OXIDATIVE COUPLING AND RING-OPENING OF FURAN ON AG(110) - FORMATION OF MALEIC-ANHYDRIDE, BENZENE, AND BIFURAN

TPRS, EELS, and isotope experiments show that furan reacts with active oxygen on Ag(110) to form CO2, H2O, and small amounts of the partially oxidized products maleic anhydride, bifuran, and benzene that evolve between 520 and 560 K. The first step in furan combustion is C-H bond activation by O(a) followed by O(a) attack at the alpha-carbon at 308 K. O-18(a) experiments prove that maleic anhydride is formed via intermediates where the furan ring has been cleaved. This contrasts with mechanisms proposed for maleic anhydride production from furan over VPO catalysts.