Bayer Aktiengesellschaft

Ruthard Potthast

Walter Horstmann

Knut Hammerstrom

Otto Horak

Werner Mentzel

Hans-Ulrich Alles

Horst-Dieter Kramer

A process for the preparation of an alkali metal salt of 3-hydroxybenzoic acid and the preparation of 3-hydroxybenzoic acid therefrom is disclosed wherein sulphophthalic acid or a salt thereof is reacted with an alkali metal hydroxide at a temperature in the range of 200.degree. to 300.degree. C. at a pressure of 10 to 30 bars.

Process for the preparation of 3-hydroxybenzoic acid

In the degradation of organic compounds in an effluent by oxidizing the effluent at an elevated temperature with oxygen, the improvement which comprises effecting the oxidation at a redox potential of from about 300 to 600 millivolts, as measured with a platinum electrode against a silver-silver chloride electrode, at a temperature of from about 80.degree. to 250.degree. C and under a pressure of from about 30 to 200 bars. The redox potential may be maintained by an Fe.sup.2+ and/or Fe.sup.3+ ion system and the pH is advantageously below about 7.

Degradation of organic compounds in effluents by wet oxidation

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Cologne, Germany

Ruthard Potthast