Bayer Materialscience Ag

Bayer Aktiengesellschaft

Bill Brady

Rainer Buse

Friedhelm Steffens

Bernd Pennemann

Berthold Keggenhoff

Kai Verkerk

Gerhard Ruffert

Gerd Greger

Aromatic amines are produced by catalytic hydrogenation of aromatic nitro compounds. The reaction mixture generated by this hydrogenation is then worked up by distillation in a manner which makes it possible to substantially free the amine of water with increased energy efficiency. Water free of amine and low boilers and the low boiling materials are also obtained.

Process for the preparation of aromatic amines

The invention relates to an energy efficient process for the distillative working-up of aqueous amine solutions that occur in the catalytic hydrogenation of nitroaromatic compounds. In this process, the amine is freed from water and also the water is obtained free from amine and low-boiling compounds and the concentrated low-boiling compounds are obtained.

Process for the distillative separation of aqueous amine solutions

Toluenediamine is produced and separated from by-products of the reaction by:

Process for the preparation of toluenediamine

Process for the purification of toluenediisocyanate from a crude distillation feed which includes toluenediisocyanate, an organic solvent and less than 2% by weight phosgene by separating the crude distillation feed in a dividing-wall distillation column into at least four product fractions PP

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Houston, TX, United States of America

Bill Brady