Dimethyl ether is converted to formaldehyde using a supported catalyst
comprising molybdenum and/or vanadium oxides. The surface density of the
oxide(s) ranges from greater than that for the isolated monomeric oxides
upwards, so long as there is a substantial absence of bulk crystalline
molybdenum and/or vanadium oxide(s). Conversion and selectivity to
formaldehyde are improved as compared to data reported for known
catalysts. Also disclosed is a supported catalyst comprising molybdenum
and/or vanadium oxides wherein the support comprises one or more reducible
metal oxides, preferably a layer or layers of one or more reducible metal
oxides disposed on the surface of a particulate alumina or zirconia
support.
