Rhodia Fiber & Resin Intermediates

Rhone-poulenc Chimie

Rhodia Operations

Henri Chiarelli

Philippe Leconte

Denis Revelant

Gerald Bocquenet

Pascal Vacus

Gérald Bocquenet

Jerome Armand

The invention concerns a method for evaporating aminonitrile and water in conditions limiting or eliminating the formation of heavy by-products in particular amino-carboxylic acid oligomers. To avoid said inconvenience, said method for evaporating aminonitrile and water is characterised in that the water in vapour state serves as balance gas for evaporation.

Method for evaporating aminonitrile

Method for treating lactams

Aromatic polyisocyanates are prepared by reacting at least one compound (A), containing at least two primary amine functions and at least one aromatic nucleus, with a relatively modest quantity of phosgene, in the gaseous phase, the amount of phosgene ranging from the stoichiometric amount to a stoichiometric excess of 100% with respect to the number of moles of amine functions of compound (A), carried out in a mixed reactor which comprises a first, homogenizing zone constituting from 20% to 80% of the total volume thereof, and a second, essentially piston flow downstream zone constituting from 80% to 20% of the total volume thereof.

Preparation of aromatic polyisocyanates in gaseous phase

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Communay, France

Henri Chiarelli