3-[[4-[(2-R3) R4 amino-3-R2] phenyl] azo]-R1-nitrobenzene red dye and preparation method thereof

Abstract

The invention belongs to the technical field of disperse red dyes, and particularly relates to a 3-[[4-[(2-R3) R4 amino-3-R2] phenyl] azo]-R1-nitrobenzene red dye and a preparation method thereof. In order to enable the obtained red dye to be stronger in red light and stronger in blue light, can replace disperse ruby SE-2GFL in color performance, is good in alkali resistance, low in cost and low in pollution, and can avoid the problem of serious pollution in the production process of the disperse ruby SE-2GFL, the invention hopes to provide a novel disperse ruby dye. The invention hopes to provide the 3-[[4-[(2-R3) R4 amino-3-R2] phenyl] azo]-R1-nitrobenzene red dye and the preparation method of the 3-[[4-[(2-R3) R4 amino-3-R2] phenyl] azo]-R1-nitrobenzene red dye.

Description

Technical Field

[0001] The invention belongs to the technical field of disperse red dyes, and specifically relates to a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye and a preparation method thereof. Background Art

[0002] Disperse red dyes are a type of dye with small molecules and no water-soluble groups in their structure. They must be dispersed evenly in the dye liquor with the help of a dispersant to dye fibers such as polyester. Disperse red dyes are mainly used for dyeing and printing polyester and its blended fabrics, and can also be used for dyeing acetate and nylon. This type of dye has bright colors, excellent wash fastness, and is widely used.

[0003] The chemical properties of disperse red dye include dark red powder form, insoluble in water, but soluble in some organic solvents. In terms of use, disperse red dye can be used for dyeing plastics, grease, wax, and ink in addition to textile dyeing. In particular, disperse red 3B is one of the main dyes for dyeing polyester. It has the characteristics of bright color, excellent light fastness, and good levelness, but slightly poor sublimation fastness. It is often used with disperse yellow RGFL and disperse blue 2BLN to form three primary colors for dyeing multiple colors, and is suitable for high temperature and high pressure dyeing. In addition, disperse red dye is also suitable for direct printing and transfer printing of polyester and nylon fabrics.

[0004] The development of disperse red dyes has undergone many product innovations. Disperse Ruby 167 was the first to replace Red 3B in a certain sense. It is lower in cost and easier to synthesize. At that time, it was widely used in the dyeing and printing of textiles, especially the dyeing of polyester fibers. It was favored for its bright color, excellent fastness, and good color matching performance. Disperse Ruby 167 is a blue-light red with a good red effect. The suitable pH value of the dye is 4-5. Its coupling component is an esterified liquid structure. The esterified liquid is expensive, resulting in a high product price. There is great pollution in the production process, and the alkali resistance is poor in the printing and dyeing process, resulting in higher consumption and greater pollution.

[0005] In order to replace Disperse Ruby 167, Disperse Ruby 73 with lower production cost appeared on the market. However, the suitable pH value of Disperse Ruby 73 is 3-7. The dye has poor alkali resistance and is easily eluted under alkaline conditions. At the same time, the color of Disperse Ruby 73 is bright blue-red, with weak red light and strong blue light. It is difficult to completely replace Disperse Ruby 167 in terms of product performance.

[0006] Until 2000, with the invention of Disperse Ruby SE-2GFL, the red and blue light performance of Disperse Ruby SE-2GFL was better and more balanced. Disperse Ruby SE-2GFL with better performance replaced Disperse Ruby 167 and Disperse Ruby 73 on the market. However, with the increasing environmental protection requirements, the preparation process of Disperse Ruby SE-2GFL with heterocyclic structure requires a large amount of concentrated sulfuric acid, and the wastewater pollution is too large and difficult to handle, so it is difficult to adapt to the market. Low-cost, low-pollution, high-performance environmentally friendly dyes are urgently needed to replace them.

[0007] Based on the above situation, in order to make the obtained red dye have stronger red light and stronger blue light, so that it can replace disperse ruby ​​SE-2GFL in color performance, and at the same time have good alkali resistance, low cost and low pollution, and can avoid the problem of large pollution in the production process of disperse ruby ​​SE-2GFL, the present invention hopes to provide a new disperse ruby ​​dye, that is, the present invention hopes to provide a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye and a preparation method thereof. Summary of the invention

[0008] The object of the present invention is to provide a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye and a preparation method thereof to solve the problems raised in the above-mentioned background technology.

[0009] To achieve the above object, the present invention provides the following technical solution: a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye having the following general structural formula:

[0010] The R3 is -CH2CH2CN or -CH2CH2CH2CN, and the R4 is -CH2CH=CH2, -CH3, -C3H7 or -C4H9.

[0011] Preferably, R1 is -Cl, -CN, -NO2 or -H.

[0012] Preferably, R2 is -H, -CH3, -NHCOCH3 or -Cl.

[0013] A method for preparing 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye comprises the following steps: S1. Take one of N-cyanoethylaniline, m-cyanoethylaniline, m-chlorocyanoethylaniline, m-acetamidocyanoethylaniline, N-cyanopropylaniline, m-cyanopropylaniline, m-chlorocyanopropylaniline or m-acetamidocyanopropylaniline, and take water and an acid-binding agent at the same time. Mix and stir evenly, add a catalyst and propylene halide, and keep the temperature rising; measure the endpoint, requiring the raw material ≤1.0%, cool and precipitate, filter and wash to obtain a coupling component; S2. Take 4-nitroaniline, 2-cyano-4-nitroaniline, 2-chloro-4-nitroaniline and 2,4-dinitroaniline to prepare a diazo solution for use; S3. After the coupling components are emulsified with water, urea is added, ice is added dropwise to cool the prepared diazo solution, stirring is maintained after the addition to the end point, filtered and washed to neutrality, and the product is dried; or S1. Take one of N-methylaniline, m-methyl N-methylaniline, m-chloro N-methylaniline or m-acetamido N-methylaniline, and take water and zinc chloride at the same time, mix and stir evenly, add catalyst and acrylonitrile, heat to 60-100 ° C, keep warm for 16 hours; measure the endpoint, require the raw material ≤1.0%, cool and stratify to obtain coupling components; S2. Take 4-nitroaniline, 2-cyano-4-nitroaniline, 2-chloro-4-nitroaniline and 2,4-dinitroaniline to prepare a diazo solution for use; S3. After the coupling components are emulsified with water, urea is added, ice is added dropwise to cool the prepared diazo solution, stirring is maintained after the addition to the end point, filtered and washed to neutrality, and the product is dried; or S1. Take one of N-methylaniline, m-methyl N-methylaniline, m-chloro N-methylaniline or m-acetamido N-methylaniline, and take water and zinc chloride at the same time, mix and stir evenly, add catalyst and crotononitrile, heat to 60-100 ° C, keep warm for 16 hours; measure the endpoint, require the raw material ≤1.0%, cool and stratify to obtain coupling components; S2. Take 4-nitroaniline, 2-cyano-4-nitroaniline, 2-chloro-4-nitroaniline and 2,4-dinitroaniline to prepare a diazo solution for use; S3. After the coupling components are emulsified with water, urea is added, and after cooling with ice, the prepared diazo solution is added dropwise. After the addition is completed, stirring is maintained until the end point, and then the mixture is filtered and washed to neutrality, and the product is obtained after drying.

[0014] Preferably, in S1, the halogenated allyl is bromide or chloride.

[0015] Preferably, when the halogenated propylene is brominated propylene, it is necessary to dropwise add brominated propylene, then heat to 60-90°C and reflux for 16-24 hours to measure the end point, and maintain until the end point, requiring the raw material ≤ 1.0%, cool down and add water to precipitate.

[0016] Preferably, when the halide is allyl chloride, add it into the reactor at room temperature, seal it and heat it to 100-200°C, react at a pressure of 0.2MPa-3.5MPa for 20-24 hours, and maintain it until the end point. The raw material is required to be ≤1.0%, cool it down and add water to precipitate it.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye, which has a strong red light and a strong blue light in color analysis, and has a relatively balanced performance and bright colors; (2) The 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye provided by the present invention avoids the appearance of a heterocyclic structure, which has a high synthesis cost and requires a large amount of concentrated sulfuric acid in the azotization process of the heterocyclic structure, making wastewater treatment difficult; (3) The 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye provided by the present invention avoids the appearance of an esterified liquid structure in the coupling component, the suitable pH value range of the product is greater than 7, and the product has strong alkali resistance. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1

[0020] Weigh 50 g (0.5376 mol) of aniline, 2 g of aluminum chloride, 30 g (0.566 mol) of acrylonitrile, and 0.3 g of hydroquinone, add them into a flask, stir and reflux at 50-80°C for 5-15 hours, take a sample and measure HPLC to the end point of aniline ≤ 1.0%, add water to precipitate, then filter and wash to obtain 79.3 g (0.5434 mol) of N-cyanoethylaniline, with a yield of 96.0%.

[0021] Weigh 17.5 g (0.1198 mol) of N-cyanoethylaniline, 8.5 g of water, and 7 g of sodium carbonate, stir evenly, add 0.2 g of dispersant MF, 0.2 g of hydroquinone, 0.2 g of tetrabutylammonium bromide, and 9.5 g (0.1242 mol) of allyl chloride, raise the temperature to 80-200°C in 4-8 hours, and keep the temperature and pressure at 0.2 MPa-3.5 MPa for 21 hours. Measure the endpoint, requiring N-cyanoethylaniline ≤ 1.0%, cool down to precipitate, filter and wash to obtain 21.7 g (0.1162 mol) of coupling component N-cyanoethyl-N-propylene aniline, with a yield of 97%.

[0022] Dissolve 16.3 g of 2-cyano-4-nitroaniline (0.1 mol) dry powder in 80-95% sulfuric acid, cool to 0-20°C, add 40 g of 40% nitrosylsulfuric acid (0.1260 mol) dropwise, keep for 3-5 hours after addition, detect the end point after the insulation is completed, and set aside.

[0023] Add 200g of water to the coupling kettle, add 10g of sulfuric acid, 0.2g of emulsifier and 0.2g of urea under stirring, add ice and 18.1g (0.097mol) of coupling component, add ice after complete dissolution, warm to 0-15℃, add the prepared diazo solution dropwise, keep it for 4-5 hours after adding until the diazonium salt disappears, add 250ml of water, raise the temperature to 60-80℃, keep it for 1-2 hours, filter and wash to neutral, and obtain 34.9g of filter cake after drying, with a yield of 96.7% and a purity of 98.2%.

[0024] After the obtained filter cake was dissolved in the dye solution, the color light and various dye performance indicators of the dye were tested and analyzed, as shown in Table 1.

[0025] Example 2

[0026] Weigh 50 g (0.4672 mol) of m-toluidine, 2 g of aluminum chloride, 25.7 g (0.4849 mol) of acrylonitrile, and 0.2 g of hydroquinone, add them into a flask, stir and reflux at 50-80°C for 5-15 hours, take a sample and measure HPLC to the end point of m-toluidine ≤ 1.0%, add water to precipitate, then filter and wash to obtain 71.9 g (0.4494 mol) of N-cyanoethyl m-toluidine, with a yield of 96.2%.

[0027] Weigh 19.2 g (0.1198 mol) of N-cyanoethyl-m-toluidine, 8.5 g of water, and 7 g of sodium carbonate, stir evenly, add 0.2 g of dispersant MF, 0.2 g of hydroquinone, 0.2 g of tetrabutylammonium bromide, and 9.5 g (0.1242 mol) of allyl chloride, raise the temperature to 80-200°C in 4-8 hours, and keep it at 0.2 MPa-3.5 MPa for 21 hours. Measure the endpoint, requiring N-cyanoethyl-m-toluidine ≤ 1.0%, cool it down to precipitate, filter and wash to obtain 23.1 g (0.1155 mol) of coupling component N-cyanoethyl-N-propylene-m-toluidine, with a yield of 96.4%.

[0028] Dissolve 16.3 g of 2-cyano-4-nitroaniline (0.1 mol) dry powder in 80-95% sulfuric acid, cool to 0-20°C, add 40 g of 40% nitrosylsulfuric acid (0.1260 mol) dropwise, keep for 3-5 hours after addition, detect the end point after the insulation is completed, and set aside.

[0029] Add 200g of water to the coupling kettle, add 10g of sulfuric acid, 0.2g of emulsifier and 0.2g of urea under stirring, add ice and 19.4g (0.097mol) of coupling component, add ice after complete dissolution, warm to 0-15℃, add the prepared diazo solution dropwise, keep it for 4-5 hours after adding until the diazonium salt disappears, add 250ml of water, raise the temperature to 60-80℃, keep it for 1-2 hours, filter and wash to neutral, and obtain 36.2g of filter cake after drying, with a yield of 96.8% and a purity of 96.4%.

[0030] After the obtained filter cake was dissolved in the dye solution, the color light and various dye performance indicators of the dye were tested and analyzed, as shown in Table 1.

[0031] Example 3

[0032] Weigh 50 g (0.4672 mol) of N-methylaniline, 2 g of aluminum chloride, 25 g (0.4717 mol) of acrylonitrile, and 0.2 g of hydroquinone, add them into a flask, stir and reflux at 50-80°C for 5-15 hours, take a sample and measure HPLC to the end point of aniline ≤ 1.0%, add water and separate the layers to obtain 73.6 g (0.4602 mol) of N-methyl-N-cyanoethylaniline, a coupling component, with a yield of 98.5%.

[0033] Dissolve 16.3 g of 2-cyano-4-nitroaniline (0.1 mol) dry powder in 80-95% sulfuric acid, cool to 0-20°C, add 40 g of 40% nitrosylsulfuric acid (0.1260 mol) dropwise, keep for 3-5 hours after addition, detect the end point after the insulation is completed, and set aside.

[0034] Add 100 g of water to the coupling kettle, add 10 g of sulfuric acid, 0.2 g of emulsifier and 0.2 g of urea under stirring, add ice and 19.4 g (0.097 mol) of coupling components, add ice water after complete dissolution to adjust the temperature to 0-15 ° C, and add the prepared diazo solution dropwise. After adding, keep it for 4-5 hours until the diazonium salt disappears, add 250 ml of water, raise the temperature to 60-80 ° C, keep it for 1-2 hours, filter and wash to neutral, and obtain 36.0 g of filter cake after drying, with a yield of 96.3% and a purity of 98.5%.

[0035] After the obtained filter cake is dissolved in the dye solvent, the color light and various dye performance indicators of the dye are detected and analyzed, as shown in Table 1.

[0036] Example 4

[0037] Weigh 50 g (0.4132 mol) of N-methyl-m-toluidine, 2 g of aluminum chloride, 23.6 g (0.4447 mol) of acrylonitrile, and 0.2 g of hydroquinone, add them into a flask, stir and reflux at 50-80°C for 5-18 hours, take a sample and measure HPLC to the end point of aniline ≤ 1.0%, add water and separate the layers to obtain 70.6 g (0.4057 mol) of N-methyl-N-cyanoethyl-m-toluidine, a coupling component, with a yield of 98.2%.

[0038] Dissolve 16.3 g of 2-cyano-4-nitroaniline (0.1 mol) dry powder in 80-95% sulfuric acid, cool to 0-20°C, add 40 g of 40% nitrosylsulfuric acid (0.1260 mol) dropwise, keep for 3-5 hours after addition, detect the end point after the insulation is completed, and set aside.

[0039] Add 100 g of water to the coupling kettle, add 10 g of sulfuric acid, 0.2 g of emulsifier and 0.2 g of urea under stirring, add ice and 16.9 g (0.097 mol) of coupling components, add ice water after complete dissolution, adjust the temperature to 0-15 ° C, and drop the prepared diazo solution. After adding, keep it for 4-5 hours until the diazonium salt disappears, add 250 ml of water, raise the temperature to 60-80 ° C, keep it for 1-2 hours, filter and wash to neutral, and obtain 33.6 g of filter cake after drying, with a yield of 96.9% and a purity of 96.5%.

[0040] After the obtained filter cake is dissolved in the dye solvent, the color light and various dye performance indicators of the dye are detected and analyzed, as shown in Table 1.

[0041] Example 5

[0042] Weigh 50 g (0.4672 mol) of N-methylaniline, 2 g of aluminum chloride, 30 g (0.4615 mol) of crotononitrile, and 0.2 g of hydroquinone, add them into a flask, stir and reflux at 50-80°C for 5-15 hours, take a sample and measure HPLC to the end point of aniline ≤ 1.0%, add water and separate the layers to obtain 90.2 g (0.4508 mol) of N-methyl-N-cyanopropylaniline, a coupling component, with a yield of 96.5%.

[0043] Dissolve 16.3 g of 2-cyano-4-nitroaniline (0.1 mol) dry powder in 80-95% sulfuric acid, cool to 0-20°C, add 40 g of 40% nitrosylsulfuric acid (0.1260 mol) dropwise, keep for 3-5 hours after addition, detect the end point after the insulation is completed, and set aside.

[0044] Add 100 g of water to the coupling kettle, add 10 g of sulfuric acid, 0.2 g of emulsifier and 0.2 g of urea under stirring, add ice and 19.4 g (0.097 mol) of coupling components, add ice water after complete dissolution to adjust the temperature to 0-15 ° C, and add the prepared diazo solution dropwise. After adding, keep it for 4-5 hours until the diazonium salt disappears, add 250 ml of water, raise the temperature to 60-80 ° C, keep it for 1-2 hours, filter and wash to neutral, and obtain 36.5 g of filter cake after drying, with a yield of 97.8% and a purity of 97.5%.

[0045] After the obtained filter cake is dissolved in the dye solvent, the color light and various dye performance indicators of the dye are detected and analyzed, as shown in Table 1.

[0046] Example 6

[0047] Weigh 50 g (0.4132 mol) of N-methyl-m-toluidine, 2 g of aluminum chloride, 28.9 g (0.4447 mol) of crotononitrile, and 0.2 g of hydroquinone, add them into a flask, stir and reflux at 50-80°C for 5-15 hours, take a sample and measure HPLC to the end point of aniline ≤ 1.0%, add water and separate the layers to obtain 87.1 g (0.4070 mol) of N-methyl-N-cyanopropyl-m-toluidine, a coupling component, with a yield of 98.5%.

[0048] Dissolve 16.3 g of 2-cyano-4-nitroaniline (0.1 mol) dry powder in 80-95% sulfuric acid, cool to 0-20°C, add 40 g of 40% nitrosylsulfuric acid (0.1260 mol) dropwise, keep for 3-5 hours after addition, detect the end point after the insulation is completed, and set aside.

[0049] Add 200 g of water to the coupling kettle, add 10 g of sulfuric acid, 0.2 g of emulsifier and 0.2 g of urea under stirring, add ice and 20.8 g (0.097 mol) of coupling component, add ice water after complete dissolution to adjust the temperature to 0-15 ° C, and add the prepared diazo solution dropwise. After adding, keep it for 4-5 hours until the diazonium salt disappears, add 250 ml of water, raise the temperature to 60-80 ° C, keep it for 1-2 hours, filter and wash to neutral, and obtain 37.6 g of filter cake after drying, with a yield of 96.8% and a purity of 97.7%.

[0050] After the obtained filter cake is dissolved in the dye solvent, the color light and various dye performance indicators of the dye are detected and analyzed, as shown in Table 1.

[0051] Table 1 Color shade and performance indicators of dyes (based on dispersed ruby ​​73) dye Red light Blu-ray Huang Guang Suitable pH range Elution rate in weak alkaline environment Scattered Ruby 167 +1.0 -1.0 / 4-5 73% Scattered Ruby 73 0 0 0 3-7 69% Dispersed Ruby SE-2GFL +2.4 -2.6 / 3-7 56% Example 1 +3.5 / +2.6 5-8 53% Example 2 +4.4 -3.7 / 5-8 45% Example 3 -0.2 / +2.5 3-7 60% Example 4 -0.5 -5.5 / 3-7 55% Example 5 -0.6 / +3.3 3-7 56% Example 6 -1.0 -3.7 / 3-7 52% Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye, characterized in that: It has the following general structural formula: The R3 is -CH2CH2CN or -CH2CH2CH2CN, and the R4 is -CH2CH=CH2, -CH3, -C3H7 or -C4H9.

2. A red dye according to claim 1, characterized in that: The R1 is -Cl, -CN, -NO2 or -H.

3. A red dye according to claim 1 or 2, characterized in that: The R2 is -H, -CH3, -NHCOCH3 or -Cl.

4. The method for preparing a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye according to claim 1, characterized in that: The following steps are involved: S1. Take one of N-cyanoethylaniline, m-cyanoethylaniline, m-chlorocyanoethylaniline, m-acetamidocyanoethylaniline, N-cyanopropylaniline, m-cyanopropylaniline, m-chlorocyanopropylaniline or m-acetamidocyanopropylaniline, and take water and an acid-binding agent at the same time. Mix and stir evenly, add a catalyst and propylene halide, and keep the temperature rising; measure the endpoint, requiring the raw material ≤1.0%, cool and precipitate, filter and wash to obtain a coupling component; S2. Take 4-nitroaniline, 2-cyano-4-nitroaniline, 2-chloro-4-nitroaniline and 2,4-dinitroaniline to prepare a diazo solution for use; S3. After the coupling components are emulsified with water, urea is added, ice is added dropwise to cool the prepared diazo solution, stirring is maintained after the addition to the end point, filtered and washed to neutrality, and the product is dried; or S1. Take one of N-methylaniline, m-methyl N-methylaniline, m-chloro N-methylaniline or m-acetamido N-methylaniline, and take water and zinc chloride at the same time, mix and stir evenly, add catalyst and acrylonitrile, heat to 60-100 ° C, keep warm for 16 hours; measure the endpoint, require the raw material ≤1.0%, cool and stratify to obtain coupling components; S2. Take 4-nitroaniline, 2-cyano-4-nitroaniline, 2-chloro-4-nitroaniline and 2,4-dinitroaniline to prepare a diazo solution for use; S3. After the coupling components are emulsified with water, urea is added, ice is added dropwise to cool the prepared diazo solution, stirring is maintained after the addition to the end point, filtered and washed to neutrality, and the product is dried; or S1. Take one of N-methylaniline, m-methyl N-methylaniline, m-chloro N-methylaniline or m-acetamido N-methylaniline, and take water and zinc chloride at the same time, mix and stir evenly, add catalyst and crotononitrile, heat to 60-100 ° C, keep warm for 16 hours; measure the endpoint, require the raw material ≤1.0%, cool and stratify to obtain coupling components; S2. Take 4-nitroaniline, 2-cyano-4-nitroaniline, 2-chloro-4-nitroaniline and 2,4-dinitroaniline to prepare a diazo solution for use; S3. After the coupling components are emulsified with water, urea is added, and after cooling with ice, the prepared diazo solution is added dropwise. After the addition is completed, stirring is maintained until the end point, and then the mixture is filtered and washed to neutrality, and the product is obtained after drying.

5. A method for preparing a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye according to claim 4, characterized in that: In S1, the halogenated allyl is allyl bromide or allyl chloride.

6. A method for preparing a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye according to claim 5, characterized in that: When the halogenated propylene is brominated propylene, add brominated propylene dropwise, then heat to 60-90℃ and reflux for 16-24 hours to measure the endpoint, maintain the concentration until the endpoint, and require the raw material to be ≤1.0%, cool down and add water to precipitate.

7. A method for preparing a 3-[[4-[(2-R3)R4amino-3-R2]phenyl]azo]-R1-nitrobenzene red dye according to claim 5, characterized in that: When the halide propene is chloropropene, add it into the reactor at room temperature, seal it and heat it to 100-200℃, react for 20-24 hours at a pressure of 0.2MPa-3.5MPa, and keep it until the end point. The raw material is required to be ≤1.0%, cool it down and add water to precipitate it.

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