Covestro Deutschland Ag

Bayer Aktiengesellschaft

Bayer Intellectual Property Gmbh

Bayer Materialscience Ag

Erwin Dieterich

Bernd Pennemann

Heinz-Josef Hamacher

Berthold Keggenhoff

Dietmar Wastian

Michael Merkel

Peter Lehner

Jürgen Münnig

Karl-Heinz Wilke

Manfred Keller-Killewald

Anke Hielscher

Andre Lago

A method for continuously producing a product (A) by way of at least two coupled-together chemical reactions (C, C), wherein at least two input substances (E, E) are fed to a first chemical reaction (C), wherein a plurality of intermediate substances (Z, Z) are produced from the input substances (E, E) by the first chemical reaction (C), wherein at least one of the intermediate substances (Z) is fed to a second chemical reaction (C), wherein the at least one fed intermediate substance (Z) is further processed by the second chemical reaction (C), in particular using at least one further substance (W, W) in a second chemical reaction (C) to form a plurality of output substances (A, A), that is to say to form the chemical product (A) and at least one further output substance (A), wherein the flow rates (F) of the fed substances (E, E, Z, W, W, A) that are fed to one of the reactions (C, C) are set by a respective actuating element (V, V, V, V, V, V), wherein each of the fed substances is assigned a separate actuating element, wherein a manipulated variable (S, S) that is stipulated by a controller (R, R) is respectively applied to at least one of the actuating elements, wherein, for changing the production rate of the chemical product (A), a temporary manipulated variable (S, S) is respectively applied during a transient phase (II, III) to at least one of these actuating elements (V, V) instead of the manipulated variables (S, S) stipulated by the respective controllers (R, R), wherein the temporary manipulated variable (S, S) or the temporary manipulated variables is/are generated by at least one control unit (SE) in dependence on a default value (NV).

Method for continuously producing a product by way of at least two coupled-together chemical reactions

The invention relates to a process for the continuous preparation of aromatic amines by hydrogenation of the corresponding nitroaromatics in the presence of catalysts arranged in reaction spaces, in which an adiabatically operated reaction space RA is connected downstream of an isothermally operated reaction space RI and RA additionally also has a separate feed for the nitroaromatic to be hydrogenated, RI is fed with the nitroaromatic to be hydrogenated from the start to the end of the hydrogenation, and the product mixture emerging from RI is fed into RA from the start to the end of the hydrogenation, wherein RA can additionally be fed via the separate feed with the nitroaromatic to be hydrogenated.

Process for preparing aromatic amines

The invention relates to a process for the production of dinitrotoluene by the two-stage nitration of toluene. In the first stage of this process, toluene was reacted adiabatically with nitrating acid so that at least 90% of the toluene was reacted off and no more than 70% of the toluene formed dinitrotoluene. The resulting organic phase containing mononitrotoluene and the aqueous acid phase containing sulfuric acid were separated, and the aqueous acid phase containing sulfuric acid was concentrated by flash evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage, and/or into the reaction in the second stage, and/or into the concentration in the second stage. In the second stage, the organic phase containing mononitrotoluene from the first stage was completely reacted isothermally with nitrating acid. The organic phase and the aqueous acid phase containing sulfuric acid were then separated, and the aqueous acid phase containing sulfuric acid was concentrated by vacuum evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage and/or the second stage.

Process for the two-step production of dinitrotoluene

Growing community of inventors

Kö'ln, Germany

Erwin Dieterich