Covestro Deutschland Ag

Bayer Materialscience Ag

Covestro LLC

Bayer Intellectual Property Gmbh

Covestro Intellectual Property Gmbh & Co. Kg

Richard Adamson

Stefan Wershofen

Fritz Pohl

Thomas Knauf

Wolfgang Lorenz

Rudolf Uchdorf

Torsten Hagen

Daniel Koch

Heinz-Herbert Müller

Karsten Becker

Andreas Bulan

Rainer Weber

Friedhelm Steffens

Berthold Keggenhoff

Volker Michele

Hans-Georg Pirkl

Knut Sommer

Stefan Grabowski

Matthias Böhm

Jürgen Spriewald

Anke Hielscher

Ricardo Serra

Jeffrey S Bolton

Georg Pirkl

Christian Six

Matthias Boehm

Bodo Temme

Dolan OConnor

Susan Dadd

Dolan Oconnor

Wolfgang Paura

Ralf Esser

Berthold Kegenhoff

Jeffrey Bolton

Enke Liu

Bernd Fruhen

The present invention relates to a process for preparing di- and polyamines of the diphenyl methane series. More specifically, the process comprises reacting aniline and formaldehyde by (1a) mixing aniline with hydrochloric acid to form aniline hydrochloride, and (1b) mixing the aniline hydrochloride with a first portion of aqueous formaldehyde; or (1c) mixing aniline with a first portion of aqueous formaldehyde to form an aminal, and (1d) mixing the aminal with hydrochloric acid; to obtain a first reaction product; (2) converting the first reaction product to a second reaction product comprising di- and polyamines of the diphenyl methane series in a cascade of 4 to 25 reaction zones arranged in series, wherein a second portion of aqueous formaldehyde is added to the second of the reaction zones, in which second reaction zone the temperature is equal to or up to 20&#xb0; C. higher than the temperature in the first reaction zone, and wherein the temperature consecutively increases from the third to the last of the reaction zones, the temperature in the third of the reaction zones being from 15&#xb0; C. to 50&#xb0; C. higher than in the second of the reaction zones, and (3) working-up the second reaction product to obtain the di- and polyamines of the diphenyl methane series.

Process for preparing di- and polyamines of the diphenyl methane series

The invention relates to a process for the preparation of di- and polyamines of the diphenylmethane series (MDA), in which firstly crude MDA is prepared and is then subjected to a distillation process, wherein the distillation process comprises the following:

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

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 present invention relates to a process for producing diamines and polyamines of the diphenylmethane series (MDA) by reacting aniline and formaldehyde in the presence of an acid catalyst, wherein the aniline contains in total less than 0.5 wt. %, based on the total weight of aniline, of one or more compounds which contain at least one carbonyl group or of one or more compounds that are formed by reaction of these compounds which contain at least one carbonyl group with aniline.

Process for producing diamines and polyamines of the diphenylmethane series

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series in which, by using a coalescence auxiliary in the phase separation of the process product obtained in the scrubbing of the neutralized crude product, the fraction of water and thus also of water-soluble impurities in the organic MDA-containing phase is reduced. According to the invention, the coalescence auxiliary used is a filter bed made of coalescence fiber material. The di- and polyamines of the diphenylmethane series obtained after distillative purification of this MDA-containing organic phase are exceptionally suitable for the preparation of the corresponding isocyanates.

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, wherein first aniline and formaldehyde are reacted in the absence of an acidic catalyst to form a reaction mixture containing animal and water and, after the water has been separated the aminal is reacted by acid catalysis to form a reaction mixture containing diamines and polyamines of the diphenylmethane series, wherein the separation of the water from the aminal is supported by the use of a coalescence aid. According to the invention, a filter bed made front coalescence fiber material is used an coalescence aid.

Method for producing diamines and polyamines of the diphenylmethane series

The invention relates to a process for preparing methylenediphenyl diisocyanates which comprises at least the steps: A) reaction of aniline with formaldehyde in the presence of hydrochloric acid as catalyst to give a mixture of diamines and polyamines of the diphenylmethane series (MDA) and subsequent at least partial neutralization of the hydrochloric acid by means of alkali metal hydroxide, B) reaction of the mixture of diamines and polyamines of the diphenylmethane series obtained in step A) with phosgene to give a mixture of diisocyanates and polyisocyanates of the diphenylmethane series (MDI) and hydrogen chloride, wherein C) the hydrochloric acid which has been neutralized in step A) is separated off in the form of a solution containing alkali metal chloride and is subsequently at least partly fed to an electrochemical oxidation to form chlorine, alkali metal hydroxide and optionally hydrogen and D) at least part of the chlorine produced in step C) is used for preparing the phosgene used in step B).

Process for preparing methylenediphenyl diisocyanates

The present invention relates to a process for the preparation of isocyanates by reacting the appropriate amines with phosgene, condensing the gas mixture thereby obtained, stripping the liquid phase thereby obtained and returning the solvent so retained in liquid form to the reaction stage. The gaseous constituents are then purified further in an absorption process.

Process for the preparation of isocyanates

The invention provides an improved process for preparing diamines and polyamines from the diphenylmethane series by reacting aniline and formaldehyde in the presence of an acid catalyst, the improvement involving the aniline containing less than about 3 wt. % of diamines and polyamines from the diphenylmethane series, based on the weight of the aniline.

Process for preparing diamines and polyamines from the diphenylmethane series

The present invention relates to a process for the production of mixtures of di- and polyamines of the diphenylmethane series (MDA) containing less than 1,000 ppm of water and less than 200 ppm of aniline by reaction of aniline and formaldehyde in the presence of acid catalysts and subsequent separation of the acid catalyst and subsequent distillative separation of water and aniline in an at least a two-stage distillation including a flash evaporation and subsequent cooling.

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

The invention provides a process for the preparation of polyamines of the diphenylmethane series. This process comprises

Process for the preparation of polyamines of the diphenylmethane series at a low degree of protonation

Di- and polyamines of the diphenylmethane series are prepared by a) mixing a first portion of aniline with an acid catalyst, b) mixing a second portion of aniline with formaldehyde, and c) mixing and reacting the mixtures prepared in each of steps a) and b). The diamines produced by this process may then be phosgenated to produce the corresponding di-/polyisocyanate.

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Leichlingen, Germany

Richard Adamson