Basf Se Corporation

Holgar Braunsberg

Andreas Raichle

Johannes Buettner

Ulrich Penzel

Samuel Neto

Gerrit Waters

Peter Renze

Ruediger Fritz

Stefanie Haase

Markus Hiller

Kathrin Richter

Lothar Bruntsch

Arndt Hofmann

Burkhard Hantel

Helmut Rueger

Michael Herrich

Joana Coelho Tsou

Steffen Oehlenschlaeger

Michael Zoellinger

Rüdiger Fritz

Johannes Büttner

Michael Zöllinger

Steffen Oehlenschläger

Urlich Penzel

Helmut RÜGER

The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

Optimized introduction of the starting materials for a process for preparing aromatic amines by hydrogenation of nitroaromatics

The present invention relates to a continuous process for preparing at least one aromatic amine by hydrogenation of at least one nitroaromatic by means of hydrogen, where a liquid phase comprising at least the aromatic amine and a gas phase comprising at least hydrogen are present, in the presence of a catalyst suspended in the liquid phase at a temperature of from 50 to 250&#xb0; C. and a pressure of from 5 to 50 bar, wherein the pressure in the reactor is kept essentially constant by continuous adaptation of the amount of hydrogen fed to the reactor, the total amount of hydrogen fed to the reactor is monitored and the introduction of the at least one nitroaromatic is interrupted if the hydrogen uptake in the reactor is not at least 50 mol % of the amount of hydrogen required for stoichiometric reaction of the at least one nitroaromatic to form the at least one aromatic amine.

Monitoring of the stoichiometric ratio in the reaction of nitroaromatics with hydrogen

The invention relates to a process for the continuous preparation of toluenediamine by liquid-phase hydrogenation of dinitrotoluene by means of hydrogen in the presence of a suspended, nickel-comprising catalyst in a reactor with a product isolation unit downstream of the reactor to give a product output from the reactor comprising a liquid phase comprising toluenediamine and dinitrotoluene, in which the nickel-comprising catalyst is suspended, wherein the concentration of dinitrotoluene in the liquid phase of the product output from the reactor in the region between the reactor and the downstream product isolation unit is set to a value in the range from 1 to 200 ppm by weight, based on the total weight of the liquid phase of the product output from the reactor.

Process for preparing toluenediamine by hydrogenation of dinitrotoluene

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Senftenberg, Germany

Holgar Braunsberg