Bayer Aktiengesellschaft

Dieter Becher

Harro Witt

Gunter Lailach

Udo Birkenstock

Rudolf Gerken

Heiko Beckhaus

Christian Konig

Uwe J Zarnack

Hermann Dallmeyer

Eckart Waldau

Wilhelm Hagen

Eckhard Tiemann

Hans Czwalinna

Aromatic diamino compounds are produced by hydrogenating the corresponding dinitro compounds in the presence of a modified Raney catalyst. The modified Raney catalyst is obtained by treating an alloy made up of 50-95 wt % of aluminum, 4-45 wt % nickel and/or cobalt and 1-46 wt % of at least one modifying metal with an alkali material. The modifying metal is selected from the metals of the first, fourth, fifth, sixth, seventh and eighth subgroups of the Periodic Table of Elements. The hydrogenation is preferably carried out at from 170.degree. to 250.degree. C. and a pressure of 15-50 bar. The heat generated during hydrogenation is preferably used to produce steam.

Production of aromatic diamino compounds using a modified Raney catalyst

An amine is separated from an aqueous solution of amine and volatile organic compounds by distillation in a column. The vapors generated during distillation are condensed. The condensed vapors are then passed into a separating device in which the volatile organic compounds are removed. The liquid remaining in the separating device is then fed to the head of the distillation column. Water is removed from the column in a sidestream and diamine is the residue. This process is particularly effective in recovering aromatic diamines from solutions which accumulate during hydrogenation of dinitro aromatic compounds.

Process for working-up aqueous amine solutions

In the production of dinitrotoluene by a two-stage reaction of toluene with nitric acid in the presence of sulphuric acid, wherein toluene is nitrated to mononitrotoluene in the first stage using spent acid from the second stage, and the mononitrotoluene is nitrated to dinitrotoluene in the second stage using concentrated spent acid from the first stage, the improvement which comprises concentrating spent acid under vacuum in an indirectly-heated evaporator and feeding mononitrotoluene into the superheated vapor of the evaporator.

Process for the production of dinitrotoluene

Carbon monoxide is produced in an improved process in a carbon-filled, water-cooled generator in the configuration of a truncated cone in the longitudinal section, by the gasification of said carbon with a mixed gas of oxygen and carbon dioxide, wherein the improvement comprises injecting the mixed gas into the generator through at least one downwardly-directed, coolable nozzle arranged in the generator sidewall and removing the carbon monoxide formed.

Process for the production of carbon monoxide

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Dormagen, Germany

Dieter Becher