Catalytic Oxidation of Dichloromethane on γ-Al2O3: A Combined Flow and Infrared Spectroscopic Study☆

摘要: When γ-Al2O3is applied as a support for noble metals in the catalytic oxidation of dichloromethane, reaction primarily takes place on alumina. In our flow study, dichloromethane was completely converted at 600 K γ-Al2O3, CO being main product, especially higher temperatures. Methyl chloride observed substantial amounts an intermediate product. The formation CH3Cl, reduction product formed under oxidative conditions, has been described before, but no satisfactory explanation given. To this end, between alumina and CH2Cl2has studied by FTIR spectroscopy well. spectrum adsorbed species 523 clearly different from that 298 K. Apparently, reacted with surface hydroxyl groups, which disappeared. Experiments CD2Cl2enabled identification species. bands found could be attributed to methoxy groups formate. With these products experiments explained: formates are into can react HCl form CH3Cl. The first step, group, yields chloromethoxy This leads chemisorbed formaldehyde analogue, appears disproportionate due some hydride shift, formate groups. Cl CH2Cl2is released and/or reacts aluminum chlorides. rate enhancing effect added water gas stream explained chlorinated restoration active sites dichloromethane.