Catalytic dehydration of methanol to dimethyl ether over modified γ-Al2O3 catalyst

A γ-Al2O3 catalyst was modified with metal oxide (Nb2O5) in order to improve its activity and stability for dimethyl ether (DME) synthesis from methanol. A series of modified γ-Al2O3 catalysts were prepared with Nb2O5 and characterized by X-ray diffraction and temperature programmed desorption of ammonia. Results showed that the γ-Al2O3 catalyst containing 10 wt.% of Nb2O5 exhibited the highest surface area among the modified ones. The number of acid sites of the modified catalysts was increased by the Nb2O5 modification. In the chemical reaction of DME synthesis, it was found that the Nb2O5 modified γ-Al2O3 catalyst exhibited a higher activity in the low temperature region (240 °C–260 °C) and a higher activity than did the untreated γ-Al2O3 catalyst.