Bayer Materialscience Ag

Covestro Deutschland Ag

Covestro LLC

Bayer Materialscience, LLC

Spotswood Miller

Ricardo Serra

Gerhard Wegener

Bernd Pennemann

Dietmar Wastian

Fritz Pohl

Daniel Koch

Ulrich Westphal

Jürgen Kirsch

Jeffrey S Bolton

Dieter Förtsch

Richard G Hillman

Amber R Hicks

James E Sager

Xiaoyan Wang

Sara DeLucia

Dieter Foertsch

Matthias Ehlers

Ralf Ochel

Gary B Solak

Kirk J Bourgeois

Gregory L McCullough

The invention relates to a method for reducing the concentration of nitrogen oxides in waste gases released dating the production of organic amino compounds, wherein an organic compound is first reacted with NOand/or nitric acid to form an organic nitro compound with the formation of an NO-containing waste gas stream and the organic nitro compound is converted to the organic ammo compound by means of hydrogen-containing reaction gas, the reaction of the organic nitro compound with the hydrogen-containing reduction gas taking place with the formation of a hydrogen-containing waste gas stream, the method being characterised in that the NO-containing waste gas stream is combined with the hydrogen-containing waste gas stream and/or an externally supplied hydrogen stream and is reacted at a temperature of 800 to 1700&#xb0; C. for the at least partial reduction of the NOconcentration. The invention additionally relates to an apparatus for carrying out the method.

Method and apparatus for denenoxing waste gases from nitration

A two-stage process for the preparation of organic isocyanates by reacting primary amines with phosgene in which: a) in a first stage, amine and phosgene are reacted in an adiabatically managed reaction, in which the temperature of reaction is restricted to values between 100 and 220&#xb0; C. by actively adjusting the absolute pressure in the reactor to values between 8 and 50 bar by decompression, and the temperature is held at values between 100 and 220&#xb0; C. until the stoichiometric conversion of phosgene has reached at least 80%; and then b) in a second stage, the reaction mixture from a) is decompressed to an absolute pressure of 1 to 15 bar and the reaction mixture is reacted further at temperatures between 90 and 240&#xb0; C., optionally with the introduction of heat.

Process for preparing polyisocyanates by the adiabatic phosgenation of primary amines

Isocyanates are produced by reacting an organic amine with phosgene in process which includes at least three stages. The first stage is carried out in a dynamic mixer. The second stage is carried out in at least one reactor. The third stage is carried out in at least one material separating apparatus. The pressure in the reactor of the second stage must be greater than or equal to the pressure in the dynamic mixer. The pressure in the third stage material separating apparatus must be lower than the pressure in the second stage reactor.

Process for the continuous preparation of isocyanates

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