DE493813C - Process for the preparation of Kuepen dyes - Google Patents

Description

Process for the preparation of vat dyes It has been found that new vat dyes are produced when using pyrazole anthrone in the presence of alkaline condensing agents. i Amino-a-halogenanthraquinones or their substitution products treated with heat. You can work in the presence or absence of catalysts. According to the properties of the new dyes, not only should a nitrogen-carbon chain take place with the escape of hydrogen halide, but a further condensation, probably in the sense of the following formulas, should occur The new products are strong vat dyes with good fastness properties. Example iii parts of pyrazolanthrone are heated to boiling together with 15.1 parts of i amino-z-bromoanthraquinone, 10 parts of potash, 0.5 parts of copper powder and zoo parts of nitrobenzene until the formation of dye no longer increases. It is suctioned off while still warm and the undissolved material is freed from solvents and salts in a known manner. The crude dye is conveniently obtained by recrystallization from organic solvents, e.g. B. o-dichlorobenzene or trichlorobenzene, in which it is relatively easily soluble in the heat, purified or by fractional precipitation from sulfuric acid. When the solution of the crude product is diluted in 10 parts of concentrated sulfuric acid with 20 parts of sulfuric acid at 50 ° B6, in the main only the pure dye precipitates. You can also combine both methods of cleaning. In its pure state, the dye is a dark powder that dissolves in concentrated sulfuric acid with a bright blue color. He dyes cotton from a violet vat in strong blue-violet, chlorine-like shades.

The dye is also formed in the absence of catalysts. Example 2 1 1 pyrazolanthrone parts are heated with 15.9 parts of i-amino-2-bromo-Q.-oxyanthrachinon, io parts potash and Zoo parts of nitrobenzene about 20 hours to boiling. The work-up and the purification of the resulting dye are carried out in the manner described in Example i. In its pure state, the dye is a dark powder, which dissolves in concentrated sulfuric acid with a green-blue color. It dyes cotton from a blue vat in deep blue-green tones that turn gray when chlorinated.

Claims (1)

PATENT CLAIM: Process for the representation of vat dyes, thereby characterized in that one pyrazolanthrone with 1Amino-2-halogenanthraquinones or their Substitution products in the presence of alkaline condensation agents in the Heat treated.