Bayer Aktiengesellschaft

Ciba-geigy Ag

Bayeraktiengesellschaft

Bayer Aktiengsellschaft

Bayer Aktiengesselschaft

Horst Behre

Heinz U Blank

Alexander Klausener

Helmut Fiege

Guido Steffan

Rolf Putter

Willi Schossler

Lars Rodefeld

Erich Hammerschmidt

Wolfgang Eymann

Hans W Linden

Otto Lindner

Gerhard Marzolph

Heinz-Ulrich Blank

Axel Vogel

Willi Streicher

Dietmar Mayer

Reinhard Kaiser

Werner Mentzel

Wolfgang Schenk

Bruno Kruger

Nikolaus Muller

Michael Preiss

Helmut Kraus

Holger Heidenreich

Ferdinand Hagedorn

Michael Dockner

Paul Uhrhan

Wolfgang Gau

Gunter Rauchschwalbe

Peter Schnegg

Adolf Winkler

Johannes Scherer

Frank Arndt

Jurgen Zander

Bernhard Albrecht

Robert S&ouml;llner

Rudolf Wiemers

Hans-Joachim Becker

Eike Gabel

Wilfried Kohler

Uwe Heinz

Fritz Pohl

Thomas H&ouml;pfner

Otto Barth

Vinzenz Habermacher

Hans Frey

Lutz Kienitz

Roland Busse

Gerhard Burmeister

Lothar Jakob

Friedrich Müller-Hauck

Albert Hullen

Jurgen Dammann

Alfred Seyberlich

Heinz U Blnak

The invention relates to an improved process for preparing 3-acyloxy-2-methylbenzoic acids by heating substituted naphthalenes in the presence of alkali metal hydroxides and subsequently acylating.

Preparation of 3-acyloxy-2-methylbenzoic acids

According to the invention, N-butyryl-4-amino-3-methyl-methyl benzoate is obtained in a particularly advantageous manner by, initially, reacting o-toluidine with butyric acid chloride, by brominating the reaction product and by reacting the bromide obtained therefrom with carbon monoxide and methanol in the presence of a palladium catalyst. The invention also relates to the important novel chemical compound N-(4-bromine-2-methylphenyl)-butanamide.

Method for producing n-butyryl-4-amino-3-methyl-methyl benzoate and the novel compound n-(4-bromine-2-methylphenyl)-butanamide

A process is provided for preparing 4-hydroxy-3-nitrobiphenyl from 4-hydroxy-biphenyl by nitrating in the position adjacent to the phenolic hydroxyl group in high selectivity and yield, and the nitric acid used as the nitrating reagent is metered into the reaction system in a specific manner.

Method for producing 4-hydroxy-3-nitrobiphenyl

Methyl carbazate which is particularly pure and has a particularly low tendency toward discoloration is obtained from hydrazine and dimethyl carbonate if the two reactants are metered simultaneously into an initially introduced first solvent at from &minus;20 to &plus;30&deg; C., the solvent and low-boiling components are then distilled off under reduced pressure, and then either a second solvent is added to the crude methyl carbazate present and this solvent is distilled off under reduced pressure or an inert gas is passed through the crude methyl carbazate present.

Method for preparing methyl carbazate

The invention relates to a process for the preparation of specific salts of 1-substituted 2,4-diaminobenzenes by catalytic hydrogenation of 1-substituted 2,4-dinitrobenzenes and addition of the reaction product obtained after the hydrogenation and separated from the catalyst to an aqueous solution of an acid.

Process for the preparation of salts of 1-substituted 2,4-diaminobenzenes

N-Phenyl-1-naphthylamine can be prepared by reaction of aniline and 1-naphthylamine in the liquid phase at 100-400.degree. C. under normal pressure, a catalyst mixture comprising boron and fluorine being employed. Such catalyst mixtures can be obtained, for example, by reaction of hydrogen fluoride, boric acid and aniline and/or 1-naphthylamine. The catalyst is recovered and can be employed again. The reaction can be carried out discontinuously or continuously.

Preparation of N-phenyl-1-naphthylamine

Process for preparing 4,6-diamino-resorcinol dihydrochloride

2-Amino-5-alkyl-phenols, which are suitable as intermediates in the production of crop-protection agents or photographic couplers, can be prepared by subjecting 2-amino-5-alkyl-benzenesulphonic acids or their salts to alkaline hydrolysis.

Process for the preparation of 2-amino-5-alkyl-phenols

4-Hydroxybiphenyl is obtained in non-thixotropic form if a reaction mixture which is obtained by alkaline hydrolysis of biphenyl-4-sulfonic acid and contains 4-hydroxybiphenyl is heated at elevated pressure at above 115.degree. C. and at a pH from 0 to below 6.5.

Process for the preparation of 4-hydroxybiphenyl

2-(Arylimino-methyl)-3-dialkylaminoacrylonitriles can be obtained by reaction of .beta.-anilino-acrylonitriles with ortho-formamides. They are suitable as starting substances for the preparation of 4-amino-5-iminiummethylene-2-pyrimidines or 4-amino-5-formyl-2-pyrimidines.

2-(arylimino-methyl)-3-dialkylaminoacrylonitriles, a process for their

4,6-diaminoresorcinol can be prepared in a plurality of steps in such a way that a) 1,3-dichlorobenzene is nitrated with a mixed acid of HNO.sub.3, H.sub.2 SO.sub.4 and SO.sub.3 at 0 to 40.degree. C. in anhydrous H.sub.2 SO.sub.4, b) the resulting 1,3-dichloro-4,6/2,4-dinitrobenzene isomeric mixture is first reacted with benzyl alcohol in the presence of a strong base at -15.degree. C. to +15.degree. C. and then at 20.degree. to 40.degree. C. to give the dibenzyloxy compound and c) the 1,3-dibenzyloxy-4,6-dinitrobenzene isomer arising in pure form in b) is converted to the 4,6-diaminoresorcinol by catalytic hydrogenation.

Process for the preparation of 4,6-diaminoresorcinol

When 2-naphthylamine-1,5-disulphonic acid is precipitated from the as-sulphonated reaction mixtures by dilution, a purer product is obtained, with a low level of adherent sulphuric acid, if the precipitation by dilution of the reaction mixture is carried out under precisely defined conditions.

Process for the isolation of 2-naphthylamine-1,5-disulphonic acid

The characteristic of the improved process for the preparation of 1,5-dihydroxynaphthalene and 1,5-diaminonaphthalene is to carry out the alkaline pressure hydrolysis of the disodium salt of naphthalene-1,5-disulphonic acid at temperatures from 270.degree. to 290.degree. C. and under 14 to 20 bar using an excess of sodium hydroxide solution such that the molar ratio NaOH/disodium salt of naphthalenesulphonic acid is at least 12:1. The 1,5-dihydroxynaphthalene which is obtained in this manner, without hazard and in substantially higher purity, is then aminated with ammonia in the presence of ammonium bisulphite to give 1,5-diaminonaphthalene, it being possible to achieve a further increase in the degree of purity of the 1,5-diaminonaphthalene by increasing the molar ratio NH.sub.3 /1,5-dihydroxynaphthalene to at least 6:1.

Process for the preparation of 1,5-dihydroxynaphthalene and

New process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic acid and, if appropriate, 1,7-Cleve's acid, in which 1-nitronaphthalene is reacted by the Piria method with bisulphites in a manner which is known per se, the sulphamate mixture obtained in this Piria reaction is sulphonated with sulphur trioxide in sulphuric acid to give 1-aminonaphthalene-2,4,7-trisulphonic acid and, if appropriate, this is hydrolysed to 1,7-Cleve's acid by heating in aqueous sulphuric acid.

Process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic

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

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Odenthal, Germany

Horst Behre