Basf Aktiengesellschaft

Hans J Raabe

Rainer Ohlinger

Bernd Blumenberg

Harald Schnez

Ludwig Pfannenstiehl

The invention relates to a process for the continuous preparation of organic isocyanates, preferably polyisocyanates, through the reaction of organic amines, preferably polyamines, with phosgene in the presence of organic solvents under pressure, for example from 5 to 100 bar, at elevated temperatures, for example from 100 to 220.degree. C., whereby the reaction mixture is partially recycled, preferably using natural circulation, and the hydrogen chloride content in the reaction mixture prior to the addition of the amine is less than 0.5 percent by weight based on the total weight of the reaction mixture and the molar ratio of phosgene to NH.sub.2 group in the organic amines is from 12:1 to 200:1.

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Wachenheim, Germany

Hans J Raabe