Catalytic oxidation of CH2Cl2 on sodium doped Al2O3

Influence of the deposition of Na+ ions on gamma-Al2O3 on its surface prope rties and catalytic activity in oxidation of CH2Cl2 by gas phase oxygen has been studied. IR spectra indicate that the concentration of OH groups is s ignificantly reduced and Lewis acidity, related to exposed Al ions, is simu ltaneously decreased. Therefore, total catalytic activity is strongly depre ssed, no CH3Cl is formed as intermediate product, Cl-2 appears in the produ cts which is absent on pure gamma-Al2O3 and the amount of CO2 is at all tem peratures higher than that of CO. This indicates that parallel to the two m echanisms, operating in case of gamma-Al2O3 and starting with mono- and bid entate adsorption of CH2Cl2 through its chlorine atoms on Lewis sites, a th ird reaction pathway appears starting with adsorption through hydrogen atom s. (C) 1999 Elsevier Science B.V. All rights reserved.