Bayer Aktiengesellschaft

Hans-Joachim Raatz

Bernd-Michael K&ouml;nig

Eberhard Zirngiebl

Hans-Martin Weber

Thomas Linn

Ricarda Leiberich

Ralf Demuth

Johannes D&uuml;hr

Manfred Kaczorowski

The present invention relates to a continuous adiabatic process for preparing nitrochlorobenzene, in which the waste sulfuric acid produced during the practice of the process is reconcentrated and recycled into the nitration reaction.

Continuous adiabatic process for preparing nitrochlorobenzene

1,2-Dichlorobenzene can be reacted very selectively under adiabatic reaction conditions to give 3,4-dichloronitrobenzene by intensively mixing 1,2-dichlorobenzene with nitric acid, sulphuric acid and water, simultaneously or successively, in their total amount, using a mixing energy of 1-50 watts per litre of the total reaction mixture, preferably 3-30 W/l, and maintaining a temperature of from 0 to 60&deg; C. during mixing.

Process for the adiabatic preparation of 3,4-dichloronitrobenzene

In the reaction of aromatic compounds with nitrating acids comprising HNO,and, if appropriate, H,SO,and/or H,O and/or H,PO,to form aromatic nitro compounds, according to the invention an amount of from 0.5 to 20,000 ppm of one or more surface-active substances from the group of the anionic, cationic, zwitterionic or nonionic surface-active substances is added to the reaction mixture.

Method for producing aromatic nitro compounds

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Leverkusen, Germany

Hans-Joachim Raatz