High-performance polyazo reactive dye as well as preparation method and application thereof

Abstract

The invention discloses a high-performance polyazo reactive dye as well as a preparation method and application thereof. The reactive dye is shown in a structural general formula (I). The reactive dye disclosed by the invention is a polyazo reactive dye which takes 2, 4-diaminobenzene sulfonic acid as a coupling component, has a molecular structure containing two vinyl sulfone sulfate active groups and four azo bonds, and is orange or reddish brown in color. The dye has remarkable symmetry and high molecular coplanarity and is particularly suitable for dyeing cellulose fibers at the high temperature (130 DEG C), dyed fabrics have good color fastness indexes, and the technical problem that existing dye containing vinyl sulfone sulfate active groups can only dye at about 60 DEG C and cannot dye at the high temperature is solved. A foundation is laid for applying the dye containing the vinyl sulfone sulfate active group to the'polyester-cotton one-bath 'process to dye cellulose fibers, and the dye has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of reactive dye technology, and in particular to a high-performance polyazo reactive dye, its preparation method, and its application. Background Technology

[0002] Dyes containing vinyl sulfone sulfate reactive groups (domesticated as KN-type reactive dyes) are an important class of reactive dyes. These dyes are typically used for dyeing at 40-50℃ and for fixing at 60℃ under alkaline conditions. However, due to the high reactivity of vinyl sulfone sulfate, severe hydrolysis occurs at high temperatures, making it difficult to apply to high-temperature (130℃) dyeing. This makes them unsuitable for the "polyester-cotton one-bath" dyeing process. The "polyester-cotton one-bath" dyeing process allows for the simultaneous dyeing of polyester and cotton with disperse and reactive dyes, respectively. However, since disperse dyes need to dye polyester at high temperatures (130℃), to achieve this, the reactive dyes must be able to withstand the high temperatures, and the reactive groups must undergo minimal hydrolysis at high temperatures to ensure satisfactory dyeing results. To enable the "polyester-cotton one-bath" dyeing process with traditional dyes containing vinyl sulfone sulfate reactive groups, the amount of dye used needs to be increased to improve the dyeing depth. Typically, the dye amount needs to be more than doubled, but this results in a large amount of hydrolyzed dye, causing serious pollution of dyeing and printing wastewater. Therefore, this technique of increasing the amount of reactive dyes to improve the dyeing depth is not feasible and has not been adopted by any printing and dyeing companies.

[0003] Compared to the traditional "two-bath, two-step" dyeing process for polyester-cotton blended fabrics, the "one-bath" dyeing process for polyester-cotton reduces the reduction washing after dyeing polyester with disperse dyes and the subsequent multiple washing steps, significantly lowering energy and material consumption, making it a cleaner dyeing process. However, traditional dyes containing vinyl sulfone sulfate reactive groups suffer severe hydrolysis at high temperatures, while the "one-bath" dyeing process requires reactive dyes to have high stability and minimal hydrolysis of reactive groups at high temperatures. This contradictory problem has become a serious obstacle to the rapid and widespread adoption of this dyeing process.

[0004] Patent CN1010922522A describes a reactive dye (structure shown below):

[0005]

[0006] The dye structure disclosed in CN1010922522A

[0007] The C group is:

[0008]

[0009] Structurally, the two benzene rings in the C group are connected by a single bond, which can rotate freely. To maintain an optimal conformation and reduce cohesive energy, the dye molecule must undergo spatial distortion through the rotation of these connecting single bonds. This reduces the dye's coplanarity and directness, ultimately making it indistinguishable from conventional dyes and limiting its use to low-temperature (60°C) dyeing. Based on the application examples in this patent, this dye can only be used for dyeing at 60°C.

[0010] Polyazo dyes typically have larger molecular weights, which is beneficial for improving their directness and coplanarity. Utilizing principles such as low-temperature dye association reducing the probability of hydrolysis of reactive groups, and high-temperature disruption of intermolecular interactions allowing for deassociation and improved permeation, innovative dye molecular structures could be designed to enable the use of dyes containing vinyl sulfone sulfate reactive groups in the "one-bath" dyeing process for polyester-cotton. However, this requires precise design of the dye molecule structure, including the number and position of sulfonic acid groups and the spatial position of azo bonds.

[0011] Patent WO2013 / 008201 A2 discloses a series of polyazo dye structures, two of which are:

[0012]

[0013]

[0014] The dye structure published in WO2013 / 008201 A2

[0015] As can be seen from the contents of the patent (WO2013 / 008201 A2 Examples 3 and 4), the preparation process of these two structures is as follows: 4-(β-sulfate ethyl sulfone) aniline (para ester) or 4-β-hydroxyethyl sulfonyl sulfate aniline-2-sulfonic acid (sulfonated para ester) is first prepared into a diazonium salt. Under conditions where the pH of the reaction system is not adjusted, it undergoes a first coupling reaction with 2,4-diaminobenzenesulfonic acid, and the formed azo bond is located in the middle position of the two amino groups (i.e., position 3 of 2,4-diaminobenzenesulfonic acid). Then, 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD acid) is prepared into a diazonium salt and then reacted with the first coupling product. At this time, the formed azo bond is located in position 5 of 2,4-diaminobenzenesulfonic acid. Since one part of DSD acid has two aromatic primary amines, it can form two diazonium salts. Therefore, it can react with two parts of the first coupling product to form two azo bonds, ultimately forming a polyazo dye. From the application process disclosed in the patent (WO2013 / 008201 A2, lines 26-29), it can be found that the dye immersion and dyeing temperature in the patent is 40-90℃, the optimal temperature is 70-90℃, and it is not suitable for dyeing under high temperature (130℃) conditions. Summary of the Invention

[0016] The purpose of this invention is to provide a high-performance polyazo reactive dye suitable for high-temperature dyeing, thereby solving the technical problem mentioned in the background art that dyes containing vinyl sulfone sulfate reactive groups undergo severe hydrolysis at high temperatures, making them difficult to apply to high-temperature (130°C) dyeing. The technical solution of this invention addresses the problem that existing technical solutions are too simplistic and provides a solution significantly different from existing technologies. Another purpose of this invention is to provide a method for preparing a high-performance polyazo reactive dye. Yet another purpose of this invention is to provide an application of a high-performance polyazo reactive dye.

[0017] To achieve the above objectives, the present invention provides the following technical solution:

[0018] This invention provides a high-performance polyazo reactive dye, wherein the reactive dye is a compound with the general structural formula (Ⅰ):

[0019]

[0020] In the general structural formula (Ⅰ), R1 is –H or –SO3M; R2 is –SO2CH2CH2OSO3M or –SO2CH=CH2;

[0021] M is –H or an alkali metal.

[0022] More preferably, in the general structural formula (Ⅰ), R1 is –H or –SO3M; and R2 is –SO2CH2CH2OSO3M or –SO2CH=CH2;

[0023] M is Na, K, or Li.

[0024] More preferably, in the general structural formula (Ⅰ), R1 is –H or –SO3M; and R2 is –SO2CH2CH2OSO3M or –SO2CH=CH2;

[0025] M is Na.

[0026] This invention provides a method for preparing reactive dyes. The preparation method of the compound represented by general structural formula (Ⅰ) is carried out according to the following process:

[0027]

[0028] Preparation of S1 vinyl sulfone sulfate monoazo dye c:

[0029] Aromatic amine compound a containing vinyl sulfone sulfate, crushed ice, and a small amount of water were added to a beaker and ground on ice for 45 minutes. After grinding, concentrated hydrochloric acid was added to the beaker, and stirring was continued for 10 minutes. Sodium nitrite solution was added dropwise to the reaction system, and the reaction was continued for 1-1.5 hours after the addition was complete. The reaction endpoint was detected by Ehrlich's reagent (1 g N,N-dimethylbenzaldehyde dissolved in 5 mL concentrated hydrochloric acid and 95 mL ethanol). Excess nitrite was removed by aminosulfonic acid to obtain a suspension of diazonium salt b of aromatic amine containing vinyl sulfone sulfate.

[0030] A solution of 2,4-diaminobenzenesulfonic acid was added to the suspension of the above diazonium salt b. The pH of the reaction was adjusted to between 3.0 and 3.5 with sodium bicarbonate. The temperature was kept below 20°C, and the reaction was carried out for 2-4 hours. The reaction was monitored by the permeation method. The disappearance of diazonium salt b was taken as the endpoint. After the reaction was completed, a solution containing vinyl sulfone sulfate monoazo dye c was obtained.

[0031] Preferably, the molar ratio of compound a to sodium nitrite is 1:1 to 1:1.02; the molar ratio of compound a to hydrochloric acid is 1:0.5 to 1:1.8; and the molar ratio of diazonium salt b to 2,4-diaminobenzenesulfonic acid is 1:0.95 to 1:1.0.

[0032] Preparation of S2 polyazo dye e containing vinyl sulfone sulfate groups:

[0033] 4,4'-Diaminostilbene-2,2'-disulfonic acid (DSD acid) and a certain amount of water were added to a beaker, and the pH was adjusted to 7.0-8.0 with dilute alkali. A certain amount of sodium nitrite solution was added to the above system and mixed thoroughly. The mixture was then slowly added to an aqueous hydrochloric acid solution, keeping the reaction system temperature below 10°C during the addition process, and ensuring that the reaction solution turned starch-potassium iodide test paper slightly blue. After the addition was complete, the reaction was continued for 1-2 hours. After the reaction was completed, excess nitrite was removed by aminosulfonic acid to obtain a suspension of the diazonium salt d of DSD acid.

[0034] The suspension of the diazonium salt d of the above-mentioned DSD acid was added to the solution of the vinyl sulfone sulfate monoazo dye c prepared in step S1. The pH of the system was adjusted to 6.0-7.0, the temperature was kept below 15℃, and the reaction was continued for 1.5-2 hours under these conditions. The reaction endpoint was detected by the percolation method, with the disappearance of the diazonium salt as the endpoint. After the reaction was completed, the product was dried at 75℃ and ground to obtain the final reactive dye solid powder with the general formula (Ⅰ).

[0035] Preferably, the molar ratio of DSD acid to sodium nitrite is 1:2 to 1:2.02; the molar ratio of DSD acid to hydrochloric acid is 1:2.5 to 1:3.0; and the molar ratio of diazonium salt d to compound c is 1:1.9 to 1:2.0.

[0036] This invention provides the application of the above-mentioned reactive dyes in high-temperature dyeing of cellulose fibers, wherein the cellulose fibers are cellulose fibers containing hydroxyl groups and / or nitrogen.

[0037] More preferably, the cellulose fiber is cotton fiber, viscose fiber, or a blend of cotton and viscose fiber.

[0038] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: Traditional reactive dyes containing vinyl sulfone sulfate can only dye at 60°C; at high temperatures (130°C), the reactive groups undergo severe hydrolysis, making them unsuitable for high-temperature dyeing. The innovative reactive dye structure provided by this invention can achieve good dyeing performance on cotton fibers at high temperatures. Its significant technical effects are as follows:

[0039] (1) This reactive dye is a polyazo reactive dye, with DSD acid as the diazo component. This diazo component contains two aromatic primary amines, and after diazotization, it contains two diazonium salt groups. One part of the diazo component can be coupled with two parts of a monoazo dye containing vinyl sulfone sulfate to prepare a symmetrical polyazo reactive dye. The two benzene rings of DSD are connected together by carbon-carbon double bonds. The double bonds cannot rotate, so the entire dye molecule cannot undergo spatial distortion, maintaining good coplanarity. The entire dye molecule has a good linear structure, improving directness and enabling strong binding force with fibers. This diazo component also contains two sulfonic acid groups, ensuring the hydrophilicity of the dye and achieving a good balance between affinity and reluctance. This ensures that the dye has good directness while preventing the dye from having excessively high directness and resulting in severe poor staining fastness. This is significantly innovative and structurally different from the dye structure disclosed in patent CN1010922522A.

[0040] (2) More importantly, the polyazo dye in this invention achieves good dyeing results under special application conditions (i.e., high temperature (130℃)) by precisely controlling the position of each group in the molecular structure to change the essential molecular properties of the dye. The ingenuity of the precise control of the dye molecule in this invention lies in the fact that when the first para-ester diazonium salt is coupled with 2,4-diaminobenzenesulfonic acid, the pH value of the reaction is controlled between 3.0 and 3.5 to precisely control the azo bond formed to fall at the 5th position of 2,4-diaminobenzenesulfonic acid. Then, the diazonium salt of DSD acid is prepared and reacted with the first coupling product so that the azo bond formed again falls at the middle position of the two amino groups, i.e., the 3rd position of 2,4-diaminobenzenesulfonic acid. The resulting dye structure, with its two azo bonds formed by the DSD acid at the 3-positions of the two 2,4-diaminobenzenesulfonic acids, and the strong hydrogen bonds between the H atoms on the two amino groups and the nitrogen atoms on the azo bonds, constructs additional stable five- and six-membered ring systems. This results in better stability and planarity of the dye molecule. During dyeing, at low temperatures, strong association between dye molecules promotes aggregation, which reduces hydration and lowers the water content around the vinyl sulfone sulfate reactive groups, significantly reducing the probability of hydrolysis. This provides a beneficial guarantee for the reactivity of the reactive groups. As the temperature increases, energy increases, disrupting the intramolecular and intermolecular hydrogen bonds in the dye molecules. The dye molecules deassociate, and the dye is adsorbed by the fiber and penetrates into the fiber interior. Because a large number of reactive groups do not undergo hydrolysis due to dye association, the effective reactive groups react with the hydroxyl groups on the fiber, resulting in good dyeing properties. This unique and precise group positioning control makes the dye suitable only for dyeing at high temperatures (130℃) and not suitable for dyeing at low temperatures (60℃), which is fundamentally different from the dye structure and application effects reported in WO2013 / 008201 A2. Attached Figure Description

[0041] Figure 1 The dyeing process is at 160℃.

[0042] Figure 2 The dyeing process is at 130℃. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045]

[0046] I-1

[0047] The preparation method of the reactive dye I-1 includes the following steps:

[0048] Preparation of S1 Vinyl Sulfone Sulfate Monoazo Dye

[0049] 0.1 mol of 4-(β-sulfate ethyl sulfone)aniline (para ester), 150 g of ice, and 20 mL of water were added to a 1000 mL beaker and ground on ice for 45 minutes. 12.2 g of industrial hydrochloric acid (30%) was added, and the reaction was stirred for another 10 minutes. 0.1 mol of sodium nitrite solid was dissolved in 25 mL of water and slowly added dropwise to the system, maintaining a slightly blue color on Congo red and KI paper during the addition. After the addition was complete, the reaction system temperature was maintained at 0-5°C, and the reaction was continued for 1 hour. The reaction endpoint was detected using Ehrlich's reagent (1 g of N,N-dimethylbenzaldehyde dissolved in 5 mL of concentrated hydrochloric acid and 95 mL of ethanol). After the reaction, excess nitrite was removed with sulfamic acid to obtain a diazonium salt suspension of the para ester.

[0050] 0.1 mol of 2,4-diaminobenzenesulfonic acid and 200 mL of water were added to a 500 mL beaker. The solution was dissolved with baking soda and then added to the above-mentioned para-ester diazonium salt suspension. The pH of the reaction was adjusted to between 3.0 and 3.5 with baking soda. The temperature was kept below 20°C and the reaction was carried out for 2-4 hours. The reaction was monitored by the percolation method. The endpoint was the disappearance of the para-ester diazonium salt. After the reaction was completed, a solution containing vinyl sulfone sulfate monoazo dye was obtained.

[0051] Preparation of S2 polyazo dyes containing vinyl sulfone sulfate groups

[0052] Add 0.05 mol of 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD acid) and 200 mL of water to a beaker, and adjust the pH to 7.0-8.0 with 30% alkali solution. Dissolve 0.1 mol of sodium nitrite solid in 25 mL of water and add it to the above system, mixing thoroughly. Then slowly add this mixture to a mixture of 24 g of concentrated hydrochloric acid (approximately 37% by mass) and 100 mL of water, keeping the reaction temperature below 10°C during the addition process, and ensuring the reaction solution turns starch-potassium iodide test paper slightly blue. After the addition is complete, continue the reaction for 1-2 hours. After the reaction is complete, remove excess nitrite with aminosulfonic acid to obtain a suspension of the diazonium salt of DSD acid.

[0053] The suspension of the above-mentioned DSD acid diazonium salt was added to the solution of the vinyl sulfone sulfate monoazo dye prepared in step S1. The pH of the system was adjusted to 6.0-7.0, the temperature to below 15℃, and the reaction was continued for 1.5-2 hours under these conditions. The reaction endpoint was detected by the percolation method, with the disappearance of the diazonium salt as the endpoint. After the reaction was completed, the solution was dried at 75℃ and ground to obtain the final reactive dye solid powder with the general formula I-1.

[0054] By changing the proportions of the reactants in the above reaction process, compound I-1 can also be obtained. The changed proportions are as follows: the molar ratio of 4-(β-sulfate ethyl sulfone)aniline (para ester) to sodium nitrite is 1:1.02; the molar ratio of 4-(β-sulfate ethyl sulfone)aniline (para ester) to hydrochloric acid is 1:0.5; the molar ratio of diazonium salt to 2,4-diaminobenzenesulfonic acid is 1:0.95; the molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to sodium nitrite is 1:2; the molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to hydrochloric acid is 1:2.5; and the molar ratio of diazonium salt to vinyl sulfone sulfate monoazo dye is 1:1.9. The modified reactant ratios are as follows: the molar ratio of 4-(β-sulfate ethyl sulfone)aniline (para-ester) to hydrochloric acid is 1:1.8; the molar ratio of diazonium salt to 2,4-diaminobenzenesulfonic acid is 1:1.0; the molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to sodium nitrite is 1:2.05; the molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to hydrochloric acid is 1:3.0; and the molar ratio of diazonium salt to vinyl sulfone sulfate monoazo dye is 1:2.0. Compound I-1 can be prepared under both of these reactant ratios.

[0055] Example 2

[0056]

[0057] I-2

[0058] In this embodiment, the preparation method of reactive dye I-2 is the same as that in Example 1, except that 4-β-hydroxyethyl sulfonyl sulfate aniline-2-sulfonic acid (sulfonated para ester) is used instead of the para ester in step S1 of Example 1 to prepare the corresponding diazonium salt before preparing the final reactive dye.

[0059] Test example:

[0060] The reactive dye provided by this invention, along with the structures reported in CI Reactive Orange 131, Example 3 of patent CN1010922522A, and Examples 3 and 4 of patent WO2013 / 008201 A2, were used to dye cotton fabrics using conventional and high-temperature immersion dyeing processes. The dyeing depth was 2%, the liquor ratio was 1:10, and the amount of sodium sulfate was 40 g / L. The various properties of the dyed cotton fabrics were compared and tested. The product performance test results are shown in Table 1.

[0061]

[0062]

[0063] Structure of Embodiment 3 in Patent CN1010922522A

[0064]

[0065] WO2013 / 008201 A2 Example 3 Dye Structure

[0066]

[0067] WO2013 / 008201 A2 Example 4 Dye Structure

[0068] The dyeing process flow is as follows Figure 1-2 As shown.

[0069] Test method:

[0070] The fixation rate of the dye was determined according to GB / T 2391-2024 "Determination of Fixation Rate of Reactive Dyes"; the rubbing fastness of the dyed fabric was determined according to GB / T 3920-2008 "Textiles - Tests for Color Fastness - Color Fastness to Rubbing"; and the washing fastness of the dyed fabric was determined according to GB / T3921-2008 "Textiles - Tests for Color Fastness - Color Fastness to Soap Washing".

[0071] Table 1

[0072]

[0073] First, as shown in Table 1, the dyes provided by this invention have higher maximum absorption wavelengths of 483 nm and 493 nm, respectively, which are 60-70 nm larger than those of CI Reactive Orange 131 and the dye structure of Example 3 in patent CN1010922522A, and 13 nm and 18 nm higher than those of the dye structures of Examples 3 and 4 in patent WO2013 / 008201 A2, respectively. The maximum absorption wavelength is the characteristic absorption wavelength of a dye, determined by its structure. Therefore, the dyes provided by this invention have a high degree of π-conjugation. Even with the same dye intermediates, precise control of different group positions can achieve a fundamental change in the dye structure and properties, proving that the essential structures of dyes are significantly different.

[0074] Secondly, as can be seen from the data in Table 1, CI Reactive Orange 131, the structural dye of Example 3 of Patent CN1010922522A, and the structural dyes of Examples 3 and 4 of Patent WO2013 / 008201 A2 have low fixation rates when used at 130℃, making them unsuitable for the "polyester-cotton one-bath" high-temperature dyeing process. In contrast, the reactive dye provided by this invention has a high fixation rate (greater than 80%) at 130℃, which is more than 30% higher than CI Reactive Orange 131 and more than 17% higher than the structural dyes of Example 3 of Patent CN1010922522A and Examples 3 and 4 of Patent WO2013 / 008201 A2. Furthermore, the apparent color depth of the dyed fabric is more than twice that of CI Reactive Orange 131 and the structural dye of Example 3 of Patent CN1010922522A, and more than 1.5 times higher than the structural dyes of Examples 3 and 4 of Patent WO2013 / 008201A2. Other staining fastness and rubbing fastness are comparable to the comparative dyes. Therefore, the dye provided by this invention not only has a high fixation rate at a high temperature of 130°C, but also produces a high apparent color depth value for the dyed fabric with the same amount of dye, demonstrating significant innovation and market demand.

Claims

1. A high-performance polyazo reactive dye, characterized in that, The reactive dye is a compound with the general structural formula (Ⅰ): In the general structural formula (Ⅰ), R1 is –H or –SO3M; R2 is –SO2CH2CH2OSO3M or –SO2CH=CH2; M is –H or an alkali metal.

2. The reactive dye according to claim 1, characterized in that, In the general structural formula (Ⅰ), R1 is –H or –SO3M; R2 is –SO2CH2CH2OSO3M or –SO2CH=CH2; M is Na, K, or Li.

3. The reactive dye according to claim 1, characterized in that, In the general structural formula (Ⅰ), R1 is –H or –SO3M; R2 is –SO2CH2CH2OSO3M or –SO2CH=CH2; M is Na.

4. A method for preparing the reactive dye according to any one of claims 1 to 3, characterized in that, The preparation method of the compound represented by general structural formula (Ⅰ) is carried out according to the following procedure: 。 5. The method for preparing reactive dyes according to claim 4, characterized in that, The molar ratio of compound a to sodium nitrite is 1:1 to 1:1.02; the molar ratio of compound a to hydrochloric acid is 1:0.5 to 1:1.

8.

6. The method for preparing reactive dyes according to claim 4, characterized in that, The molar ratio of diazonium salt b to 2,4-diaminobenzenesulfonic acid is 1:0.95 to 1:1.

0.

7. The method for preparing reactive dyes according to claim 4, characterized in that, The molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to sodium nitrite is 1:2 to 1:2.05; the molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to hydrochloric acid is 1:2.5 to 1:3.

0.

8. The method for preparing reactive dyes according to claim 4, characterized in that, The molar ratio of diazonium salt d to compound c is 1:1.9 to 1:2.

0.

9. The application of the reactive dye according to any one of claims 1-3 in the high-temperature dyeing of cellulose fibers, characterized in that, The cellulose fiber is a cellulose fiber containing hydroxyl groups and / or nitrogen.

10. The application according to claim 4, characterized in that, The cellulose fibers are selected from cotton fibers, viscose fibers, and blends of cotton and viscose fibers.

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