol dehydrogenation was studied in a continuous flow micro fixed-bed reactor at atmospheric pressure.The products in acetaldehyde synthesis from ethanol dehydrogenation at atmospheric pressure are analyzed by gas chromatography-mass spectrometry. Acetaldehyde, ethanol, butanal, 1-butanol, ethyl acetate and 1,1-diethoxyethane are separated and qualitatively analyzed respectively, and the formation of them are explained from the reaction mechanism.The effects of different prepared method, copper loading, alkaline-earth oxide additives etc are examined. Acetaldehyde is prepared efficiently and selectively under mild reaction conditions over the Cu/SiO2 catalyst. The incipient impregnation method is adopted with the silica spherical carrier of 0.5～1mm size. The optimum reaction temperature lies in 275℃and the suitable gas hourly space velocity (GHSV) is 3600h-1 considering both acetaldehyde production and ethanol conversion. A catalyst with 5wt.% Cu-loading and 1wt.% K-loading performs best, the yield of acetaldehyde is 29.9% with the 31.9% ethanol conversion and 93.8% acetaldehyde selectivity. Simultaneously, the catalyst retains the activity during 165h.From the analytical results of TPD offered in the study, the additives of K or Na enhance the weak basic sites below 500K, and the additives of Mg and Ca enhance the strong basic sites of 500K700K and 750K1100K. It could draw a conclusion that the weak basic sites are favorable for the synthesis of acetaldehyde and the strong basic sites have no evidently promotional effect.
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