Covestro Deutschland Ag

Bayer Aktiengesellschaft

Bayer Materialscience Ag

Manfred Keller-Killewald

Dietmar Wastian

Reinhard Halpaap

Josef Sanders

Christian Steffens

Martin Ehrig

Armin Schymura

Berthold Keggenhoff

Andreas Karl Rausch

Joachim Ritter

Jürgen Münnig

Jan Busch

Matthias Böhm

Jürgen Arras

Anke Hielscher

Erwin Dieterich

Marcus Grünewald

Holger Conzelmann

Andreas Rausch

The invention relates to a method for producing 1,5-pentanediisocyanate (PDI) by reacting 1,5-pentanediamine (PDA) with phosgene in the gas phase.

Method for producing 1,5-pentanediisocyanate in the gas phase

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 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 a process for the production of dinitrotoluene by the two-stage nitration of toluene. In the first stage of this process, toluene was reacted adiabatically with nitrating acid so that at least 90% of the toluene was reacted off and no more than 70% of the toluene formed dinitrotoluene. The resulting organic phase containing mononitrotoluene and the aqueous acid phase containing sulfuric acid were separated, and the aqueous acid phase containing sulfuric acid was concentrated by flash evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage, and/or into the reaction in the second stage, and/or into the concentration in the second stage. In the second stage, the organic phase containing mononitrotoluene from the first stage was completely reacted isothermally with nitrating acid. The organic phase and the aqueous acid phase containing sulfuric acid were then separated, and the aqueous acid phase containing sulfuric acid was concentrated by vacuum evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage and/or the second stage.

Process for the two-step production of dinitrotoluene

Growing community of inventors

Dormagen, Germany

Manfred Keller-Killewald