DE278871C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

-JVl 278871 - ■ CLASS 22a. GROUP

Process for the preparation of a yellow cotton dye.

Patented in the German Empire on January 8, 1913.

In the patent specification 108634 and in the American patent specification 639042 it is stated, inter alia, that the combination of the tetrazo compounds from p-diamines of the diphenyl series with i-aminophenylpyrazolone-3-carboxylic acid produces red to burgundy cotton dyes. After further diazotization on the fiber and combination with ß-naphtol, these dyes produce burgundy shades. It has now been found that by combining the tetrazo compound from mm ¹ -dichlorobenzidine (NH ₂ : Cl = 1: 3), which is known to be little or not at all suitable for the production of cotton dyes (cf. e.g. Wi nt her, Patents of organic chemistry vol. 2, p. 1154), with 2 mol. Im-aminophenylpyrazolone-3-carboxylic acid or with 2 mol. Im-nitrophenylpyrazolone-3-carboxylic acid and subsequent reduction of the nitro groups to amino groups, a dye is formed which cotton in yellow tones, which change into a bright orange when diazotized and developed with ß-naphtol. The nuances obtained in this way are considerably purer and more valuable than those of the dyes in the above-mentioned patents. The yellow disazo dyes described in patent 108634 ^lln d of Swiss patent 54418 and additions to main patent 46184, which are produced by combining the intermediate product from the tetrazo compound of a p-diamine and salicylic acid with p- or ■ m-aminophenyl-S-pyrazolone-s-carboxylic acid or m-aminophenylmethylpyrazolone, yeasts are formed when diazotizing the fiber and developing with ß-naphtol, less washfast nuances than the present dye and bleeding heavily soaped white cotton. Dyes with properties similar to the present ones have already been described in patent specification 237169, but these owe their properties to the use of certain bases of the constitution:

.R-NH ₂
X <

R ₁ -NH ₂ ,

and from the information in patent specification 237169 could the result of the present proceedings not be foreseen for the sake of because not all bases of the constitution:

.R-NH ₂
X <

R ₁ -NH ₂

are usable in the process of that patent and z. B. in the case that X = NH, not yellow, but blue dyes are formed. The pyrazolone dyes described in patent specification 235949, which are also derived from m · m ¹ -dichlorobenzidine, are wool dyes and are completely unsuitable for dyeing cotton.

Example.

6.3 parts of m · m ^ dichlorobenzidine in 250 parts of water and 22.8 parts of hydrochloric acid Dissolve at 20 ° Βέ hot, if necessary filtered and after cooling with ice with a concentrated Solution of 3.45 parts of sodium nitrite diazotized. The tetrazo solution obtained leaves are poured into a solution of 12.5 parts of i-m-nitrophenylpyrazolone-3-carboxylic acid in 7 parts of sodium hydroxide solution 35 ° Be and 200 parts

45

50

55

60

Claims (1)

Water, to which a concentrated solution of 15 parts of soda was added, and which is cooled with ice. When the combination is complete, it is heated to 50 °, and after the addition of a solution of 36 parts of sodium sulphide in 100 parts of water, one hour held at 55 to 60 °. Then the dye obtained is precipitated with salt. The same Dye is formed when the tetrazo solution shown above is in a soda-alkaline solution with i-m-aminophenylpyrazolone-3-carboxylic acid is combined. It stains cotton in yellow tones, which after diazotization and the combination with ß-naphtol turn into a bright orange. This is extremely soap-proof and can be etched in pure white. Ρλϊεντ claim: Process for the preparation of a yellow cotton dye, consisting in that the tetrazo compound of m m ¹ -dichlorobenzidine (NH ₂ : Cl = 1: 3) with 2 mol. carboxylic acid combined and in the latter case the nitro groups are reduced to amino groups.