The activity of dimethyl ether (DME) hydrolysis was investigated over a series of solid acid and non-acid catalysts, zeolite Y [Si/Al = 2.5 and 15: denoted Y(Si/Al)], zeolite ZSM-5 [Si/Al = 15, 25, 40, and 140: denoted Z(Si/Al)], silica, zirconia, gamma-alumina, and BASF K3-110 (commercial Cu/ZnO/Al2O3 catalyst). Dimethyl ether hydrolysis was carried out in an isothermal packed-bed reactor at ambient pressure. 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 degrees C). Z(15), Z(25), and Z(40) reached equilibrium conversions at 200 degrees C, while Z(140), Y(15), and Y(2.5) reached equilibrium at 275 degrees C. gamma-Alumina, the most active non-zeolite solid acid, attained equilibrium at 350 degrees 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: [Graphics] (c) 2005 Elsevier B.V. All rights reserved.