Bayer Aktiengesellschaft

Reinhard Schom Acker

Helmut Waldmann

Hans-Joachim Traenckner

Hans-Georg Pirkl

Gerhard Wiechers

Thomas Schieb

Uwe Klingler

J Urgen Zimmermann

An aromatic compound is polynitrated in a continuous process in a single apparatus under adiabatic conditions in an emulsion as the reaction medium. From 1.3 to 3.5 mol of HNO.sub.3 per mol of aromatic compound are introduced in the form of a nitronium ion solution into the reactor with the aromatic compound under conditions such that an emulsion forms. The emulsion, which has a tendency to coalesce, is maintained by repeated dispersion. The first dispersion of the liquid streams to produce the emulsion takes place in less than one second. At least 20% of the total amount of HNO.sub.3 to be used should generally be present during this first dispersion. It is preferred, however, that the total amount of nitronium ion solution to be used be present at the time the aromatic compound and nitronium ion solution are first dispersed.

Process for the polynitration of aromatic compounds

The preparation of 4,4'-dinitrostilbene-2,2'-disulphonic acid by oxidation of 4-nitrotoluene-2-sulphonic acid with oxygen in alkaline medium in aqueous ether alcohol makes possible a simplified work-up.

Process for preparing 4,4'-dinitrostilbene-2,2'-disulphonic acid and its

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Leverkusen, Germany

Reinhard Schom Acker