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AssigneeBASF SE
InventorsDIANA CAROLINA GALEANO NUNEZ, Christian WALSDORFF, Jurgen ZQHLKE, Hans-Martin ALLMANN
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The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA) comprising at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active material of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %. The present invention further relates to a process for gas phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active materials of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.
-14. (canceled)
A catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride comprising at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the catalytically active material of the catalyst is applied to an inert catalyst carrier and comprises vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.
A process for production of a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride with at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition, comprising the step of applying a catalytically active material comprising antimony, vanadium and titanium dioxide to a catalyst carrier in one or more shells, wherein the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.
Dependencies are inferred from the claim text.