MODIFICATION OF GAMMA-ALUMINA WITH CHLOROTRIMETHYLSILANE

The solid and gaseous products from the silation of partially dehydrox ylated gamma-alumina with chlorotrimethylsilane have been determined f or a wide range of pretreatment and reaction conditions. Unexpectedly and contrary to previous assumptions, in all cases there was no HCl pr oduced. Methane was the only gaseous product detected for silation rea ctions up to 500 degrees C. Under very severe conditions a very small amount of higher hydrocarbons was also obtained. The silating reagent is first irreversibly adsorbed by reaction with coordinatively unsatur ated aluminum cations and oxygen anions, Subsequent reaction of the si lyl methyl group with isolated, highly acidic hydroxyls affords the me thane product.