Increase in Concentration and Strength of Acidic Catalytic Sites on Sulfated Zirconia by Doping with Silica

Doping sulfated zirconia with silica increases the acidity of the sulfated zirconia. This modified catalyst was used for liquid-phase dehydration of methanol at 413–453 K as a model reaction. Methanol is sequentially dehydrated to dimethyl ether and ethylene over both sulfated zirconia and silica-doped sulfated zirconia in a single step. Also, significant amounts of propylene are formed by the silica-doped catalyst but not by the undoped catalyst. The data were discussed in relation to increased acid active sites after doping with silica, which electronically modified the catalyst surface.