CS261189B1 - Method of preparing a 1: 1 chromium complex - Google Patents

Abstract

A method for preparing a 1:1 chromium complex of formula (1), aimed at reducing the content of insoluble by-products of side reactions by conducting an azo coupling reaction of l-diazo-2-hydroxy- -4-naphthalenesulfonic acid (DNSK) with 2-hydroxynaphthalene at a temperature of 50 to 70 °C and a concentration of 0^009 5 to 0.012 mol of DNSK per 1 mol of water for 1 to 3 hours, in the presence of 0.001 to 0.07 mol of Zn2+ and/or Cu^+ cations per 1 mol of DNSK. Subsequent chromization is carried out at a concentration of 0.004 5 to 0.001 5 mol of dye per 1 mol of water and a temperature of 125 to 130 °C. The dye is suitable for wool and polyamide fibers.

Description

The invention relates to a process for preparing a 1: 1 chromium complex of the formula

HO ₃ S

used to prepare 1: 2 chromocomplex dyes.

Presently, the 1: 1 chromium complex is prepared by reacting the 2-hydroxy-4-naphthalenesulfo-1-azo-1 '- (2'-hydroxynaphthalene) semi-dye with chromium salts at temperatures of 130-135 ° C and pH 3-6. The starting 2-hydroxy-4-naphthalenesulfo-1-azo-1 '- (2'-hydroxynaphthalene) semi-dye is prepared by the azocopulation reaction of 1-diazo-2-hydroxy-4-naphthalenesulfo acid with 2-hydroxy-naphthalene. The reaction is conveniently carried out in the presence of ammonium cations, at a temperature of 50 to 60 ° C. Both the coupling and the chromation are carried out at concentrations ranging from 0.018 to 0.03 moles of 1-diazo-2-hydroxy-4-naphthalenesulfoacid per mole of water.

In the prior art there are described processes using zinc salts in an amount of 0.5 mol per 1 mol of 1-diazo-2-hydroxy-4-naphthalenesulfoacid, with a concentration of reactants of 0.031 mol per 1 mol of water.

The known procedures describe the use of copper (II) cations, and operate at very low concentrations and temperatures up to 20 ° C in the azocopulation. Under these conditions the reaction takes about 24 hours with a yield of 70 to 75 S,

The disadvantages of the hitherto known processes are, on the one hand, low yields and, on the other hand, the formation of varying amounts of poorly soluble to insoluble fractions. These insoluble fractions are in part a stream of oxidation of the o, o'-dihydroxyazo dyes in an alkaline medium. Oxidation involves cleavage of the o, o'-dihydroxyazo dye, with the azo group being converted to the passive component and the active component to the cleavage of the sulfo group to the quinoid structure. Furthermore, it was found that the formation of insoluble fractions is also influenced by the temperature of chromation. With the chromating temperature rising above 130 ° C, the proportion of insoluble side reaction products, which is also influenced by the content of the oxidation products o, o'-dihydroxyazo dye and probably also by the content of unreacted components, increases significantly.

It has now been found that the above disadvantages are overcome by a process for preparing a 1: 1 chromium complex of formula

by reacting the 2-hydroxy-4-naphthalenesulfo acid-1-azo-1 '- (2' '- hydroxynaphthalene) semi-dye prepared by the azocopulation reaction of 1-diazo-2-hydroxy-4-naphthalenesulfo acid with 2-hydroxy-naphthalene in the presence of ammonium cations of zinc and optionally electrolytes in a weakly acidic to strongly alkaline medium, with chromium salts at 130 ° C, pH 3 to 6, for 2 to 3 hours, according to the invention by carrying out an azocopulae in the presence of 0.001 to 0.07 moles of cations zinc and / or cupric, based on 1 mole of 1-diazo-2-hydroxy-4-naphthalenesulfoic acid, at a concentration of 0.009 5 to 0.012 mole of 1-diazo-2-hydroxy-4-naphthalenesulfoic acid per mole of water and 50 to 70 ° C, for 1 to 3 hours and chromation is performed at concentration

0.004 5 to 0.001 5 moles of 2-hydroxy-4-naphthalenesulfo-1-azo-1 (2'-hydroxynaphthalene) per mole of water at 125-130 ° C.

The advantages of the process according to the invention consist in an increase in the yield and an improvement in the quality of the 1: 1 chromium complex, which is particularly evident in the final dye, which does not need to be filtered because it does not contain more insoluble fumes. drying the dye, which need not be diluted for filtration.

The temperature and concentration ranges found are the optimum conditions for the preparation of the chromium complex in question with the interaction of all the above mentioned influences.

He did

12.5 g of 100% 1-diazo-2-hydroxy-4-naphthalenesulfoacid are stirred in 40 ml of water, then the diazo is neutralized by the addition of 5.5 ml of NaOH-1N. A solution was added to the diaza solution

1.5 g (NH ₄ > ₂ SO ₄ and 0.25 g ZnCl ₂ in 10 ml water) After perfect mixing, a 90 ° C warm 2-hydroxynaphthalene solution prepared by dissolving 8 g of 2-hydroxynaphthalene in 34 ml is added to the diaza solution. The reaction mixture is stirred for 1 hour at 60 [deg.] C. (0.21 g of unreacted diazo and 1.65 g of oxidation products are determined by spectrometry). HCl to pH 3.5 and diluted with 130 mL of water.

After dilution, a solution of chromium (III) formate prepared by dissolving 6.75 g of Cr (OH> ₃ in 80 ml of 85% HCOOH) is added to the reaction mixture, followed by chromation in a stirred autoclave at 128 ° C for 3 hours. the complex was isolated by filtration (73.45 g of paste with a dry substance of 32.8 l).

Example 2

12.5 g of 100% 1-diazo-2-hydroxy-4-naphthalenesulfoacid are stirred in 40 ml of water, then the diazo is neutralized by addition of 5.5 ml of NaOH-10N. To the diaza solution was added a mixture of 0.2 g ZnCl ₂ , 0.012 5 g Cu (CO ₄ ). 5 H ₂ O and 1.5 g (NH ₄ ) ₂ SO ₄ , stirred in 10 mL of water. After vigorous stirring for 5 minutes, a 90 ° C warm 2-hydroxynaphthalene solution, prepared as in Example 1, and 6.25 g solid NaCl are added to the diaza solution. The reaction mixture is stirred for 3 hours at 50 ° C (0.14 g of unreacted diazo and 0.96 g of oxidation products determined spectrophotometrically). The procedure was as in Example 1 (78.43 g of a 1: 1 chromium complex paste having a dry matter content of 30.5% was obtained).

Example 3

12.5 g of 100% 1-diazo-2-hydroxy-4-naphthalenesulfoacid are stirred in 30 ml of water and neutralized by the addition of 5.5 ml of NaOH-1N. To the solution was added diaza solution of 1.5 g (NH ^ ^ JjSO in 9 mL solution of 1 g _CuSO4 cryst. In 25 ml water. After thorough stirring, to the solution was added diaza 90 ° C warm solution of 2-hydroxy-naphthalene, prepared Dissolve 8 g of 2-hydroxynaphthalene in 26 ml of water and 6 ml of NaOH-ION (0.44 g of unreacted diazo and 1.2 g of oxidation products determined spectrophotometrically). Acidification of chromium, including dosing of the chromating agent, is carried out as in Example 1 (74.23 g of a chromium complex paste having a dry matter content of 28.7%) is obtained.

Claims (1)

Process for the preparation of a 1: 1 chromium complex of the formula by the azocopulation reaction of 1-diaza-2-hydroxy-4-naphthalenesulfoic acid with 2-hydroxynaphthalene in the presence of ammonium, zinc and possibly electrolyte cations in weakly acidic to strongly alkaline medium and subsequent reaction of 2-hydroxy- 4-naphthalenesulfo-1-azo-1 '- (2'-hydroxy-naphthalene with overheated salts at 13 ° C, pH 3 to 6, for 2 to 3 hours, characterized in that the azocopulation is carried out in the presence of 0.001 to 0.07 mol of zinc and / or cupric cations, based on 1 mol of 1-diazo-2-hydroxy-4-naphthalene sulfonic acid, at a concentration of 0.009 5 to 0.012 mol of 1-diazo-2-hydroxy-4-naphthalene sulfo acid per 1 mol of water; 50 to 70 ° C, for 1 to 3 hours and chromation is carried out at a concentration of 0.004 5 to 0.001 5 moles of 2-hydroxy-4-naphthalenesulfo-1-azo-1 (2'-hydroxynaphthalene) per 1 mol of water and temperature Mp 125-130 ° C.