TRANSIENT OXIDATION OF VOLATILE ORGANIC-COMPOUNDS ON A CUO AL2O3 CATALYST/

Temperature-programmed desorption (TPD) and oxidation (TPO) were used to study decomposition and oxidation of methanol, ethanol, acetaldehyd e, formic acid, and acetic acid on a CuO/Al2O3 catalyst. The volatile organic compounds (VOCs) were adsorbed on the alumina surface and diff used to the CuO to react. Lattice oxygen in CuO is active for deep oxi dation, and as lattice oxygen is depleted, diffusion of lattice oxygen to the surface limits the rate of oxidation. Supported CuO dehydrogen ates and oxidizes VOCs and the order of reactivity is: HCOOH > CH3OH > CH3COOH > C2H5OH > C2H4O. Nearly all the oxygen in CuO can be extract ed by VOCs. In the absence of gas-phase O-2, extraction of lattice oxy gen limits the oxidation rates of acetaldehyde and acetic acid, but ga s-phase O-2 rapidly replenishes the lattice oxygen. No less-reactive, partial oxidation products were detected. (C) 1997 Elsevier Science B. V.