An acid yellow and a preparation method thereof

Abstract

The present application relates to the field of dyes and preparation method thereof, and particularly relates to an acid yellow and a preparation method thereof. The acid yellow is characterized in that a molecular structure formula is as follows: Bridge group D is any one of 4,4'-diamino benzene sulfonyl aniline, 4,4-diamino benzoyl aniline, 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl, 3,3'-dinitro-p-diamino biphenyl, benzidine disulfonic acid, 4,4'-diamino diphenyl styrene-2,2'-disulfonic acid, 3,3'-dichlorobenzidine, 4,4'-diamino diphenylamine-2-sulfonic acid, benzidine. The acid yellow dye has excellent water washing, sunlight resistance and sweat fastness performance.

Description

Technical Field

[0001] This invention relates to the field of dyes and their preparation methods, and more particularly to an acid yellow and its preparation method. Background Technology

[0002] Acid Yellow is an acidic monoazo dye. Due to its bright color and good coloring properties, it is widely used in textile printing and dyeing, coatings, and polyamide fibers. Acid Yellow is also known as Acid Fluorescent Yellow, a fluorescent substance. Because of the conjugated π bonds in its structure, it emits yellow-green light under ultraviolet light, making printed fabrics using this dye more vibrant and dazzling.

[0003] Existing technologies mainly employ methods such as color-fixing post-treatment, molecular structure optimization, metal complexation, and the addition of commercially available auxiliaries. For example, color-fixing agent treatment can improve various fastness grades to above 4, and the light fastness of novel long-chain acid yellow can reach grade 7 under optimized processes. Azo groups complexing with metal ions can also enhance lightfastness. However, these improved solutions often have limitations in terms of cost, process complexity, or applicability, making it difficult to simultaneously achieve vibrant color, fluorescence properties, and high overall fastness. Patent publication number CN105176134A discloses a highly soluble acid yellow dye. The preparation steps include: reacting m-aminobenzenesulfonic acid with sodium nitrite in an inorganic acid medium to obtain a diazonium salt, then adding dimethyl 2-acetylsuccinate, adding an acid-binding agent for condensation until the diazonium salt disappears, and adjusting the pH to weakly alkaline by adding alkali. p-Aminobenzenesulfonic acid reacts with sodium nitrite in an inorganic acid medium to obtain a diazonium salt, which is then coupled with a condensation solution. The coupling solution is then hydrolyzed by adding alkali and heating, followed by spray drying to obtain the final product.

[0004] When the aforementioned Acid Yellow dye is applied to fabrics, its low wash fastness, due to the large number of sulfonic acid groups in its molecular structure (which are hydrophilic), easily causes the dye to detach and dissolve in aqueous solutions during washing, limiting its application. Furthermore, since yellow is the dominant hue in Acid Yellow dyes, its wash fastness and lightfastness are of paramount importance. Therefore, existing Acid Yellow dyes require improvement in these aspects. Summary of the Invention

[0005] In order to comprehensively improve the lightfastness, washfastness and perspiration fastness of Acid Yellow while maintaining its excellent coloring properties, this application provides an Acid Yellow and a method for preparing it.

[0006] In a first aspect, this application provides an acid yellow, the molecular structure of which is as follows:

[0007] ;

[0008] The bridging group D is any one of 4,4'-diaminobenzenesulfonylaniline (16803-97-7), 4,4-diaminobenzenesulfonylaniline (785-30-8), 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl (84-67-3), 3,3'-dinitro-p-diaminobiphenyl (6271-79-0), benzidine disulfonic acid (117-61-3), 4,4'-diaminostilbene-2,2'-disulfonic acid (81-11-8), 3,3'-dichlorobenzidine (91-94-1), 4,4'-diaminodiphenylamine-2-sulfonic acid (119-70-0), and benzidine (92-87-5).

[0009] Furthermore, an acidic yellow is any one of formulas 1 to 8:

[0010] Formula 1:

[0011] ;

[0012] Formula 2:

[0013] ;

[0014] Formula 3;

[0015] ;

[0016] Formula 4:

[0017] ;

[0018] Formula 5:

[0019] ;

[0020] Formula 6:

[0021] ;

[0022] Formula 7:

[0023] ;

[0024] Formula 8:

[0025] .

[0026] Furthermore, an acidic yellow is any one of Formulas 1 to 4 and Formula 6.

[0027] Secondly, this application provides a method for preparing acid yellow, comprising the following steps:

[0028] Preparation of diazonium salt: Compound D with the structure D in the general formula is mixed with an acidic reagent and ice water to form a mixture, which is stirred for 30-50 min; the mixture is cooled to 0-10℃, and then nitrite solution is added and stirred for 1-3 h to obtain diazonium salt;

[0029] Preparation of alkaline solution: Add an acid-binding agent to an aqueous solution of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) to adjust the pH to 7.0-7.5 to prepare an alkaline solution;

[0030] Preparation of Acid Yellow Powder: Diazonium salt is added to an alkaline solution of 5-pyrazolone, the pH of the solution is adjusted to 5.5-8.5, and the reaction is carried out for 2-4 hours to obtain an azo intermediate. The pH is then adjusted to 6.0-7.0, and the solution is dried to obtain Acid Yellow Powder.

[0031] Furthermore, the molar ratio of bridging group D to 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone is 0.45~0.55:1.

[0032] Furthermore, the mass ratio of 4,4'-diaminobenzenesulfonyl aniline, acidic reagent, and ice water is 10-15:10-15:50-90.

[0033] Furthermore, acidic reagents include hydrochloric acid and / or sulfuric acid.

[0034] Furthermore, the mass ratio of sodium nitrite to ice water in the nitrite solution is 2-5:10.

[0035] Furthermore, the aqueous solution of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) was prepared by pulping 30-40 parts by weight of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone with 100-130 parts by weight of water.

[0036] Furthermore, the acid-binding agent includes any one or more of liquid alkali, soda ash, baking soda, and ammonia water.

[0037] Beneficial effects: 1. The acid yellow dye provided in this application has excellent wash fastness, light fastness and perspiration fastness. Its acid yellow adopts a benzidine-like linear structure as a bridging group to construct a molecular skeleton that has both affinity and stability.

[0038] Regarding wash fastness, the linear structure of benzidine endows the dye with good affinity for fibers such as nylon and silk, enabling them to be tightly packed and firmly bonded. At the same time, the sulfonamide and multiple sulfonic acid groups in the molecule enhance water solubility, which helps the dye penetrate the fiber and makes it less likely to come off during washing.

[0039] In terms of light and perspiration fastness, the polyazo structure effectively disperses ultraviolet energy and inhibits photo-oxidation, while the sulfonyl group enhances the overall chemical stability of the molecule, synergizing with the chlorine group and the polyazo structure to improve light fastness. Furthermore, the sulfonic acid group remains stable in acidic sweat, ensuring that the dye does not easily change color or migrate, resulting in perspiration fastness of 4-5 or higher in both acidic and alkaline perspiration tests, achieving a synergistic effect of dual protection against light and perspiration.

[0040] 2. Preferably, Acid Yellow of Formulas 1 to 4 and 6 exhibits superior lightfastness, perspiration resistance, and washability. The bridging group D of the core azo dye in the structure of Acid Yellow of Formulas 1 to 4 and 6 adopts a structure with stronger rigidity and a more stable electronic conjugation system (such as sulfonamides, amides, biphenyls, etc.), while retaining pyrazolone chromophores with polychlorinated substitutions and sulfonic acid / potassium sulfonate salts at both ends. This combination of "rigid bridging + strongly polar ionizable groups + conjugation stabilization" enhances light stability and lightfastness by strengthening intramolecular hydrogen bonds and π-π stacking. Furthermore, it improves water solubility and reduces the damage to dyeing by ions in sweat by introducing hydrophilic sulfonate groups, thus enhancing perspiration resistance. Simultaneously, the rigid bridging group inhibits the mechanical shedding and diffusion of dye molecules during washing, improving washability. The overall structure is superior to ordinary azo dyes in terms of thermodynamic stability and chemical resistance, thus exhibiting excellent colorfastness.

[0041] Instruction manual illustrations

[0042] Figure 1 The performance testing stage of this application uses a schematic diagram of the staining process. Detailed Implementation

[0043] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1: A method for preparing acid yellow, the preparation method is as follows:

[0045] 13.85 g of 4,4'-diaminobenzenesulfonyl aniline (16803-97-7) and 12.2 g of hydrochloric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Sodium nitrite solution (7.26 g sodium nitrite + 20 g ice water) was added and the mixture was stirred for 2 h to obtain a diazonium salt (1-3 h in other embodiments). Excess sodium nitrite was removed with aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0046] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were mixed and dissolved by adjusting the pH to 7.25±0.25 with 15% sodium hydroxide to obtain an alkaline solution.

[0047] The diazonium salt of 4,4'-diaminobenzenesulfonyl aniline was added to an alkaline solution of 5-pyrazolone for coupling reaction. During the reaction, a 15% liquid alkali solution was used at pH 7±1.5, and the temperature was controlled below 20℃ for 3±1 hours. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain an acidic yellow powder with the following structural formula:

[0048] .

[0049] Example 2, a method for preparing acid yellow, the preparation method is as follows:

[0050] 12.6 g of 4,4'-diaminobenzoyl aniline (785-30-8) and 11.86 g of hydrochloric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (7.26 g sodium nitrite + 20 g ice water) was added and the mixture was stirred for 2 h (1-3 h in other embodiments) to obtain a diazonium salt. Excess sodium nitrite was removed with aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0051] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were mixed and dissolved by adjusting the pH to 7.25±0.25 with 15% sodium hydroxide to obtain an alkaline solution of 5-pyrazolone.

[0052] The diazonium salt of 4,4'-diaminobenzoyl aniline was added to an alkaline solution of 5-pyrazolone for a coupling reaction. During the reaction, a 15% liquid alkali solution was used at pH 7±1.5, and the temperature was controlled below 20℃. The reaction was carried out for 3±1 hours to obtain an azo intermediate. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain an acidic yellow powder with the following structural formula:

[0053] .

[0054] Example 3, a method for preparing acid yellow, the preparation method is as follows:

[0055] 22.55 g of 2,2-dimethylbenzidine (84-67-3) and 12.02 g of hydrochloric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (7.26 g sodium nitrite + 20 g ice water) was added and the mixture was stirred for 2 h (1-3 h in other embodiments) to obtain a diazonium salt. Excess sodium nitrite was removed with aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0056] 19.3 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 65 g of water were mixed and slurried. The pH was adjusted to 7.25±0.25 with 15% sodium hydroxide to dissolve the slurry, thus obtaining an alkaline solution of 5-pyrazolone.

[0057] The 2,2-dimethylbenzidine diazonium salt was added to an alkaline solution of 5-pyrazolone for coupling reaction. During the reaction, 15% liquid alkali was used at pH 7±1.5 and the temperature was controlled below 20℃. The reaction was carried out for 3±1 h to obtain the azo intermediate.

[0058] An alkaline solution of 5-pyrazolone (19.3 g, 65 g water, dissolved in 15% sodium hydroxide) was added to the azo intermediate to initiate a diazo reaction. The pH of the solution was adjusted to 7 ± 1.5 with 15% liquid alkali, and the reaction was carried out at a temperature below 20°C for 1.5 ± 0.5 hours to obtain azo intermediate 2. After the reaction was complete, the pH was adjusted to 6.5 ± 0.5 with hydrochloric acid, and the product was dried to obtain acid yellow powder, the structural formula of which is as follows:

[0059] .

[0060] Example 4, a method for preparing acid yellow, the preparation method is as follows:

[0061] 18.84 g of 3,3'-dinitro-p-diaminobiphenyl (6271-79-0) and 10.78 g of sulfuric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (7.96 g sodium nitrite + 22 g ice water) was added and the mixture was stirred for 2 h (1-3 h in other embodiments) to obtain a diazonium salt. Excess sodium nitrite was removed with a small amount of aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0062] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were mixed and dissolved by adjusting the pH to 7.25±0.25 with 15% potassium hydroxide to obtain an alkaline solution of 5-pyrazolone.

[0063] The 3,3'-dinitro-p-diaminobiphenyl diazonium salt was added to an alkaline solution of 5-pyrazolone for a coupling reaction. During the reaction, the pH was adjusted to 7±1.5 with 15% potassium hydroxide, and the temperature was controlled below 20℃. The reaction was carried out for 3±1 hours to obtain an azo intermediate. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain an acidic yellow powder with the following structure:

[0064] .

[0065] Example 5, a method for preparing acid yellow, the preparation method is as follows:

[0066] 18.71 g of benzidine disulfonic acid (117-61-3) and 11.86 g of sulfuric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (7.2 g sodium nitrite + 22 g ice water) was added and the mixture was stirred for 2 h (1-3 h in other embodiments) to obtain a diazonium salt. Excess sodium nitrite was removed with a small amount of aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0067] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were pulped, and the solution was dissolved by adjusting the pH to 7.25±0.25 with soda ash solution to obtain an alkaline solution of 5-pyrazolone.

[0068] A coupling reaction was carried out by adding benzidine disulfonic acid diazonium salt to an alkaline solution of 5-pyrazolone. During the reaction, the pH was adjusted to 7±1.5 with sodium carbonate solution, and the temperature was controlled below 20℃. The reaction was carried out for 3±1 hours to obtain an azo intermediate. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain acid yellow powder, the structural formula of which is as follows:

[0069] .

[0070] Example 6, a method for preparing acid yellow, the preparation method is as follows:

[0071] 12.66 g of 3,3′-dichlorobenzidine (91-94-1) and 9 g of sulfuric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (6.6 g sodium nitrite + 20 g ice water) was added and the mixture was stirred for 2 ± 1 h to obtain a diazonium salt. Excess sodium nitrite was removed with a small amount of aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0072] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were pulped, and the solution was dissolved by adjusting the pH to 7.25±0.25 with soda ash solution to obtain an alkaline solution of 5-pyrazolone.

[0073] A coupling reaction was carried out by adding 3,3′-dichlorobenzidine diazonium salt to an alkaline solution of 5-pyrazolone. During the reaction, the pH was adjusted to 7±1.5 with baking soda, and the temperature was controlled below 20℃. The reaction was carried out for 3±1 hours to obtain an azo intermediate. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain an acidic yellow powder with the following structure:

[0074]

[0075] Example 7, a method for preparing acid yellow, the preparation method is as follows:

[0076] 20.6 g of 4,4'-diaminostilbene-2,2'-disulfonic acid (81-11-8) and 11.4 g of hydrochloric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (7.4 g sodium nitrite + 24 g ice water) was added and the mixture was stirred for 2 h (1-3 h in other embodiments) to obtain a diazonium salt. Excess sodium nitrite was removed with a small amount of aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0077] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were pulped, and the solution was dissolved by adjusting the pH to 7.25±0.25 with soda ash solution to obtain an alkaline solution of 5-pyrazolone.

[0078] A coupling reaction was carried out by adding 4,4'-diaminostilbene-2,2'-disulfonic acid diazonium salt to an alkaline solution of 5-pyrazolone. During the reaction, the pH was adjusted to 7±1.5 with baking soda, and the temperature was controlled below 20℃. The reaction was carried out for 3±1 hours to obtain an azo intermediate. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain an acid yellow powder with the following structural formula:

[0079] .

[0080] Example 8, a method for preparing acid yellow, the preparation method is as follows:

[0081] 19.2 g of 4,4'-diaminodiphenylamine-2-sulfonic acid (119-70-0) and 12.6 g of hydrochloric acid were introduced into a reaction vessel, and ice water was added to mix. The mixture was stirred for 40 min (30-50 min in other embodiments). Ice was added to cool the mixture to 0°C (0-10°C in other embodiments). Then, sodium nitrite solution (7.96 g sodium nitrite + 26 g ice water) was added and the mixture was stirred for 2 h (1-3 h in other embodiments) to obtain a diazonium salt. Excess sodium nitrite was removed with a small amount of aminosulfonic acid solution, and the diazonium salt was reserved for later use.

[0082] 38.61 g of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone (84-57-1) and 128.69 g of water were pulped, and the solution was dissolved by adjusting the pH to 7.25±0.25 with soda ash solution to obtain an alkaline solution of 5-pyrazolone.

[0083] A coupling reaction was carried out by adding 4,4'-diaminodiphenylamine-2-sulfonic acid diazonium salt to an alkaline solution of 5-pyrazolone. During the reaction, the pH was adjusted to 7±1.5 with sodium carbonate solution, and the temperature was controlled below 20℃. The reaction was carried out for 3±1 hours to obtain an azo intermediate. After the reaction was completed, the pH was adjusted to 6.5±0.5 with hydrochloric acid, and the product was dried to obtain an acid yellow powder with the following structure:

[0084] .

[0085] Performance testing

[0086] The staining process is as follows Figure 1 The dyeing process is as follows:

[0087] Yellow dye: 2% (ratio to the weight of the fabric sample (nylon or nylon))

[0088] Leveling agent: 1.0% (ratio to fabric sample weight)

[0089] Acetic acid / sodium acetate: 1-3 g / L (used for adjusting the pH of the dye bath)

[0090] pH value of the dye bath: controlled between 4.5 and 5.5.

[0091] Light fastness: ISO 105-B2, Wash fastness: ISO 105-C06, Perspiration fastness: ISO 105-E04; Fastness class is the lowest, 0-1. The performance test results of the examples and comparative examples are shown in Table 1.

[0092] Table 1. Performance Test List of Examples and Comparative Examples

[0093] distinguish Sun fastness Wash fastness sweat fastness Yield % purity% Example 1 5-6 4-5 4-5 95 95 Example 2 5-6 4-5 4-5 94.5 96 Example 3 5-6 4-5 4-5 95 96.5 Example 4 5-6 4-5 4-5 95.5 95.5 Example 5 5 4 4-5 93.5 95 Example 6 5-6 4-5 4-5 94.5 94.5 Example 7 5 3-4 4 93.5 95 Example 8 5 4 4 94 94

[0094] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An acid yellow, characterized in that, Its molecular structure is as follows: ； The bridging group D is any one of 4,4'-diaminobenzenesulfonylaniline, 4,4-diaminobenzenesulfonylaniline, 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl, 3,3'-dinitro-p-diaminobiphenyl, benzidine disulfonic acid, 4,4'-diaminostilbene-2,2'-disulfonic acid, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenylamine-2-sulfonic acid, and benzidine.

2. The acid yellow according to claim 1, characterized in that, For any one of Equations 1 to 8: Formula 1: ； Formula 2: ； Formula 3; ； Formula 4: ； Formula 5: ； Formula 6: ； Formula 7: ； Formula 8: 。 3. The acid yellow according to claim 2, characterized in that, It can be any one of Equations 1 to 4 and Equation 6.

4. A method for preparing acid yellow according to any one of claims 1-3, characterized in that, Includes the following steps: Preparation of diazonium salt: Compound D with the structure D in the general formula is mixed with an acidic reagent and ice water to form a mixture, which is stirred for 30-50 min; the mixture is cooled to 0-10℃, and then nitrite solution is added and stirred for 1-3 h to obtain diazonium salt; Preparation of alkaline solution: Add an acid-binding agent to an aqueous solution of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone to adjust the pH to 7.0-7.5 to prepare an alkaline solution; Preparation of Acid Yellow Powder: Diazonium salt is added to an alkaline solution of 5-pyrazolone, the pH of the solution is adjusted to 5.5-8.5, and the reaction is carried out for 2-4 hours to obtain an azo intermediate. The pH is then adjusted to 6.0-7.0, and the solution is dried to obtain Acid Yellow Powder.

5. The method for preparing acid yellow according to claim 4, characterized in that, The molar ratio of bridging group D to 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone is 0.45~0.55:

1.

6. The method for preparing acid yellow according to claim 4, characterized in that, The mass ratio of 4,4'-diaminobenzenesulfonyl aniline, acidic reagent, and ice water is 10-15:10-15:50-90.

7. The method for preparing acid yellow according to claim 6, characterized in that, Acidic reagents include hydrochloric acid and / or sulfuric acid.

8. The method for preparing acid yellow according to claim 4, characterized in that, The mass ratio of sodium nitrite to ice water in a nitrite solution is 2-5:

10.

9. The method for preparing acid yellow according to claim 4, characterized in that, The aqueous solution of 1-(2,5-dichloro-4-sulfonic phenyl)-3-methyl-5-pyrazolone was prepared by pulping 30-40 parts by weight of 1-(2,5-dichloro-4-sulfonic phenyl)-3-methyl-5-pyrazolone with 100-130 parts by weight of water.

10. The method for preparing acid yellow according to claim 4, characterized in that, Acid-binding agents include any one or more of liquid alkali, soda ash, baking soda, and ammonia water.

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