CH284992A - Process for preparing a copper-containing azo dye of the stilbene series. - Google Patents

Description

Process for preparing a copper-containing azo dye of the stilbene series. It has been found that a valuable, copper-containing azo dye of the stilbene series can be obtained by looking at the dye

end on the other hand with the aminomonoazo dye of the formula

condenses, copper-releasing agents can act. The new dye forms a dark powder which, when wet, has a brown color and dyes cotton in lovely, olive-brown shades.

The condensation of 4,4'-dinitrostilbene-2,2'-disulfonic acid with the aminoazo dyes, which are suitably used in the form of alkali metal salts, is advantageously carried out in a dry medium and in the presence of alkali metal hydroxide. Good results are obtained, for example, if the substances to be reacted with one another are diluted, e.g. B. 2 to 8% alkali hydroxide itization smoldering for a long time, e.g. B. 5 to 24 hours at elevated temperature, e.g. B. in a substance which can be obtained by reacting 4,4'-dinitrostilbene-2,2'-disulphonic acid on the one hand with the aminodisazo dyestuff of the formula open in a vessel at the boiling point of the reaction mixture end enter RfeklluMliüblun or at even higher temperatures end enter pressure interact lâf3t.

In the present process, e.g. B. Salts of monovalent or divalent copper such as copper (I) - chloride or copper (II) sulfate come into consideration, as well as other compounds containing copper in complex compound. In particular, copper ammine complexes are suitable for this purpose, such as B. the Iromplexen copper compounds obtainable from ammonia, alkylamines such as thylamine, morpholine, pyridine or piperidine. The treatment with the copper-releasing agent is expediently carried out in a wet medium. If necessary, the treatment can be carried out with the copper-releasing substances in the presence of suitable additives. As such, bases such as ammonia and organic bases, preferably an excess, may be mentioned

(prepared e.

(Prepared by oxidation of the monoazo compound obtained by coupling diazotized 4-nitro-4'-aminostilbene-2,2'-disulfonic acid with 2-naphthylamine-6-sulfonic acid and reducing the nitro compound thus obtained to the corresponding amino compound 47.4 parts of the sodium salt of 4,4'-dinitrostilbene-2,2'-disulphonic acid, 2400 parts of water and 240 parts of 30% sodium hydroxide solution and heated to boiling under reflux for 22 hours. The condensation product formed can be separated from the reaction mixture by adding sodium chloride and neutralizing part of the excess alkali with hydrochloric acid. For the conversion into the complex copper compound, the

that base which is already contained in the molecule of the copper ammine complex which may be used.

Example: 65 parts of the sodium salt of the disazo dyestuff of the formula: 60 parts of the condensation product filtered with 66.8 parts of the trisodium salt of the aminotriazole of the formula: . 40 parts of 25% strength ammonia solution are added. The stirred mixture is heated to 75 for half an hour with 240 parts of a 2N copper sulphate solution and 240 parts of 25% ammonia solution. The complex copper compound can be separated and filtered off by salting out.

Claims (1)

PATENT CLAIM: Process for the preparation of a copper-containing azo dye of the stilbene series, characterized in that) the dye, which can be obtained by reacting 4,4'-dinitrostilbene-2,2'-disulphonic acid, on the one hand with the aminodisazo dye of the formula and on the other hand with the aminomonoazo dye of the formula condensed, let copper-releasing agents act. The new dye forms a dark powder that turns brown in water and dyes cotton in lightfast, olive-tinged brown shades. SUB-CLAIM: Process according to patent claim, characterized in that a copper-tetrammine compound is used as the copper-releasing agent.