PARTIAL OXIDATION OF HYDROCARBONS ON SILVER - CONVERSION OF 1-BUTENE TO MALEIC-ANHYDRIDE BY ATOMICALLY ABSORBED OXYGEN ON AG(110)

The reaction of 1-butene with atomically adsorbed oxygen on Ag(110) has been studied using temperature-programmed reaction mass spectrometry (TPRS) and high-resolution electron-energy-loss vibrational spectroscopy (HREELS). The reaction was studied as a function of oxygen coverage from 0.00 to 0.50 ML. 1-Butene is oxidized by atomically chemisorbed oxygen via a sequence of reactions on the surface to 1,3-butadiene, 2,5-dihydrofuran, furan, carbon dioxide, and small amounts of maleic anhydride. 1,3-Butadiene is the principal oxidation product; the 2,5-dihydrofuran and furan yields are approximately 50% and 10%, respectively, of the 1,3-butadiene yield for oxygen atom coverages of 0.05 monolayers. 1,3-Butadiene is formed from 1-butene via C-H bond activation of the acidic allylic C-H bonds by atomically chemisorbed oxygen, a reaction that has a precedent in the oxidation of cyclohexene on Ag(110). The oxygen-containing products are formed via oxygen atom addition to 1,3-butadiene; this addition resembles the epoxidation of norbornene and styrene on Ag(110) and the epoxidation of styrene and 3,3-dimethylbutene on Ag(111).