The room-temperature adsorption of methyl iodide on an oxidized copper silica catalyst has been investigated using FT-IR spectroscopy. After reaction of methyl iodide with an oxidized Cu/SiO2 catalyst, oxygenated hydrocarbons including methoxy and bidentate formate are present on the copper surface. The data suggest that the carbon-iodine bond in adsorbed methyl iodide dissociates on the oxidized copper particles, methyl groups then react with surface oxygen to form adsorbed methoxide and formate. The reactions of adsorbed methoxide and formate were monitored in the temperature range extending from approximately 300 to 600 K.