Bayer Aktiengesellschaft

Siemens-allis, Inc.

Peter Schnegg

Heinz U Blank

Herbert Emde

Horst Behre

Nikolaus Muller

Bernhard Vosteen

Gunther Klag

Wilfried Kohler

Ernst Goldschmitt

Heinz U Blnak

Walter Rapp

Aminoaryl-sulphonic acids can be prepared by reaction of arylamines and sulphuric acid at elevated temperature and under pressure, where water formed and, where appropriate, water present as water of dilution, is left in the reaction mixture until the end of the reaction.

Process for the preparation of aminoaryl-sulphonic acids

A new process for the preparation of aromatic sulphonic acids, in which the sulphonation of the aromatic compounds is carried out with sulphur trioxide in organic solvents in the presence of hydrogen halide.

Process for the sulphonation of aromatic compounds with sulphur trioxide

Aromatic aminosulphonic acids which have a reduced content of discoloring by-products are obtained when aromatic amines are reacted with a sulphonating agent in a reaction medium at least some of which consists of tetramethylene sulphone.

Process for the preparation of aminoarylsulphonic acids in sulfolene

Aminoarylsulphonic acids which have a relatively high purity and a relatively low content of aminoaryldisulphonic acids can be obtained, if they are prepared, from the corresponding arylammonium hydrogen sulphates, by an improved version of the so-called baking process, wherein the reaction is carried out under pressure at a temperature of at least 140.degree. C. and, at least partially, in the presence of water.

Process for the preparation of aromatic aminosulphonic acids

In a process for the preparation of 4-nitrotoluene-2-sulphonic acid by reacting 4-nitrotoluene with gaseous sulphur trioxide at an elevated temperature, the improvement wherein molten 4-nitrotoluene is reacted with gaseous sulphur trioxide at a temperature in the range from 60.degree. to 150.degree. C. under a pressure above the vapor pressure of 4-nitrotoluene, in a molar ratio of sulphur trioxide to 4-nitrotoluene of 0.1:1 to 1.5:1, and, after a conversion of at least 70 percent of the reaction component not employed in excess is achieved, the sulphonation mixture is treated with water.

Process for the preparation of 4-nitrotoluene-2-sulphonic acid

A process for delignifying lignocellulosic material with a digestion liquor of nitroanthraquinones and/or dinitroanthraquinones. The process can be carried out in a closed reaction vessel at temperatures of 150.degree.-200.degree..+-. C. for 0.5 to 480 minutes with 0.001 to 10% nitroanthraquinone and/or dinitroanthraquinone by weight of lignocellulosic material.

Process for the delignification of lignocellulose materials with

Alkali metal salts of hydroxybenzoates are claimed which are substantially anhydrous and free from hydrobenzoic acid and have the formula ##STR1## in which R.sup.1 denotes alkyl, alkenyl, cycloalkyl or aralkyl,

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Odenthal, Germany

Peter Schnegg