Basf Aktiengesellschaft

Bernhard Ulrich

Thomas Heidemann

Peter Reuter

Bernd Bessling

Matthias Kummer

Peter M Lorz

Werner Peschel

Walter Scheidmeir

Thomas R&uuml;hl

Otto Kratzer

Gerhard Hefele

Jean Werner Knab

Thomas Cimniak

On-spec phthalic anhydride is prepared by distillative purification of crude phthalic anhydride by a process in which crude phthalic anhydride is fed to a distillation column which is operated at reduced pressure, the low boilers are removed at the top or in the vicinity of the top of the distillation column and the on-spec phthalic anhydride is removed from the column via a side take-off.

Method for producing phthalic anhylic anhydride according to specifications

In a process for preparing phthalic anhydride by catalytic gas-phase oxidation of o-xylene or naphthalene or o-xylene/naphthalene mixtures with a gas comprising molecular oxygen over a coated catalyst comprising an inert, nonporous support material on which a catalytically active composition comprising titanium dioxide and vanadium pentoxide is applied in layer form, a catalyst whose catalytically active composition comprises from 3 to 6% by weight of vanadium pentoxide, calculated as V O , from 0.3 to 0.5% by weight of a cesium compound, calculated as Cs, and the remainder to 100% by weight of titanium dioxide in the anatase modification is used in the presence or absence of a coated catalyst, differing therefrom, for the catalytic gas-phase oxidation of o-xylene or naphthalene or o-xylene/naphthalene mixtures and, in the presence of such a second catalyst, the latter is used in a combined bed with the catalyst of the above composition in the reactor.

Method for producing acid phthalic anhydride and an appropriate shell catalyst containing titanium-vanadium-cesium

The invention relates to a method for producing gas-phase catalysts gas-phase oxidation of aromatic hydrocarbons into carboxylic acids and/or carboxylic acid anhydrides upon whose carrier material a coating containing catalytically active metal oxide is applied in the form of a shell, wherein a powder is initially produced from a solution and/or suspension of catalytically active metal oxides and the precursor compounds thereof or simply the precursor compounds in the presence or absence of auxiliary agents in order to produce the catalyst. Said powder is then applied, in the form of a shell, to the carrier in the presence or absence of auxiliary agents after or without previous conditioning and without previous thermal treatment to produce the catalyst. The carrier which is thus coated undergoes thermal treatment in order to produce catalytically active metal oxides.

Method for producing shell catalysts for catalytic gas-phase oxidation of aromatic hydrocarbons

Growing community of inventors

Bockenheim, Germany

Bernhard Ulrich