CH130618A - Process for the preparation of an orange-colored vat dye of the anthanthrone series. - Google Patents

Description

  

  Process for the preparation of an orange-colored vat dye of the anthanthrone series. Subject of the present patent :: is a process for the preparation of a reddish, orange-colored vat dye of the anthanthrone series of the probable formula:
EMI0001.0007
    characterized in that anthrone bromine is allowed to act in the presence of a diluent, so that approximately 2 atoms of bromine enter the molecule.



  When dry, the vat dye obtained is a bright red powder, soluble in concentrated sulfuric acid with a bright green color. Together with alkaline hydrosulphite, it forms a violet vat from which the vegetable fibers are colored in the same tones, which are transformed into a bright red-orange with excellent authenticity, especially lightfastness, by hanging or soaking.



       Examples 1. 1 part of anthanthrone is mixed with about 20 parts of nitrobenzene or another suitable organic solvent, such as, for example, highly chlorinated benzene. Then 3 parts of bromine are added and it is heated to 160 with stirring until no more hydrobromic acid escapes. To bring the reaction to the end, it is briefly heated to a boil.

   After cooling, the deposited dye is filtered off, washed with the solvent used and then with fuel and dried. 2. 8 parts of anthanthrone are dissolved in about 100 parts of sulfuric acid 66 B6, then 0.1 part of iodine and 8 to 6 parts of bromine are added and the whole is heated to about 50 to <B> 100 '</B> for a few hours. After the reaction has ended, the mixture is poured onto ice, filtered and the precipitated dye is washed, with any bromine adhering to it being removed in the usual way.

   The dye thus obtained is practically identical to the dye described in Example 1.



  If one adds so much fuming sulfuric acid (for example with 65% SO3) to the sulfuric acid solution of the anthanthrone that enough SO3 is available to absorb the. To oxidize the hydrobromic acid formed by the reaction back to bromine, the bromination of the anthanthrone can be carried out with half the amount of bromine given above.



  This method can advantageously be linked to the manufacture of the anthanthrone itself. The procedure is then approximately as follows: 25 parts of 1.1'-dinaphthyl-8.8'-dicarboxylic acid (see patent no. 122066) are gradually increased to about. 200 parts of sulfuric acid monohydrate entered, where the temperature should not rise above 60. This creates anthanthrone in quantitative yield. The bromination of the anthanthrone formed is then carried out as described above.

 

Claims (1)

PATENT CLAIM: Process for the preparation of a reddish, orange-colored vat dye of the anethane ', hron series, characterized in that on anthanthrone bromine is present. a diluent can act, so that almost two atoms of bromine enter the molecule. When dry, the vat dye obtained is a bright red powder, soluble in concentrated sulfuric acid with a bright green color. Together with alkaline hydrosulphite, it forms a violet vat from which the vegetable fibers are colored in the same tones, which are transformed into a shining red-orange with excellent authenticity, especially lightfastness, through hanging or soaps. SUBCLAIMS: 1. Method according to claim, thereby. characterized in that a bromine transfer agent is added to the reaction mass. 2. Process according to claim, characterized in that the reaction is carried out in the presence of a diluent of an inorganic nature. Ä. Process according to claim, characterized in that ar processed in the presence of an organic diluent.