Methane, and not HCl, is the gaseous product from the silation of the surface of gamma-alumina using (CH3)(3-) SiCl in the temperature range 140-260 degrees C and during thermolysis of silated gamma-alumina to 500 degrees C. A minimum of 1 mol of CH4 is produced per mol of(CH3)(3)SiCl reacted, and all chloride remains firmly bound to the silated alumina.