DE2058816C3 - Water-soluble disazo dye, process for its preparation and its use for dyeing leather and fur - Google Patents

Description

2. Process for the preparation of the water-soluble disazo dyes of the formula

OH

HO, S

characterized in that sulfanilic acid is indirectly diazotized un coupling, the resulting suspension of amino monoazo dyes The mixture is added dropwise to dilute hydrochloric acid with cooling and the resulting D " with a weakly alkaline aqueous solution of 2-amino-5-naphthol-7-s

3 Use of the disazo dyes mentioned in claim 1 for coloring leather and fur.

V-N = N- ^ f V-N = N

HO ₃ S

Vere.mgu

It has been found that a valuable, readily water-soluble dye of the formula

OH

HO ₃ S

can produce, in which sulfanilic acid is indirectly diazotized by well-known processes and im alkaline range with m-toluidine couples, the resulting suspension of the aminomonoazo dye mixed with sodium nitrite solution, the mixture is added dropwise with cooling in dilute hydrochloric acid and the obtained diazo suspension at pH 7 to 8 with a weakly alkaline aqueous solution of 2-amino-5-naphthol-7-sulfonic acid united.

The readily water-soluble disazo dye obtained in this way has good compatibility with formaldehyde, Formic acid and alkali, good resistance to water hardness, shows good leveling power and has a good lickfastness. It is particularly suitable for dyeing leather and fur, whereby one very strong dyeings of good light fastness, good solvent fastness, especially to Light petrol, perchlorethylene and carbon tetrachloride and other good general fastness properties.

Compared to the dye known from Austrian patent specification 43 580 (Table Example 8) p-toluidine-o-sulfonic acid + p-xylidine + 2,5-aminonaphthol-7-sulfonic acid ("Dye A"),

the dye corresponding to German patent specification 98 842 sulfanilic acid + m-toluidine + 2-ethylamino-5-hydroxynaphthalene-7-sulfonic acid ("Dye B"),

corresponding to that of German patent specification 114 248 Dye p-toluidine-m-sulfonic acid + I-aminonaphthalene + 2-amino-5-hydroxynaphthalene-7-sulfonic acid ("dye C"),

the dye corresponding to the German patent specification 229 303 sulfanilic acid + aminohydro-

Λ,

HO ₃ S-

NH,

quinone dimethyl ether + 2-amino-5-hydroxynaphthalene-7-sulfonic acid ("Dye D"),

corresponding to the German patent specification 237 742 Dye l-amino-2,4-dimethylbenzene

6-sulfonic acid + p-xylidine ("dye E"),

that corresponds to the Swiss patent specification 48 546 Dye 1-amino-2,4-dimethylbenzene-6-sulfonic acid + o-toluidine + 2-phenylamino-5-hydroxynaphthalene-7-sulfonic acid ("Dye F") and opposite

the dye corresponding to the French patent 404 536 sulfanilic acid + 1-amino-2-hydroxy-5-methylbenzene + 2-amino-5-hydroxynaphthalene-7-sulfonic acid ("dye G"), the dye according to the invention of a similar structure is characterized by better uniformity and better compatibility with sodium carbonate and better water solubility at 20 ¹ C (dyes A. D and G), through better lightfastness when dyeing box calf (dyes E and F), through better exhaustion of the aqueous dyebath (dye B) and through better uniformity and better compatibility with sodium carbonate (dye C).

It is to be regarded as surprising that the crlindungsgemeinschaft Dye in comparison to the known dyes of similar structure the proven Has surprising, advantageous properties.

At spit M

51.9 parts by weight of sulfanilic acid are in 300 parts by volume Slurried water and dissolved with sodium carbonate. To this solution are added 45 volumes

Leile Ndtriumnitritelösung 40% ig and drip the mixture while cooling at 0 to 5 ° C. in 75 parts by volume of ion-centered sulphate and 75 parts by weight of ice.

The mixture is stirred for 10 minutes and then eliminated Excess of nitrous acid with sulfamic acid.

The diazo suspension thus obtained is added to a solution of 32.1 parts by weight of m-toluidine in 38 parts by volume Concentrated hydrochloric acid and 38 parts by volume of water flow, then adjust the pH value with concentrated inert Sodium hydroxide solution to 8.5 and stir; over night. The amino monoazo dye formed partially falls

45 parts by volume of 40% sodium nitrite solution are added to this suspension and then added dropwise stir well at 0 to 5 ° C. in a mixture of 150 parts by volume of concentrated hydrochloric acid and 150 parts by weight l: is a. After half an hour of stirring, excess nitrous acid is replaced by sulfamic acid destroyed.

A solution of 75.3 parts by weight of 2-amino-5-naphthol-7-sulfonic acid in 50% by volume is placed Water and 30 parts by volume of concentrated sodium hydroxide solution are placed in a socket and the diazo suspension is added dropwise of the aminomonoazo dye simultaneously with concentrated sodium hydroxide solution so that the pH is kept in the range of 7 to 8.

After 2 hours the mixture is heated to 50 ° C. and salted out with 800 parts by weight of sodium chloride. Afterward the pH is adjusted to 4.0 with concentrated hydrochloric acid. Received after stirring overnight a precipitate is filtered off with suction and dried in a drying cabinet at 60.degree. Man receives 270 parts by weight of a gray powder that dyes leather and fur in strong Bordeaux tones.

Example ?

Coloring example for box calf, tanned with a commercially available Chromium chloride and neutralized with 0.4% sodium acetate and 0.5% sodium bicarbonate:

A leather triangle of 10 parts by weight of shaved weight is made into 15 parts by volume in the running Wacker barrel Water colored with 0.10 parts by weight of the disazo dye obtained above at 55 to 60 C for 20 minutes.

0.05 part by weight of a mixture of alkane sulfonates with synthetic is used for fatliquoring oil, 0.03 parts by weight sulfated hawk oil. 0.03 part by weight of unsulfated neat foot oil and 0.03 part by weight a synthetic leather oil based on chlorinated hydrocarbons. After 30 minutes Was greased, is acidified with 0.05 parts by weight of formic acid 85%, then rinsed and wilted. After drying at 60 ° C., a strong bordo dyeing with good fastness properties is obtained.

Example 3

Dyeing example for bath velor dyeing on sheepskin

5.0 parts by weight of dry sheepskin are dissolved in 150 parts by volume of water with 0.11 parts by weight of the Sodium salt of a fatty acid condensation product and 0.15 parts by volume of 25% ammonia for 1 hour pretreated at 35 ° C. The final pH value must not be below 7.0 or above 7.8, otherwise it must corrected and neutralization continued for 20 minutes.

Then 0.11 part by weight of the sodium salt of a condensation product is added to the liquor, 0.05 parts by volume of ammonia 25% and O. 11 parts by weight of the disazo dye prepared as described above and stains for 3 hours at 25 C. The dyebath should then have a pH of 5.0 to 5.3. Then it is rinsed, wilted and with 60 ° C. The fur leather has a rich bordo dyeing, while the hair side is only weak is stained.

Claims (1)

Palent claims. 1. Water soluble disazo dye of the formula OH HO ₃ S -N = N NH,