SELECTIVE OXIDATION OF PROPENE USING AN ELECTROCHEMICAL MEMBRANE REACTOR WITH CEO2-BASED SOLID-ELECTROLYTE

The partial oxidation of propene to acrylaldehyde on an inert gold ele ctrode has been studied at 350 to 450 degrees C over an electrochemica l membrane reactor using (CeO2)(0.8)(SmO1.5)(0.2) as a solid electroly te. This material has a high ionic conductivity at low temperatures. O n applying a direct current to the reaction cell, acrylaldehyde was fo rmed at the gold anode, and the formation rate of acrylaldehyde increa sed linearly with increasing current density. The addition of oxygen t o the propene-mixed gas at the anode space did not affect the acrylald ehyde production. Hence, it is likely that partial oxidation of propen e was carried out by the oxygen species produced electrochemically thr ough the electrolyte, and appearing at the gold-electrolyte gas-phase triple-phase boundary. From the dependence of the acrlylaldehyde selec tivity on the amount and the type of dopants, it was found that the co mplete oxidation of propene with lattice oxygen from the rare-earth-do ped CeO2 surface was significant, and that the reactivity of lattice o xygen in CeO2 with hydrocarbons decreased with increasing ionic conduc tion of the oxide.