Bayer Intellectual Property Gmbh

Covestro Deutschland Ag

Bayer Materialscience Ag

Bayer Materialscience, LLC

Peter Lehner

Michael Merkel

Knut Sommer

Andre Lago

Stefan Wershofen

Thomas Knauf

Karl-Heinz Wilke

Friedhelm Steffens

Stephan Schubert

Alfred Soppe

Markus Dugal

Franz-Ulrich Von Gehlen

Ido Schwarz

Susanne Buchholz

Benie Marotz

Eric Jakobs

Wolfgang Lorenz

Rainer Bruns

Andreas Karl Rausch

Amgad Salah Moussa

Hans-Georg Pirkl

Jürgen Kintrup

Andre Düx

Jürgen Münnig

Knud Werner

Thomas Turek

Bastian Mahr

Matthias Brandt

Erwin Dieterich

Holger Orzesek

Andre Rittermeier

Murat Kalem

Henrike Fink

Jürgen Bittner

Franz-Ulrich Gehlen

Micky Qian

Luyan Wu

Alexandra Groβe Böwing

Rainer Hellmich

The present invention relates to a method and a system for separating and treating impurities from a hydrogen chloride liquid mixture from the process for preparing isocyanate with phosgenation including sending hydrogen chloride liquid mixture into a gas-liquid separation column for separation to yield a liquid phase flow with impurities at the bottom of the gas-liquid separation column, neutralizing the liquid phase flow comprising impurities with an alkaline liquid in the neutralization tank to yield a neutralized solution, and sending the neutralized solution into a waste liquid treatment device from said neutralization tank for treatment.

Method and a system for separating and treating impurities from a hydrogen chloride liquid mixture

The present invention concerns a process for the preparation of pure aniline, comprising the steps of a) providing a crude aniline fraction containing up to 20.000% by weight of phenol; b) dividing the crude aniline fraction from step a) into a first partial stream and a second partial stream; c) distilling the first partial stream from step b) in a first distillation column and distilling the second partial stream from step b) in a second distillation column, wherein the first distillation column is operated at a higher head pressure than the second distillation column, with the proviso that each of the first distillation column and the second distillation column is operated at a head pressure in the range from 1.0 mbarto 500 mbar, and wherein from each of the first distillation column and the second distillation column, (i) a gaseous aniline distillate (=purified aniline) is removed as the overhead product and subsequently condensed, wherein a first partial stream of the condensed aniline distillate is returned to the first and/or the second distillation column as a reflux stream and a second partial stream of the condensed aniline distillate is removed as the product stream, and (ii) a liquid bottom stream which is concentrated in phenol is removed, from which a first portion is partially or completely vaporised and is returned to the respective distillation column, and from which a second portion is discharged; d) using the heat released during the condensation of the aniline distillate from the first distillation column in order to provide the heat necessary for vaporising the first portion of the bottom stream from the second distillation column.

Aniline purification process

Methods for the preparation of diisocyanates by the reaction of the corresponding primary diamines with phosgene in the gas phase are described, wherein the pressure in the diamine evaporation chamber during the transfer of the diamine into the gas phase is less than the pressure in the reaction chamber during the reaction to the diisocyanates, and wherein the pressure difference between the diamine evaporation chamber and the reaction chamber prior to the mixing of diamine and phosgene is overcome by a pressure-increasing element.

Method for preparing diisocyanates in the gas phase

The present invention relates to a process for the purification of aniline which originates from gas phase hydrogenations. In this process, only a minimum proportion of the aniline has to be evaporated and condensed again. The process is highly efficient in removing compounds which have phenolic hydroxyl groups and results in minimal losses of aniline. This process also reduces the unwanted coupling mechanisms in the division of the overall crude product in the fraction condensation into individual substreams and the subsequent workup of these.

Process for the purification of aniline from gas phase hydrogenations

The present invention relates to a catalyst comprising a ceramic support with a BET surface area of less than 40 m/g and (a) 1.0 to 100 g of at least one metal of groups 8 to 12 of the periodic table of the elements, (b) 1.0 g to 100 g of at least one metal of groups 4 to 6 and 12 of the periodic table of the elements and (c) 1.0 g to 100 g of at least one metal of groups 14 and 15 of the periodic table of the elements per liter of bulk volume of the ceramic support, wherein the catalyst is additionally doped with (d) potassium in a content of from 0.0050% by weight to 0.20% by weight, based on the total weight of the catalyst. The present invention also provides the use of such a catalyst in the catalytic gas phase hydrogenation of nitroaromatics.

Catalyst and method for producing aromatic amines in the gas phase

The invention relates to a process for purifying aniline produced by gas-phase hydrogenation of nitrobenzene, by fractional condensation of the crude reaction product obtained in gaseous form so that at least two liquid process products, a partial condensate (PK) and a total condensate (TK), are obtained.

Process for purifying aniline from gas phase hydrogenations

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

Aromatic amines are produced by adiabatic hydrogenation of nitroaromatic compounds in the gas phase on one or more fixed catalysts. The nitroaromatic reactant is passed over the catalyst under pressure and at elevated temperature with hydrogen, water, optionally nitrogen and substantially in the absence of the aromatic amine produced from the nitroaromatic.

Process for producing aromatic amines

The invention relates to a process for the preparation of isocyanates in a system network comprising an isocyanate production plant, a chlorine production plant and a phosgene production plant, in which carbon dioxide formed as a by-product is partially to completely condensed out with the gaseous chlorine formed in the chlorine production plant and enters into the phosgene preparation process and, after the preparation of phosgene, the predominant part of the carbon dioxide formed is thereby sluiced out of the system network in gaseous form.

Process for the preparation of isocyanates

Aromatic amines which have been obtained by reduction of aromatic nitro compounds are purified by mixing the crude amine obtained after phase separation with an aqueous, alkali metal hydroxide solution and subsequent distillation of this mixture over a distillation column. The distillation column has at least an upper and a lower rectifying part and a stripping part. The bottom product of the distillation column is partly to completely sluiced out and is partly evaporated in a main evaporator and at least one downstream re-evaporator and partly recycled back into the column.

Process for the purification of aromatic amines

Crude aniline is produced by hydrogenating nitrobenzene in the presence of a catalyst. This crude aniline is then purified by means of a single-step or multi-step distillation process in which aqueous alkali metal hydroxide solution is added to the crude aniline prior to distillation and/or during distillation of the crude aniline.

Process for preparing aniline

Compounds containing phenolic hydroxy groups are removed from a gas stream which contains at least one aromatic amine generated during the gas-phase hydrogenation reaction of the corresponding nitroaromatic compounds with hydrogen, by adsorption on a basic solid.

Process for removing compounds containing phenolic hydroxy groups from aromatic amines

The invention describes a process for the production of aromatic amines by the catalytic hydrogenation of aromatic nitro compounds, with the process being characterized by at least one catalytic hydrogenation step and the catalyst consists at least of a monolithic support and a catalytically active coating.

Process for the production of aromatic amines by heterogeneously catalysed hydrogenation

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Baytown, TX, United States of America

Peter Lehner