Basf Se Corporation

Thomas Lautensack

Frank Rosowski

Jürgen Zühlke

Hagen Wilmer

Hans-Martin Allmann

Cornelia Katharina Dobner

Markus Schubert

Thomas Hill

Michael Krämer

Reinhard Körner

Michael KRÄMER

The present invention relates to a process for gas-phase oxidation, in which a gaseous stream comprising an aromatic hydrocarbon and molecular oxygen is passed through two or more catalyst zones. Furthermore, the present invention relates to a catalyst system for gas-phase reaction using a preliminary zone.

Catalyst system and method for gas phase oxidation using an upstream layer

What is described is a process for starting up a gas phase oxidation reactor for oxidation of o-xylene to phthalic anhydride, said reactor comprising at least one catalyst layer and being temperature-controllable by means of a heat carrier medium, wherein a) the catalyst layer is interrupted by a moderator layer which is less catalytically active than the catalyst layer or is catalytically inactive, b) a gas stream is passed through the reactor with an initial loading of o-xylene and at an initial temperature of the heat transfer medium, c) the loading of the gas stream is increased to a target loading and, in parallel, the temperature of the heat transfer medium is lowered to an operating temperature. The introduction of the moderator layer allows the loading to be increased more rapidly and the startup time to be shortened.

Method for starting a gas-phase oxidation reactor

The invention relates to a catalyst for the oxidation of SOto SO. The catalyst contains an active substance which contains vanadium, alkali metal compounds and sulfate applied to a support. The support contains naturally occurring diatomaceous earth, wherein the support contains at least one relatively soft naturally occurring uncalcined diatomaceous earth which has a percentage reduction of at least 35% in its Dvalue determined in a particle size determination according to the dry method in comparison with the wet method.

[object Object]

A process for gas phase oxidation in which a gaseous stream which comprises at least one aromatic hydrocarbon and molecular oxygen is passed through one or more catalyst layers, wherein a moderator layer is arranged between two catalyst layers arranged in succession in flow direction of the gaseous stream, the moderator layer being less catalytically active than the catalysts adjacent upstream and downstream or being catalytically inactive. The desired oxidation products are obtained in high yield over prolonged periods.

Method for gas phase oxidation using a moderator layer

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Birkenau, Germany

Thomas Lautensack