Covestro Deutschland Ag

Bayer Materialscience Ag

Bayer Aktiengesellschaft

Bayer Intellectual Property Gmbh

Covestro Intellectual Property Gmbh & Co. Kg

Other

Covestro Duetschland Ag

Thomas Knauf

Stefan Wershofen

Klaus-Gerd Gruner

Volker Hartjes

Michael Merkel

Dirk Manzel

Peter Plathen

Wolfgang Lorenz

Andreas Karl Rausch

Antoni Mairata

Alexandre Racoes

Peter Drinda

Richard Adamson

Wilfried Braubach

Jürgen Spriewald

Juergen Spriewald

Friedhelm Steffens

Rainer Bruns

Dietmar Wastian

Christian Steffens

Erik Sluyts

Franz-Ulrich Von Gehlen

Karl-Heinz Wilke

Wolfgang Taube

Anke Hielscher

Gerd Sylvester

Bernd Pennemann

Akhtar Osman

Volker Michele

Peter Lehner

Cliff Andre Peters

Thorsten Schmidt

Wolfgang Dohmen

Michael Gr&uuml;n

Francisco Munoz Velasco

Jörg Schmiedler

Karsten Becker

Charles Bjoerndahl

Matthias Ehlers

Carlos Alvarez Herrero

Jan Van Tricht

Jürgen Münnig

Jeffrey Bolton

Claudia Schmid

Juergen Muennig

Christian Drumm

Klaus Pilarczyk

Murat Kalem

Dietrich Wulf

Joerg Schmiedler

Esteve Obis Torruella

Klaus Wiemann

Josef-Werner Naunheim

Denise Chan

Bodo Temme

Andreas Rausch

Charles BJÖRNDAHL

Ralf Esser

Wolfgang Paura

Susan Dadd

Bernd Fruhen

The invention relates to a continuously operating process for producing nitrobenzene, comprising the following steps: a) nitriding benzene in adiabatic conditions with sulfuric acid and nitric acid, using a stoichiometric excess of benzene in relation to the nitric acid; b) first separating a gaseous phase containing benzene and gaseous secondary components from the raw process product of the nitridation in a gas separator provided specifically for this purpose, then separating, in a downstream phase-separating apparatus, the resulting liquid phase, which is depleted in gaseous components and contains nitrobenzene and sulfuric acid, into a sulfuric acid phase and a nitrobenzene phase; and c) processing the nitrobenzene phase, obtaining nitrobenzene. The invention also relates to a production plant suitable for carrying out the claimed process.

Process for the continuous production of nitrobenzene

The invention relates to a method for operating a production plant for producing a chemical product () by reacting a H-functional reactant () with phosgene () during an interruption in production when taking at least one plant part of the production plant out of operation, wherein low-oxygen and oxygen-rich phosgene-containing exhaust gas flows are directed separately from one another in different phosgene decomposition directions and separately from one another&#x2014;at spatially different points&#x2014;into a combustion device, wherein plant parts that have not been taken out of operation are operated in a closed-circuit operating mode. The invention also relates to a production plant for producing a chemical product by reacting H-functional reactants with phosgene, which is suitable for being operated with the method according to the invention.

Production plant for producing a chemical product by reacting H-functional reactants with phosgene, and method for operating same with an interruption to production

The present invention relates to a process for the continuous production of nitrobenzene by the nitration of benzene with nitric acid and sulphuric acid under adiabatic conditions, not the entire production plant being shut down during a production stop, but the production plant being entirely or at least partly operated in recirculation mode. The invention further relates to a plant for producing nitrobenzene and to a method for operating a plant for producing nitrobenzene.

Process for producing nitrobenzene

The invention relates to a method for producing methylene-diphenylene-diisocyanate and optionally a mixture of methylene-diphenylene-diisocyanate and polymethylene-polyphenylene-polyisocyanate, wherein, in a step &#x3b1;), a fraction () containing a methylene-diphenylene-diisocyanate and secondary components is provided, optionally via a step &#x3b1;.), the separating of methylene-diphenylene-diisocyanate and secondary components from a fraction () containing methylene-diphenylene-diisocyanate and polymethylene-polyphenylene-polyisocyanate, and wherein, in a step &#x3b2;), the fraction () containing methylene-diphenylene-diisocyanate and secondary components is subjected to a purification comprising an isomer separation by distillation and/or crystallization in two or more sub-steps (a, b, . . . ), obtaining two or more methylene-diphenylene-diisocyanate-reinfractions (--, . . . ) and a secondary component fraction (), wherein the secondary component fraction () obtained in step &#x3b2;) is returned to one of the sub-steps of step &#x3b2;), wherein none of the methylene-diphenylene-diisocyanate-reinfractions (--, . . . ) from step &#x3b2;) are obtained as distillation or crystallization, and/or to step &#x3b1;.), insofar as carried out.

Method for producing methylene-diphenylene-diisocyanates and polymethylene-polyphenylene-polyisocyanates

The present invention relates to a process for preparing an isocyanate by reacting a primary amine with phosgene, comprising I) providing an amine solution, II) providing a phosgene solution, III) mixing the amine solution with the phosgene solution in a mixing unit, followed by IV) further conversion in an adiabatically operated reaction zone and the removing of the gas phase formed as a result of the chemical reaction in a separation zone, V) expanding the remaining liquid phase in two or three stages, VI) further conversion of the liquid phase remaining after the last expansion stage in an indirectly heated reaction zone and VII) isolating the isocyanate from the reaction solution obtained therein.

Process for preparing an isocyanate by partly adiabatic phosgenation of the corresponding amine

A process for preparing an isocyanate by reacting a primary amine with phosgene. The process includes providing an amine solution and adjusting its temperature in a heat exchanger, providing a phosgene solution and adjusting its temperature in a heat exchanger, mixing the amine solution with the phosgene solution, further conversion in an adiabatically operated reaction zone and the removing of the gas phase formed as a result of the chemical reaction in a separation zone, expanding the remaining liquid phase, further conversion of the liquid phase remaining after expansion in an indirectly heated reaction zone, and isolating the isocyanate from the obtained reaction solution. The temperature in the reaction zone and the temperature in the separation zone is adjusted by fixing a target value of 110&#xb0; C. to 145&#xb0; C. for the temperature of the reaction mixture and using the actual temperature of the reaction mixture for closed-loop control of the temperature of the solution of the primary amine and/or of the temperature of the solution of phosgene.

Process for preparing an isocyanate by partly adiabatically operated phosgenation of the corresponding amine

The invention relates to a method for continuous production of nitrobenzene by means of nitration of benzene with nitric acid and sulfuric acid, in which load change (i.e. a reduction or increase in the quantity of nitric acid supplied to the process per time interval) is particularly advantageously developed. The invention particularly relates to a method in which, in the case of a load reduction, the ratio of the masses of benzene and nitric acid supplied per time interval is significantly increased compared to said ratio before the load change and/or the ratio of the masses of nitric acid and sulfuric acid supplied per time interval is significantly reduced compared to said ratio before the load change. In the event of a load increase, the reverse is carried out.

Method for producing nitrobenzene

The present invention relates to a process for preparing di- and polyamines of the diphenylmethane series (MDA), a system for producing MDA and a process for operating a system for preparing MDA. The invention enables optimization of production standstills during operation of the MDA process with respect to time expenditure and optionally also with respect to energy and material consumption by means of a so-called recirculation mode for individual system components. During interruption of the process or interruption of the operation of individual system components, formaldehyde is not introduced into the reaction and the system components that are not affected by a revision, repair, or cleaning measure are operated in so-called recirculation mode. This enables, among other things, that only the affected system component can be put in standstill during the time period of the measure, which is advantageous in terms of productivity and economy of the process as well as in terms of the quality of the products produced.

Process for preparation of di- and polyamines of the diphenylmethane series

The invention relates to a method for the preparation of di- and polyamines of the diphenylmethane series, care being taken during the shutdown of the production process that an excess of aniline and respect to formalin is ensured.

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities with alteration of the isomer composition in the resulting diamines of the diphenylmethane series (altering the 2,4'-MDA content). Adapting the molar ratios of the total used aniline to the total used formaldehyde and of the total used acid catalyst to the total used aniline, and adapting the reaction temperature, allows the rearrangement reaction to be fully completed despite the change in dwell time inevitably associated with a change in production capacity, and allows the formation of undesired by-products to be avoided as far as possible; the intended modification to binuclear content is likewise achieved.

Method of producing diamines and polyamines of the diphenylmethane series

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities with alteration of the content of diamines of the diphenylmethane series (altering the binuclear content). Adapting the molar ratio of the total used aniline to the total used formaldehyde and adapting the reaction temperature allows the rearrangement reaction to be fully completed despite the change in dwell time inevitably associated with a change in production capacity, and allows the formation of undesired by-products to be avoided as far as possible; the intended modification to binuclear content is likewise achieved.

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities. Adapting the respective molar ratios of the total used aniline to the total used formaldehyde and of the total used acid catalyst to the total used aniline allows the rearrangement reaction to be fully completed despite the change in dwell time inevitably associated with a change in production capacity and ensures that no undesired fundamental changes occur in the product composition.

Method of producing diamines and polyamines of the diphenylmethane series at different production capacities

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities. By adapting the temperatures in the acid-catalysed rearrangement step, the rearrangement reaction can be fully completed despite the change in dwell time inevitably associated with changed production capacity, with no undesired changes occurring in the product composition.

The present invention relates to a process for producing isocyanates in process chains, each of which produce an isocyanate end product via at least one intermediate product, wherein the heat energy liberated in a first production plant in a heat-emitting operation of producing an intermediate product, an isocyanate end product or a catalyst required for a substep of the process chain (first chemical product) is at least partly utilized for generating vapour, in particular water vapour, having a pressure of 1.31 barto 1.91 barand a temperature of 107&#xb0; C. to 119&#xb0; C. and the thus generated vapour is employed for performing a heat-consuming operation in the preparation of another chemical product (second chemical product) in a second production plant.

Process for producing isocyanate and at least one further chemical product in an integrated production

The invention relates to a method for an economically and technically improved embodiment of a production interruption in a production method for isocyanates by phosgenation of the corresponding amines, in which the entire production plant is not closed while one or more parts of the plant is taken out of operation, rather the input materials and/or reaction products available in the production plant are recirculated through at least one part of the plant that has not been taken out of operation. The invention further relates to a plant for producing isocyanates and to a method for operating a plant for producing isocyanates.

Method for producing isocyanates

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Dormagen, Germany

Thomas Knauf