RADIOLYSIS OF ETHANOL ADSORBED ON SILICA

Ethanol on high-surface silica (Cabosil) is mainly held by physical adsorption, but a few per cent is held irreversibly in a form shown by infrared absorption studies to consist of Si-O-C2H5 and Si-O-H groups. When the system is irradiated by γ rays, considerable decomposition of ethanol results from transfer of excitation energy from the silica. The major gaseous products (hydrogen, carbon monoxide, and methane) occur in about the same ratio as in radiolysis of liquid ethanol and probably result from excitation of adsorbed ethanol molecules, but small yields of ethane and ethylene vary in a peculiar manner which suggests that they arise from ethyl carbonium ions formed at acid sites created by radiation on the silica surface.