Role of acidity on the hydrolysis of dimethyl ether (DME) to methanol

Acid catalyzed dimethyl ether hydrolysis is equilibrium limited. All solid acid catalysts, with the exception of ZrO2, attained equilibrium-limited conversions in the temperature range of interest (125-400 °C). Z(15), Z(25), and Z(40) reached equilibrium conversions at 200 °C, while Z(140), Y(15), and Y(2.5) reached equilibrium at 275 °C. γ-Alumina, the most active non-zeolite solid acid, attained equilibrium at 350 °C. Silica and BASF K3-110 were both ineffective in converting dimethyl ether to methanol. The observed activity trend for DME hydrolysis to methanol as a function of Si-Al ratio and catalyst type was:Z(15)Z(25)Z(40)>Z(140)Y(15)>Y(2.5)≫γ-Al2O3>ZrO2.