Bayer Aktiengesellschaft

Friedrich Durholz

Guido Skipka

Heinz U Blank

Helmut Fiege

Franz-Josef Mais

Guido Steffan

Rudolf Sundermann

Rolf Putter

Herbert Emde

Axel Vogel

Dietmar Mayer

Dorde Jovcic

Thomas Essert

Walter Bohm

Roland Busse

Josef Heinen

Adolf Hamers

2-Chloroacrylonitrile is prepared in a particularly advantageous and readily industrially practicable manner by chlorinating acrylonitrile and then thermally cleaving the 2,3-diehloropropionitrile formed, by chlorinating acrylonitrile in the presence of a catalyst system comprising dimethylformamide and pyridine and/or pyridine derivatives and subjecting the resulting crude 2,3-dichloropropionitrile to thermal cleavage in the presence of the same catalyst system without the addition of further catalysts.

Process for the preparation of 2-chloroacrylonitrile

Reactions of liquid starting substances to give chemical compounds in which these chemical compounds are obtained as solids can be carried out by spraying the liquid starting substances from separate nozzles such that the liquid starting substances are mixed in the spray cones, which penetrate one another, and thereby react.

Process for the preparation of chemical compounds obtained as solids

4,4-40 -Dinitrostilbene-2,2'-disulphonic acid salts are prepared by the oxidation of 4-nitrotoluene-2-sulphonic acid or salts thereof in an aqueous alkaline medium, by adding potassium, calcium and/or magnesium ions during the reaction at the rate of which 4,4'-dinitrostilbene-2,2'-disulphonic acid is formed, the amount of added potassium, calcium and/or magnesium ions at any point during the reaction being 10 to 150 mol %, relative to the amount of 4,4'-dinitrostilbene-2,2'-disulphonic acid present in the reaction mixture at that particular time, and by removing the precipitated salt of 4,4'-dinitrostilbene-2,2'-disulphonic acid.

Process for the preparation of 4,4'-dinitrostilbene-2,2'-disulphonic

1,5- AND 1,8-DINITRONAPHTHALENES ARE ISOLATED FROM MIXTURES OF ISOMETRIC DINITRONAPHTHALENES AT LEAST CONTAINING THE SAME. The mixture of isomers is treated successively with a more polar solvent and a less polar aromatic solvent for dinitronaphthalenes thereby dissolving the mixture of isomers except for 1,5-dinitronaphthalenes which remains largely undissolved in the more polar solvent. The residual mixture of isomers is subsequently treated, after removal of the more polar solvent, with a less polar aromatic solvent at elevated temperatures in which 1,8-dinitronaphthalenes remains as a largely insoluble residue.

Process for isolating dinitronaphthalenes

Nitroderivates of aromatic compounds which are difficult to nitrate, can readily be obtained by nitration providing that the aromatic compound is treated with nitric acid or another nitrating agent in the presence of aliphatic or cycloaliphatic hydrocarbons monosubstituted or polysubstituted by halogen, the nitro group or an alkyl sulphonyl group, and the nitro derivative formed subsequently isolated.

Process for the production of nitro derivatives of aromatic compounds

Diamino naphthalene having the formula ##STR1## wherein R.sup.1 is hydrogen or amino is prepared by treating dinitro naphthalene having the formula ##STR2## wherein R.sup.2 is hydrogen or nitro WITH HYDROGEN IN THE PRESENCE OF HYDROGENATION CATALYSTS AND ORGANIC SOLVENTS HAVING THE FORMULA ##STR3## wherein R.sup.3 is hydrogen, halogen or alkyl;

Process for manufacturing diaminonaphthalene

Dinitronaphthalenes are prepared by reacting nitronaphthalene at temperatures of from 20.degree. to 50.degree. C which 60 to 80% strength by weight aqueous nitric acid. The resulting dinitronaphthalene is separated off in a known manner and the residual nitric acid is enriched until a concentration of 60 to 80% by weight is reached and is then recycled to the reaction.

Process for preparing dinitronaphthalenes

5-Nitro-1,4-naphthoquinone is prepared by reducing 8-nitro-1,4-naphthoquinone-1-oxime and/or 5-nitro-1,4-naphthoquinone-1-oxime in an aqueous and/or organic reaction medium in the presence of iron (II) ions and a hydrogen halide at a temperature in the range of from -20.degree. to 100.degree.C, and thereafter oxidizing the 8- and and/or 5-nitro-4-amino-1-naphthol formed, or the corresponding salt, optionally without intermediate isolation, at a temperature in the range of from -10.degree. to 100.degree.C to form the desired 5-nitro-1,4-naphthoquinone.

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Remscheid, Germany

Friedrich Durholz