Basf Aktiengesellschaft

Jean Werner Knab

Bernd Bessling

Bernd Lohe

Peter Reuter

Walter Disteldorf

Matthias Kummer

Wolfgang Brox

Peter M Lorz

Werner Peschel

Thomas R&uuml;hl

Bernhard Ulrich

Rudiger Welker

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

Method and device for obtaining isobutenes from conjugated hydrocarbons

A process for preparing esters from alcohol and carboxylic acid by a) feeding a mixture, comprising at least alcohol and/or carboxylic acid as educts, into a distillation column with separated sections containing reactive and conventional internals, wherein the reactive internals are arranged below the inlet of the mixture and conventional internals are arranged above the inlet of the mixture, b) reaction of the alcohol and the carboxylic acid in the reactive internals in presence of a catalyst, c) distillative separation of the evolving reaction mixture into the higher boiling ester and a lower boiling azeotrope containing alcohol, water and ester, wherein the ester accumulates in the bottom and the azeotrope is removed overhead, d) separation of the azeotrope in a phase separator in an aqueous phase and in an organic phase and the organic phase to be returned to the top of the column, wherein in step b) a heterogenous catalyst is utilized and in step c) the ester is taken off above the bottom as pure product between further conventional internals which differ in their arrangement from those in step a) and which are arranged above the inlet of a circulating evaporator.

Process for preparing esters of carboxylic acids

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Limburgerhof, Germany

Jean Werner Knab