CH639116A5 - METHOD FOR PRODUCING 1: 2 CR COMPLEXES OF DYES, SULFOGROUP-FREE. - Google Patents

Description

The present invention relates to a process for the preparation of sulfo-free 1: 2-Cr complexes of dyes based on at least one dye of the general formula I

COOH

40

(I)

45

wherein

K = the remainder of a phenolic or enolic coupling component of the hydroxybenzene, hydroxynaphthalene, acetoacetic acid amide or pyrazolone series coupling in the o-position to the azo group and 50

A can optionally be further substituted by nonionic substituents, which is characterized in that the metal-free dye (I) in the form of the free acid in an aqueous medium in the presence of 1-6 mol of a trialkanolamine, in particular triethanolamine, in particular at least 55 1.5 moles, preferably 2-3 moles, with the stoichiometric amount of a compound of hexavalent chromium in the presence of reducing agents at about 80-105 ° C. A particularly suitable reducing agent is glucose. 60

Suitable compounds with hexavalent chromium are, for example, alkali or ammonium bichromates, in particular sodium bichromate.

Suitable nonionic substituents are, for example, C1-C5-alkyl, C1-C5-alkoxy, halogen such as F, Cl, Br; es NOj, optionally Q-Q-alkyl-substituted sulfonamide, optionally C rC5-alkyl-substituted carbonamide, Q-C5-alkyl sulfone, aryl sulfone.

wherein

R2 = C [-C5-alkyl, phenyl and in which the radicals C and B can be nonionically substituted, for example by halogen such as F, Cl, Br, by Q-Q-alkyl or NO2, the alkyl radicals not being further substituted.

The process is carried out in detail so that the dye (I), which was prepared in the usual manner by coupling, is isolated in the form of the free acid - expediently at pH values below 3 - in particular at pH values between 2 and 0, 5, then as far as possible freed from inorganic salts - for example by washing with water and then in the form of the moist paste or as a dried dye in an aqueous medium in the presence of the specified amount of trialkanolamine with compounds, the 6-valent chromium, in particular sodium bichromate, and reducing agents , especially dextrose, chromed at approx. 80-105 ° C.

The process generally enables virtually complete chromating and leads to dyes which are practically free of chromium which is not bound to the complex.

The dyes are preferably isolated in the form of their alkali metal salts, in particular sodium salts, which precipitate out of the solutions in crystalline form. In order to make the precipitation as alkali salt as complete as possible, alkali metal hydroxides, in particular sodium hydroxide solution and / or alkali metal salts, in particular sodium chloride, can be added to the chromating mixture.

The chromating reaction is generally carried out in the presence of about 1-20 times the amount of water, based on the dye. Preferably 3 to 10 times the amount of water is used.

3rd

639 116

The 1: 2 Cr complexes can of course be a dye

Hue to be a) symmetrical and asymmetrical based on 2 moles (1), i.e. those of 2 identical or non-identical dyes (I), or b) unsymmetrical complexes based on 1 mol (I) and 1 mol of any chromable dye, as described in large numbers in the literature.

The dyes obtained are suitable for dyeing and printing natural and synthetic fiber materials made from polyamides and in particular also for dyeing plastics and lacquers and for dyeing leather.

example 1

1 mol of anthranilic acid is diazotized in a conventional manner and coupled to 1 mol of 1-phenylene-3-methyl-pyrazolone-5. The mixture is then heated to 95-100 ° C, adjusted to pH 0.5 with hydrochloric acid, suction filtered and washed with 1,380 ml of water.

1 mol = 775.9 g of washed coupling paste (dye content 41.5%) are stirred in 2,000 ml of water and 447 g of triethanolamine and heated to 95-100 ° C (at 70-80 ° C a clear solution is formed). A solution consisting of 74.5 g of NaiCr; 07.2 H20, 50 g of glucose and 400 ml of water is added dropwise with stirring in 30 minutes and stirring is continued at 95 ° C. for 90 minutes. The mixture is then cooled to 90-95 ° C. and a solution consisting of 330 g of sodium chloride, 132.5 g of 40% sodium hydroxide solution and 1,650 ml of water is added dropwise over the course of 2 hours. The dye precipitates in a crystalline form. It is suctioned off and washed in the usual way with water at 90-95 ° C. on the suction filter. If necessary, you can also wash with 1% sodium hydroxide solution. After drying at 100 ° C in a vacuum, a dye is obtained which is well suited for dyeing film varnishes in yellow shades.

COOH

Ù "

N

HO

yir

Ù

CH,

yellow

C2 «5

COOH fi \ -N - N

O-

yellow

Cl

25th

COOH

O-

CH,

Cl yellow

35

Example 2

1 mol of dye anthranilic acid -> I- (2'-chlorophenyl) -3-methylpyrazolone-5 = 564.1 g paste with a dye content of 63.2%, low in salt and in acid form, prepared analogously to Example 1, are mixed of 655 g of water and 298 g of triethanolamine at 70-80 ° C. The mixture is then heated to 100 ° C. and a solution consisting of 74.5 g of Na2Cr207.2 H20.50 g of glucose and 440 ml of water is added dropwise at 100 ° C. in 30 minutes, and the mixture is stirred at this temperature for 90 minutes. After chroming, the mixture is cooled to 50 ° C., the crystalline dye which has precipitated is filtered off and dried at 70 ° C. in vacuo. A brown powder is obtained which dyes wool from organic acid baths in yellow tones.

Using the procedure of Examples 1 and 2, the symmetrical 1: 2-Cr complexes with the specified shades can be prepared from the dyes listed in the table:

COOH

òr * ■ "jt" ™ 2

HO

%

yellow

50

(Ôr "N

HO £

yellow

55

c

Claims (2)

639116 PATENT CLAIMS 1. Process for the preparation of sulfo-free 1: 2-Cr complexes of dyes based on at least one dye of the general formula I. Preference is given to the preparation of 1: 2-Cr complexes which differ from dyes of the formula COOH N = N - K (I) 10th 20th wherein K = the residue of a phenolic or enolic coupling component of the hydroxybenzene, hydroxynaphthalene, acetoacetic acid amide or pyrazolone series which couples in the o-position to the azo group and A may optionally be further substituted by nonionic substituents, characterized in that the metal-free dye (I) in the form of the free acid in an aqueous medium in the presence of 1-6 mol of a trialkanolamine with the stoichiometric amount of a compound of the 6-valent Chromium chromed in the presence of reducing agents 25 at 80-105 ° C. 2. The method according to claim 1, characterized in that in the presence of 1-20 times, preferably 3-1 times, amount of water, based on the dye, is chromed. 30th deduce what R = Ci-Cyalkyl, phenyl, CN, optionally Cr-C5-alkyl-substituted carbonamide, Ri = H, aryl, alkyl, aralkyl, benzenesulfonyl. Aryl preferably represents optionally substituted phenyl, alkyl preferably represents optionally substituted C1-C5-alkyl and aralkyl preferably represents optionally substituted benzyl. The alkyl, alkoxy, aryl and aralkyl radicals can i.ü. generally be further substituted by usual residues. As described above, ring A can be further substituted by nonionic substituents. The production of 1: 2 Cr complexes based on two metal-free dyes of the formula is particularly preferred COOH ^ ti'n = N-fi — r XJ H(