Bayer Aktiengesellschaft

Udo Thiel

Gerold Schade

Gunter Silber

Sodium salts of aromatic sulphinic acids containing nitro groups are obtained in particularly pure form and good yield by introducing the corresponding sulphonyl chlorides into an aqueous alkali metal sulphite solution which is at a temperature of -10.degree. to 45.degree. C. and has a pH of 6 to 10, then cooling the suspension to -10.degree. to 0.degree. C., then metering in sodium hydroxide solution in such a way that the temperature does not exceed 0.degree. C. throughout the reaction, and then raising the temperature, maintaining stirring and simultaneously keeping the pH at 8 to 9 by the addition of sodium hydroxide solution.

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Leverkusen, Germany

Udo Thiel