Oxidation of methanol over iron oxide based aerogels in supercritical CO2

The oxidation of methanol over iron oxide on silica or molybdenum aerogels using supercritical CO2 as the carrier was investigated for iron oxide content from 1 to 20 wt%. A pure iron oxide aerogel was also prepared. Partial oxidation products of dimethyl ether, methyl formate, or formaldehyde were found between 200 to 300 degrees C. Selectivity was influenced by the catalyst used. Pure iron oxide favored dimethyl ether, low levels of iron oxide on silica favored methyl formate, and iron oxide on molybdenum favored formaldehyde. Results demonstrate the feasibility of aerogels as model catalyst systems for reactions in supercritical fluids. (C) 1998 Elsevier Science B.V. All rights reserved.