A method for preparing a water-soluble yellow reactive dye

Abstract

This invention relates to a method for preparing a water-soluble yellow reactive dye, comprising: adding water and ice to 2-naphthylamine-3,6,8-trisulfonic acid and slurrying, followed by a diazotization reaction to obtain a diazo material; adding water and ice to m-ureidoaniline, adding an alkali agent, and stirring to dissolve and obtain a clear m-ureidoaniline solution; adding the diazo material to the clear m-ureidoaniline solution and performing a coupling reaction at a controlled temperature to obtain a yellow base; adding water and ice to cyanuric chloride, adding dispersant CS and dispersant MF and slurrying, then adding sodium 2,4-diaminobenzenesulfonate and mixing and slurrying, with staged heating and pH adjustment to react and obtain a bicondensed material; adding the yellow base to the bicondensed material, heating and adjusting the pH, and performing a controlled reaction to obtain a dye slurry. The preparation method provided by this invention features high chroma conversion rate, short production cycle, and reasonable and efficient process, resulting in a product with excellent solubility, high fixation rate, good storage resistance, and bright color.

Description

Technical Field

[0001] This invention belongs to the field of reactive dye synthesis, and specifically relates to a method for preparing a water-soluble yellow reactive dye. Background Technology

[0002] Reactive dyes are a class of dyes that react with amino, primary alcohol hydroxyl, and amide groups in fabrics to form stable covalent bonds and fix the color. Their dyeing process is economical, simple, and convenient, making them popular in the market. With societal progress, customers not only have increasingly higher requirements for the application performance of reactive dyes, but also for the product's storage stability and supply capacity. Yellow, as one of the three primary dye colors, has a very large market demand; therefore, the research and development of yellow reactive dyes is an urgent market need.

[0003] Currently, many yellow reactive dyes have emerged in the market. Chinese patent CN103756359A discloses a method for treating p-β-hydroxyethyl sulfone acetanilide mother liquor wastewater, which introduces a method for preparing yellow dye using mother liquor wastewater. This method can achieve the goal of turning waste into treasure and saving energy and reducing emissions in the chemical production process. However, since this dye synthesis method itself falls under the category of wastewater reuse, the synthesized yellow dye will naturally contain many by-product impurities, resulting in low purity, average quality, and a high risk of secondary pollution. It can only meet the requirements of the low-to-mid-end market and has great limitations.

[0004] In addition, Chinese patent application CN201611103377.5 and US patent application US3647778A also involve a series of dyes with similar structures to this invention. The dyes produced by these dyes have good light and wash fastness and can be widely used in dyeing processes such as impregnation, pad dyeing, and inkjet printing of cotton, linen, and rayon fibers. However, the process is relatively rough, the unit reaction parameters are widely controlled, and there is a high risk of quality problems when used for large-scale production.

[0005] The dye described in Chinese patent application CN201611103377.5, while possessing advantages such as short dyeing time, low dyeing temperature, and low sodium sulfate usage, suffers from several drawbacks. The described preparation method primarily involves synthesizing a chromophore first, followed by a single and double condensation reaction to obtain the final product. This linear reaction route results in a long process, high time costs, and a long production cycle, making it difficult to meet the demands of large-scale supply. Furthermore, the chromophore synthesis method is relatively traditional, mainly involving dissolution followed by alkali coupling in a pot. This method introduces randomness in the bond connections of the diazo materials during coupling, leading to low purity of the chromophore, generally rarely exceeding 90%. High levels of chromophore byproduct residue, sometimes reaching over 9%, result in low purity and yield of the final dye, poor quality, and even the need for salting out for purification, generating large amounts of high-salt, high-COD wastewater, which fails to meet the increasingly stringent standards of today's market. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a water-soluble yellow reactive dye, which produces less wastewater and yields a reactive yellow dye with good solubility, high purity, excellent storage stability, and fastness properties.

[0007] The technical solution provided by this invention is as follows:

[0008] A method for preparing a water-soluble yellow reactive dye, the method comprising the following steps:

[0009] 1) Add water and ice to 2-naphthylamine-3,6,8-trisulfonic acid and slurry, add sodium nitrite solution dropwise, and keep warm to diazotize the material.

[0010] 2) Add water and ice to m-ureidoaniline, add an alkaline agent, stir and dissolve until clear to obtain a clear m-ureidoaniline solution;

[0011] 3) Add the diazo material obtained in step 1) to the m-ureidoaniline solution obtained in step 2), and perform a coupling reaction at a constant temperature to obtain a yellow base;

[0012] 4) Add water and ice to cyanuric chloride, add dispersant, slurry, then add sodium 2,4-diaminobenzenesulfonate and continue mixing and slurrying. Increase the temperature in stages and adjust the pH to react and obtain bicondensed material.

[0013] 5) Add the yellow base obtained in step 3) to the bicondensed material obtained in step 4), heat and adjust the pH, and maintain the temperature for condensation reaction to obtain a water-soluble yellow reactive dye.

[0014] The chemical structural formula of the dye of this invention is as follows:

[0015]

[0016] The method for preparing water-soluble yellow reactive dyes provided by this invention can solve problems such as excessive by-products of dye pigments, low purity, long product production cycle, high time cost, and poor storage stability. The preparation process generates less wastewater, and the resulting reactive yellow dye has good solubility, high purity, excellent storage stability, and satisfactory fastness performance in the market.

[0017] In step 1) of this invention, 2-naphthylamine-3,6,8-trisulfonic acid has three sulfonic acid groups. The acid value of this raw material can provide the acidic conditions required for the diazo reaction. Therefore, inorganic acid is no longer added in the diazo reaction in step 1), which saves auxiliary materials, reduces the formation of inorganic salts, and improves the strength of the dye.

[0018] In step 1), the molar ratio of 2-naphthylamine-3,6,8-trisulfonic acid to sodium nitrite is 1.0:1.0-1.1, and the temperature of the diazo reaction is 0-5℃.

[0019] Preferably, the sodium nitrite solution in step 1) is a 30% solution prepared by adding water to sodium nitrite, and the addition time is 10-15 minutes.

[0020] The main reaction equation for step 1) is as follows:

[0021]

[0022] In step 2) of this invention, m-ureidoaniline is poorly soluble in water. Adjusting the alkali can make m-ureidoaniline dissolve completely, which is beneficial for subsequent reactions. On the other hand, in order for m-ureidoaniline to fully react with the diazo material to generate the main chromophore structure when it participates in the next coupling reaction, a high alkaline environment is required. Therefore, an excess of alkali is added. Finally, in order to meet the requirement of mild coupling reaction, the alkali should have a buffering effect. Therefore, a suitable alkali needs to be screened.

[0023] Preferably, the alkali agent in step 2) is selected from two or three of disodium hydrogen phosphate, trisodium phosphate, sodium acetate, sodium tetraborate, and sodium carbonate.

[0024] Further preferred, the alkaline agent is composed of two or three of the following: disodium hydrogen phosphate, trisodium phosphate, sodium acetate, sodium tetraborate, and sodium carbonate, in a mass ratio of 1:1 or 1:1:1.

[0025] Further preferably, in step 2), an alkali agent is used to adjust the final pH of the m-ureidoaniline solution to 8.5-9.0.

[0026] In step 3) of this invention, the diazo material is added to the m-urea-aniline solution to couple and generate a yellow base, reducing the need for a secondary alkali adjustment step. During the addition process, the alkaline environment of the m-urea-aniline solution can inhibit the N / N double bond of the diazo compound from attaching to the adjacent bond of the amino bond of m-urea-aniline, reducing the generation of chromogenic byproducts and increasing the proportion of the main structure. Furthermore, as the reaction proceeds, the alkalinity of the material gradually decreases, and there is still a chance of generating chromogenic byproducts in subsequent coupling. Research has shown that this can be achieved by gradually slowing down the feeding rate. This reduces the contact amount and contact area per unit time, allowing sufficient time for the diazo material to mix and couple alkalinely with m-urea-aniline, preventing m-urea-aniline from entering the local acidic environment within the diazo material and causing side reactions, thus further improving the purity of the chromogenic material.

[0027] Preferably, in step 3), the time for adding the diazo material to the m-ureidoaniline solution is 20-30 minutes, the addition rhythm is such that 60-70% of the total amount of diazo material is added evenly in the first half of the time, and the remaining part is added evenly in the second half of the time, and the coupling reaction temperature is 5-10℃.

[0028] The main reaction equation for step 3) is as follows:

[0029]

[0030] In step 4) of this invention, two portions of cyanuric chloride undergo condensation reactions with two amino groups on the structure of one portion of sodium 2,4-diaminobenzenesulfonate. The reaction proceeds gradually, increasing the difficulty of bond connection. Given the easy hydrolysis of cyanuric chloride and the need to avoid excessively high reaction temperatures, higher requirements are placed on the pulping effect to ensure efficient synthesis of the bicondensate material. Dispersant CS exhibits high stability under acidic and alkaline conditions, and when combined with the commonly used dispersant MF, it can achieve better pulping and dispersing effects.

[0031] Preferably, the dispersant in step 4) includes dispersant CS (sodium cellulose sulfate) and dispersant MF (sodium polynaphthalene sulfonate).

[0032] Further preferred, the dispersant CS is 0.5-1% of the mass of cyanuric chloride, and the dispersant MF is 0.5-1% of the mass of cyanuric chloride.

[0033] In step 4), the pH of the mixture is adjusted to 2.0-2.5 with baking soda, and the temperature is controlled at 0-5℃ for 1-1.5 hours. Then the temperature is increased, and the pH is adjusted to 4.0-4.5 with baking soda. The temperature is controlled at 15-20℃ for 3.5-4 hours to obtain the bicondensed material.

[0034] The entire process of step 4) takes about the same amount of time as steps 1) through 3). To save time and ensure that step 5) proceeds smoothly, the start time of step 4) is adjusted.

[0035] Preferably, the start time of step 4) is the same as that of step 1).

[0036] The main reaction equation for step 4) is as follows:

[0037]

[0038] In step 5) of this invention, as the reaction proceeds, the molecular structure gradually becomes more complex, the steric hindrance increases, and the condensation reaction needs to be carried out at high temperature.

[0039] In step 5), the condensation reaction temperature is 60-65℃, and the pH is adjusted to 6.8-7.0.

[0040] Preferably, in step 5), the yellow base should be added to the bicondensed material quickly; the pH should be adjusted with a 20% soda ash solution.

[0041] The main reaction equation for step 5) is as follows:

[0042]

[0043] Preferably, the molar ratio of 2-naphthylamine-3,6,8-trisulfonic acid, m-ureidoaniline, cyanuric chloride and sodium 2,4-diaminobenzenesulfonate in steps 1) to 5) is 1.0-1.05:1.0-1.05:1.0:0.45-0.49.

[0044] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0045] (1) In this invention, the synthesis of yellow base and the synthesis of bicondensed material can be completed simultaneously. Then, the active yellow dye slurry is obtained by post-condensation reaction in a pot. The preparation time of the slurry is greatly shortened. Under this synthesis route, the product production cycle is shortened by 25-35%. Under the same energy consumption, equipment occupation and labor costs, the time cost is significantly reduced.

[0046] (2) The color base is synthesized under alkaline steady state, with good conversion effect, high purity of color base and few by-products. The prepared dye paste has bright color and good storage stability in liquid state.

[0047] (3) Mix cyanuric chloride and sodium 2,4-diaminobenzenesulfonate in a two-component mixture and then add a two-component dispersant to coordinate and complement each other, enhance the mixing effect, reduce the temperature required for the synthesis of the two components, and avoid excessive hydrolysis of cyanuric chloride, which would result in low dye fixation rate. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to specific embodiments.

[0049] Example 1

[0050] 1) Preparation of yellow base

[0051] Add 1000 kg of bottom water and 2000 kg of crushed ice to a 10 cubic meter diazo reactor, start stirring, add 570 kg of 2-naphthylamine-3,6,8-trisulfonic acid, slurry for 1 hour, and then rapidly add 250 kg of 30% sodium nitrite solution over 10-15 minutes, controlling the temperature at 0-5°C. After the addition is complete, continue to keep the reaction at the temperature for 1 hour to obtain the diazo material.

[0052] Add 500 kg of bottom water and 500 kg of crushed ice to a 10 cubic meter coupling reactor, start stirring, add 225 kg of m-ureaaniline, add an alkaline agent (composed of disodium hydrogen phosphate, sodium acetate and sodium carbonate in a mass ratio of 1:1:1) to adjust the pH to 8.8, stir for 1 hour to dissolve, and obtain a clear solution of m-ureaaniline.

[0053] After about 10 to 15 minutes, add 70% of the diazo material from the 10 cubic meter diazo reactor to the m-ureidoaniline solution in the 10 cubic meter coupling reactor. Then, after about 10 to 15 minutes, add the remaining 30% of the diazo material evenly. Control the temperature at 5 to 10°C. After the addition is complete, continue the reaction for 4 hours to obtain the yellow base.

[0054] 2) Preparation of double-condensed materials

[0055] Add 500 kg of bottom water and 1000 kg of ice to a 15 cubic meter condensation reactor, start stirring, add 200 kg of cyanuric chloride, 2 kg of dispersant CS and 1 kg of dispersant MF, and slurry for 30 min. Then add 140 kg of sodium 2,4-diaminobenzenesulfonate, continue mixing and slurrying for 1 h, control the temperature at 0-5℃, adjust and maintain the pH at 2.0-2.5 with baking soda, and keep the reaction at this temperature for 1-1.5 h.

[0056] When the reaction time is up, turn on the steam to raise the temperature and control it at 15-20°C. Continue to adjust and maintain the pH at 4.0-4.5 with baking soda and keep the reaction at this temperature for 3.5-4 hours to obtain the bicondensed material.

[0057] 3) Preparation of raw pulp

[0058] The yellow base in the 10 cubic coupling reactor is quickly added to the double condensation material in the 15 cubic condensation reactor. Steam is turned on to continue heating, and the temperature is controlled at 60-65℃. Then, the pH is adjusted and maintained at 6.8-7.0 with 20% soda ash solution. The reaction is kept at this temperature for 4-5 hours to obtain the yellow reactive dye slurry.

[0059] Example 2

[0060] The difference from Example 1 is that the alkaline agent used in the 10 cubic coupling reactor is composed of trisodium phosphate, sodium acetate, and sodium tetraborate in a mass ratio of 1:1:1.

[0061] Example 3

[0062] The difference from Example 1 is that the amount of dispersant CS added to the 15 cubic meter condensation reactor is 1 kg and the amount of dispersant MF is 2 kg.

[0063] Comparative Example 1

[0064] Unlike Example 1, after adding m-ureidoaniline to the 10 cubic coupling reactor, the pH was adjusted to 8.5-9.0 using 30% liquid alkali.

[0065] Comparative Example 2

[0066] Unlike Example 1, no dispersant was added during the pulping process in the 15 cubic meter condensation reactor.

[0067] Comparative Example 3

[0068] The dye was prepared using a traditional linear process, as detailed below:

[0069] 1) Preparation of yellow base

[0070] Add 1000 kg of bottom water and 2000 kg of crushed ice to a 10 cubic meter diazo reactor, start stirring, add 580 kg of 2-naphthylamine-3,6,8-trisulfonic acid, slurry for 1 hour, and then rapidly add 260 kg of 30% sodium nitrite solution over 10-15 minutes, controlling the temperature at 0-5°C. After the addition is complete, continue to keep the reaction at the temperature for 1 hour to obtain the diazo material.

[0071] Add 500 kg of bottom water and 500 kg of crushed ice to a 10 cubic meter coupling reactor, start stirring, add 230 kg of m-ureaaniline, adjust the pH to 6.5-7.0 with baking soda, stir for 1 hour to dissolve, and obtain a clear solution of m-ureaaniline.

[0072] The diazo material in the 10 cubic meter diazo reactor was added to the m-ureidoaniline solution in the 10 cubic meter coupling reactor. Then, the pH was adjusted to 5.5-6.0 with sodium bicarbonate, and the temperature was controlled at 5-10℃. The reaction was carried out for 4 hours to obtain a yellow base.

[0073] 2) Preparation of raw pulp

[0074] Add 500 kg of bottom water and 1000 kg of ice to a 15 cubic meter condensation reactor, start stirring, add 200 kg of cyanuric chloride, and slurry for 1 hour. Then add the yellow base from the 10 cubic meter coupling reactor to this reactor, adjust the pH to 3.5-5.0 with baking soda, maintain the temperature at 0-10℃, and react for 4-6 hours. After the endpoint is reached by measuring with an amino indicator, turn on the steam and raise the temperature to 40-60℃. Add 140 kg of sodium 2,4-diaminobenzenesulfonate, while adjusting and maintaining the pH at 4.0-6.0 with baking soda, maintaining the temperature at 40-60℃, and react for 4-6 hours until the liquid is clear and transparent. After the endpoint is reached by measuring with an amino indicator, adjust the pH to 7.0 to obtain the yellow reactive dye slurry.

[0075] The dyes prepared in Examples 1-3 of the present invention are compared with those prepared in Comparative Examples 1-3. Table 1 compares the quality of the yellow base during the synthesis process, mainly including the appearance and purity of the base; Table 2 compares the quality of the prepared dye slurry, mainly including the solubility, synthesis cycle, relative yield and storage performance of the slurry, with the relative values ​​based on the sample of Example 1.

[0076] Table 1. Yellow base quality during the synthesis process of Examples 1-3 and Comparative Examples 1-3

[0077]

[0078] Table 2. Quality of dye pastes prepared in Examples 1-3 and Comparative Examples 1-3

[0079]

[0080] As shown in Table 1, the chromophore obtained by the preparation method provided by the present invention has high purity, few side reactions, and the main byproducts are only about 2%, which is an improvement over Comparative Example 1 and Comparative Example 3. In particular, the main byproducts are reduced by about 7% compared with Comparative Example 3. As shown in Table 2, the improvement in chromophore purity significantly increases the final yield of dye. In addition, the preparation method provided by the present invention saves more than 4 hours in the synthesis cycle of a single batch of dye compared with Comparative Example 3, and the dye obtained has significant advantages in solubility, fixation rate and storage stability.

Claims

1. A method for preparing a water-soluble yellow reactive dye, characterized in that, The preparation method includes the following steps: 1) Add water and ice to 2-naphthylamine-3,6,8-trisulfonic acid and slurry, add sodium nitrite solution dropwise, and keep warm to diazotize the material to diazo material. The temperature of the diazo reaction is 0-5℃. 2) Add water and ice to m-ureidoaniline, add an alkaline agent, stir and dissolve to obtain a m-ureidoaniline solution. The pH of the m-ureidoaniline solution is 8.5-9.

0. The alkaline agent is composed of two or three of the following: disodium hydrogen phosphate, trisodium phosphate, sodium acetate, sodium tetraborate, and sodium carbonate, in a mass ratio of 1:1 or 1:1:

1. 3) Add the diazo material obtained in step 1) to the m-ureidoaniline solution obtained in step 2), and perform a coupling reaction at a constant temperature to obtain a yellow base; wherein, the time for adding the diazo material to the m-ureidoaniline solution is 20-30 min; wherein, 60-70% of the total amount of diazo material is added evenly in the first half of the time, and the remaining part is added evenly in the second half of the time, and the coupling reaction temperature is 5-10℃; 4) Add water and ice to cyanuric chloride, add dispersant CS and dispersant MF, pulp, then add sodium 2,4-diaminobenzenesulfonate and continue mixing and pulping. Increase the temperature in stages and adjust the pH to obtain bicondensed material. Among them, adjust the pH to 2.0-2.5 with baking soda during mixing and pulping, control the temperature at 0-5℃ and react for 1-1.5h. Then increase the temperature and continue to adjust the pH to 4.0-4.5 with baking soda, control the temperature at 15-20℃ and react for 3.5-4h to obtain bicondensed material. 5) Add the yellow base obtained in step 3) to the bicondensed material obtained in step 4), raise the temperature and adjust the pH, and maintain the temperature for condensation reaction to obtain a water-soluble yellow reactive dye; wherein, the condensation reaction temperature is 60-65℃, and the pH is adjusted to 6.8-7.

0.

2. The method for preparing the water-soluble yellow reactive dye according to claim 1, characterized in that, The molar ratio of 2-naphthylamine-3,6,8-trisulfonic acid to sodium nitrite is 1.0:1.0 to 1.

1.

3. The method for preparing the water-soluble yellow reactive dye according to claim 1, characterized in that, The start time of step 4) is the same as that of step 1).

4. The method for preparing the water-soluble yellow reactive dye according to claim 1, characterized in that, In step 4), the dispersant CS is 0.5-1% of the mass of cyanuric chloride, and the dispersant MF is 0.5-1% of the mass of cyanuric chloride.

5. The method for preparing the water-soluble yellow reactive dye according to any one of claims 1 to 4, characterized in that, The molar ratio of 2-naphthylamine-3,6,8-trisulfonic acid, m-ureidoaniline, cyanuric chloride and sodium 2,4-diaminobenzenesulfonate is 1.0-1.05:1.0-1.05:1.0:0.45-0.49.

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