Red direct dye, process for its preparation and use thereof

Abstract

The present application provides a kind of red direct dye, the red direct dye includes the compound with formula (I) shown as follows: Wherein, R1, R2, R3, R4, R5, R6 each independently is H, -SO3M, -NO2, -OCH3 or halogen, M is H, Na or K.The red direct dye and its composition of the present application are bright and brilliant, high fastness to sunlight, and excellent in environmental protection (without aniline) performance.The preparation method of the red direct dye and its composition of the present application has less wastewater, and is friendly to the environment.

Description

Technical Field

[0001] This invention relates to a red direct dye, its preparation method, and its uses, belonging to the field of dye synthesis. Background Technology

[0002] Direct dyes are dyes that can be directly dissolved in water or suspended in water with the help of dispersants. They have a wide range of applications, including dyeing textiles such as protein fibers and cellulose fibers, as well as dyeing inks and paper, resulting in a large market demand. Red direct dyes can be used not only for single-color dyeing but also for mixed-color dyeing, leading to a large market consumption.

[0003] Currently, commercially available direct red dyes suffer from problems such as dull color and low lightfastness. Therefore, developing a direct red dye with bright, vibrant color, high lightfastness, and low wastewater production has become an urgent technical challenge. Summary of the Invention

[0004] The problem the invention aims to solve

[0005] In view of the technical problems existing in the prior art, and considering the requirements for environmentally friendly dyes (free from aniline structures), dull dye colors, and poor dyeing performance, this invention first provides a red direct dye and its composition. The red direct dye and its composition of this invention have the characteristics of bright and vivid colors, high color fastness, and environmental friendliness (free from aniline).

[0006] Solution for solving the problem

[0007] This invention provides a red direct dye comprising a compound having the following formula (I):

[0008]

[0009] Among them, R1, R2, R3, R4, R5, and R6 are each independently H, -SO3M, -NO2, -OCH3, or halogens, while R2, R3, R5, and R6 are not all H at the same time; M is H, Na, or K.

[0010] According to the present invention, the red direct dye comprises one or more of the compounds shown in formulas (I-1)-(I-6):

[0011]

[0012]

[0013] The present invention also provides a method for preparing a red direct dye according to the present invention, which includes the following steps:

[0014] The steps for obtaining scarlet acid are as follows: reacting a J salt solution with bis(trichloromethyl) carbonate to obtain scarlet acid reaction product, and then obtaining the dissolved scarlet acid from the scarlet acid reaction product;

[0015] The steps to obtain a diazonium salt solution are as follows: a diazotization reaction is carried out on one or more of p-nitroaniline, o-aminoanisole-4-sulfonic acid and o-chloroaniline to obtain a diazonium salt solution.

[0016] Coupling reaction step: The dissolved scarlet acid is coupled with the diazonium salt solution to obtain the coupling product;

[0017] Post-processing step: The coupling product is post-processed to obtain a red direct dye.

[0018] According to the preparation method of the present invention, in the step of obtaining scarlet acid, the J salt solution is an aqueous solution of the J salt with a pH of 6.5 to 8.5 and a temperature of 40 to 50°C; and / or,

[0019] After adjusting the pH of the scarlet acid reaction product to 8-9, it was stirred with baking soda and then settled to obtain dissolved scarlet acid.

[0020] According to the preparation method of the present invention, the step of obtaining scarlet acid includes: mixing bis(trichloromethyl) carbonate with a J salt solution and reacting for 2-4 hours under reaction conditions of pH 5-8 and temperature 40-50°C; continuing to react for 12-18 hours under reaction conditions of pH 5-8 and temperature 52-57°C; and finally reacting for 2-4 hours under reaction conditions of pH 5-8 and temperature 58-63°C.

[0021] According to the preparation method of the present invention, the step of obtaining the diazonium salt solution includes: under acidic conditions, mixing one or more combinations of p-nitroaniline, o-aminoanisole-4-sulfonic acid and o-chloroaniline with nitrite to carry out a diazotization reaction to obtain the diazonium salt solution; preferably, the temperature of the diazotization reaction is -2 to 5°C, and the time of the diazotization reaction is 1.5 to 3 hours.

[0022] According to the preparation method of the present invention, the coupling reaction is carried out by adding a diazonium salt solution dropwise to a solution of scarlet acid; preferably, the pH value of the coupling reaction is 6.5 to 7.5, the time of the coupling reaction is 5 to 8 hours, and the temperature of the coupling reaction is 5 to 25°C.

[0023] According to the preparation method of the present invention, the post-treatment step includes post-treatment of the coupling product with soda ash to obtain a red direct blended dye.

[0024] According to the preparation method of the present invention, the post-processing step includes: adding soda ash to the coupling product, adjusting the pH value to 9.5-11, mixing for 0.5-2 hours, then heating to 50-70°C and spray drying to obtain a red direct dye.

[0025] The present invention also provides the use of the red direct dye according to the present invention for dyeing and / or printing fabrics.

[0026] The effects of the invention

[0027] The red direct dye and its composition of the present invention have bright and vivid colors, high color fastness, and excellent environmental protection (aniline-free).

[0028] The preparation method of the red direct dye and its composition of the present invention generates less wastewater and is environmentally friendly. Detailed Implementation

[0029] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0030] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0031] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0032] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0033] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0034] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0035] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0036] <First Aspect>

[0037] A first aspect of the present invention provides a red direct dye, wherein the red direct dye comprises a compound having the following formula (I):

[0038]

[0039] Among them, R1, R2, R3, R4, R5, and R6 are each independently H, -SO3M, -NO2, -OCH3, or halogens, while R2, R3, R5, and R6 are not all H at the same time; M is H, Na, or K.

[0040] The red direct dye of this invention has a bright and vivid color, high color fastness, and excellent dyeing performance.

[0041] Preferably, the red direct dye of the present invention comprises a combination of two or more compounds having the above formula (I). The inventors of the present invention have discovered that by using a combination of two or more compounds having the above formula (I), a red direct dye with superior lightfastness can be obtained.

[0042] In some specific embodiments, the red direct dye comprises one or more combinations of compounds shown in formulas (I-1)-(I-6):

[0043]

[0044] <Second aspect>

[0045] A second aspect of the present invention provides a method for preparing a red direct dye according to claim 1 or 2, comprising the following steps:

[0046] The steps for obtaining scarlet acid are as follows: reacting a J salt solution with bis(trichloromethyl) carbonate to obtain scarlet acid reaction product, and then obtaining the dissolved scarlet acid from the scarlet acid reaction product;

[0047] The steps to obtain a diazonium salt solution are as follows: a diazotization reaction is carried out on one or more of p-nitroaniline, o-aminoanisole-4-sulfonic acid and o-chloroaniline to obtain a diazonium salt solution.

[0048] Coupling reaction step: The dissolved scarlet acid is coupled with the diazonium salt solution to obtain the coupling product;

[0049] Post-processing step: After post-processing the coupling product, a red direct dye is obtained.

[0050] The method for preparing the red direct dye of the present invention is simple and easy to implement, the raw materials are readily available, and the wastewater generated during the preparation process is small, which is environmentally friendly.

[0051] Steps for synthesizing scarlet acid

[0052] The present invention obtains scarlet acid reaction product by reacting a J salt solution with bis(trichloromethyl) carbonate, wherein the scarlet acid reaction product contains soluble scarlet acid.

[0053] In some specific implementations, in the step of obtaining scarlet acid, the J salt solution is an aqueous solution of J salt with a pH value of 6.5 to 8.5 and a temperature of 40 to 50°C. Specifically, the pH value of the J salt aqueous solution can be 6.8, 7, 7.2, 7.5, 7.8, 8, 8.2, etc.; and the temperature can be 42°C, 45°C, 48°C, etc.

[0054] The inventors have discovered that when the J salt solution is an aqueous solution of J salt with a pH of 6.5 to 8.5 and a temperature of 40 to 50°C, bis(trichloromethyl) carbonate is relatively stable, while bis(trichloromethyl) carbonate is easily hydrolyzed when the pH is too high or too low; when the temperature is too high, the hydrolysis of bis(trichloromethyl) carbonate is accelerated, while when the temperature is too low, bis(trichloromethyl) carbonate does not react.

[0055] In some other specific embodiments, the step of obtaining scarlet acid includes: mixing bis(trichloromethyl) carbonate with a J salt solution and reacting it for 2-4 hours under reaction conditions of pH 5-8 and temperature 40-50°C. During this reaction, the pH can be 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, etc., the temperature can be 42°C, 45°C, 48°C, etc., and the reaction time can be 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, etc.; continuing the reaction for 12-18 hours under reaction conditions of pH 5-8 and temperature 52-57°C. During this reaction, the pH can be 5.2. The pH values ​​can be 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, etc., and the temperatures can be 53℃, 54℃, 55℃, 56℃, etc., with reaction times of 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, etc. Finally, the reaction is carried out for 2-4 hours under reaction conditions of pH 5-8 and temperature 58-63℃. During this reaction, the pH can be 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, etc., the temperature can be 59℃, 60℃, 61℃, 62℃, etc., and the reaction time can be 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, etc.

[0056] This invention employs a segmented heating method to react the J salt solution with bis(trichloromethyl) carbonate, which can reduce the hydrolysis of bis(trichloromethyl) carbonate and the formation of salts.

[0057] The present invention does not impose any particular limitation on the method of mixing bis(trichloromethyl) carbonate with the J acid salt solution. Considering the effective progress of the reaction, bis(trichloromethyl) carbonate can be added to the J acid salt solution for the reaction.

[0058] Furthermore, the present invention does not impose any particular limitation on the concentration of the J acid salt solution. Generally, its mass concentration can be 5-20%, for example: 8%, 10%, 12%, 15%, 18%, etc.

[0059] During the reaction, a liquid alkali is generally used to control the pH value of the synthesis reaction. Specifically, the J acid can be dissolved in a solvent, and the pH value can be adjusted to 6.5–8.5 using a liquid alkali, for example: 6.8, 7, 7.2, 7.5, 7.8, 8, 8.2, etc., to obtain a J acid salt solution.

[0060] Furthermore, dissolved scarlet acid can be obtained by adjusting the pH of the scarlet acid reaction product to 8-9 using liquid alkali, followed by stirring and sedimentation, for example, 8.2, 8.5, 8.8, etc., thereby obtaining dissolved scarlet acid. The inventors of this invention have discovered that stirring and sedimentation with baking soda can promote the ionization and dissolution of scarlet acid. The present invention does not particularly limit the sedimentation time, as long as dissolved scarlet acid can be obtained. Preferably, the sedimentation time is generally 2-5 hours, for example, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, etc.

[0061] Steps for synthesizing diazonium salt solutions

[0062] The present invention obtains a diazonium salt solution by subjecting one or more of p-nitroaniline, o-aminoaniline-4-sulfonic acid and o-chloroaniline to a diazotization reaction.

[0063] Specifically, in this invention, under acidic conditions, one or more combinations of p-nitroaniline, o-aminoanisole-4-sulfonic acid, and o-chloroaniline are mixed with nitrite and subjected to a diazotization reaction to obtain a diazonium salt solution.

[0064] Further, nitrite is dissolved in a solvent to obtain a nitrite solution. One or more combinations of p-nitroaniline, o-aminoaniline-4-sulfonic acid, and o-chloroaniline are dissolved in a solvent to obtain a diazo component solution. To obtain two or more red direct dye components, two or more diazo component solutions can be used. Preferably, when using two or more diazo component solutions, two or more of p-nitroaniline, o-aminoaniline-4-sulfonic acid, and o-chloroaniline can be dissolved separately in a solvent to obtain a first diazo component solution (e.g., p-nitroaniline solution), a second diazo component solution (e.g., o-aminoaniline-4-sulfonic acid solution), a third diazo component solution (e.g., o-chloroaniline solution), etc.

[0065] Specifically, the first diazonium component solution can be diazotized with a nitrite solution to obtain a first diazonium salt solution. Then, the second diazonium component solution can be diazotized with a nitrite solution to obtain a second diazonium salt solution. Optionally, a third diazonium component solution can be diazotized with a nitrite solution to obtain a third diazonium salt solution, and so on. Alternatively, the first, second, and optionally third diazonium components can be directly mixed and dissolved to obtain a diazonium component solution. This solution can then be diazotized with a nitrite solution to obtain a mixed diazonium salt solution.

[0066] The present invention does not impose a particular limitation on the mass concentration of the diazo component in each diazo component solution, and it can generally be 5-30%, for example: 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, etc. Similarly, the present invention does not impose a particular limitation on the concentration of nitrite in the nitrite solution, and it can generally be 5-35%, for example: 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, etc.

[0067] Furthermore, to ensure a suitable reaction temperature, ice cubes, crushed ice, or ice-water mixtures can be used for cooling during the preparation of each diazo component solution. Additionally, an acidic substance is included in the diazo component solution to facilitate the reaction. This invention does not specifically limit the acidic substance; it can be any commonly used acidic substance in the art, such as hydrochloric acid or sulfuric acid. The amount of acidic substance used is not specifically limited; generally, it is sufficient to maintain the pH of the diazo component solution below 2.

[0068] Finally, after lowering the temperature of the reaction system to -2 to 5°C, each diazonium component solution or a mixed diazonium component solution is added dropwise to the nitrite solution. The dropwise addition time for each diazonium component solution or the mixed diazonium component solution can be 5-60 minutes, followed by the diazotization reaction. Specifically, the temperature of the diazotization reaction is -2 to 5°C, for example: -1°C, 0°C, 1°C, 2°C, 3°C, 4°C, etc.; the time of the diazotization reaction is 1.5 to 3 hours, for example: 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, etc.

[0069] Coupling reaction steps

[0070] The dissolved scarlet acid is coupled with the diazonium salt solution to obtain a coupled product. When two or more diazonium salt solutions are present, they can be coupled sequentially or together. Preferably, to obtain a product with superior properties, two or more diazonium salt solutions are used sequentially for the coupling reaction.

[0071] In some specific implementations, the coupling reaction is carried out by adding a diazonium salt solution dropwise to soluble scarlet acid; when using two or more diazonium salt solutions, the first diazonium salt solution is first added dropwise to soluble scarlet acid for a coupling reaction for a period of time, then the second diazonium salt solution is added dropwise to soluble scarlet acid for a coupling reaction for a period of time, and subsequently the third diazonium salt solution, etc., are added dropwise to soluble scarlet acid for a coupling reaction.

[0072] Specifically, the first diazonium salt solution is typically added dropwise to the dissolved scarlet acid for a coupling reaction that lasts no more than 1 hour. Then, the second diazonium salt solution is added dropwise to the dissolved scarlet acid for a coupling reaction that lasts no more than 1 hour. Subsequently, the third diazonium salt solution, the fourth diazonium salt solution, and so on are added dropwise to the dissolved scarlet acid for a coupling reaction in the same manner.

[0073] The time for adding each diazonium salt solution to the dissolved scarlet acid is generally 0.5-2 hours, for example: 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, etc.; the pH value at the time of addition is 6.5-7.5, for example 6.8, 7, 7.2, etc.

[0074] Furthermore, for the entire coupling reaction process, the pH value of the coupling reaction is 6.5 to 7.5, the coupling reaction time is 5 to 8 hours, and the coupling reaction temperature is 5 to 25°C.

[0075] Post-processing steps

[0076] The present invention obtains a red direct dye by post-processing the coupling product.

[0077] In some specific embodiments, the post-treatment step includes treating the coupling product with soda ash to obtain a red direct dye. This invention, by using soda ash to treat the coupling product, eliminates the need for salting out the red direct dye of this invention. Therefore, the preparation method of this invention reduces wastewater and protects the environment.

[0078] Specifically, the post-processing step includes: adding soda ash to the coupling product and adjusting the pH value to 9.5–11, such as 9.8, 10, 10.2, 10.5, 10.8, etc., mixing for 0.5–2 hours, such as 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, etc., and then heating to 50–70°C, such as 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, etc., followed by spray drying to obtain a red direct dye. Generally, the pH value can be adjusted to 9.5–11 using liquid alkali.

[0079] The present invention also provides the use of a red direct dye according to the invention for dyeing and / or printing fabrics.

[0080] Example

[0081] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0082] Example 1

[0083] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 30g of bis(trichloromethyl) carbonate to the dissolved J acid salt solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0084] (2) Dissolve 22g of sodium nitrite in 100g of water, stir until completely dissolved, and let stand for later use. Add 200g of bottom water and 200g of crushed ice to a three-necked flask, then start stirring. Add 80g of hydrochloric acid and 44g of p-nitroaniline in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining a diazonium salt solution.

[0085] (3) Start stirring and add the diazonium salt solution obtained in (3) dropwise to the soluble scarlet acid obtained in (1). Use baking soda to keep the pH of the system at 7 during the dropwise addition. The dropwise addition time is 1 hour. After the dropwise addition is completed, raise the temperature to 15°C and continue the reaction for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0086] (4) Add 10g of soda ash to the coupling product obtained in step (3), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60℃, and then spray dry directly through a spray tower to obtain a red direct dye, the structural formula of which is shown in (I-3).

[0087] Example 2

[0088] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0089] (2) Dissolve 22g of sodium nitrite in 100g of water, stir until completely dissolved, and let stand for later use. Add 200g of bottom water and 200g of crushed ice to a three-necked flask, then start stirring. Add 50g of hydrochloric acid and 65g of o-aminoanisole-4-sulfonic acid in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining a diazonium salt solution.

[0090] (3) Start stirring and add the diazonium salt solution obtained in (2) dropwise to the soluble scarlet acid obtained in (1). Use baking soda to keep the pH of the system at 7 during the dropwise addition. The dropwise addition time is 1 hour. After the dropwise addition is completed, raise the temperature to 15°C and continue the reaction for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0091] (4) Add 10g of soda ash to the coupling product obtained in step (3), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60℃, and then spray dry directly through a spray tower to obtain a red direct dye, the structural formula of which is shown in (I-2).

[0092] Example 3

[0093] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0094] (2) Dissolve 11g of sodium nitrite in 80g of water, stir until completely dissolved, and let stand for later use. Add 100g of bottom water and 100g of crushed ice to a three-necked flask, then start stirring. Add 40g of hydrochloric acid and 22g of p-nitroaniline in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining diazonium salt solution A.

[0095] (3) Dissolve 11g of sodium nitrite in 80g of water, stir until completely dissolved, and let stand for later use; add 33g of o-aminoanisole-4-sulfonic acid to a beaker, then add 300g of ice-water mixture, stir for 1 hour, add 40g of hydrochloric acid, stir for 10 minutes, cool down to 0℃, add 50g of ice, and at the same time add the dissolved sodium nitrite solution at a rate of first fast and then slow, keeping the temperature at 0℃ during the dropwise addition, and the dropwise addition time is 30 minutes; after the sodium nitrite solution is completely added, keep the reaction system at 0℃ for 2 hours to complete the reaction, and the reaction ends to obtain diazonium salt solution B.

[0096] (4) Start stirring and add the diazonium salt solution A obtained in step (2) dropwise to the soluble scarlet acid reaction product obtained in step (1). Keep the pH of the system at 7 during the dropwise addition and the dropwise addition time is 1 hour. After the dropwise addition is completed, keep the pH of the system at 7. After the reaction is completed for 0.5 hours, add the diazonium salt solution B obtained in step (3) dropwise to the mixture. Keep the pH of the system at 7 during the dropwise addition and the dropwise addition time is 1 hour. After the dropwise addition is completed, keep the pH of the system at 7. At the same time, raise the temperature to 15°C and react for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0097] (5) Add 10g of soda ash to the coupling product obtained in step (4), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60°C, and then spray dry directly through a spray tower to obtain a red direct dye composition, the structural formula of which is shown in (I-1), (I-2), (I-3).

[0098] Example 4

[0099] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0100] (2) Dissolve 22g of sodium nitrite in 200g of water, stir until completely dissolved, and let stand for later use. Add 300g of bottom water and 600g of crushed ice to a three-necked flask, then start stirring. Add 80g of hydrochloric acid and 40g of o-chloroaniline in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining a diazonium salt solution.

[0101] (3) Start stirring and add the diazonium salt solution obtained in (2) dropwise to the soluble scarlet acid obtained in (1). Use baking soda to keep the pH of the system at 7 during the dropwise addition. The dropwise addition time is 1 hour. After the dropwise addition is completed, raise the temperature to 15°C and continue the reaction for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0102] (4) Add 10g of soda ash to the coupling product obtained in step (4), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60℃, and then spray dry directly through a spray tower to obtain a red direct dye, the structural formula of which is shown in (I-6).

[0103] Example 5

[0104] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0105] (2) Dissolve 10g of sodium nitrite in 80g of water, stir until completely dissolved, and let stand for later use. Add 100g of bottom water and 100g of crushed ice to a three-necked flask, then start stirring. Add 40g of hydrochloric acid and 20g of o-chloroaniline in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining diazonium salt solution A.

[0106] (3) Dissolve 10g of sodium nitrite in 80g of water and stir until completely dissolved. Let stand for later use. Add 32g of o-aminoanisole-4-sulfonic acid to a beaker and then add 100g of ice-water mixture. Stir for 1 hour and then add 40g of hydrochloric acid. Stir for 10 minutes and then cool down to 0℃. Add 50g of ice and add the dissolved sodium nitrite solution at the same time at a rate that is fast at first and then slow. Keep the temperature at 0℃ during the dropwise addition and the dropwise addition time is 30 minutes. After the sodium nitrite solution is completely added, keep the reaction system at 0℃ and react for 2 hours to end the reaction and obtain diazonium salt solution B.

[0107] (4) Start stirring and add the diazonium salt solution A obtained in step (2) dropwise to the soluble scarlet acid reaction product obtained in step (1). Keep the pH of the system at 7 during the dropwise addition and the dropwise addition time is 1 hour. After the dropwise addition is completed, keep the pH of the system at 7. After the reaction is completed for 0.5 hours, add the diazonium salt solution B obtained in step (3) dropwise to the mixture. Keep the pH of the system at 7 during the dropwise addition and the dropwise addition time is 1 hour. After the dropwise addition is completed, keep the pH of the system at 7. At the same time, raise the temperature to 15°C and react for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0108] (5) Add 10g of soda ash to the coupling product obtained in step (4), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60°C, and then spray dry directly through a spray tower to obtain a red direct dye composition, the structural formula of which is shown in (I-2), (I-5), (I-6).

[0109] Example 6

[0110] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0111] (2) Dissolve 22g of sodium nitrite in 100g of water, stir until completely dissolved, and let stand for later use. Add 300g of bottom water and 600g of crushed ice to a three-necked flask, then start stirring. Add 80g of hydrochloric acid, 32g of o-aminoanisole-4-sulfonic acid, and 20g of o-chloroaniline in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining a mixed diazonium salt solution.

[0112] (3) Start stirring and add the mixed diazonium salt solution obtained in (2) dropwise to the dissolved scarlet acid obtained in (1). Use baking soda to keep the pH of the system at 7 during the dropwise addition. The dropwise addition time is 1 hour. After the dropwise addition is completed, raise the temperature to 15°C and continue the reaction for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0113] (4) Add 10g of soda ash to the coupling product obtained in (3), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60℃ and spray dry directly through a spray tower to obtain a red direct dye composition, the structural formula of which is shown in (I-2), (I-5), (I-6).

[0114] Example 7

[0115] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid. Start stirring and stir for 1 hour. Then raise the temperature to 45℃, adjust the pH to 7 with liquid alkali, and dissolve the solution for later use. Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution. While maintaining the system temperature at 45℃, adjust the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7, and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7, and react for 3 hours to reach the endpoint, obtaining the scarlet acid reaction product. Adjust the pH of the scarlet acid reaction product to 8 with liquid alkali and dissolve the solution. Add 20g of baking soda, stir for 30 minutes, then turn off the stirring and let it settle. After 3 hours, take out the supernatant to obtain dissolved scarlet acid. Cool the dissolved scarlet acid to 15℃ for later use.

[0116] (2) Dissolve 22g of sodium nitrite in 80g of water, stir until completely dissolved, and let stand for later use. Add 200g of bottom water and 270g of crushed ice to a three-necked flask, then start stirring. Add 80g of hydrochloric acid, 11g of p-nitroaniline, 21.6g of o-aminoaniline-4-sulfonic acid, and 14g of o-chloroaniline in sequence, and stir for half an hour. Cool the reaction system to 0℃ and add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining a mixed diazonium salt solution.

[0117] (3) The mixed diazonium salt solution obtained in step (2) is added dropwise to the soluble scarlet acid reaction product obtained in step (1). The pH of the system is kept at 7 during the dropwise addition. At the same time, the temperature is raised to 15°C and the reaction is carried out for 5 hours to reach the reaction endpoint and obtain the coupling product.

[0118] (4) Add 10g of soda ash to the coupling product obtained in step (3), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60°C, and then spray dry directly through a spray tower to obtain a red direct dye composition, the structural formula of which is shown in (I-1)-(I-6).

[0119] Comparative Example 1

[0120] (1) Add 50ml of water to a 500ml beaker, add 14ml of 30% hydrochloric acid solution, add ice to cool to 0℃, and add 3.83g of p-aminoacetanilide and 2.28g of aniline. Add 11.5g of 30% sodium nitrite solution at 0-5℃, and maintain a slight excess of sodium nitrite for 30 minutes.

[0121] (2) Add 150ml of water to a 1000ml beaker. Add 11.95g of 100% silicic acid, add sodium carbonate to adjust the pH to 7, add 3.4g of triphosgene, keep the temperature at about 30℃ and the pH at about 6.8 and react for 6 hours.

[0122] (3) Add sodium carbonate to the condensation solution to adjust the pH to about 9.5, and add ice to cool it down to about 5°C. Add diazonium solution and react for 3 hours at a temperature of about 12°C and a pH of about 7.2. Add a 7% salt solution for salting out, filter and dry to obtain a red direct dye.

[0123] Comparative Example 2

[0124] (1) Add 600g of bottom water to a three-necked flask, then add 85g of J acid, start stirring, stir for 1 hour, then heat to 45℃, adjust the pH to 7 with liquid alkali and dissolve for later use.

[0125] Add 23g of bis(trichloromethyl) carbonate to the dissolved J acid solution, while maintaining the system temperature at 45℃ and adjusting the pH to 7 with baking soda. After reacting for 3 hours, raise the temperature to 55℃, maintain the pH at 7 and react for 15 hours. Then raise the temperature to 60℃, maintain the pH at 7 and react for 3 hours to reach the endpoint, obtaining scarlet acid solution.

[0126] The scarlet acid solution was adjusted to pH 8 with liquid alkali and then dissolved. 20g of baking soda was added, and the mixture was stirred for 30 minutes. The stirring was then turned off and the mixture was allowed to settle. After 3 hours, the supernatant was taken out to obtain dissolved scarlet acid. The dissolved scarlet acid was then cooled to 15℃ for later use.

[0127] (2) Dissolve 23g of sodium nitrite in 70g of water, stir until completely dissolved, and let stand for later use. Add 200g of bottom water and 300g of crushed ice to a three-necked flask, then start stirring. Add 80g of hydrochloric acid, 15g of aniline, and 22g of p-aminoacetanilide in sequence, and stir for half an hour. Cool the reaction system to 0℃, then add sodium nitrite solution dropwise over 10 minutes. After the addition is complete, keep the temperature at 0℃ and stir for 2 hours to reach the reaction endpoint, obtaining a diazonium salt solution.

[0128] (3) Start stirring and add the diazonium salt solution obtained in (2) dropwise to the soluble scarlet acid obtained in (1). Keep the pH of the system at 7 during the dropwise addition and the dropwise addition time is 1 hour. After the dropwise addition is completed, keep the pH of the system at 7 and heat to 15°C. After the reaction is completed, the reaction endpoint is reached after 6 hours, and the coupling product is obtained.

[0129] Add 10g of soda ash to the coupling product obtained in (3), then adjust the pH of the system to 10 with liquid alkali, stir for 1 hour, raise the temperature to 60℃, and then spray dry directly through a spray tower to obtain a red direct dye.

[0130] Staining methods

[0131] Take 1g of each of the red direct dyes obtained in Examples 1-7 and Comparative Examples 1-2, 100g of cotton fabric and 2-4g of sodium sulfate, place them in hot water at 40℃, stir evenly, and then heat to 98-100℃ at a rate of 1-1.5℃ / min. Add another 10g of sodium sulfate, stir evenly, keep warm for 45min, and then gradually cool down to 70℃. After thorough washing, dry directly.

[0132] Performance testing

[0133] The dried dyed fabrics were tested for their resistance to rubbing, washing, perspiration, light, and sunlight, and their dyeing depth and dyeing rate were calculated. The methods used were in accordance with GB / T 3920-2008, GB / T 3921-2008, GB / T 3922-2013, GB / T 8426-1998, and GB / T 8427-1998, respectively. Simultaneously, 50g of the dyeing wastewater was taken to measure its Abs and COD values. The methods used were UV-Vis spectrophotometry (wavelength 380nm~750nm) and GB11914-89 Chemical Oxygen Demand-Dichromate Method, respectively. The properties of the red direct dyes prepared in Examples 1-7 and Comparative Examples 1-2 are shown in Table 1 below.

[0134] Table 1

[0135]

[0136] Note: / indicates that it was not detected.

[0137] As can be seen from Table 1, the red direct dyes prepared in Examples 1-7 have the same dyeing depth as the red direct dyes obtained in the comparative examples, which meets the commercial requirements. At the same time, the dye uptake rate of the dyes in Examples 1-7 is higher than that of the dyes in Comparative Examples 1-2, indicating that dye waste can be reduced and dye utilization can be improved during the dyeing process.

[0138] Regarding dyeing performance, the dyes in Examples 1-7 exhibited better resistance to washing, perspiration, rubbing (dry rubbing), light, and sunlight than the dyes in Comparative Examples 1-2. This indicates that the dyes prepared in Examples 1-7 have superior dyeing performance. In Examples 3 and 5-7, the light fastness of the dye compositions consisting of two or more dyes was superior to that of the single dye compositions in Examples 1-2 and 4.

[0139] Meanwhile, regarding wastewater, neither Abs nor COD was detected in the product wastewater of Examples 1-7 and Comparative Example 2, while both were present in Comparative Example 1. This proves that the dye prepared by this method produces no wastewater, saving subsequent wastewater treatment costs and also preventing environmental pollution.

[0140] Therefore, the red direct dye of the present invention improves the various properties of the dye while reducing production wastewater, thus protecting the environment and promoting clean and green production.

[0141] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0142] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A red direct dye, characterized in that, The red direct dye comprises a combination of compounds shown in formulas (I-1), (I-2), and (I-3), or a combination of compounds shown in formulas (I-2), (I-5), and (I-6), or a combination of compounds shown in formulas (I-1)-(I-6): （I-1） （I-2） （I-3） （I-4） （I-5） （I-6）。 2. A method for preparing a red direct dye according to claim 1, characterized in that, Includes the following steps: The steps for obtaining scarlet acid are as follows: reacting a J salt solution with bis(trichloromethyl) carbonate to obtain scarlet acid reaction product, and then obtaining the dissolved scarlet acid from the scarlet acid reaction product; The steps to obtain a diazonium salt solution are as follows: a combination of two or more of p-nitroaniline, o-aminoanisole-4-sulfonic acid and o-chloroaniline is subjected to a diazotization reaction to obtain a diazonium salt solution. Coupling reaction step: The dissolved scarlet acid is coupled with the diazonium salt solution to obtain the coupling product; Post-processing step: The coupling product is post-processed to obtain a red direct dye.

3. The preparation method according to claim 2, characterized in that, In the step of obtaining scarlet acid, the J salt solution is an aqueous solution of the J salt with a pH of 6.5-8.5 and a temperature of 40-50°C; and / or, After adjusting the pH of the scarlet acid reaction product to 8-9, it was stirred with baking soda and then settled to obtain dissolved scarlet acid.

4. The preparation method according to claim 2 or 3, characterized in that, The steps for obtaining scarlet acid include: mixing bis(trichloromethyl) carbonate with a J salt solution and reacting for 2-4 hours under reaction conditions of pH 5-8 and temperature 40-50°C; continuing to react for 12-18 hours under reaction conditions of pH 5-8 and temperature 52-57°C; and finally reacting for 2-4 hours under reaction conditions of pH 5-8 and temperature 58-63°C.

5. The preparation method according to claim 2 or 3, characterized in that, The steps for obtaining a diazonium salt solution include: under acidic conditions, mixing one or more of p-nitroaniline, o-aminoanisole-4-sulfonic acid, and o-chloroaniline with nitrite to carry out a diazotization reaction to obtain a diazonium salt solution.

6. The preparation method according to claim 5, characterized in that, The diazotization reaction is carried out at a temperature of -2 to 5°C for 1.5 to 3 hours.

7. The preparation method according to claim 2 or 3, characterized in that, The coupling reaction was carried out by adding a diazonium salt solution dropwise to a solution of scarlet acid.

8. The preparation method according to claim 7, characterized in that, The coupling reaction has a pH of 6.5 to 7.5, a reaction time of 5 to 8 hours, and a temperature of 5 to 25°C.

9. The preparation method according to claim 2 or 3, characterized in that, The post-processing step includes post-treating the coupling product with soda ash to obtain a red direct blended dye.

10. The preparation method according to claim 9, characterized in that, The post-processing steps include: adding soda ash to the coupling product, adjusting the pH value to 9.5~11, mixing for 0.5~2 hours, then heating to 50~70℃ and spray drying to obtain a red direct dye.

11. Use of the red direct dye according to claim 1 for dyeing and / or printing fabrics.

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