Effect of preparation method for γ-Al₂O₃ catalyst on dehydration of ethanol

γ-Al₂O₃ catalysts for dehydration of ethanol to ethylene were prepared by both sol-gel and precipitation methods, and characterized by means of XRD, TG, N₂ adsorption-desorption and NH₃-TPD. The activities of ethanol dehydration on the two γ-Al₂O₃ catalysts were observed. Effects of -OH group density and surface acidity of the catalysts were analyzed. The catalyst prepared by sol-gel method was higher in surface acidity and was more active in the dehydration. Under optimal conditions: 350°C, LHSV of ethanol 0.6 h^-l and ethanol mass fraction in feed 92.4%, ethanol conversion and selectivity to ethylene on γ-Al₂O₃ catalyst prepared by sol-gel method could reach 99.3% and 97.7%, respectively.