DE607393C - Process for the production of a Kuepen dye - Google Patents

Description

Method of making a vat dye In '586 patent 515 describes a process which allows, for example, 8-chloro-i-amino-2-methyl.anthraquinone Manufacture by reacting on leuco-i-chloranthraquinone formaldehyde or formaldehyde-releasing Allow substances to act and reoxidize the products obtained.

As is already known, from q., ¢ '- dichloro - 2; 2'-dimethyl - ii'- dianthraquinonyl and from 6,6'- or 7, 7'-dichloro-2, 2'-dimethyl-i, i'-dianthraquinonyl pyranthrone dyes obtained by alkaline melt; on the other hand, the alkaline melt of 5, 5'-dichloro-2, 2'-dimethyli, i'-dianthraquinonyl after own findings no technical interest.

It has now been found that 8-chloro-i-, amino-2-ynethylanthraquinone can be obtained by known methods can convert into 8, 8'-dichloro-2, 2'-dimethyl - i, 1 '- dianthraquinonyl and that if you look at these latter bodies in an alcoholic, alkaline melt subjects a valuable orange vat dye: receives the reddish-tinged one is probably the one as pyranthrone and its Kionstitution. of the S, 8'-dichloropyranthrone is equivalent to. It dyes cotton vividly red-orange and has excellent fastness properties.

The invention now allows - and that is the new technical effect - the utilization of a waste product that has so far been of little practical interest possessed: It is the i, 8-Nitroanthraquinionesulfonic acid, which in the technical Preparation of the isomers i; 5-Nitroanthrachh 1.onsulfonic acid in fairly large Quantities is obtained.

This 1,8-nitroanthraquinone sulfonic acid is easily converted into the 8-chloro-i-aminoanthrachi; non. This is again used to produce 8-chloro-i-amino-2-methylanthraquinone, which is then converted into a valuable vat dye using the above process. EXAMPLE 10 parts of 8-chloro-i-amino-2-niethylanthraquinone, which is obtained by the process of patent 586515, are dissolved in 100 parts of concentrated sulfuric acid and dianotized with 2.9 parts of N: atrium nitrite. The solution is gradually diluted, the temperature being kept at 10 ° to 15 ° by adding 150 parts of ice. The precipitation is completed by adding sodium sulfate, then the diazonium sulfate is filtered and washed with a small amount of concentrated sodium sulfate solution.

The diazo compound is carried in an aqueous suspension at up to 95 ° of 8 parts of copper chloride and holds at this temp.eratu @ until complete Conversion: Then the 8, 8-dichloro-z, a'-dimethyl-i, V-dianthraquinonyl formed is isolated and removes the copper salts by known methods.

Parts of the product thus obtained are in a mixture of 2o Parts of caustic potash with 20 parts of alcohol are introduced at i 6o to 170 ° (bath temperature). One keeps this. Temperature up to complete conversion into the dye.

This is isolated from the melt by dilution and filtration; the R.coxydation of the leuco derivative formed during the alkali melt is carried out by completes an air flow. The crude dye obtained can optionally by Recrystallization or fractionation of its solution in concentrated sulfuric acid cleaned by adding water. An orange-colored, crystalline one is obtained Powder that gives a blue-green sulfuric acid solution.

The vat is purple; the colorations on; Cotton is a very lively reddish orange and have excellent authenticity properties. .

Claims (1)

PATENT REQUIREMENT: i. Process for the production of a vat dye the pyranthrone series, characterized in that the 8-chloro-i-amino-2-methylanthraquinone according to methods known per se into the 8, 8'-dichloro-a, 2'-dimethyl-i, i'-dianthraquinonyl transferred and this treated with alkaline condensation agents. z. procedure according to claim i, characterized in that the yellow dye obtained by fractionating the solution containing sulfuric acid by adding water.