| abstract |
Shell catalyst for the catalytic gas phase oxidation of hydrocarbons, containing, on an inert, non-porous support, a catalytically active composition with a content, based on the total amount of the catalytic composition, of 1 to 40% by weight of vanadium oxide, calculated as V¶2¶O ¶5¶, 60 to 99% by weight of titanium oxide, calculated as TiO¶2¶, up to 1% by weight of cesium compound, calculated as Cs, up to 1% by weight of a phosphorus compound, calculated as P and up to one Total content of 10% by weight of antimony oxide, calculated as Sb¶2¶O¶3¶, characterized in that the catalytically active composition is applied in two or more layers, the inner layer or layers having an antimony oxide content of up to 15 % By weight and the outer layer have a 50 to 100% reduced antimony oxide content, and the amount of the catalytically active mass of the inner layer or layers 10 to 99% by weight of the amount of the total catalytically active M isse and its use for the production of carboxylic acids, especially phthalic anhydride. |