DD153126A1 - PROCESS FOR PREPARING A WATER-SOLUBLE MONOAZOREACTIVE DYE - Google Patents

Abstract

The invention relates to the preparation of the water-soluble monoazo reactive dye of the formula ## STR5 ## by diazotization of 2-naphthylamine-1,5-disulphonic acid, coupling to 2-N-methylacetamino-5-naphthol-7-sulfo acid, saponification, condensation with cyanuric chloride and reaction with ammonia. It is essential to the invention that the dissolution and subsequent diazotization of the 2-naphthylamine-1,5-disulphonic acid in the reaction mixture of the reaction of the 2-N-methylamino-5-naphthol-7-sulfonic acid is carried out with acetic anhydride and that, for the termination of the coupling reaction. Value is set between 4.8 and 5.9. -Formula-

Description

224115

• A "

VEB CHEMIEKOBIBIHAT BITTERPELD

Bitterfeld, 19. 9. 2078

Process for the preparation of a monoazo reactive dyestuff

Application area of the invention

The invention relates to a process for the preparation of the water-soluble monoazo reactive dye, which in the acid form of the formula

SO ₃ H

corresponds to

Characteristic of the known technical solutions

From BB-AS 1 143 949 the dye of the above formula is known. It is obtained, inter alia, via coupling of the separately prepared diazonium salt of 2-naphthylamine-1,5-disulfonic acid with 2-N-methylacetamino-S-naphthol-T-sulfonic acid, saponification of the dye intermediate, condensation of the intermediately isolated monoazo dyes with cyanuric chloride and reaction of the resulting primary condensation product with ammonia. The separate presentation of the sparingly soluble diazonium salt of 2-naphthylamine-1,5-bisulfonic acid requires an appreciable volume of liquid, so that the coupling to the 2-N-methylacetamino-5-naphthol-7-sulfonic acid is carried out only in relatively low concentrations is possible, which adversely affects the stability of the biazonium salt of 2-haphthylamine-1 _$ 5-disulfonic acid in the Kupplixngsmedium and apparently also its tendency to love couplings reinforced, so that only incomplete reactions are achieved. The process cited in DE-AS mentioned above for the preparation of the above monoazo reactive dye via the coupling of the diazonium salt of 2-uraphthylamine-1,5-disulphonic acid with the secondary condensation product of 2-H-methylamino-5-naphthol-7-sulphonic acid and that described in US Pat DD-PS 142 715, Example 3, cited preparation process via the coupling of the diazonium salt of 2 ~ llaphthylamine-1,5-disulfonic acid with the primary condensation product of 2-N-methylamino-5-naphthol-7-sulfonic acid, can be with good economy in the case of equilateral assurance of the quality of the final dyestuff product, it is not possible to realize the process because, owing to the pronounced tendency of the 2-diazonium salt of 2-haphthylamine-1,5-disulphonic acid to secondary couplings to 2-N-methylamino-5-naphthol-7-sulphonic acid condensates, undesirable alkali-sensitive secondary dyestuffs arise that can not be separated.

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In another method (CS-PS 160 792), the stability of the diazonium salt of 2 ~ Uaphthylamin-1 , 5- disulfonic acid in the coupling medium of 2 ~ N ~ methylacetamino-5-naphthol-7-sulfonic acid by, the presence of magnesium ions, which are already contained in the starting diazonium salt, and the formation of undesirable living dyes is minimized by the use of chalk as the acid-binding agent in the coupling.

The necessary elimination of alkaline earth ions via a double intermediate isolation of the Parbstoffzwischenprodukte requires a large Apparate- and'Zeitaufwand, so that the utilization of this method on an industrial scale, despite the good material yields, is impaired.

Object of the invention

The aim of the invention is a comparison with the known prior art much simplified and economically cheaper production process for the dye of the above formula.

Explanation (JeS ₁ essence of the invention

The invention relates to a process for the preparation of the dyestuff of said formula, which comprises reacting the 2-l-taphthylamine-1,5-disulphonic acid in the acetic acid reaction mixture of the reaction of 2-bis-methylamino-5-naphthol-7-sulfonic acid Acetic anhydride dissolves, in which strongly acidic reaction mixture gives the equimolar amount of ITatriumnitrit, '. wherein using the released in the acetylation of acetic acid and the acid content of the

4 1 1 S ²⁰ ? ^8th

2-Uaphthylamin-1,5-cLisulfosäure diazotization and coupling takes place and after completion of the coupling saponification by means of sodium hydroxide makes. The resulting mono-azo dye is then condensed in a known manner with cyanuric chloride, reacted with ammonia, separated and dried. The 2-naphthylamine-1,5-disulfonic acid is preferably added in solid form to the acetylation reaction mixture of 2-N-methyl-8-nino-5-naphthol 7-sulfonic acid introduced. Sodium nitrite is added dropwise as an aqueous solution, which still uses during the Diazotienmg the coupling, so that a rapid reaction sequence takes place. Towards the end of the coupling, by adding acid-binding gown, in particular by adding the combination of sodium acetate and sodium bicarbonate, a pH value of 4.8 to 5 _S 9 which is more favorable for the termination of the coupling reaction is set.

The process according to the invention has, in addition to the acetic acid liberated in the acetylation of 2 ~ N-methylamino-5-naphthol-7-sulfonic acid with acetic anhydride and the use of the acid content of 2-naphthylamine-1,5-disulfonic acid for the Diazotization resulting advantages, such as reducing the equipment requirements by Y / egfall a separate Diazotierungsansatzes and reducing the reaction volume, in particular by the ability to use the diazo component in solid form, which enlarged approaches in the same reaction vessel can be driven, which is a much more favorable, space-time -Usebeute, the advantage that as a result of.der prior dissolution of 2-naphthylamine-1,5 ~ disulfonic acid in the reaction mixture of acetylation a

- 5 - 2 2 4 115 ₂₀₇₈

achieved better Durchdiazotierung and apparently the stability of the diazonium salt of 2 ~ lTaphthylamin-1,5-disulfoic acid in Kupplungsrailieu due to the high concentrations of the reactants favorably influenced and its tendency to love couplings on the 2 ~ N-methylacetamino-5-naphthol-7 sulfonic acid is surprisingly reduced, which manifests itself in an '' improved material yield. The need for auxiliaries, such as alkali, hydrochloric acid and common salt, is lower, which in turn leads to a significant reduction in the salt load of the wastewater.

The following example is intended to explain the process of the invention in more detail, wherein the parts indicated represent parts by weight.

Exemplary embodiment

To 400 parts of water, v / 101.2 parts of 2-N-methylamino-5-naphthol-7-sulfonic acid unter.Zusatz dissolved 21 parts of ground soda slightly acidic at 30 ⁰ C. It is then acetylated by the inlet of 44 parts of acetic anhydride. Stirring is continued for 30 minutes, then 121.2 parts of 2-naphthylamine-1,5-disulphonic acid are added and stirred until complete dissolution. It is then cooled with ice to 0 C and diazotized by the addition of 112.4 parts of sodium nitrite solution 24 »64 % ± ß in 30 minutes. To complete the coupling, 100 parts of sodium acetate and 80 parts of sodium bicarbonate are added. It is hochgeheist to 95 ⁰ C and mixed with 120 parts of sodium hydroxide 35 ⁰ Be. The reaction mixture is stirred for 1 hour at this temperature and is added after cooling to 70 C with 200 parts of sodium chloride, made slightly acidic with 100 parts of hydrochloric acid 20 ⁰ Be and filtered.

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The monoazo dye (89 % of theory) is slightly alkaline in 800 parts of water and dissolved in 30 minutes in a suspension of 56 * 5 parts of cyanuric chloride, 1 part Protektol Y / 100 %, 100 parts of water and 300 parts of ice. Then, by adding 40 parts of sodium bicarbonate, a pH of 6.5 is set to terminate the condensation. Thereafter, 140 parts of ammonia water (density Oj910 g / cnr), stirred for 2 hours at 45 ⁰ C and 300 parts Sodium chloride is added. The monoazo oractive dye is separated off and dried. 430 parts of the sodium salt of 6 - ( .A- "-chloro-6" -aminotriazine ~ 2 "-yl) -methylamino-1-hydroxo are obtained: y-2i2 ^f azonaphthalene-1 ': 3? 5'-trisulfonic acid.

Claims (3)

-7-22411 2078 Invention claim A process for the preparation of the water-soluble monoazo reactive dye which is in the acid form of the formula OH N = C < corresponds, by diazotization of 2-Naphthylamine 1 j 5-disulfosäiire, coupling to 2-N-methylacetamino-5 ~ naphthol-7-sulfonic acid, saponification ^ condensation with cyanuric chloride and reaction with ammonia, characterized in that the 2-ITaphthylamin- 1,5 ~ disulfonic acid in the aqueous reaction mixture ~ ⁸ - 2 2 4 115 2078 2 «method according to item 1, characterized in that the setting of the favorable for the termination of the coupling pH between 4> 8 and 5» 9 by adding a combination of an effective buffer in the weak acid range and a weakly alkaline range v / active buffering agent. 2-SF-methylamino-5-naphthol-7-sulfonic acid and acetic anhydride dissolves in the strongly acidic reaction mixture, the equimolar amount of sodium nitrate, by addition of acid-binding agents for the completion of the coupling reaction favorable pH of 4 * 8 to 5 »9 and continues to implement after completion of the coupling according to known methods. 3 «method according to points 1 and 2, characterized in that a combination of sodium acetate and sodium bicarbonate is used as the buffering agent.