Bayer Aktiengesellschaft

Rolf Putter

Ernst Grigat

Rudolf Sundermann

Horst Behre

Gunther Rottloff

Heinz U Blank

Theodor Pfister

Peter P Wenzl

Willi Schossler

Guido Steffan

Axel Vogel

Friedrich Durholz

Friedrich Werner

Gunther Klag

Reinhard Kaiser

Manfred Niese

Jurgen Dammann

A process has been provided for the preparation of nitro-T-acid by nitration of naphthalene-1,3,6-trisulphonic acid from a nitration mixture which has reacted to the extent of at least 80% which naphthalene-1,3,6-trisulphonic acid or a mixture containing the latter. Nitro-T-acid (and T-acid) is an intermediate for the preparation of H-acid which, in turn, is an intermediate for the preparation of dyestuffs.

Process for the preparation of nitro-T-acid

Process for the preparation of a bis-(amino-phenyl)-disulphide of the formula ##STR1## in which R represents hydrogen or halogen, which comprises contacting an amino-thiophenol of the formula ##STR2## or a salt thereof in which R has the abovementioned meaning with sulphur or a sulphur-donating substance in an aqueous dispersion at a temperature of 10.degree. to 120.degree. C. and a pH value of 3 to 9.

Process for the preparation of bis-(amino-phenyl)-disulphides

A process for the preparation of 1-amino-2-ethoxy-naphthalene-6-sulphonic acid from 2-hydroxy-naphthalene-6-sulphonic acid which comprises:

Process for the preparation of 1-amino-2-ethoxy-naphthalene-6-sulphonic

A process has been invented for the preparation of naphthalene-1,3,6-trisulphonic acid by sulphonating naphthalene with sulphuric acid and oleum, characterized in that naphthalene and most of the oleum are simultaneously metered into sulphuric acid or oleum of low concentration, which has been initially introduced, at about 140.degree. to 240.degree. C., the temperature is kept at about 140.degree. to 240.degree. C. for some time, the remainder of the oleum is then added at about 140.degree. to 240.degree. C. and the mixture is then further stirred for some time. Naphthalene-1,3,6-trisulphonic acid is a known important intermediate used, for example, in the preparation of T-acid, H-acid and chromotropic acid.

Process for the preparation of naphthalene-1,3,6-trisulphonic acid

A process has been invented for the preparation of a mono-alkali metal salt of 1-amino-8-naphthol-3,6-disulphonic acid comprising reacting 1-naphthylamine-3,6,8-trisulphonic acid and/or a salt thereof and/or a naphthylamine-trisulphonic acid isomer mixture and/or salt thereof with an alkali metal hydroxide solution at elevated pressure and elevated temperature and in the presence of an alcohol or alcoholate, and separating out the mono-alkali metal salt by acidification. The process results in the procurement of higher yields of the desired product and in the formation of less by-products.

Process for the preparation of 1-amino-8-naphthol-3,6-disulphonic acid

A process has been invented for the preparation of a mono-alkali metal of 1-amino-8-naphthol-3,6-disulphonic acid, comprising reacting 1-naphthylamine-3,6,8-trisulphonic acid and/or a salt thereof and/or a naphthylamine trisulphonic acid isomer mixture and/or salt thereof with an alkali metal hydroxide solution in the presence of an alcohol and/or alcoholate and in the presence of a substance which contains at least one oxygen atom bonded to a nitrogen atom, at elevated pressure and elevated temperature, and separating out the mono-alkali metal salt of 1-amino-8-naphthol-3,6-disulphonic acid by acidification. The process results in the procurement of higher yields of the desired product and in the formation of less by-products.

A process for the preparation of a 2-hydroxycarbazole of the formula ##STR1## wherein R.sup.1 represents hydrogen, halogen or an optionally substituted alkyl, aryl or alkoxy radical Which comprises contacting a diphenylamine of the formula ##STR2## wherein R.sup.1 has the above-described meaning and

Process for the preparation of 2-hydroxycarbazoles

Non-inflammable, high molecular weight polytriazines are obtained by condensing less than 3 mols of polyfunctional (amino)phenols with 1 mol phosphorus (oxy) trihalide in the presence of a base, subsequently reacting the still free primary amino or phenolic hydroxyl groups with cyanogen halide in the presence of a base to form cyanamide or organic ester groups and polymerizing thereafter the reaction product at a temperature of up to 350.degree. C, optionally in the presence of polymerization promoters. The polytriazine may be used as plastics and lacquers.

Process for the production of non-inflammable polytriazines

Process for the production of polytriazines in the presence of

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

Process for the preparation of s-triazine prepolymers which comprises

Process for preparation of s-triazine prepolymers

Highly pure aromatic polyfunctional cyanic acid esters having a high stability in storage and being extraordinary suitable for use as starting compound for the production of plastics by cyclopoly-trimerization are obtained by a special process. Alkaline earth and/or alkali metal salts of polyfunctional aromatic hydroxy compounds said alkaline earth and/or alkali metal compound capable of phenolate formation are used in excess of up to 0.1 mol per mol of aromatic hydroxy group are reacted with an excess of cyanogen halide. The cyanogen halide excess comprises up to 1 mol per mol of aromatic hydroxy group plus excess mol of the metal compound used for salt production.

Process for the production of polyfunctional cyanic acid esters

Highly pure aromatic polyfunctional cyanic acid esters having a high stability in storage and being extraordinarily suitable for use as starting compound for the production of plastics by cyclopoly-tri-merization are obtained by a special process. A di- or polytrialkyl ammonium phenolate of the formula: ##STR1## in which Ar represents an optionally substituted aromatic radical,

S-Triazine prepolymers, useful in the preparation of polytriazines, are prepared by condensing an aromatic dihydroxy or polyhydroxy compound with less than one-third mol of cyanuric chloride per hydroxy group. Thereafter the free hydroxy groups in the condensation product are reacted with a cyanogen halide in the presence of a base. The condensation is preferably carried out in a melt at temperatures of from 100.degree.-240.degree.C.

Process for preparing s-triazine prepolymers by condensation of an

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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Duesseldorf, Germany

Rolf Putter