Bayer Materialscience Ag

Covestro Deutschland Ag

Lanxess Deutschland Gmbh

Bayer Intellectual Property Gmbh

Bayer Aktiengesellschaft

Covestro Intellectual Property Gmbh & Co. Kg

Rainer Bruns

Wolfgang Lorenz

Friedhelm Steffens

Martin Kugler

Andreas Karl Rausch

Tim Loddenkemper

Fritz Pohl

Klaus Biskup

Stefan Wershofen

Thomas Jaetsch

Herbert Stutz

Hermann Uhr

Oliver Kretschik

Wolfgang Taube

Hans-Ludwig Elbe

Heiko Rieck

Thomas Knauf

Dietmar Kuhnt

Erasmus Vogl

Olaf Gebauer

Lars Padeken

Peter Wachtler

Bernd Pennemann

Volker Michele

Heinz-Joachim Rother

Peter Lehner

Gerd-Friedrich Renner

Knut Sommer

Peter Spetmann

Michel Haas

Artur Mausbach

Frank Diehl

Alexander Schwarz

Bernhard Neumann

Andreas Rausch

Michel DrDr Haas

The invention relates to a method for preparing an isocyanate by phosgenating the corresponding primary amine in the gas phase, wherein the gaseous reaction product mixture is cooled by being brought into contact with at least one flow stream of a quenching liquid in a quenching zone, wherein the quenching liquid used in total comprises, based on the total mass, organic solvents in a proportion of maximally 50.0% by mass, and the remainder of up to 100% by mass consists of at least the isocyanate to be produced, thereby obtaining a mixture of the reaction product mixture and the quenching liquid. Furthermore, the mixture obtained in this manner of the reaction product mixture and the quenching liquid is separated into a liquid and a gaseous phase in a collection zone, and a liquid solvent intermediate flow comprising more than 50.0% by mass of organic solvents, based on the total mass of the liquid solvent intermediate flow, is conducted into the collecting zone and/or into a collecting tank arranged fluidically downstream of the collection zone for the liquid phase obtained in the collection zone.

Method for producing isocyanates

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

This invention relates to a process for operating a gas phase phosgenation plant () to form an isocyanate () by reacting an amine () with phosgene (), in which the gas phase phosgenation plant is shut down by first stopping the amine stream and still maintaining the phosgene stream. After a period of time which corresponds to at least 10 times the residence time of phosgene () in the main parts of the gas phase phosgenation plant () in regular operation, calculated from the time at which the amine inflow has been completely stopped, the feed of phosgene is also stopped. An inert gas stream () is maintained through the amine and phosgene feeding devices and through all the other essential parts of the gas phase phosgenation plant () during the shutdown.

Process for operating a gas phase phosgenation plant

This invention relates to a process for operating a gas phase phosgenation plant () to form an isocyanate () by reacting an amine () with phosgene (), in which the gas phase phosgenation plant is started up by first charging the plant with phosgene. At the same time as, or after the first charge of phosgene, the amine supply devices are rendered inert using a hot inert gas stream (). Then, amine is admixed for the first time. In this way and by maintaining a pressure drop in the amine and phosgene devices to the mixing zone, the back mixing of phosgene into the amine-containing reactant stream during start-up is prevented.

Method for operating a gas-phase phosgenation plant

The invention relates to a method for preparing isocyanates by phosgenating the corresponding amines, wherein low-boiling secondary components, excess phosgene, and the co-product hydrogen chloride are separated from the crude liquid isocyanate stream, which is obtained after the phosgenation has occurred, within a maximum of 60 minutes, and wherein the crude liquid isocyanate stream is not exposed to temperatures above 250&#xb0; C. until said separation.

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 process for the preparation of isocyanates by reaction of the corresponding amines with phosgene in the gas phase, wherein a diluent containing between 90.0000% by weight and 99.9999% by weight of substances which are inert in the phosgenation process and between 0.0001% by weight and 10.0000% by weight of oxygen is present during the conversion of the amine into the gas phase and the molar ratio of amine to oxygen (O) is &#x2267;1,000:1.

Method for producing isocyanates in the gas phase

Chlorine is prepared by catalytic oxidation of a hydrogen chloride stream having a content of sulfur in elemental or bonded form of less than 100 ppm, preferably less than 50 ppm, more preferably less than 5 ppm, most preferably less than 1 ppm, based on the weight of the hydrogen chloride stream.

Process for the oxidation of a gas mixture containing hydrogen chloride

Isocyanates are produced by reacting a primary amine with phosgene in the gas phase. In this process, the amine is vaporized and then superheated prior to introduction into the reactor. The amine is superheated to a temperature at least 10&#xb0; C. above dew point before entry into the reactor. A pressure difference between the vaporizer and entry into the reactor of from 1 to 500 mbar is maintained.

Aromatic isocyanates are produced by reacting one or more aromatic primary amines with phosgene in the gas phase. The phosgene and primary aromatic amine(s) are reacted at a temperature above the boiling temperature of the amine(s) in a reactor having a reaction space which is essentially rotationally symmetric to the direction of flow. The flow fate, averaged over the cross-section, of the reaction mixture along the axis of the essentially rotationally symmetric reaction space in the section of the reaction space in which the conversion of the amine groups into isocyanate groups is between 4 and 80% is not more than 8 m/sec. The flow rate averaged over the cross-section of the reaction mixture along the axis of the essentially rotationally symmetric reaction space in the section of the reaction space in which the conversion of the amine groups into isocyanate groups is 4 to 80% is always below the flow rate averaged over the cross-section at the start of this section.

Active compound mixtures comprising ipconazole and at least one further fungicidally active compound are highly suitable for protecting industrial materials against colonization and destruction by microorganisms.

Fungicidally active compound combinations

An isocyanate is produced by continuously reacting an amine with phosgene in the presence of an inert substance in the gas phase. In this process, a phosgene-containing stream and a stream containing both the amine and the inert substance are fed into a reactor. The molar ratio of the inert substance to the amino groups in the stream is greater than 0 but less than 45 mol %. This molar ratio changes by no more than 99% during a 20 minute period.

An isocyanate is produced by reacting an amine with a stoichiometric excess of phosgene in the gas phase. This reaction is carried out at a temperature above the amine's boiling point to obtain a liquid stream containing the isocyanate and a gas stream containing hydrogen chloride and phosgene. The gas stream containing hydrogen chloride and phosgene thus produced is separated into a gas stream containing hydrogen chloride and a liquid stream containing phosgene. At least part of the liquid stream containing phosgene is then converted to a gas stream containing phosgene which gas stream is then recycled. The gaseous phosgene stream is maintained at a higher pressure than the liquid phosgene stream.

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Leverkusen, Germany

Rainer Bruns