Preparation of mesoporous alumina and its catalytic performance in ethanol dehydration

A series of mesoporous aluminas were synthesized by a sol-gel method and then respective calcination at 500, 600, and 800°C with P123 as the nonionic template, aluminium isopropoxide as the aluminum source and ethanol as the solvent. The mesoporous aluminas were characterized by means of XRD, BET, NH₃-TPD and TEM, and used in the catalytic dehydration of ethanol to ethylene. The effects of calcination temperature on the catalyst morphology and the catalytic performance were investigated. The results showed that the mesoporous aluminas calcined at different temperature had different crystal shape, and their specific surface areas, pore volumes and average pore diameters decreased with calcination temperature rise. The mesoporous alumina calcined at 800°C, which showed the best catalytic performance, was modified by impregnation with Fe, which obviously improved the catalyst performance. Under the conditions of 380°C, ethanol concentration 99.7%(w), LHSV 2.5 h^-1 and the mesoporous alumina calcined at 800°C with 1% Fe loading (based on the mass fraction of Fe₂O₃) as the catalyst, the conversion of ethanol and the selectivity to ethylene reached 98.2% and 99.8%, respectively.