Covestro Deutschland Ag

Bayer Materialscience Ag

Christian Steffens

Dietmar Wastian

Stefan Wershofen

Thomas Knauf

Jan Busch

Jürgen Arras

Manfred Keller-Killewald

Juergen Spriewald

Anke Hielscher

Jens Krause

Volker Michele

Andreas Karl Rausch

Torsten Hagen

Joachim Ritter

Jeffrey Bolton

Matthias Böhm

Marcus Grünewald

Marc Seekamp

Jörg Laue

Werner Kilian

Matthias Ruhland

Holger Conzelmann

Andreas Rausch

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 an improved process for making available the coproduct hydrogen chloride obtained in the preparation of an isocyanate by phosgenation of the corresponding amine for a desired subsequent use (i.e. a chemical reaction), in which part of the total hydrogen chloride obtained is isolated in gaseous form at a pressure which is higher than the pressure desired for the subsequent use of the hydrogen chloride by lowering the pressure of the crude product from the phosgenation and the remaining part of the total hydrogen chloride obtained is separated off at a pressure lower than that desired for the subsequent use from the liquid crude product from the phosgenation remaining after lowering of the pressure and is subsequently compressed to a pressure which is higher than that desired for the subsequent use, and in which the two hydrogen chloride streams obtained in this way are, preferably together after having been combined, purified so as to give a purified hydrogen chloride at a pressure which is higher than the pressure desired for the subsequent use.

Process for providing hydrogen chloride for chemical reactions

The present invention relates to a continuous process for preparing a polyisocyanate, in which a polyamine and phosgene are first converted predominantly to carbamoyl chloride and amine hydrochloride and only in minor proportions to polyisocyanate, and a portion of the carbamoyl chloride- and amine hydrochloride-containing reaction mixture thus obtained is recycled into the reaction with phosgene, wherein polyamine, phosgene and the carbamoyl chloride- and amine hydrochloride-containing reaction mixture are mixed intimately in a mixing unit. The portion of the carbamoyl chloride- and amine hydrochloride-containing reaction mixture which is not recycled into the phosgenation is worked up to give the polyisocyanate.

Process for preparing polyisocyanates

The invention relates to a method for producing organic diisocyanates by reacting the corresponding diamines with phosgene in inert solvents. High-melting diamines from the series of 1,5-naphthalenediamine, tetralindiamine, 1,4-phenylenediamine, durenediamine, and o-tolidinediamine are used as diamines. According to the invention, a suspension of the diamines in inert solvents is produced, wherein dynamic mixing units, selected from dispersion disks and rotor-stator systems, are used, and the obtained suspension is phosgenated.

Method for producing diisocyanates by phosgenating diamine suspensions

The invention relates to a mixer reactor of the rotor-stator type. This mixer reactor comprises a substantially rotationally symmetric housing which has a distributing chamber, a mixing chamber, a front plate that modifies the cross-section of the housing between these two chambers, and there are separate inlets into the mixing chamber for at least two substances and an outlet for removing the mixed material or product. The inlet for the first substance is provided in the axis of rotation of the mixing chamber. Two or more channels are aligned radially outward from this inlet, and the first substance is transported through these channels and into the mixing chamber. The inlet for the at least second substance is constructed in the form of a plurality of openings in the front plate, these inlet openings being are arranged rotationally symmetrically to the axis of rotation. Each of these inlet openings for the at least second substance has a corresponding pin which can be displaced in the axial direction.

Process and mixing unit for the preparation of isocyanates by phosgenation of primary amines

The invention relates to an improved process for the production of isocyanates by the reaction of an amine or a mixture of two or more amines with phosgene, the improvement involving the phosgene containing less than about 100 ppm of sulfur in elemental or bound form. The inventive process yields light-colored isocyanates that are suitable for the production of polyurethanes or their precursors (e.g. prepolymers) without the treatment processes heretofore required.

Process for the production of light-colored isocyanates

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Kö'ln, Germany

Christian Steffens