Bayer Aktiengesellschaft

Uwe J Zarnack

Hermann Dallmeyer

Berthold Keggenhoff

Heiko Beckhaus

Harro Witt

Bernd Weber

Heinz Sauer

Rudolf Sundermann

Helmut Judat

Hartmut Hetzel

Gerhard Wiechers

Dieter Grenner

Thomas Schieb

Christian Konig

Dieter Becher

Fritz Pohl

Volker Weintritt

Sludge phase reactor and process for performing sludge phase reactions

Aromatic diamines and polyamines are produced by a continuous process for the catalytic hydrogenation of the corresponding dinitro and polynitro compounds at elevated temperature. Heat removed from the reaction mixture may be used to produce steam with an overpressure of .gtoreq.2 bar.

Continuous process for preparing aromatic amines

A continuous process for the preparation of isomeric mixtures of dinitrotoluene by a single stage nitration of toluene under adiabatic conditions. The reaction enthalpy is used for the removal by distillation of the water of reaction formed during nitration. In this process, toluene is reacted with a nitrating acid having from about 80 to about 100% by weight of an inorganic component having a specified composition and from about 0 to about 20% by weight of an organic component having a specified composition.

Process for the preparation of dinitrotoluene

A process for recovering a distillate of tolylene diisocyanate and an isocyanate-group-containing sump product containing less than 200 ppm (by weight) tolylene diisocyanate from A) distillation residues obtained in the production of tolylene diisocyanate by mixing of the distillation residues A) with B) optionally urethane- and/or allophanate-modified polyisocyanates or polyisocyanate mixtures of the diphenyl methane series, heating of the mixture to 190.degree. to 250.degree. C. and simultaneously or subsequently working up by distillation.

Process for recovering polysocyanates from the distillation residues

The present invention is directed to a mixer for mixing at least two free-flowing, reactive or unreactive substances comprising

Mixer for mixing at least two free-flowing substances, especially those

The present invention is directed to a process for the production of a mono- and/or polyisocyanate by the phosgenation of a mono- and/or polyamine in a mixer which comprises

Process for the production of isocyanates

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

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Brunsbuettel, Germany

Uwe J Zarnack