AT72815B - Process for the preparation of green-blue dyes of the gallocyanin series and leuco derivatives thereof. - Google Patents

Description

  

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  Process for the preparation of green-blue dyes of the gallocyanin series and of leuco derivatives thereof.



   The parent patent specification No. 34778 describes condensation products of gallocyanine dyes, which are obtained by heating aromatic diamines containing at least one free amido group with gallocyanines. To prevent the simultaneous formation of leukogallocyanines, dinitrobenzene is added to the reaction mixture in a number of the examples given.



   As is then further explained in patent specification No. 34778, the condensation products are converted into their leuco compounds.



   It has now been found that the same condensation products as described in the parent patent specification No. 34778 can also be obtained if a mixture of a gallocyanine with a diamine is stirred for a long time at ordinary temperature. The advantage of this method is primarily that it is necessary for the condensate products from diamonds and the gallocyanines from gallic acid.
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   Example!.



   To dissolve 130 ky of amidodimethylailine in 200 l of alcohol! a mixture of 100 k / gallocyanin (prepared from gallic acid and nitrosodimethylaniline) and 200 l of alcohol is added and the mixture is stirred for 24 hours. It is then suction filtered and the reaction product is freed from any diamine still adhering by stirring with weak hydrochloric acid. Most of the condensation product goes into solution with the diamine, and it is precipitated again by adding sodium chloride. The
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 soluble in aqueous sodium carbonate solution. It is finally reduced to be converted into its leuco derivative.



    Example H.
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   Amidodimethylaniline stirred in and stirred with it for 60 hours at ordinary temperature, d. H. until a sample of the mixture has become insoluble in aqueous sodium carbonate solution after the diamine has been removed. Once this has been achieved, the reaction product is diluted with alcohol and separated from the mother liquors by suction. It is then stirred with weak hydrochloric acid, filtered off, pressed and reduced.

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 Example III.



   100 kir of the gallocyanine prepared from gallic acid methyl ester and nitrosodine ethyl aniline are introduced into 500 kg amidodimethyl aniline and vigorously stirred in an enamelled vessel at normal temperature for 48 hours. The reaction product is then diluted with 100 l of cold alcohol, separated from the mother liquors on the suction filter and finally pressed. The press cakes are then crushed and stirred with dilute hydrochloric acid to completely remove any diamine that is still adhering. The reaction product is finally filtered off and converted into its leuco derivative by reduction.

 

Claims (1)

PATENT CLAIM: Modification of the process of the parent patent No. 34778 for the representation of green-blue dyes of the GaUocyanin series and leuco derivatives of the same by condensation of Gallocyaninen with aromatic diamines, which at least one free amino. group, characterized in that the condensation of the products takes place alone or with the addition of diluents at ordinary temperature with stirring and the end products are converted into their Louko compounds in the usual way.