CS240098B1 - Process for preparing black metal complex dye - Google Patents

Abstract

The purpose of the invention was a more advantageous method of preparing a metallocomplex dye by azocoupling of 6-nitro-1-diazo-2-naphthol-4-sulfonic acid with 2-naphthol and subsequent chromating of the reaction product. The purpose was achieved by carrying out the azocoupling in the presence of a divalent zinc cation or a trivalent cobalt cation in the form of an amino complex in an amount of 1.10-2 to 1.10“1 mol per 1 mol of diazotizing component.

Description

The invention relates to a process for the preparation of a black metal-complex dye of the constitution:

consisting of the azocopulation reaction of 6-nitro-1-diazo-2-naphthol-4-sulfonic acid with 2-naphthol and subsequent protection of the resulting azo compound.

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Hitherto commonly used methods for preparing the aforementioned metallocomplex azo dye consist in the interaction of a diazotizing component, 6-nifro-1-diazo-2-naphthol-4-sulfoacid, with a coupling component, 2-naphthol, in a weakly acidic to strongly alkaline reaction medium and subsequent amazement of the resulting azo dye with various chromating agents. Due to the fact that the electrophilicity of the diazotization component is strongly influenced by the intramolecular interaction of adjacent functional groups (-N * S N and -OH), a quantitative course of the azo-depression reaction cannot be achieved under these conditions. Therefore, a considerable excess of the coupling component is commonly used in practice, which is also a disadvantage of the previously used methods for preparing the constitutional dye. A further disadvantage is the need to remove unreacted reaction components or reactants. their degradation products, which would otherwise cause in the final rhesalocomplex dye, besides reducing the content of the desired synthetized metal-complex azo dye in the final product, also its shade deviation from the desired hue and deterioration of some of its coloristic properties.

It has now been found that the above disadvantages of the preparation of the constitutional metal-complex dye are eliminated by the process of azocopulation of a diazotizing component, 6-nitro-1-diazo-2-naphthol-4-sulfonic acid with a coupling component, 2-naphthol and chromium of the azocopulation reaction product according to the invention, in that the azocopulation is carried out in the presence of a divalent zinc cation or a trivalent cobalt cation in the form of an amide complex " 2 " in an amount of 1.10 to 1.10 per mole of diazotization component.

The process for the preparation of the metal-complex dye of constitution I according to the invention is carried out by adding aqueous solutions of inorganic salts of a divalent zinc cation or a trivalent cobalt cation to the reaction mixture before starting the azocopulation reaction conducted in an ammonia medium. Conveniently

-4240 098 is to use said conversion catalyst in the form of a preformed zinc or cobalt amocomplex by converting the corresponding halide or sulphate or nitrate by adding a defective ammonia solution, the cobalt amocomplex formed by converting the cabalt salt by adding aqueous ammonia solution while oxidizing with oxygen. The azocopulation reaction is carried out in the presence of alkali metal or ammonium carbonates or bicarbonates at relatively high temperatures, typically 50 to 100 ° C, whereby a quantitative course of the reaction is achieved while maintaining an equimolar ratio of the reacting components. This means that favorable conditions for the subsequent reaction of the azocopulation reaction product directly in the reaction mixture are obtained without isolation of the resulting azo compound by the action of a suitable cleaving agent, which is an advantage of the process according to the invention. Another advantage of the process of the present invention is the achievement of the selective course of the azocopulation reaction and the high yield of subsequent chromium, which in turn results in a significant improvement in the coloristic properties of the final metallized product.

Example 1

17 parts of 1-diazo-2-naphthol-6-nitro-4-sulfoacid are dissolved in 50 parts of water at about 20 DEG C. and the solution is neutralized to pH 5-7 by addition of ammonia. cobalt prepared by dissolving 7 parts of cobalt sulphate in 20 parts of water and then adding 15 parts of a conjugated ammonia solution, spontaneous oxidation with air oxygen being indicated by a color change from green to pink after mixing. The mixture is fed into a coupling reactor with the 25Ο parts of water 00 and 60 ° C, 72 parts of 2-naphthalene, U5 parts of sodium carbonate and 12 parts of NaOH are introduced with stirring. The reaction mixture is maintained at 00 and 60 ° C for 1 hour. After this time, the chromatizing agent is prepared by mixing 150 parts of hot water and 37 parts of potassium dichromate and 60 parts of oxalic acid, a chroma azo dye at a temperature of 00 and 95 ° C for 1 hour to obtain a 2: 1 metallocomplex dye coloring the PAD and wool. black shade.

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Example 2

148 parts of 1-diazo-2-naphthol-6-nitro-4-sulfoacid are dissolved in 450 parts of water at a temperature of about 20 DEG C. and the solution is neutralized to pH 5-7 by the addition of ammonia. by dissolving 6 parts zinc chloride in 30 parts water and then adding 30 parts concentrated ammonia solution.

The mixture is fed into a coupling reactor with the 25Ο parts of water and about 60 ° C warm, 72 parts of 2-naphthol, parts of sodium carbonate and 12 parts of NaOH are introduced with stirring. The reaction mixture is maintained at about 60 ° C for 1 hour. After this time, the chromatizing agent is prepared by mixing 150 parts of hot water with 37 parts of potassium dichromate and 60 parts of oxalic acid, Chromao azo dye at a temperature of about 95 ° C for 1 hour to give a 2x1 metal-complex PAD coloring dye and wool.

Claims (1)

SUBJECT OF THE INVENTION A process for preparing a metal-complex dye of constitution 0 _o N N —N OE azo copopulation component of 6-nitro-indole-2-naphthol-4-sulfonic acid and a coupling component which is 2-naphthol and a chromocase of the azocopulation reaction product characterized in that the azocopulation is carried out in the presence of a divalent zinc cation or trivalent cations of cobalt in the formS of amocomplex in an amount of -2-2 1.10 to 1.10 mol per 1 mol of diazotization component.