Bayer Aktiengesellschaft

Bayer Materialscience Ag

Covestro Deutschland Ag

Covestro LLC

Bayer Materialsceince Ag

Bayer Intellectual Property Gmbh

Herbert Stutz

Hartmut Knofel

Michael Brockelt

Stefan Penninger

Rainer Bruns

Friedhelm Steffens

Heiko Herold

Fritz Pohl

Klaus Biskup

Gunter Hammen

Martin Friedrich

Reinhard Halpaap

Wolfgang Lorenz

Volker Michele

Jurgen Dahmer

Hans-Joachim Leimkühler

Peter Fuhrmann

Eckart Waldau

Hans-Georg Frosch

Eric Bischof

Heinrich Grave

Andreas Flink

Wolfgang Leuckel

Hans-Joachim Brockhaus

Attila Molnar

Jürgen Meyn

Frank Diehl

Marc Jenne

Helmut Schmidt

Alexander Schwarz

Hans-Joachim Leimk&uuml;hler

Tilak Suren Lewkebandara

Peter Briedenbach

The invention relates to the preparation of isocyanates by phosgenation of amines in the gas phase, with these isocyanates having a comparatively low proportion of color-imparting compounds.

Preparation of light-colored isocyanates

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.

Process for the preparation of isocyanates

Processes comprising providing an amine reactant, and reacting the amine reactant with a stream of phosgene in a reaction zone to form a product comprising a corresponding isocyanate, wherein the phosgene stream has a CO content of 0.5% by weight or more.

Processes for preparing low-chlorine isocyanates

Isocyanates are produced by reaction of primary amines with phosgene in the gas phase. In this process, the reaction is terminated by guiding the reaction mixture from the reaction chamber through a cooling stretch into which liquids are injected. Direct cooling takes place in the cooling stretch in one stage in two or more cooling zones connected in series.

Process for the preparation of isocyanates in the gas phase

An isocyanate is produced by reacting a primary amine with phosgene in the gas phase above the boiling point of the amine over an average contact time of 0.05 to 15 seconds under adiabatic conditions.

The present invention relates to a process for the production of an isocyanate corresponding to the formula R(NCO)wherein

Process for the production of (poly)isocyanates in the gas phase

The invention relates to a process for the preparation of isocyanates in the gas phase, in which the possibilities for back-mixing and byproduct formation are reduced by improving the mixing of the starting materials in a tubular reactor.

Process for the preparation of diisocyanates

The present invention relates to a process for preparing (cyclo)aliphatic diisocyanates and triisocyanates corresponding to the formulaR&#x2014;(NCO)&#x2003;&#x2003;(I),wherein

Process for preparing (cyclo)aliphatic isocyanates

Isocyanates are produced in the gas phase in a manner such that temperature fluctuations over time and temperature distribution asymmetry are prevented. In this improved process, performance of the reaction in tubular reactors is accomplished by flow-related measures such as homogenization and centering of the educt streams. The formation of polymeric secondary products, which result in baked-on deposits in the reactor and a reduction in reactor service life, is consequently prevented.

Process for the production of isocyanates in the gas phase

The present invention provides a process for quenching a gaseous reaction mixture during the phosgenation of diamines in the gas phase to produce diisocyanates. The gaseous reaction mixture contains at least a diisocyanate, phosgene and hydrogen chloride. The quenching liquid is injected into the gas mixture continuously flowing out of a cylindrical reaction zone into the downstream cylindrical quenching zone with the aid of at least two spray nozzles which are arranged at the entrance to the quenching zone at equal distances along the circumference of the quenching zone.

Process for quenching a gaseous reaction mixture during the gas phase phosgenation of diamines

The present invention relates to a novel process for preparing (cyclo)aliphatic diisocyanates and triisocyanates by phosgenation of (cyclo)aliphatic diamines and triamines in the gas phase by accelerating the flow of at least one of reactants in the region where the reactants are mixed.

Diisocyanates are produced by gas-phase phosgenation of aliphatic diamines having two primary amino groups in the 1,2- or 1,3-position to one another or by cycloaliphatic diamines having two primary amino groups in the 1,2- or 1,3-position to one another.

Process for the production of diisocyanates

Diisocyanates and isomer mixtures of diisocyanates corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, m and n are as defined herein are produced by phosgenating diamines and isomer mixtures of diamines corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, m and n are as defined herein. These diisocyanates which are liquid at room temperature and highly compatible with polyols are particularly useful in the production of polyurethanes.

Cycloaliphatic diisocyanates optionally in the form of isomer mixtures

A diisocyanate corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein is prepared by phosgenating a diamine corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein. The diisocyanate may contain C.sub.1 -C.sub.12 -monoalkyl-substituted methylene-bis-(cyclohexylisocyanate)isomers in an amount of up to 40 wt. %. These new diisocyanates which are liquid at room temperature and compatible with polyols are particularly useful in the production of polyurethanes.

Cycloaliphatic diisocyanates, optionally in the form of isomeric

The present invention relates to a process for the preparation of diisocyanates corresponding to the formula

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Dormagen, Germany

Herbert Stutz