Bayer Aktiengesellschaft

Gunther Klag

Heinz U Blank

Rolf Putter

Karlheinrich Meisel

Marko Zlokarnik

Peter Schnegg

Friedrich-Wilhelm Ullrich

Willi Streicher

Georg Spielberger

Nikolaus Schulz

Dieter Irmscher

Hermann Wunderlich

Indoles of the formula ##STR1## can be prepared by reaction of a phenylhydrazine of the formula ##STR2## which is unsubstituted in at least one ortho-position, with a ketone of the formula ##STR3## in an aqueous medium in the presence of an acid compound, less than 5 equivalents, based on 1 mol of phenylhydrazine, of an acid compound having a pK value of 1.3-4.5 being employed.

Process for the preparation of indoles

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

1-Amino-naphthalene-7-sulphonic acid is prepared by reacting 1-chloro-naphthalene-4,7-disulphonic acid with ammonia at elevated temperatures in the presence of water and optionally in the presence of a catalyst such as a copper catalyst.

Process for preparing 1-amino-naphthalene-7-sulphonic acid

Aminonaphthalene derivatives are prepared by reacting the corresponding naphthol derivative with ammonia or amines in the presence of bisulfites. The reaction is carried out in a continuous procedure in reaction apparatus which consists wholly or partly of titanium or a titanium alloy, carbon largely excluded. Suitable alloys are titanium/palladium, titanium/nickel or titanium/molybdenum.

Process for preparing aminonaphthalene derivatives in a titanium or

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Leverkusen, Germany

Gunther Klag