Covestro Deutschland Ag

Bayer Materialscience Ag

Bayer Intellectual Property Gmbh

Covestro LLC

Bayer Materialscience, LLC

Lanxess Deutschland Gmbh

Covestro Intellectual Property Gmbh & Co. Kg

Bernd Pennemann

Wolfgang Lorenz

Friedhelm Steffens

Thomas Knauf

Eberhard Zirngiebl

Andreas Karl Rausch

Fritz Pohl

Lars Padeken

Gerhard Wiechers

Bill Brady

Erwin Dieterich

Rainer Buse

Juergen Muennig

Heinz-Josef Hamacher

Rainer Bruns

Dietmar Wastian

Volker Michele

Joachim Zechlin

Klaus Biskup

Amgad Salah Moussa

Jürgen Münnig

Antoni Mairata

Bastian Mahr

Wulf Dietrich

Spotswood Miller

Jürgen Bausa

Zhangyong Ming

Ulrich Westphal

Dieter Förtsch

Martina Gerdinand

Gerd Greger

Jesse Caravaggio

Kameh Tajvidi

Shuang Liang

Juergen Bausa

John F Gisch, Jr

Dieter Foertsch

Wenbin Ji

Lothar Weismantel

Antonia Zock

Bodo Temme

Juergen Munnig

Lennart Sandbrink

Hans-Jürgen Quella

Marc Williams

Andreas Rausch

Ji Wenbin

The present invention relates to a method for preparing an apparatus (or a plant comprising a plurality of apparatuses), for example a heat exchanger, a vaporizer or a distillation column, for use in a process (in particular a continuously operated process) for concentrating a mineral acid by evaporation of water, wherein the apparatus or the plant comprises (at least) a device which is resistant to the mineral acid and the device is flushed with an aqueous alkali metal hydroxide solution having a concentration by mass of alkali metal hydroxide in the range from 1% to 30% at a temperature in the range from 40° C. to 90° C. for a time of from 2 hours to 7 days.

Method of cleaning an apparatus used in the concentration of a mineral acid

The present invention provides a method for operating a rectification column () for separating a mixture (S) containing a component A and a component B having a boiling point higher than that of the component A at an operating pressure of the rectification column () which is lower than ambient pressure, wherein the method comprises a step for controlling the mass fraction of the component B in the product stream of the component A (P) to a value within a first target range from 0.1% to 5.0% and the mass fraction of the component A in the product stream of the component B (P) to a value within a second target range from 0.1% to 5.0%, wherein the control is carried out as a function of a controlling temperature (TC) for which a setpoint TCis calculated according to the equation TC=T2+F&#xb7;(T1&#x2212;T2), where F is a factor which is in the range from 0.1 to 0.9 and T1 and T2 are reference temperatures, wherein in the case of a deviation in the measured control temperature (TC) from its setpoint TCbeing found the control temperature (TC) is readjusted to the setpoint TCby varying one or more of the following actuating variables: (i) heating of the column bottom () by the evaporator (), (ii) the mass flow {dot over (m)}of the reflux (A) fed back into the rectification column, (iii) the mass flow {dot over (m)}of the product stream Pand (iv) the mass flow {dot over (m)}of the product stream P

Method for operating a rectification column

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 cascade tray suitable for use in a rectifying column and comprising openings in the weir-type cascade edge, to a rectifying column containing at least one cascade tray according to the invention, to a method for operating such a rectifying column, and to the use of a claimed rectifying column in the fractionation of specific substance mixtures.

Cascade tray, rectifying column containing said cascade tray, method for operating such a rectifying column, and use of same

The invention concerns a method for producing toluenediamine by hydrogenation of dinitrotoluene in the presence of a catalyst, a dinitrotoluene being used as starting material and being processed by applying an electrical voltage.

Method for producing toluenediamine

The invention relates to a method for producing organic amino compounds from organic nitro compounds, wherein the organic nitro compound hydrogenated to the organic amino compound with a hydrogen-containing gas stream by means of a catalyst, the reaction course of the hydrogenation being monitored by analysis of secondary products forming during hydrogenation, wherein the method is characterized in that the concentration of one or more gaseous secondary products is determined in the gas phase and if the concentration falls below a predefinable minimum concentration the hydrogenating activity of the catalyst is increased. The present invention also relates to a device for performing said method.

Device and method for producing aromatic amines

The invention relates to a method for producing dinitrotoluene, comprising the following steps: a) nitrating toluene with a mixture of nitric acid and sulfuric acid and subsequently separating a sulfuric-acid-containing aqueous phase that arises in the nitration, wherein a raw dinitrotoluene is obtained, b) washing the raw dinitrotoluene in a water wash with neutral and/or alkaline washing water, wherein a pre-cleaned dinitrotoluene, which contains at least water in addition to dinitrotoluene, is obtained after the washing water used in the last wash has been separated, and c) separating the water from the pre-cleaned dinitrotoluene, d) collecting the waste water from steps a), b), and/or c), e) optionally extracting the collected waste water from step d) with toluene and returning the thus obtained organic phase to step a), f) freeing the collected waste water from step d), or, if the optional step e) is performed, the extracted waste water from step e), of toluene in a toluene stripper, wherein a toluene-containing exhaust gas flow is obtained, g) feeding at least one exhaust gas flow from steps a), b), c), d), e), or f) into an exhaust gas condenser and removing the toluene contained in the at least one exhaust gas flow in said exhaust gas condenser, wherein the method comprises the following further step: h) feeding the exhaust gas flow arising in step g) after the condensing out of the toluene to a thermal exhaust air cleaning, wherein nitrogen is added to the exhaust gas flow to be fed to the exhaust gas condenser or to the exhaust gas flow leaving the exhaust gas condenser, wherein preferably a nitrogen concentration in the exhaust gas flow of at least 0.1 vol % is set, especially preferably of at least 0.5 vol %.

Exhaust gas cleaning in a method for continuously producing dinitrotoluene

The invention relates to an industrial-scale method for the vapor-phase hydrogenation of dinitrotoluene (DNT). According to said method, a stream containing DNT is sprayed into a carrier-gas stream containing hydrogen, optionally in the presence of an atomizing gas, unevaporated liquid droplets are extracted from the substantially gaseous stream that is obtained and the resultant gas stream is catalytically hydrogenated to form diaminotoluene.

Method for producing diaminotoluene

Meta-toluene-diisocyanate is produced by reacting meta-toluenediamine with phosgene in the gas phase. The meta-toluenediamine to be vaporized for use in this phosgenation process must contain less than 0.5 wt. % of toluenediamine residue, a total of less than 0.2 wt. % of ammonia and cycloaliphatic amines, and less than 20 ppm of heavy metals. At least 0.1 wt. % of the liquid meta-toluenediamine being to be vaporized must not be vaporized. This non-vaporized content of the meta-toluenediamine must not be fed to the phosgenation reactor.

Process for the preparation of isocyanates in the gas phase

The invention relates to a method for reducing the concentration of nitrogen oxides in waste gases released dating the production of organic amino compounds, wherein an organic compound is first reacted with NOand/or nitric acid to form an organic nitro compound with the formation of an NO-containing waste gas stream and the organic nitro compound is converted to the organic ammo compound by means of hydrogen-containing reaction gas, the reaction of the organic nitro compound with the hydrogen-containing reduction gas taking place with the formation of a hydrogen-containing waste gas stream, the method being characterised in that the NO-containing waste gas stream is combined with the hydrogen-containing waste gas stream and/or an externally supplied hydrogen stream and is reacted at a temperature of 800 to 1700&#xb0; C. for the at least partial reduction of the NOconcentration. The invention additionally relates to an apparatus for carrying out the method.

Method and apparatus for denenoxing waste gases from nitration

The invention relates to a process for the preparation of aromatic amines in the liquid phase by catalytic hydrogenation of the corresponding nitroaromatic compounds in at least two reaction spaces connected in series, wherein at least one reaction space is operated isothermally and at least the reaction space connected downstream thereof is operated adiabatically, and in preferred embodiments the sudden adiabatic temperature change is used for monitoring the reaction.

Method for producing aromatic amines in the liquid phase

The present invention relates to a process and a plant for the production, in particular the continuous production, of nitrobenzene by means of adiabatic nitration of benzene with nitric acid in the presence of sulfuric acid, in which, following the nitration, a multi-stage concentration of the sulfuric acid is carried out by means of heating at a pressure that is reduced as compared with ambient pressure, and wherein the heating takes place using the heat generated in the adiabatic nitration of benzene.

Method and system for producing nitrobenzene

Nitrobenzene is continuously produced by nitration of benzene with mixed acid under adiabatic conditions. In this process, the pressure upstream of the nitration reactor is from 14 bar to 40 bar above the pressure in the gas phase of the phase separation apparatus used to separate crude nitrobenzene and waste acid.

Process for the continuous preparation of nitrobenzene

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

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Bergisch Gladbach, Germany

Bernd Pennemann