| abstract |
FIELD OF THE INVENTION The present invention relates to catalysts for the formation of aldehydes, carboxylic acids and / or carboxylic anhydrides, in particular phthalic anhydrides, from aromatic hydrocarbons by catalytic gas phase oxidation, wherein the active agent of the catalyst is vanadium oxide, preferably pentoxide Vanadium, titanium dioxide, preferably anatase type titanium dioxide, and at least one silver mixed element oxide of silver with certain elements, preferably vanadium and / or molybdenum and / or tungsten and / or niobium and / or antimony, And / or vanadium mixed element oxides of vanadium with certain elements, preferably bismuth and / or molybdenum and / or tungsten and / or antimony and / or niobium, in particular when preparing the catalyst At least one silver and / or barna during the preparation of the powder mixture needed to coat the Mixing element oxide, at least one precursor compound, in particular using at least one multi-core precursor compound as a raw material source. |