Polyazo dye or complex thereof as well as preparation method and application of polyazo dye or complex thereof

Abstract

The invention discloses a direct dye compound as shown in a formula I or a copper complex of a direct dye as shown in a formula II as well as a preparation method and application of the direct dye compound or the copper complex, a one-pot continuous reaction for preparing a polyazo compound or the copper complex thereof has the advantages of mild reaction conditions, environmental friendliness, simplicity in operation, high reaction efficiency, low emission, stable product quality, high universality and the like; by controlling the types of functional groups of the azo compound, the solubility of the azo compound and the binding force of the azo compound to a PVA (Polyvinyl Alcohol) film can be improved to the greatest extent on the basis of balancing the molecular weight and the aspect ratio, so that the dyeing rate of the azo compound is improved, and the production efficiency is improved: # imgabs0, R1 is H, Me, Cl or OMe, R2 is Me, OMe, Cl or H, R3 is H or NH2, and R4 is H or NH2.

Description

Technical field:

[0001] The invention relates to the technical field of polyazo dyes, and in particular to a polyazo dye or a complex thereof, and a preparation method and application thereof. Background technology:

[0002] Polyazo compounds are important components of direct dyes. They are prepared by secondary diazotization of monoazo compounds followed by coupling reaction. However, this process is complicated and the separation and purification of intermediates is time-consuming and energy-consuming, which is not conducive to the scale-up and application of the synthesis.

[0003] Furthermore, since polyazo compounds have good directness, they can form good bonding with polyvinyl alcohol film (PVA film), and can be attached to the PVA film through a simple dip-dyeing process to prepare polarizing materials. Therefore, azo compounds play an important role in the production of polarizing films. At present, the azo compounds widely used in polarizing film dyeing have a large molecular weight, which limits their dyeing rate and the improvement of production efficiency. Summary of the invention:

[0004] The purpose of the present invention is to provide a polyazo dye or its complex and a preparation method and application thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] The direct dye compound shown in formula I or the copper complex of the direct dye shown in formula II:

[0007]

[0008] Wherein, R1 is H, Me, Cl or OMe, R2 is Me, OMe, Cl or H, R3 is H or NH2, and R4 is H or NH2.

[0009] The method for preparing the direct dye compound shown in formula I or the copper complex of the direct dye shown in formula II is characterized by comprising the following steps:

[0010] (1) subjecting p-aminobenzenesulfonic acid or sodium p-aminobenzenesulfonate to a first diazotization reaction to obtain p-aminobenzenesulfonic acid diazonium salt; subsequently, the p-aminobenzenesulfonic acid diazonium salt is first coupled with anisidine to prepare a monoazo intermediate;

[0011] (2) without separation, subjecting the monoazo intermediate to a second diazotization reaction to obtain a monoazo intermediate diazonium salt;

[0012] (3) secondary coupling of the monoazo intermediate diazonium salt with naphthol sulfonate or aniline compound to prepare the direct dye compound represented by formula I;

[0013] (4) Without separation, the disazo compound obtained in step (3) is directly subjected to a copper complex reaction with a copper salt in the presence of an organic base to prepare a copper complex of a direct dye represented by formula II.

[0014] The specific steps of step (1) are: dissolving p-aminobenzenesulfonic acid or sodium p-aminobenzenesulfonate in an alkali solution, stirring evenly, adding sodium nitrite thereto, and then dropping a dilute acid solution for diazotization to obtain p-aminobenzenesulfonic acid diazonium salt; coupling p-aminobenzenesulfonic acid diazonium salt with anisidine under neutral or weakly acidic conditions for the first time to obtain a monoazo intermediate, wherein the anisidine is selected from one of 2,5-dimethoxyaniline, 2-methoxy-5-methylaniline, or 2-methoxy-5-chloroaniline; and dissolving the anisidine in a dilute solution of sulfuric acid, hydrochloric acid, or acetic acid.

[0015] Preferably, in step (1), the base is sodium hydroxide, and the molar ratio of p-aminobenzenesulfonic acid to sodium hydroxide is 1:1.0-1.5, more preferably 1:1.1-1.2; the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:1.0-1.5, more preferably 1:1.1-1.2; the dilute acid is dilute hydrochloric acid, and the molar ratio of p-aminobenzenesulfonic acid to dilute hydrochloric acid is 1:1.0-3.0, more preferably 1:2.0-3.0. After adding dilute hydrochloric acid, the pH is adjusted to between 1 and 2 for diazotization, the reaction temperature is maintained between 5 and 10°C, and the reaction is carried out for 0.5 hour.

[0016] Preferably, the first coupling reaction temperature in step (1) is room temperature, and the reaction time is 0.5-1.0 hour.

[0017] The specific steps of step (2) are: without separation, adding alkali solution to convert the monoazo intermediate from an acidic environment to an alkaline environment, then adding sodium nitrite thereto, slowly adding a dilute acid solution to adjust the pH to acidic, and then performing a second diazotization to obtain a monoazo intermediate diazonium salt.

[0018] Preferably, the alkali solution in step (2) is a sodium hydroxide solution, and the molar ratio of the monoazo intermediate to sodium hydroxide is 1:1.0-4.0, more preferably 1:2.5-3.5; the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:1.0-2.5, more preferably 1:1.3-1.5; the dilute acid solution is dilute hydrochloric acid, and the molar ratio of p-aminobenzenesulfonic acid to dilute hydrochloric acid is 1:1.0-3.0, more preferably 1:1.5-2.0, after adding dilute hydrochloric acid, the pH is adjusted to between 1-2, the reaction temperature is maintained at between 5-10°C, and the reaction is stirred for 0.5-1 hour, more preferably 0.5 hour to obtain the monoazo intermediate diazonium salt.

[0019] The specific steps of step (3) are: reacting a monoazo intermediate diazonium salt with a naphthol sulfonate, wherein the naphthol sulfonate is selected from one of 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid, 6-amino-1-naphthol-3-sulfonic acid, 7-amino-1-naphthol-3-sulfonic acid, 3-amino-8-naphthol-4,6-disulfonic acid or its sulfonate, dissolving the naphthol sulfonate in sodium hydroxide or sodium carbonate solution, and coupling for the second time under neutral or weak alkaline conditions to obtain a disazo compound;

[0020] Alternatively, the monoazo intermediate diazonium salt is reacted with an aniline compound, the aniline compound is selected from one of 2-methoxyaniline, 2,5-dimethoxyaniline, 2-methoxy-5-methylaniline or 2-methoxy-5-chloroaniline, the aniline compound is dissolved in sulfuric acid, hydrochloric acid, acetic acid or a dilute solution thereof, and a second coupling is performed under acidic conditions to obtain a disazo compound.

[0021] Preferably, in step (3), the reaction temperature of the second coupling reaction of the monoazo intermediate diazonium salt with the naphthol sulfonate is maintained at room temperature, and the reaction time is 0.5-1.0 hour.

[0022] The specific steps of step (4) are as follows: without separation, an organic base and a copper salt are added to the reaction product of the disazo compound, wherein the organic base is selected from one of ethanolamine, diethanolamine, triethanolamine, and triethylamine, and the copper salt is selected from one of copper sulfate pentahydrate, copper chloride, and copper bromide, and the reaction is heated under reflux for 5-10 hours.

[0023] Preferably, in step (4), the molar ratio of the disazo compound to the organic base is 1:1.0-4.0, more preferably 1:2.0-2.5; the molar ratio of p-aminobenzenesulfonic acid to copper sulfate is 1:1.0-2.5, more preferably 1:1.3-1.5; the reaction temperature is maintained between 90-100°C, and the reaction time is preferably 8-10 hours.

[0024] When the raw material is p-aminobenzenesulfonic acid, the reaction equation is:

[0025]

[0026] The present invention also protects a method for preparing a polyazo dye or a complex thereof, wherein the product obtained in step (3) of the method for preparing the direct dye compound shown in formula I is not separated, the disazo compound is subjected to a third diazotization reaction to obtain a disazo intermediate diazonium salt, and then a third coupling reaction is performed to obtain a triazo compound, and so on, to prepare the polyazo dye or a complex thereof, and the specific steps are: without separation, adding an alkali solution to convert the disazo intermediate from an acidic environment to an alkaline environment, then adding sodium nitrite thereto, and slowly dropping a dilute acid solution to carry out The method comprises the following steps: performing diazotization three times to obtain a disazo intermediate diazonium salt; reacting the disazo intermediate diazonium salt with a naphthol sulfonate, wherein the naphthol sulfonate is selected from one of 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid, 6-amino-1-naphthol-3-sulfonic acid, 7-amino-1-naphthol-3-sulfonic acid, 3-amino-8-naphthol-4,6-disulfonic acid or a sulfonate thereof; dissolving the naphthol sulfonate in a sodium hydroxide or sodium carbonate solution; coupling the triazo compound for the third time under alkaline conditions, and so on to prepare a polyazo dye or a complex thereof.

[0027] The present invention can improve the solubility and binding force to the PVA film to the maximum extent by controlling the type of functional groups of the azo compound on the basis of balancing the molecular weight and the aspect ratio, thereby improving the dyeing rate and improving the production efficiency. Compared with the existing products, the product obtained by the present invention has the advantages of fast dyeing speed and deep color.

[0028] Therefore, the present invention also protects the use of the direct dye compound and the direct dye copper complex in polarizing film dyeing or polarizing plate dyeing.

[0029] The polarizing film or polarizing sheet is made of PVA.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1) The present invention selects suitable azo compound functional groups and maintains appropriate reaction acid-base conditions to allow monoazo compounds and disazo compounds to have good solubility and dispersion capabilities. At the same time, the reaction conditions are used to control the complete conversion of azo salts to avoid side reactions. Therefore, continuous diazotization reactions and series-connected reactions can be achieved without separation and purification, thereby realizing a one-pot continuous reaction to prepare polyazo compounds or their copper complexes. The present invention has the following advantages: (1) The reaction efficiency is improved. The continuous diazotization process can significantly shorten the reaction time and achieve a fast and efficient reaction. (2) The production capacity is improved. The continuous process supports large-scale production while maintaining a high reaction efficiency, which is suitable for industrial applications. (3) Cost savings. The utilization of raw materials in the continuous process is more efficient, which reduces the cost of raw materials. The continuous process reduces the need for manual operation and reduces labor costs. (4) Emissions are reduced. The optimization of reaction conditions and the efficient utilization of raw materials reduce the generation of waste, which meets the concept of green chemistry.

[0032] 2) By controlling the type of functional groups of azo compounds, their solubility and binding force to PVA film can be improved to the maximum extent on the basis of balancing molecular weight and aspect ratio, thereby improving their dyeing rate and improving production efficiency.

[0033] In summary, the present invention selects appropriate azo compound functional groups, maintains appropriate reaction acid-base conditions, realizes continuous diazotization reaction without separation and purification, and performs series combination reaction to realize one-pot continuous reaction to prepare polyazo compounds or their copper complexes, which has the advantages of mild reaction conditions, environmental friendliness, simple operation, high reaction efficiency, low emission, stable product quality, strong universality, etc. By controlling the types of azo compound functional groups, the solubility and binding force to the PVA film can be improved to the maximum extent on the basis of balancing the molecular weight and the aspect ratio, thereby improving the dyeing rate and improving the production efficiency. Description of the drawings:

[0034] Figure 1 is the UV-visible absorption spectrum of the product prepared in Application Example 1 of the present invention;

[0035] Figure 2 is the UV-visible absorption spectrum of the product prepared in Application Example 2 of the present invention;

[0036] Figure 3 is the UV-visible absorption spectrum of the product prepared in Application Example 3 of the present invention;

[0037] Figure 4 is the UV-visible absorption spectrum of the product prepared in Application Example 4 of the present invention;

[0038] Figure 5 is the UV-visible absorption spectrum of the product prepared in Application Example 5 of the present invention;

[0039] Figure 6 is the UV-visible absorption spectrum of the product prepared in Application Example 6 of the present invention;

[0040] Figure 7 is the UV-visible absorption spectrum of the product prepared in Application Example 7 of the present invention;

[0041] Figure 8 This is a comparison chart of the effects of using the product prepared in Application Example 6 and the reference standard product in the application of the product of the present invention for dyeing polarizing films. Specific implementation method:

[0042] The following is a further description of the present invention, rather than a limitation of the present invention.

[0043] Example 1: Method for preparing 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt by continuous diazotization

[0044] The steps include:

[0045] Weigh p-aminobenzenesulfonic acid (3.4 g, 20 mmol) and sodium hydroxide (0.88 g, 22 mmol) in a 250 mL beaker, add 200 mL of deionized water and stir for 5 minutes, then add sodium nitrite (1.7 g, 24 mmol), stir and dissolve, cool to 5 ° C, then slowly drop 37 wt% dilute hydrochloric acid (5 mL, 50 mmol), keep stirring at low temperature for 0.5 hours to obtain p-aminobenzenesulfonic acid diazonium salt suspension; weigh 2,5-dimethoxyaniline (3.1 g, 20 mmol) and dissolve it in dilute sulfuric acid aqueous solution, then add p-aminobenzenesulfonic acid diazonium salt suspension, stir and react at room temperature 0.5h to obtain a monoazo intermediate 4-amino-2,5-dimethoxyphenyldiazenylbenzenesulfonic acid suspension; without separation, sodium hydroxide (1.6g, 40mmol) was added to the 4-amino-2,5-dimethoxyphenyldiazenylbenzenesulfonic acid suspension to adjust it to alkalinity, and then sodium nitrite (1.7g, 24mmol) was added thereto, stirred to dissolve and then cooled to 5°C, and then 37wt% dilute hydrochloric acid (5mL, 50mmol) was slowly added dropwise thereto, and the reaction was kept stirring at low temperature for 0.5h to obtain a monoazo intermediate diazonium salt suspension: 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt suspension.

[0046] Example 2: Method for preparing 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt by continuous diazotization

[0047] Reference Example 1, the difference is that the type of anisole used in the first coupling is different, and the anisole is 2-methoxy-5-methylaniline.

[0048] The steps include:

[0049] Weigh p-aminobenzenesulfonic acid (3.4 g, 20 mmol) and sodium hydroxide (0.88 g, 22 mmol) in a 250 mL beaker, add 200 mL of deionized water and stir for 5 minutes, then add sodium nitrite (1.7 g, 24 mmol), stir and dissolve, then cool to 5 ° C, then slowly drop 37 wt% dilute hydrochloric acid (5 mL, 50 mmol), keep stirring at low temperature for 0.5 hours to obtain p-aminobenzenesulfonic acid diazonium salt suspension; weigh 2-methoxy-5-methylaniline (2.7 g, 20 mmol) and dissolve it in dilute sulfuric acid aqueous solution, then add p-aminobenzenesulfonic acid diazonium salt suspension, stir and react at room temperature 0.5h to obtain a monoazo intermediate 4-amino-2,5-dimethoxyphenyldiazenylbenzenesulfonic acid suspension; without separation, sodium hydroxide (1.6g, 40mmol) was added to the 4-amino-2,5-dimethoxyphenyldiazenylbenzenesulfonic acid suspension to adjust it to alkalinity, and then sodium nitrite (1.7g, 24mmol) was added thereto, stirred to dissolve and then cooled to 5°C, and then 37wt% dilute hydrochloric acid (5mL, 50mmol) was slowly added dropwise thereto, and the reaction was kept stirring at low temperature for 0.5h to obtain a monoazo intermediate diazonium salt suspension: 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt suspension.

[0050] Comparative Example 1: Method for preparing 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt by step-by-step diazotization

[0051] Refer to Example 1, except that the product was separated and purified after the first coupling.

[0052] The steps include:

[0053] Weigh p-aminobenzenesulfonic acid (3.4 g, 20 mmol) and sodium hydroxide (0.88 g, 22 mmol) in a 250 mL beaker, add 200 mL of deionized water and stir for 5 minutes, then add sodium nitrite (1.7 g, 24 mmol), stir and dissolve, cool to 5 ° C, then slowly drop 37 wt% dilute hydrochloric acid (5 mL, 50 mmol), keep stirring at low temperature for 0.5 hours to obtain p-aminobenzenesulfonic acid diazonium salt suspension; weigh 2,5-dimethoxyaniline (3.1 g, 20 mmol) and dissolve it in dilute sulfuric acid aqueous solution, then add p-aminobenzenesulfonic acid diazonium salt suspension, stir and react at room temperature for 0.5 hours, then add hydroxide Sodium aqueous solution, adjust the pH to neutral, precipitate a large amount of solid, filter and dry to obtain a monoazo intermediate 4-amino-2,5-dimethoxyphenyldiazenylbenzenesulfonic acid solid; add sodium hydroxide (0.88 g, 22 mmol) to the 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid suspension to adjust to alkalinity, then add sodium nitrite (1.7 g, 24 mmol), stir to dissolve and then cool to 5°C, then slowly add 37wt% dilute hydrochloric acid (5 mL, 50 mmol), keep stirring at low temperature and react for 0.5 hour to obtain a monoazo intermediate diazonium salt suspension: 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt suspension.

[0054] Comparative Example 2: Step-by-step preparation of 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt

[0055] Refer to Example 2, except that the product was separated and purified after the first coupling.

[0056] The steps include:

[0057] Weigh p-aminobenzenesulfonic acid (3.4 g, 20 mmol) and sodium hydroxide (0.88 g, 22 mmol) in a 250 mL beaker, add 200 mL of deionized water and stir for 5 minutes, then add sodium nitrite (1.7 g, 24 mmol), stir and dissolve, then cool to 5 ° C, then slowly drop 37 wt% dilute hydrochloric acid (5 mL, 50 mmol), keep stirring at low temperature for 0.5 hours to obtain a suspension of p-aminobenzenesulfonic acid diazonium salt; weigh 2-methoxy-5-methylaniline (2.7 g, 20 mmol) and dissolve it in a dilute sulfuric acid aqueous solution, then add the p-aminobenzenesulfonic acid diazonium salt suspension thereto, stir and react at room temperature for 0.5 hours, then add sodium hydroxide thereto Aqueous solution, adjusting the pH to neutral, a large amount of solids precipitated, filtered, and dried to obtain a monoazo intermediate 4-amino-2,5-dimethoxyphenyldiazenylbenzenesulfonic acid solid; sodium hydroxide (0.88 g, 22 mmol) was added to the 4-amino-2-methoxy-5-methylphenyldiazenylbenzenesulfonic acid suspension to adjust to alkalinity, and then sodium nitrite (1.7 g, 24 mmol) was added thereto, stirred and dissolved, and then cooled to 5°C, and then 37wt% dilute hydrochloric acid (5 mL, 50 mmol) was slowly added thereto, and the reaction was kept stirring at low temperature for 0.5 hours to obtain a monoazo intermediate diazonium salt suspension: 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt suspension.

[0058] Application Example 1: A method for preparing a polyazo compound 5-amino-3-((2,5-dimethoxy-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)-4-hydroxynaphthalene-2,7-disulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0059] The steps include:

[0060] Weigh 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid (6.4 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve by ultrasonication to obtain a 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid solution; then add 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 1, couple at 20 ° C for 0.5 hour to obtain a crude product, add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 14 g of product with a yield of 95%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 581 nm ( Figure 1 ).

[0061] Application Example 2: A method for preparing a polyazo compound 7-amino-3-((2,5-dimethoxy-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)-4-hydroxynaphthalene-2-sulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0062] Refer to Application Example 1, the difference is that the type of naphthol sulfonate in the second coupling is different, and the naphthol sulfonate is 6-amino-1-naphthol-3-sulfonic acid.

[0063] The steps include:

[0064] Weigh 6-amino-1-naphthol-3-sulfonic acid (4.8 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve it by ultrasonication to obtain a 6-amino-1-naphthol-3-sulfonic acid solution; then add 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 1, and couple at 20° C. for 0.5 hour to obtain a crude product; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 10.8 g of the product with a yield of 92%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 549 nm ( Figure 2 ).

[0065] Application Example 3: A method for preparing a polyazo compound 6-amino-3-((E)-(2,5-dimethoxy-4-((E)-(4-sulfophenyl)diazenyl)phenyl)diazenyl)-4-hydroxynaphthalene-2-sulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0066] Refer to Application Example 1, the difference is that the type of naphthol sulfonate in the second coupling is different, and the naphthol sulfonate is 7-amino-1-naphthol-3-sulfonic acid.

[0067] The steps include:

[0068] Weigh 7-amino-1-naphthol-3-sulfonic acid (4.8 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve it by ultrasonication to obtain a 7-amino-1-naphthol-3-sulfonic acid solution; then add 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 1, and couple at 20° C. for 0.5 hour to obtain a crude product; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 11.4 g of product with a yield of 97%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 556 nm ( Figure 3 ).

[0069] Application Example 4: A method for preparing a polyazo compound 2-amino-6-((2,5-dimethoxy-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)-5-hydroxynaphthalene-1,7-disulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0070] Refer to Application Example 1, the difference is that the type of naphthol sulfonate in the second coupling is different, and the naphthol sulfonate is 3-amino-8-naphthol-4,6-disulfonic acid.

[0071] The steps include:

[0072] Weigh 3-amino-8-naphthol-4,6-disulfonic acid (6.4 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve it by ultrasonication to obtain a 3-amino-8-naphthol-4,6-disulfonic acid solution; then add 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 1, couple at 20° C. for 0.5 hour to obtain a crude product; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 14 g of product with a yield of 95%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 566 nm ( Figure 4 ).

[0073] Application Example 5: A method for preparing a polyazo compound 5-amino-4-hydroxy-3-((2-methoxy-5-methyl-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)naphthalene-2,7-disulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0074] Referring to Application Example 1, the difference is that the type of naphthol sulfonate used in the second coupling is different, and the naphthol sulfonate is 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid. The type of monoazo intermediate diazonium salt prepared by diazotization in the second coupling is also different, and the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2 is used.

[0075] The steps include:

[0076] Weigh 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid (6.4 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve by ultrasonication to obtain a 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid solution; then add 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2, and couple at 20 ° C for 0.5 hours to obtain a crude product; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, stand, centrifuge, and dry to obtain 14 g of product with a yield of 95%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 581 nm ( Figure 5 ).

[0077] Application Example 6: Method for preparing a polyazo compound 7-amino-4-hydroxy-3-((2-methoxy-5-methyl-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0078] Refer to Application Example 5, the difference is that the type of naphthol sulfonate in the second coupling is different, and the naphthol sulfonate is 6-amino-1-naphthol-3-sulfonic acid.

[0079] The steps include:

[0080] Weigh 6-amino-1-naphthol-3-sulfonic acid (4.8 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve it by ultrasonication to obtain a 6-amino-1-naphthol-3-sulfonic acid solution; then add 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2, and couple at 20° C. for 0.5 hour to obtain a crude product; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 11.4 g of product with a yield of 99%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 536 nm ( Figure 6 ).

[0081] Application Example 7: A method for preparing a polyazo compound 7-amino-4-hydroxy-3-((2-methoxy-5-methyl-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling.

[0082] Referring to Application Example 5, the difference is that the type of naphthol sulfonate in the second coupling is different, and the naphthol sulfonate is 3-amino-8-naphthol-4,6-disulfonic acid.

[0083] The steps include:

[0084] Weigh 3-amino-8-naphthol-4,6-disulfonic acid (6.4 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve it by ultrasonication to obtain a 3-amino-8-naphthol-4,6-disulfonic acid solution; then add 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2, and couple at 20° C. for 0.5 hour to obtain a crude product; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 14 g of product with a yield of 95%; take the product and dissolve it in deionized water to prepare a 10 ppm aqueous solution, and measure the UV-visible absorption spectrum by UV-visible spectrometer, and the maximum absorption wavelength is 545 nm ( Figure 7 ).

[0085] Application Example 8: Method for preparing a polyazo compound 7-amino-4-hydroxy-3-((2-methoxy-5-methyl-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid copper complex by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling

[0086] Referring to Application Example 7, the difference is that there is an additional step of directly performing copper complexation reaction of the obtained disazo compound and copper salt under the action of an organic base without separation.

[0087] The steps include:

[0088] Weigh 3-amino-8-naphthol-4,6-disulfonic acid (6.4 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve by ultrasonication to obtain a 3-amino-8-naphthol-4,6-disulfonic acid solution; then add 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2, couple at 20° C. for 0.5 hour to obtain a crude product, which is directly used in the next reaction without separation; weigh ethanolamine (2.4 g, 40 mmol) in a 500 mL beaker, then add copper sulfate pentahydrate (7.5 g, 30 mmol) aqueous solution, stir to dissolve, and then transfer to a 95° C. oil bath and stir to react for 8 hours; add sodium chloride solid (45 g, 15 wt %), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 10.1 g of product with a yield of 70%.

[0089] Application Example 9: A method for preparing a polyazo compound 4-((4-(4-amino-2,5-dimethoxyphenyl)diazenyl)-2,5-dimethoxyphenyl)diazenyl)benzenesulfonic acid by continuous diazotization to prepare a monoazo intermediate diazonium salt and then coupling.

[0090] Referring to Application Example 1, the difference is that 2,5-methoxyaniline is used in the second coupling, which includes the following steps:

[0091] Weigh 2,5-methoxyaniline (2.7 g, 20 mmol) in a 500 mL beaker and dissolve it in a dilute sulfuric acid aqueous solution. Then add 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2, and couple at 20°C for 2 hours to obtain a crude product. After standing, centrifuging and drying, 8.5 g of the product was obtained with a yield of 85%.

[0092] Application control example 1: Method for preparing a polyazo compound 5-amino-3-((2,5-dimethoxy-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)-4-hydroxynaphthalene-2,7-disulfonic acid by step-by-step diazotization to prepare a monoazodiazonium salt and then coupling

[0093] Referring to Application Example 1, the difference is that the type of monoazo intermediate diazonium salt prepared by diazotization in the second coupling is also different, and the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Control Example 1 is used to replace the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 1.

[0094] The steps include:

[0095] Weigh 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid (6.4 g, 20 mmol) in a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve by ultrasonication to obtain a 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid solution; then add 4-amino-2,5-dimethoxy-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Reference Example 1, couple at 20°C for 0.5 hours to obtain a crude product; add sodium chloride solid (45 g, 15 wt%), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 12.5 g of product with a yield of 85%. .

[0096] By comparing Application Control Example 1 with Application Example 1, it can be seen that the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared by Example 1 in Application Example 1 has a better effect than the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared by Control Example 1. It can be seen that the product obtained by the first coupling is not separated, and the second diazotization reaction is directly carried out, and the one-pot continuous reaction is used to prepare polyazo compounds with a higher yield.

[0097] Application control example 2: Preparation of a monoazodiazonium salt by stepwise diazotization followed by coupling to prepare a polyazo compound 7-amino-4-hydroxy-3-((2-methoxy-5-methyl-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid

[0098] Referring to Application Example 6, the difference is that the type of monoazo intermediate diazonium salt prepared by diazotization in the second coupling is also different. The 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Control Example 2 is used to replace the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2.

[0099] The steps include:

[0100] Weigh 6-amino-1-naphthol-3-sulfonic acid (4.8 g, 20 mmol) into a 500 mL beaker, then add 200 mL of saturated sodium carbonate solution, and dissolve it by ultrasonication to obtain a 6-amino-1-naphthol-3-sulfonic acid solution; then add 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Example 2, and couple at 20 ° C for 0.5 hour to obtain a crude product; add solid sodium chloride (45 g, 15 wt%), salt out, stir for 1 hour, let stand, centrifuge, and dry to obtain 10.3 g of product with a yield of 90%.

[0101] By comparing Application Control Example 2 and Application Example 6, it can be seen that the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Application Example 6 using Example 2 has a better effect than the 4-amino-2-methoxy-5-methyl-phenyldiazenylbenzenesulfonic acid diazonium salt prepared in Control Example 2. It can be seen that the product obtained by the first coupling is not separated, and the second diazotization reaction is directly carried out, and the one-pot continuous reaction is used to prepare polyazo compounds with a higher yield.

[0102] Product application: Application example 6: Comparison of product application in polarizing film dyeing

[0103] The steps include:

[0104] The product of Application Example 6, 7-amino-4-hydroxy-3-((2-methoxy-5-methyl-4-((4-sulfophenyl)diazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid and a reference standard purple dye (Direct Violet 64, Shanghai Santai Dyeing Factory) were prepared into a 0.1wt% dye aqueous solution with deionized water; a PVA film was soaked and cleaned and fixed on a bracket, and then placed in the corresponding dye aqueous solution for soaking and dyeing, and the soaking time was set to 30 seconds, 60 seconds, 120 seconds, and 300 seconds respectively; after reaching the specified dyeing soaking time, the PVA film was taken out, washed, and dried at 90°C to obtain a dyed PVA film; the PVA film was cut and then placed under a polarized white light source to observe the dyeing effect and polarization effect; Figure 8 As shown in the figure on the right, the product of Application Example 6 has a polarization effect equivalent to that of the corresponding purple dye after dyeing the PVA film. When parallel to the light source, the PVA film is almost colorless; Figure 8 As shown in the left figure, the dyeing effect of the product of Application Example 6 at 60 seconds is better than the dyeing effect of the control standard purple dye at 60 or 120 seconds. The product of Application Example 6 has a significant effect of accelerating dyeing.

[0105] The above are only preferred embodiments of the present invention. It should be noted that the above preferred implementations and application modes should not be regarded as limiting the present invention. The protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A direct dye compound represented by formula I or a copper complex of a direct dye represented by formula II: in, R1 is H, Me, Cl or OMe, R2 is Me, OMe, Cl or H, R3 is H or NH2, and R4 is H or NH2.

2. The method for preparing the direct dye compound of formula I or the copper complex of the direct dye of formula II according to claim 1, characterized in that: The steps include: (1) subjecting p-aminobenzenesulfonic acid or sodium p-aminobenzenesulfonate to a first diazotization reaction to obtain p-aminobenzenesulfonic acid diazonium salt; subsequently, the p-aminobenzenesulfonic acid diazonium salt is first coupled with anisidine to prepare a monoazo intermediate; (2) without separation, subjecting the monoazo intermediate to a second diazotization reaction to obtain a monoazo intermediate diazonium salt; (3) secondary coupling of the monoazo intermediate diazonium salt with naphthol sulfonate or aniline compound to prepare the direct dye compound represented by formula I; (4) Without separation, the disazo compound obtained in step (3) is directly subjected to a copper complex reaction with a copper salt in the presence of an organic base to prepare a copper complex of a direct dye represented by formula II.

3. The method according to claim 2, characterized in that The specific steps of step (1) are as follows: dissolving p-aminobenzenesulfonic acid or sodium p-aminobenzenesulfonate in an alkali solution, adding sodium nitrite thereto after stirring evenly, and then dropping a dilute acid solution to perform diazotization to obtain p-aminobenzenesulfonic acid diazonium salt; coupling p-aminobenzenesulfonic acid diazonium salt with aminoanisole for the first time under neutral or weakly acidic conditions to obtain a monoazo intermediate, wherein the aminoanisole is selected from one of 2,5-dimethoxyaniline, 2-methoxy-5-methylaniline, or 2-methoxy-5-chloroaniline; dissolving aminoanisole in a dilute solution of sulfuric acid, hydrochloric acid, and acetic acid; and the specific steps of step (2) are as follows: without separation, adding an alkali solution to convert the monoazo intermediate from an acidic environment to an alkaline environment, and then adding sodium nitrite thereto, slowly dropping a dilute acid solution to adjust the pH to acidic, and then performing a second diazotization to obtain a monoazo intermediate diazonium salt.

4. The method according to claim 2, characterized in that: Step (1) the base is sodium hydroxide, the molar ratio of p-aminobenzenesulfonic acid to sodium hydroxide is 1:1.0-1.5; the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:1.0-1.5; the dilute acid is dilute hydrochloric acid, the molar ratio of p-aminobenzenesulfonic acid to dilute hydrochloric acid is 1:1.0-3.0, after adding dilute hydrochloric acid, the pH is adjusted to between 1-2 for diazotization, the reaction temperature is maintained at between 5-10°C, and the reaction is carried out for 0.5 hour; the temperature of the first coupling reaction in step (1) is room temperature, and the reaction time is 0 .5-1.0 hour; in step (2), the alkali solution is sodium hydroxide solution, and the molar ratio of the monoazo intermediate to sodium hydroxide is 1:1.0-4.0; the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:1.0-2.5, the dilute acid solution is dilute hydrochloric acid, and the molar ratio of p-aminobenzenesulfonic acid to dilute hydrochloric acid is 1:1.0-3.0, after adding dilute hydrochloric acid, the pH is adjusted to between 1-2, the reaction temperature is maintained at between 5-10°C, and the reaction is stirred for 0.5-1 hour to obtain the monoazo intermediate diazonium salt.

5. The method according to claim 4, characterized in that In step (1), the molar ratio of p-aminobenzenesulfonic acid to sodium hydroxide is 1:1.1-1.2; the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:1.1-1.2; the molar ratio of p-aminobenzenesulfonic acid to dilute hydrochloric acid is 1:2.0-3.0; in step (2), the molar ratio of the monoazo intermediate to sodium hydroxide is 1:2.5-3.5; the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:1.3-1.5; and the molar ratio of p-aminobenzenesulfonic acid to dilute hydrochloric acid is 1:1.5-2.

0.

6. The method according to claim 2, characterized in that The specific steps of step (3) are: reacting a monoazo intermediate diazonium salt with a naphthol sulfonate, wherein the naphthol sulfonate is selected from one of 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid, 6-amino-1-naphthol-3-sulfonic acid, 7-amino-1-naphthol-3-sulfonic acid, 3-amino-8-naphthol-4,6-disulfonic acid or its sulfonate, dissolving the naphthol sulfonate in sodium hydroxide or sodium carbonate solution, and coupling for the second time under neutral or weak alkaline conditions to obtain a disazo compound; The reaction temperature is maintained at room temperature, and the reaction time is 0.5-1.0 hours; Alternatively, the monoazo intermediate diazonium salt is reacted with an aniline compound, the aniline compound is selected from one of 2-methoxyaniline, 2,5-dimethoxyaniline, 2-methoxy-5-methylaniline or 2-methoxy-5-chloroaniline, the aniline compound is dissolved in sulfuric acid, hydrochloric acid, acetic acid or a dilute solution thereof, and a second coupling is performed under acidic conditions to obtain a disazo compound.

7. The method according to claim 2, characterized in that The specific steps of step (4) are as follows: without separation, an organic base and a copper salt are added to the reaction product of the disazo compound, wherein the organic base is selected from one of ethanolamine, diethanolamine, triethanolamine and triethylamine, and the copper salt is selected from one of copper sulfate pentahydrate, copper chloride and copper bromide, and the reaction is heated under reflux for 5-10 hours; the molar ratio of the disazo compound to the organic base is 1:1.0-4.0; the molar ratio of p-aminobenzenesulfonic acid to copper sulfate is 1:1.0-2.5; The reaction temperature was maintained between 90-100°C.

8. A method for preparing a polyazo dye or a complex thereof, characterized in that: The product obtained in step (3) of the preparation method of the direct dye compound represented by formula I described in claim 2 is not separated, and the disazo compound is subjected to a third diazotization reaction to obtain a disazo intermediate diazonium salt, which is then coupled for a third time to obtain a triazo compound, and so on, to prepare a polyazo dye or a complex thereof, the specific steps of which are: without separation, adding an alkali solution to convert the disazo intermediate from an acidic environment to an alkaline environment, then adding sodium nitrite thereto, and slowly dropping a dilute acid solution to perform a third diazotization to obtain The method comprises the steps of: reacting the disazo intermediate diazonium salt with a naphthol sulfonate, wherein the naphthol sulfonate is selected from one of 4-amino-5-hydroxy-2,7-naphthalene disulfonic acid, 6-amino-1-naphthol-3-sulfonic acid, 7-amino-1-naphthol-3-sulfonic acid, 3-amino-8-naphthol-4,6-disulfonic acid or a sulfonate thereof, dissolving the naphthol sulfonate in a sodium hydroxide or sodium carbonate solution, coupling under alkaline conditions for a third coupling to obtain a triazo compound, and so on to prepare a polyazo dye or a complex thereof.

9. Use of the direct dye compound represented by formula I or the copper complex of the direct dye represented by formula II as claimed in claim 1 in dyeing polarizing films or polarizers.

10. The use according to claim 9, characterized in that: The polarizing film or polarizing sheet is made of PVA.

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