Method for synthesizing high-performance organic pigment through high-concentration system

Abstract

The invention discloses a method for synthesizing a high-performance organic pigment by a high-concentration system. The method comprises the following steps: preparing raw materials or a raw material mixture; preparing a high-viscosity system, preferably carrying out forced mixing, and reacting under control conditions; and after the reaction is finished, carrying out post-treatment to obtain high-performance organic pigments such as azo series pigments, azo condensation series pigments, diketopyrrolopyrrole series pigments and the like. According to the synthesis method, the problems that in the traditional high-performance organic pigment production process, a large amount of solvent is adopted, and the energy consumption and the circulation cost in the rear-end separation process are high are solved, and the cost consumed by solvent recovery and wastewater treatment in the whole process is reduced.

Description

Technical Field

[0001] This invention relates to the field of organic chemistry, particularly the field of organic pigment synthesis, and specifically to a method for synthesizing high-performance organic pigments using a high-concentration system. Background Technology

[0002] High-performance organic pigments possess advantages such as vibrant colors, high tinting strength, excellent durability, good dispersibility, acid and alkali resistance, solvent resistance, and heat resistance. They are widely used in coloring inks, paints, coatings, plastics, and synthetic fibers, as well as in optoelectronic materials such as organic solar cells, organic field-effect transistors, and organic light-emitting diodes.

[0003] In the field of high-performance organic pigment synthesis, the industry commonly uses large amounts of solvents for pigment synthesis (depending on the type of pigment, this can be 4 times, 8 times, or even higher). With the continuous rise in global energy prices, the manufacturing process of traditional high-performance organic pigments is becoming increasingly expensive and profitable due to its large solvent consumption, high energy consumption, and recycling costs.

[0004] Due to the aforementioned cost considerations, high-performance organic pigments such as azo series, macromolecular series pigments, and pyrrolopyrrole dione series are difficult to replace some pigment varieties that fail to achieve intrinsic safety for users, or for which downstream manufacturers require significant costs to achieve green production. Therefore, there is an urgent need to improve and develop a green and economical method for producing high-performance organic pigments. Summary of the Invention

[0005] To address the aforementioned problems, the inventors have conducted in-depth research on organic pigment production systems and processes, and have provided a method for synthesizing high-performance organic pigments using a high-concentration system. This method solves the problems of high solvent usage, high energy consumption and recycling costs in the downstream separation process of traditional high-performance organic pigment production, and reduces the costs of solvent recovery and wastewater treatment throughout the entire process, thus completing this invention.

[0006] Specifically, the object of the present invention is to provide the following aspects: On the one hand, a method for synthesizing high-performance organic pigments in a high-concentration system is provided, comprising the following steps: 1. Prepare raw materials or mixtures of raw materials; Second, prepare a high-viscosity system, preferably by forced mixing, and carry out the reaction under controlled conditions; 3. After the reaction is complete, post-processing shall be performed.

[0007] The high-performance organic pigments described in this invention include azo series pigments, azo condensation series pigments, pyrrolopyrrole dione series pigments, etc.

[0008] According to one embodiment of the present invention, a method for synthesizing azo series pigments is provided.

[0009] In step one, the raw materials or mixture of raw materials mainly include isopropyl nitrite (IPN), chromogen, and coupling components.

[0010] The preparation of the IPN includes reacting sodium nitrite, an alcohol solvent, and an acid to prepare IPN, wherein the molar ratio of sodium nitrite, isopropanol, and hydrochloric acid is 1:1-2:0.7-1.5.

[0011] In step two, the color base and the coupling component undergo a diazo coupling reaction simultaneously under IPN conditions to obtain a crude azo pigment slurry. Preferably, the color base and the coupling component are pulped in a solvent, such as isopropanol, isoamyl alcohol, isobutyl ester, and acetic acid, preferably isopropanol, acetic acid, or a mixed solution of isopropanol and acetic acid.

[0012] After pulping, IPN is added dropwise at -5 to 50°C, preferably at 20 to 40°C. After the addition is complete, the temperature is maintained for 10 to 60 minutes. After the temperature maintenance is complete, sodium methoxide is added to adjust the pH to weakly alkaline, and then the temperature is raised to 30 to 80°C, preferably at 40 to 70°C, and maintained for 30 to 120 minutes. After the reaction is complete, the azo pigment reaction system is obtained.

[0013] In step three, the post-processing includes pigmentation. Preferably, the synthesized azo pigment reaction system is kept at 90-150℃ for 2-12 hours to remove solvent and salt, and then dried to obtain the azo pigment.

[0014] According to another embodiment of the present invention, a method for synthesizing azo condensation series pigments is provided.

[0015] In step one, the main raw materials include 2-hydroxy-3-naphthoic acid, aromatic amine, diazo reagent, sulfoxide, and aromatic diamine.

[0016] In step two, 2-hydroxy-3-naphthoic acid is added to a small amount of high-boiling-point benzene solvent, followed by the addition of an aromatic amine to prepare a high-viscosity system. Forced mixing is preferred. Then, under controlled conditions, a diazo reagent is added, preferably dropwise, to carry out the intermediate dye reaction. Preferably, 2-hydroxy-3-naphthoic acid is added to a small amount of high-boiling-point benzene solvent, preferably xylene, followed by the addition of an aromatic amine, and then the diazo reagent is added dropwise to prepare a monoazo dye. The molar ratio of 2-hydroxy-3-naphthoic acid to the aromatic amine is 1:1-1.1, preferably 1:1.02.

[0017] In this invention, the monoazo dye undergoes acyl chloride treatment. Preferably, thionyl chloride is added to the synthesized intermediate dye system to carry out the acyl chloride reaction, generating a carboxylic acid acyl chloride. The molar ratio of the intermediate to thionyl chloride is 1:1-1.2.

[0018] The carboxylic acid acyl chloride is then amidated. Preferably, the synthesized acyl chloride is heated to 60-110°C, and then an aromatic diamine is added to the system. The mixture is heated and reacted for several hours to obtain a reaction solution containing azo condensation pigment.

[0019] In step three, after the reaction is complete, the reaction solution containing the azo condensation pigment is heated to evaporate the solvent and obtain the azo condensation pigment.

[0020] According to another embodiment of the present invention, a method for synthesizing pyrrolopyrrole dione series pigments is provided.

[0021] In step one, the raw materials mainly include sodium alkoxide, benzonitrile compounds, and succinate diester compounds. The benzonitrile compounds include 4-chlorobenzonitrile, benzonitrile, 4-methylbenzonitrile, and 4-phenylbenzonitrile; the succinate diester compounds preferably include diisopropyl succinate, di-tert-amyl succinate, and / or dicyclohexyl succinate.

[0022] Step one includes the preparation of sodium alkoxide, which is prepared by reacting metallic sodium with an alcohol. Preferably, the metallic sodium is melted and then added to an alcohol solvent, which is an alcohol with 3 to 6 carbon atoms, preferably anhydrous tert-amyl alcohol. The reaction between the metallic sodium and the alcohol is carried out under reflux / pressure until the sodium is completely dissolved, wherein the mass ratio of metallic sodium to tert-amyl alcohol is 1:3.9-5.5. The resulting sodium alkoxide solution is kept at a controlled temperature of 100-115°C and is ready for use.

[0023] In step two, benzonitrile compounds and succinate diester compounds are added to the aforementioned sodium alkoxide solution to prepare a high-viscosity system. Forced mixing is preferred, followed by a condensation reaction under heat preservation conditions. After the reaction is complete, the mixture is evaporated to dryness to obtain sodium salt powder. Preferably, the benzonitrile compounds and succinate diester compounds are premixed and heated to 80-120°C, then added dropwise to the sodium alkoxide. More preferably, the dropping rate is controlled in this step. The reaction is then carried out at the reaction temperature, preferably 80-150°C, and preferably for 1-10 hours.

[0024] In this invention, a portion of the solvent is extracted during the condensation reaction and the substance is recovered. For example, a solvent with a boiling point below 90-100°C is continuously extracted and recycled.

[0025] The recovered raw materials were directly mixed with succinic acid and esterified under acid catalysis at a temperature of 50-100℃. The reaction was maintained at this temperature, and the succinic acid diesters were directly separated after the reaction was completed.

[0026] After the reaction is complete, the remaining solvent is evaporated to obtain powdered sodium salt.

[0027] The molar ratio of metallic sodium to benzonitrile compounds is 1.01~2.50:1; the molar ratio of benzonitrile compounds to succinate diester compounds is 1.50~2.02:1.

[0028] In step three, the sodium salt powder obtained above is protonated to obtain pyrrolopyrrole dione series pigments.

[0029] Preferably, the protonation involves adding the powder to water or an aqueous solution, such as alcoholic water of a certain concentration, for hydrolysis, thereby obtaining the target product, pyrrolopyrrole dione series pigments. The hydrolysis is carried out at an elevated temperature, for example, adding the powder to water at 45-50°C, allowing the hydrolysis reaction to proceed for a period of time, followed by filtration, washing, and drying to finally obtain the product.

[0030] The total mass of solvents used in the entire production process is 1:1 to 2:1 relative to the mass of the final product.

[0031] In another aspect, the present invention provides organic pigments synthesized by the method of the first aspect, including azo series pigments, azo condensation series pigments, pyrrolopyrrole dione series pigments, etc. Attached Figure Description

[0032] Figure 1 The XRD pattern of the product obtained in Example 1 is shown. Figure 2 A TEM image of the product obtained in Example 1 is shown; Figure 3 The XRD pattern of the product obtained in Example 2 is shown. Figure 4 The XRD pattern of the product obtained in Comparative Example 1 is shown. Figure 5 A TEM image of the product obtained in Comparative Example 1 is shown; Figure 6 The XRD pattern of the product obtained in Example 3 is shown. Figure 7 The XRD pattern of the product obtained in Comparative Example 2 is shown. Figure 8 The infrared spectrum of the product obtained in Example 4 is shown. Figure 9 The infrared spectrum of Pigment Red 166 standard is shown; Figure 10 A TEM image of the product obtained in Example 6 is shown; Figure 11 The TEM image of bis(p-chlorophenyl)-1,4-dionepyrrolopyrrole standard is shown. Figure 12 A TEM image of the product obtained in Example 8 is shown. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0034] According to the present invention, a method for synthesizing high-performance organic pigments in a high-concentration system is provided, comprising the following steps: 1. Prepare raw materials or mixtures of raw materials; Second, prepare a high-viscosity system, preferably by forced mixing, and carry out the reaction under controlled conditions; 3. After the reaction is complete, post-processing shall be performed.

[0035] In this invention, the high-performance organic pigments include azo series pigments, azo condensation series pigments, pyrrolopyrrole dione series pigments, etc.

[0036] According to one embodiment of the present invention, the organic pigment is an azo series pigment, preferably Pigment Yellow 155, Pigment Yellow 180, Pigment Yellow 151, Pigment Yellow 55, Pigment Yellow 74, etc., and these azo series pigments are known substances with the following structures:

[0037] Pigment Yellow 155,

[0038] Pigment Yellow 180

[0039] Pigment Yellow 151

[0040] Pigment Yellow 55,

[0041] Pigment Yellow 74.

[0042] In step one, the raw materials or mixture of raw materials mainly include isopropyl nitrite (IPN), chromogen, and coupling components.

[0043] The IPN can be commercially available or prepared in-house.

[0044] According to the present invention, step one includes the preparation of IPN, specifically, the reaction of sodium nitrite, an alcohol solvent and an acid to prepare IPN.

[0045] In a preferred embodiment of the present invention, sodium nitrite is dissolved in water and then mixed with an alcohol solvent, which may be isopropanol, isoamyl alcohol, or isobutyl ester, preferably isopropanol.

[0046] After mixing, the temperature is controlled at -10 to 5℃, concentrated hydrochloric acid is added dropwise, and after the addition is completed, the mixture is allowed to stand and separated to obtain IPN.

[0047] The molar ratio of sodium nitrite, isopropanol, and hydrochloric acid is 1:1-2:0.7-1.5.

[0048] The chromophores include: methyl 2-amino-terephthalate, o-aminobenzoic acid, 1,2-bis(2-amino-phenoxy)ethane, 2,2'-dichloroazobenzene, p-nitro-o-methoxyaniline, etc.

[0049] The coupling components include: 1,4-diacetylacetanilide, 5-acetylacetaminobenzimidazine, p-methylacetylacetanilide, o-methoxyacetylacetanilide, etc.

[0050] According to the present invention, in step two, the color base and coupling component are prepared into a high-viscosity system in a solvent, and forced mixing is carried out by pulping, and then the azo synthesis reaction is carried out under controlled conditions.

[0051] In a preferred embodiment of the present invention, the color base and the coupling component undergo a diazo coupling reaction simultaneously under IPN conditions to obtain a crude azo pigment slurry.

[0052] The chromosome and the coupling component are slurried in a solvent, such as isopropanol, isoamyl alcohol, isobutyl ester, and acetic acid, preferably isopropanol, acetic acid, or a mixture of isopropanol and acetic acid.

[0053] After pulping, IPN is added dropwise at -5 to 50°C, preferably at 20 to 40°C. After the addition is complete, the temperature is maintained for 10 to 60 minutes. After the temperature maintenance is complete, sodium methoxide is added to adjust the pH to weakly alkaline, and then the temperature is raised to 30 to 80°C, preferably at 40 to 70°C, and maintained for 30 to 120 minutes. After the reaction is complete, the azo pigment reaction system is obtained.

[0054] In step three of this invention, the post-processing includes pigmentation.

[0055] Preferably, the synthesized azo pigment reaction system is kept at 90-150℃, more preferably 100-130℃, for 2-12 hours. After solvent removal and desalting, the azo pigment is obtained after drying.

[0056] According to another embodiment of the present invention, the organic pigment is an azo condensation series pigment, such as PO31, PO55, PR139, PR140, PR141, PR142, PR143, PR144, PR165, PR166, PR214, PR217, PR218, PR220, PR221, PR242, PR248, PR262, P.Br.23, P.Br.41, and P.Br.42 pigments.

[0057] The azo condensation series pigments generally have the following general formula structure:

[0058] In the formula, A represents a diazo aromatic amine (or substituted aromatic amine) residue, wherein the aromatic amine may be an aniline with 1 to 3 substituents, including 2-chloroaniline, 2,3-dichloroaniline, 2,5-dichloroaniline, 2-chloro-5-trifluoromethylaniline, 2-methyl-3-chloroaniline, 2-methyl-4-chloroaniline, 2-methyl-5-chloroaniline, 2-nitro-4-chloroaniline, methyl 2-aminobenzoate, 2,5-dimethoxy-4-chloroaniline, ethyl 3-amino-4-methylbenzoate, isopropyl 3-amino-4-methylbenzoate, diethyl 2-aminoterephthalate, 3-amino-4-methyl-5-benzoic acid (4-propyl phenyl carboxylate), etc. B is an aromatic diamine (or substituted aromatic diamine) residue, including 1,4-p-phenylenediamine, 2-chloro-1,4-p-phenylenediamine, 2,5-dichloro-1,4-p-phenylenediamine, 1,5-naphthylenediamine, 2,5-dimethyl-1,4-p-phenylenediamine, 2-cyano-1,4-p-phenylenediamine, 4-aminobenzoyl(4-aminophenyl)amine, etc.

[0059] In step one, the raw materials or mixtures of raw materials mainly include 2-hydroxy-3-naphthoic acid, aromatic amines, diazo reagents, sulfoxide, and aromatic diamines, etc.

[0060] The aromatic amine can be aniline with 1-3 substituents, including 2-chloroaniline, 2,3-dichloroaniline, 2,5-dichloroaniline, 2-chloro-5-trifluoromethylaniline, 2-methyl-3-chloroaniline, 2-methyl-4-chloroaniline, 2-methyl-5-chloroaniline, 2-nitro-4-chloroaniline, methyl 2-aminobenzoate, 2,5-dimethoxy-4-chloroaniline, ethyl 3-amino-4-methylbenzoate, isopropyl 3-amino-4-methylbenzoate, diethyl 2-aminoterephthalate, 3-amino-4-methyl-5-benzoic acid (4-propyl benzoate) ester, etc.

[0061] The aromatic diamines include 1,4-p-phenylenediamine, 2-chloro-1,4-p-phenylenediamine, 2,5-dichloro-1,4-p-phenylenediamine, 1,5-naphthylenediamine, 2,5-dimethyl-1,4-p-phenylenediamine, 2-cyano-1,4-p-phenylenediamine, 4-aminobenzoyl(4-aminophenyl)amine, etc.

[0062] According to the present invention, in step two, 2-hydroxy-3-naphthoic acid is added to a small amount of high-boiling-point benzene solvent, aromatic amine is added, a high-viscosity system is prepared, preferably by forced mixing, and then under controlled conditions, a diazo reagent is added, preferably by dropwise addition, to carry out the intermediate dye reaction.

[0063] In a preferred embodiment, the intermediate dye synthesis reaction is carried out as follows: 2-Hydroxy-3-naphthoic acid is added to a small amount of high-boiling-point benzene solvent, preferably toluene, chlorobenzene, dichlorobenzene, trimethylbenzene, nitrobenzene, etc., more preferably xylene, and then an aromatic amine is added. The molar ratio of 2-hydroxy-3-naphthoic acid to aromatic amine is 1:1-1.1, preferably 1:1.02. Then, a diazo reagent is added dropwise to prepare a monoazo dye.

[0064] In this invention, the monoazo dye is then subjected to acyl chloride. Preferably, thionyl chloride is added to the above-synthesized intermediate dye system to carry out the acyl chloride reaction, generating a carboxylic acid acyl chloride.

[0065] The molar ratio of the intermediate to sulfoxide is 1:1-1.2, preferably 1:1.1.

[0066] The carboxylic acid acyl chloride is then amidated. Preferably, the synthesized acyl chloride is heated to a specific temperature, preferably 60-110°C, more preferably 80°C, and then an aromatic diamine is added to the system. The system is heated and reacted for several hours, preferably at 120-150°C, more preferably at 135°C, and held at that temperature for 3-8 hours, preferably 6 hours, to obtain a reaction solution containing azo condensation pigment.

[0067] In step three of this invention, the post-processing includes heating the reaction solution containing the azo condensation pigment after the reaction is completed, evaporating the solvent, and obtaining the azo condensation pigment.

[0068] According to another embodiment of the present invention, the organic pigment is a pyrrolopyrrolodione series pigment, preferably including bis(p-chlorophenyl)-1,4-dione pyrrolopyrrole, bis(phenyl)-1,4-dione pyrrolopyrrole, bis(biphenyl)-1,4-dione pyrrolopyrrole, and bis(p-tolyl)-1,4-dione pyrrolopyrrole.

[0069] The pyrrolopyrrole dione series pigments generally have the following general formula:

[0070] In the formula, R1 includes hydrogen, chlorine, methyl, and benzene rings. R2 includes hydrogen, chlorine, methyl, and benzene rings.

[0071] In step one, the raw materials or mixtures of raw materials mainly include sodium alkoxide, benzonitrile compounds, succinate diester compounds, etc.

[0072] The benzonitrile compounds include 4-chlorobenzonitrile, benzonitrile, 4-methylbenzonitrile, 4-phenylbenzonitrile, etc.

[0073] The succinate diesters preferably include diisopropyl succinate, di-tert-amyl succinate, and / or dicyclohexyl succinate, etc.

[0074] The sodium alkoxide can be commercially available or prepared in-house.

[0075] According to the present invention, step one includes the preparation of sodium alkoxide by reacting metallic sodium with an alcohol.

[0076] In a preferred embodiment, metallic sodium is melted and then added to an alcohol solvent, which is an alcohol with 3 to 6 carbon atoms, preferably anhydrous tert-amyl alcohol. The reaction between metallic sodium and the alcohol is carried out under reflux / pressure, preferably reflux for 2-10 hours, until the sodium is completely dissolved.

[0077] The resulting sodium alkoxide solution was kept at a temperature of 100-115℃ and kept for later use.

[0078] The mass ratio of metallic sodium to tert-amyl alcohol is 1:3.9-5.5.

[0079] According to the present invention, in step two, benzonitrile compounds and succinate diester compounds are added to the above-mentioned sodium alkoxide solution to prepare a high-viscosity system, preferably by forced mixing, and then a condensation reaction is carried out under controlled conditions. After the reaction is completed, the solution is evaporated to dryness to obtain sodium salt powder.

[0080] In this invention, the control condition is that the condensation reaction is carried out under heat preservation.

[0081] Preferably, the benzonitrile compound and the succinate diester compound are premixed, heated to 80-120°C, and then added dropwise to sodium alkoxide. More preferably, the dropping rate is controlled in this step and the dropping is completed within 5 to 45 minutes. Then the reaction is carried out at a reaction temperature, preferably 80°C-150°C, more preferably 100°C-125°C, and preferably for 1-10 hours.

[0082] According to a preferred embodiment of the present invention, a portion of the solvent is extracted during the condensation reaction and the substance is recovered. Preferably, the solvent with a boiling point below 90-100°C is continuously extracted and recycled.

[0083] In this invention, the recovered raw materials are directly mixed with succinic acid and esterified under acid catalysis at a temperature of 50-100°C, preferably 70-80°C. The reaction is maintained at this temperature, and the succinic acid diester compounds are directly separated after the reaction is completed.

[0084] After the reaction is complete, the remaining solvent is evaporated to obtain a powder, which is the sodium salt of the target product.

[0085] In this invention, the molar ratio of sodium metal to benzonitrile compound is 1.01~2.50:1, preferably 1.2~2.2:1, more preferably 1.50-2.10:1; the molar ratio of benzonitrile compound to diisopropyl succinate is 1.50~2.02:1, preferably 1.60-2.00:1.

[0086] In step three, the post-processing includes protonating the sodium salt powder obtained above to obtain pyrrolopyrrole dione series pigments.

[0087] Preferably, the protonation involves adding the powder to water or an aqueous solution, such as alcohol water of a certain concentration, for hydrolysis, and then processing it to obtain the target product, pyrrolopyrrole dione series pigments.

[0088] As an aqueous solution, it can be an alcohol-water solution, wherein the alcohol is preferably methanol, ethanol, propanol, butanol, etc., and more preferably an aqueous methanol solution, such as a 0-80% concentration aqueous methanol solution.

[0089] The hydrolysis described in this invention is carried out at an elevated temperature, for example, by adding the powder to water at 45-50°C and hydrolyzing for a period of time, for example, 0.5-5 hours, preferably 1-2 hours, followed by filtration, washing, and drying to finally obtain the product.

[0090] In the preparation method of the present invention, the total mass of solvent used in the entire production process is 1:1 to 2:1 relative to the mass of the final product; the solvent includes the amount of alcohol required for the synthesis of sodium alkoxide and the amount of alcohol used as a solvent.

[0091] In a second aspect, the present invention provides organic pigments synthesized according to the above method, including azo series pigments, azo condensation series pigments, and pyrrolopyrrole dione series pigments. The pyrrolopyrrole dione series pigments are, for example, one or more of bis(phenyl)-1,4-dionepyrrolopyrrole, bis(biphenyl)-1,4-dionepyrrolopyrrole, and bis(p-tolyl)-1,4-dionepyrrolopyrrole, preferably bis(p-chlorophenyl)-1,4-dionepyrrolopyrrole.

[0092] The synthesis method provided by this invention, which uses the above route, can reduce the amount of solvent used in the production process to 1 / 4 to 1 / 2 of the original amount of solvent; the product yield and performance are good, and at least reach the level of existing processes. The present invention provides a simple and energy-efficient method for solvent recovery, which fundamentally reduces the cost of pigment synthesis and provides a possibility for replacing traditional pigments. Example

[0093] The present invention is further described below through specific examples; however, these examples are merely exemplary and do not constitute any limitation on the scope of protection of the present invention.

[0094] Example 1 79.1 g of sodium nitrite was dissolved in 160 g of water, then mixed with 87.7 g of isopropanol. At -5 to 0 °C, 124.9 g of 36.5% hydrochloric acid solution was added dropwise. After the addition was complete, the mixture was allowed to stand. The upper layer was a light yellow liquid, which was the product, isopropyl nitrite, and the lower layer was an aqueous phase. 100 g of isopropyl nitrite was obtained.

[0095] 232.5 g of methyl 2-amino-terephthalate and 157 g of 1,4-diacetylacetanilide were mixed evenly in 800 g of isopropanol. 100 g of isopropyl nitrite was added dropwise over 60 minutes at 35°C. After the addition was complete, the mixture was kept at this temperature for 30 minutes. Then, 28.55 g of sodium methoxide was added, and the mixture was kept at 50°C for 60 minutes. The reaction was then complete.

[0096] The reaction system was pressurized and heated to 120℃, and held at this temperature for 3 hours to obtain a yellow paste containing 29.04% pigment. After washing and drying the paste, 382.8 g of Pigment Yellow 155 was obtained, and its XRD pattern is shown below. Figure 1 As shown, its TEM image is as follows Figure 2 As shown. The yield was calculated based on the starting material methyl 2-amino-terephthalate, and was 97.05%.

[0097] Example 2 79.1 g of sodium nitrite was dissolved in 160 g of water, then mixed with 87.7 g of isopropanol. At -5 to 0 °C, 124.9 g of 36.5% hydrochloric acid solution was added dropwise. After the addition was complete, the mixture was allowed to stand. The upper layer was a light yellow liquid, which was the product, isopropyl nitrite, and the lower layer was an aqueous phase. 100 g of isopropyl nitrite was obtained.

[0098] 232.5 g of methyl 2-amino-terephthalate and 157 g of 1,4-diacetylacetanilide were mixed evenly in 800 g of isopropanol. 100 g of isopropyl nitrite was added dropwise over 60 minutes at 25°C. After the addition was complete, the mixture was kept at this temperature for 30 minutes. Then, 28.55 g of sodium methoxide was added, and the mixture was kept at 70°C for 60 minutes. The reaction was then complete.

[0099] The reaction system was pressurized and heated to 120℃, and held at this temperature for 3 hours to obtain a yellow paste containing 29.07% pigment. After washing and drying the paste, 383.2 g of Pigment Yellow 155 was obtained, and its XRD pattern is shown below. Figure 3 As shown, the yield was calculated based on the starting material methyl 2-amino-terephthalate, and the yield was 97.16%.

[0100] Comparative Example 1 Synthesis of Traditional Pigment Yellow 155: 16.2 g (0.1376 mol) of 31% hydrochloric acid was added to 20 mL of water, followed by 10 g (0.0473 mol) of dimethyl 2-aminoterephthalate, and the mixture was stirred for 1 hour. The mixture was cooled to 0-5°C with ice, and 15 g (0.0646 mol) of 30% sodium nitrite solution was quickly added. The mixture was maintained for 0.5 hours, and then turquoise oil (an auxiliary agent) was added, followed by stirring for another 0.5 hours. The solution was filtered, and the mother liquor was collected to obtain a diazo solution.

[0101] On the other hand, 6.59 g (0.0236 mol) of diacetyl-p-phenylenediamine and 1.95 g (0.0483 mol) of sodium hydroxide were added to 80 mL of water, stirred until completely dissolved, and filtered to obtain a diacetyl-p-phenylenediamine solution. 6 g of acetic acid was added to 15 g of water and stirred until homogeneous. 2 g of wetting and dispersing agent Tego® Disper 755w and 4 g of silica were added to the diacetyl-p-phenylenediamine solution, stirred for 10 minutes, and then the prepared acetic acid solution was added. The mixture was stirred for 1 hour to obtain a suspension slurry of diacetyl-p-phenylenediamine.

[0102] Add an appropriate amount of sodium acetate to the diazonium solution to adjust the pH to 3-4. Then, at 35℃-40℃, add the prepared diacetyl-p-phenylenediamine slurry dropwise to the diazonium salt solution. After the addition is complete, use acetic acid to check whether the diazonium salt is in excess. If it is in excess, add the coupling component slurry until the diazonium salt reaction is complete, resulting in a yellow pigment suspension.

[0103] The pigment suspension was heat-treated at reflux temperature for 25-30 hours. After heat treatment, the pigment content in the system was 12%. The mixture was filtered, washed with water until neutral, and the filter cake was dried and pulverized to obtain 22.6 grams of yellow pigment. Its XRD pattern is shown below. Figure 4 As shown, its TEM image is as follows Figure 5 As shown.

[0104] Example 3 3.16 g of sodium nitrite was dissolved in 64 g of water, then mixed with 35.08 g of isopropanol. At -5 to 0 °C, 49.96 g of 36.5% hydrochloric acid solution was added dropwise. After the addition was complete, the mixture was allowed to stand. The upper layer was a light yellow liquid, which was the product, isopropyl nitrite, and the lower layer was an aqueous phase. 40 g of isopropyl nitrite was obtained.

[0105] 54.65 g of 2,2'-dichloroazobenzene and 84.26 g of p-methylacetylacetanilide were mixed thoroughly in 500 g of isopropanol and 32 g of acetic acid. 40 g of isopropyl nitrite was added dropwise over 60 minutes at 35°C. After the addition was complete, the mixture was kept at this temperature for 30 minutes. Then, 59.5 g of sodium methoxide was added, and the mixture was kept at 70°C for 60 minutes. The reaction was then complete.

[0106] The reaction system was pressurized and heated to 100℃, and held at this temperature for 2 hours to obtain a yellow paste containing 26.68% pigment. After washing and drying the paste, 139.4 g of Pigment Yellow 55 was obtained, and its XRD pattern is shown below. Figure 6 As shown, the yield was calculated based on the starting material 2,2'-dichloroazobenzene, and the yield was 98.17%.

[0107] The comparison shows that the pigment content in the system after the reaction in Comparative Example 1 was 12%; while the pigment content in the systems after the reaction in Examples 1, 2, and 3 was >25%. It is estimated that the amount of solvent used to produce the same amount of pigment can be reduced by about 60%, and the energy used for solvent recovery and solvent loss during the recovery process can be reduced by about 60%, which can significantly reduce production costs and reduce the cost of waste disposal.

[0108] Comparative Example 2 The traditional method for synthesizing Pigment Yellow 55 is as follows: 50.6 g of 2,2'-dichloroazobenzene was added to 190 g (30%) hydrochloric acid at 0-5°C for 4 h, stirred overnight at room temperature, and then reacted at 50°C for 5 h until complete rearrangement to 3,3'-dichlorobenzidine. The reaction mixture was cooled to 0-5°C with 3000 g of ice and then diazotized with 26.2 g of sodium nitrite. Separately, 70.1 g of p-methylacetylacetanilide was dissolved in 700 g of water and 25 g of sodium hydroxide solution, precipitated with 40 g of acetic acid, and the pH was adjusted to 5-6. The mixture was cooled to 0-5°C and added to the diazotized solution, maintaining the coupling pH at 4-5. After coupling, the mixture was heated to boiling for 1.5 h, at which point the pigment content was approximately 3%. The mixture was filtered, washed with water, and dried at 70°C to obtain 115.6 g of Pigment Yellow 55. Its XRD pattern is shown below. Figure 7 As shown, the yield was calculated based on the feedstock 2,2'-dichloroazobenzene, and the yield was 86%.

[0109] Experimental Example 1 Figure 1 , 3 Figures 4 and 5 are XRD patterns of the samples from Example 1, Example 2 and Comparative Example 1 after testing with an X-ray diffractometer, showing that the three samples have the same crystal form. Figure 6 and Figure 7The images show the XRD patterns of the samples from Example 3 and Comparative Example 2 after testing with an X-ray diffractometer, indicating that the two samples have the same crystal form.

[0110] Experimental Example 2 Figure 2 and Figure 5 The transmission electron microscopy (TEM) tests of the samples from Example 1 and Comparative Example 1 show that the dispersion effect of the sample from Example 1 is better.

[0111] Experiment Example 3 In waterborne acrylic coatings, Examples 1, 2 and Comparative Example 1 were evaluated from four dimensions: hue, viscosity, tinting strength and gloss.

[0112] Test method for water-based acrylic coatings: Weigh 10g of each of the pigment products in Examples 1 and 2 and Comparative Example 1, and mix them with 9.60g of acrylic resin, 0.20g of dispersant and 50g of distilled water respectively. Add 30g of glass beads with a diameter of 2mm, and shake and disperse on a shaker for 0.5 hours to prepare pigment paste.

[0113] Preparation of colored lacquer flakes: Take an appropriate amount of the above pigment pastes onto coated paper and scrape them into lacquer flakes using a 4μm wire rod.

[0114] Preparation of diluted paint flakes: Stir 15g of latex paint and 3g of pigment dispersion evenly, take an appropriate amount onto coated paper, and scrape it into paint flakes with a 4μm wire rod.

[0115] Method for comparing color and intensity: After the above paint sheets are dried, measure the color with a colorimeter (datacolor400, USA) and compare the differences.

[0116] Viscosity comparison method: The viscosity of the samples was measured using a rotational viscometer (BROOKFIELD Viscometer, USA) and compared.

[0117] Method for comparing gloss: The gloss of the uncolored lacquer flakes was measured and compared using a triangular digital gloss meter (Weida Measurement Instrument Factory, Quanzhou, Fujian, China).

[0118] The results for Pigment Yellow 155 are shown in Table 1 below: Table 1:

[0119] Remark: DL represents color brightness, with positive for bright and negative for dark. DC represents color saturation; positive indicates vibrancy, while negative indicates dullness. DH represents the hue of a color; a positive value indicates a greenish tint, while a negative value indicates a reddish tint. Values ​​between -0.8 and 0.8 are considered relatively close.

[0120] As can be seen from the data in Table 1, the pigment quality of Example 1 and Example 2 is quite similar; compared with Comparative Example 1, the color saturation of Example 1 is higher and the viscosity of the pigment paste is lower. Moreover, compared with the comparative example, the greater advantage of the present invention is that the process of the embodiment is more green and economical, and the production efficiency is higher.

[0121] Following the above method, the pigment yellow 55 of Example 3 and Comparative Example 2 were evaluated in water-based acrylic coatings from four dimensions: hue, viscosity, tinting strength, and gloss. The results are shown in Table 2 below. Table 2:

[0122] As can be seen from the data in Table 2, the pigment quality of Example 3 is similar to that of Comparative Example 2, with a reddish hue, higher saturation, and lower viscosity of the pigment paste. Furthermore, a greater advantage of this invention is that the process described in the embodiments is more green and economical, with higher production efficiency and energy conservation and emission reduction, as shown in Table 3 below: Table 3:

[0123] Table 3 shows that, compared with the traditional process, the high-concentration strong mixing synthesis scheme of the present invention significantly reduces the amount of solvent, and the corresponding energy consumption and emissions are reduced.

[0124] Example 4 Add 9.4 g (approximately 0.05 mol) of 2-hydroxy-3-naphthoic acid and 8.1 g (approximately 0.05 mol) of 2,5-dichloroaniline to 19.5 g of xylene. Add 4.9 g (approximately 0.055 mol) of isopropyl nitrite dropwise over 1 hour at room temperature. After the addition is complete, keep warm for 2 hours.

[0125] The temperature was then raised to 80°C, and 6.55 g (approximately 0.055 mol) of thionyl chloride was added dropwise over 30 minutes. After the addition was complete, the temperature was maintained at 110°C for 3 hours. After the maintenance was complete, the residual thionyl chloride was distilled off. After distillation, the temperature was raised to 80°C, and 2.67 g (approximately 0.025 mol) of solid 1,4-p-phenylenediamine was added. The temperature was raised to 135°C and maintained for 6 hours. After the maintenance was complete, the mixture was evaporated to dryness, yielding a total of 19.65 g of Pigment Red 166, with a yield of 99%. Its infrared spectrum is shown below. Figure 8 As shown, for reference, the infrared spectrum of Pigment Red 166 standard is as follows. Figure 9 As shown.

[0126] The performance of Pigment Red 166 product prepared in Example 4 was tested, and the results are shown in Table 4 below: Table 4:

[0127] Example 5 Add 9.4 g (approximately 0.05 mol) of 2-hydroxy-3-naphthoic acid and 9.78 g (approximately 0.05 mol) of 2-chloro-5-trifluoromethylaniline to 19.5 g of xylene. Add 4.9 g (approximately 0.055 mol) of isopropyl nitrite dropwise over 1 hour at room temperature. After the addition is complete, keep warm for 2 hours.

[0128] The temperature was then raised to 80°C, and 6.55 g (approximately 0.055 mol) of thionyl chloride was added dropwise over 30 minutes. After the addition was complete, the temperature was maintained at 110°C for 3 hours. After the maintenance was complete, the residual thionyl chloride was distilled off. After distillation, the temperature was raised to 80°C, and 4.43 g (approximately 0.025 mol) of solid 2,5-dichloro-1,4-p-phenylenediamine was added. The temperature was raised to 135°C and maintained for 6 hours. After the maintenance was complete, the mixture was evaporated to dryness, yielding a total of 23.03 g of Pigment Red 242, with a yield of 99%.

[0129] Example 6 31 g (approximately 1.35 mol) of metallic sodium was melted and 150 g (approximately 1.70 mol) of tert-amyl alcohol preheated to 90 °C was introduced into a microchannel reactor preheated to 120 °C. The residence time was controlled at 0-0.2 MPa for 2 h. A tert-amyl alcohol solution of sodium tert-amyl alcohol was introduced into a reactor; 90 g of p-chlorobenzonitrile and 78 g of diisopropyl succinate were added, and the reaction was carried out at 120 °C. During the reaction, solvents with boiling points below 90 °C were continuously collected. After the reaction was completed, the remaining solvent was evaporated to obtain sodium salt powder of the product, and the solvent components with boiling points below and above 90 °C were recovered separately.

[0130] The sodium salt of the product was hydrolyzed by reacting with 800 g of water in a reactor at 45 °C for 1 hour. After separation, the product was dried to obtain bis(p-chlorophenyl)-1,4-dione pyrrolopyrrole. Its infrared spectrum was basically consistent with that of the purchased BASF standard bis(p-chlorophenyl)-1,4-dione pyrrolopyrrole, with a mass of 107.8 g and a yield of 90.3% (based on the complete reaction of p-chlorobenzonitrile). The transmission electron microscopy image of the obtained product is shown below. Figure 10 As shown, the transmission electron microscope (TEM) image of the purchased BASF bis(p-chlorophenyl)-1,4-dione pyrrolopyrrole standard is as follows. Figure 11 As shown. From Figure 10 and 11 It can be seen that the overall difference between the prepared sample particles and the standard is small.

[0131] The 41g of solvent with a boiling point below 90°C that was recovered was directly subjected to concentrated sulfuric acid catalytic esterification at a temperature of 70-80°C to synthesize 68g of diisopropyl succinate, which was then used as a raw material (see Example 9 below).

[0132] Comparative Example 3 (referring to the method disclosed in CN108250789A) Under nitrogen protection, 11.3 parts of metallic sodium were added to 120 parts of anhydrous tert-amyl alcohol, followed by 0.02 parts of anhydrous ferric chloride. The mixture was refluxed for 3 hours until all sodium was dissolved, and then cooled to 110°C. 40 parts of 4-chlorobenzonitrile were dissolved in 50 parts of tert-amyl alcohol and added to the sodium alkoxide solution. 30.8 parts of diisopropyl succinate were dissolved in 30 parts of tert-amyl alcohol and added dropwise to the reaction flask over 1.5 hours, maintaining the temperature at 105-110°C. After the addition was complete, the mixture was refluxed for 0.5 hours, and then reacted for another 1.5 hours with a reflux ratio of 6-7, maintaining the column top temperature below 90°C. Isopropanol was removed continuously, and the mixture was cooled to 65°C. 200 parts of methanol were added to the reaction flask, followed by the slow addition of 34 parts of glacial acetic acid. The mixture was refluxed for 0 hours. After 0.5 hours of complete protonation, the mixture was filtered, washed with methanol until the filtrate was colorless, rinsed with distilled water, dried at 80°C for 10 hours, and pulverized to obtain 44.5 parts of pigment product, with a yield of 86%.

[0133] Comparison shows that, in Comparative Example 3, the ratio of tert-amyl alcohol to pigment product used in the reaction is approximately 4.5:1 (mass ratio); in Example 6, the ratio of tert-amyl alcohol to pigment product used in the reaction is approximately 1.5:1 (mass ratio). The amount of solvent used to produce the same amount of pigment is reduced by approximately 67%, and the energy used for solvent recovery and solvent loss during the recovery process can be reduced by approximately 67%, which can significantly reduce production costs and reduce the cost of waste disposal.

[0134] Example 7 90 g (approximately 3.91 mol) of metallic sodium was melted and 440 g (approximately 5.00 mol) of tert-amyl alcohol preheated to 90 °C was introduced into a batch reactor. The reaction was carried out at 120 °C for 9 hours to obtain a sodium tert-amyl alcohol solution. 280 g of p-chlorobenzonitrile and 250 g of diisopropyl succinate were added and reacted at 125 °C. After the reaction was completed, the sodium salt of the product was obtained. After the reaction was completed, the product was evaporated to dryness to obtain sodium salt powder. Solvent components with boiling points below and above 100 °C were recovered separately.

[0135] The sodium salt of the product was hydrolyzed by reacting with 2800g of water at 40℃ for 2 hours. After separation and drying, 308g of the product was obtained, with a yield of 86.0%.

[0136] The 134g of solvent with a boiling point below 100°C that was recovered was directly subjected to concentrated sulfuric acid-catalyzed esterification to synthesize 216g of diisopropyl succinate, which was then used as a raw material (see Example 10 below).

[0137] Example 8 60 g (approximately 2.61 mol) of metallic sodium was melted and 300 g (approximately 3.40 mol) of tert-amyl alcohol preheated to 90°C was introduced into a reaction vessel reactor. The reaction was carried out at 120°C for 10 hours to obtain a sodium tert-amyl alcohol solution. 280 g of p-chlorobenzonitrile and 250 g of diisopropyl succinate were added and reacted at 125°C. After the reaction was completed, the product sodium salt powder was obtained by evaporation.

[0138] The sodium salt of the product was hydrolyzed by reacting with 3500g of water at 40℃ for 2 h. After separation and drying, 300g of the product was obtained, with a yield of 83.7%. The transmission electron microscopy (TEM) image of the obtained product is shown below. Figure 12 As shown, and with Figure 10 and 11 The comparison shows that the overall difference between the prepared sample particles and the standard is small. There may be slight differences in particle size, crystallinity, etc. between batches. These differences will cause fluctuations in parameters such as strength in the test data. The application performance of each product in the PVC system can be found in Experiment Example 4 and Table 5 below.

[0139] Example 9 Diisopropyl succinate obtained by solvent recovery esterification in Example 6 was used as a raw material, as detailed below: 27 g (approximately 1.17 mol) of metallic sodium was melted and mixed with 130 g (approximately 1.47 mol) of tert-amyl alcohol preheated to 90 °C. The mixture was then introduced into a microchannel reactor preheated to 120 °C, with a residence time controlled at 1 h. A tert-amyl alcohol solution of sodium tert-amyl alcohol was obtained and introduced into the reactor. 78 g of p-chlorobenzonitrile and 68 g of diisopropyl succinate were added, and the reaction was carried out at 120 °C. Solvents with boiling points below 90 °C were continuously sampled during the reaction. After the reaction was completed, the remaining solvent was evaporated to obtain the sodium salt powder of the product.

[0140] The sodium salt of the product was hydrolyzed by reacting it with 700 g of water in a reactor at 45°C for 1 hour. After separation, the product was dried to obtain bis(p-chlorophenyl)-1,4-dione pyrrolopyrrole, with a mass of 93.4 g and a yield of 89.7%.

[0141] Example 10 Diisopropyl succinate obtained by solvent recovery esterification in Example 7 was used as a raw material, as detailed below: 78 g (approximately 3.39 mol) of metallic sodium was melted and 380 g (approximately 4.31 mol) of tert-amyl alcohol preheated to 90 °C was introduced into a reaction vessel. The reaction was carried out at 120 °C for 10 hours to obtain a sodium tert-amyl alcohol solution. 242 g of p-chlorobenzonitrile and 216 g of diisopropyl succinate were added and reacted at 125 °C. After the reaction was completed, the sodium salt of the product was obtained. After the reaction was completed, the product sodium salt powder was obtained by evaporation.

[0142] The sodium salt of the product was hydrolyzed by reacting with 2400g of water at 40℃ for 2 hours. After separation and drying, 264g of the product was obtained, with a yield of 85.4%.

[0143] Experiment Example 4 The performance of the bis(p-chlorophenyl)-1,4-dione pyrrolopyrroles prepared in Examples 6-10 was tested using the following methods: (1) The pigment-made color chips were tested using a two-roll mill (Shanghai Weisheng Scientific Instruments LRM-S-150 / T3E), a flat vulcanizing machine (Dongguan Xihua Testing Instruments 406), and a computer colorimeter (Hunterlab ColorQuest XE).

[0144] (2) Mix PVC resin, diisodecyl phthalate and barium zinc stabilizer evenly to obtain PVC resin mixture; (3) Production of natural color film: Mix PVC resin mixture and pigment in a fixed ratio evenly, and then use a two-roller machine to make film at low temperature and high temperature respectively; (4) Diluted color sheet production: Mix PVC resin mixture, titanium dioxide and pigment in a fixed ratio evenly, and then use a two-roller machine to make film at low temperature and high temperature respectively. (5) The above-prepared membrane is molded into a plastic sheet to be tested using a specific mold and a flat vulcanizing machine; (6) Using the standard sample as a reference, evaluate the color intensity and color of the sample using a computer colorimeter.

[0145] The test results are shown in Table 5 below: Table 5:

[0146] Remark: Strength: The difference in coloring strength between a pigment sample and a standard sample of equal amount; DL: Difference in brightness, the difference in brightness between the same amount of pigment sample and the standard (positive for good, negative for poor); DC: Poor saturation, the difference in saturation between the same amount of pigment sample and the standard (positive means good, negative means poor). DH: Hue difference, the difference in hue between a pigment sample and a standard of equal quantity (positive for good, negative for poor); DA: Red-Green Difference, the difference in red and green between an equal amount of pigment sample and a standard (positive indicates redder, negative indicates greener). DB: Yellow-blue difference, the difference in yellow and blue between the same amount of pigment sample and the standard (positive indicates yellowish, negative indicates bluish). DE: Total color difference, the overall hue difference between a pigment sample and a standard of equal quantity (smaller is better, larger is worse); In the industry, it is generally believed that sub-items < ±0.8 and total color difference < 1 indicate that the quality is relatively close. Furthermore, the quality of the finished product can be made consistent with the standard product by mixing samples with large positive and negative deviations.

[0147] Analysis showed that the bis(p-chlorophenyl)-1,4-dione pyrrolopyrroles prepared in Examples 6-10 had excellent properties and met the product indicators and specifications.

[0148] The present invention has been described in detail above with reference to preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments are merely illustrative explanations of the invention and do not constitute any limitation on the scope of protection of the invention. Various improvements, equivalent substitutions, or modifications can be made to the technical content and embodiments of the present invention without departing from the spirit and scope of protection of the invention, and all such modifications fall within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for synthesizing organic pigments, comprising the following steps:

1. Prepare raw materials or mixtures of raw materials; Second, prepare a high-viscosity system, perform forced mixing, and carry out the reaction under controlled conditions; 3. After the reaction is complete, post-processing shall be performed.

2. The method according to claim 1, characterized in that, The high-performance organic pigments include azo series pigments, azo condensation series pigments, and pyrrolopyrrole dione series pigments.

3. The method according to claim 1 or 2, characterized in that, When synthesizing azo series pigments, In step one, the raw materials mainly include isopropyl nitrite (IPN), chromophore and coupling components. The preparation of IPN includes: sodium nitrite, reaction of alcohol solvent and acid, wherein the molar ratio of sodium nitrite, isopropanol and hydrochloric acid is 1:1-2:0.7-1.

5. In step two, the chromophore and the coupling component undergo a diazo coupling reaction simultaneously under IPN conditions to obtain a crude azo pigment slurry; the chromophore and the coupling component are then pulped in a solvent, which is isopropanol, acetic acid, or a mixed solution of isopropanol and acetic acid. After pulping, IPN is added dropwise at -5 to 50°C; after the addition is completed, the temperature is maintained, and then sodium methoxide is added. The temperature is raised to 30 to 80°C and the reaction is maintained to obtain the azo pigment reaction system.

4. The method according to claim 3, characterized in that, In step three, the post-processing includes pigmentation, in which the synthesized azo pigment reaction system is kept at 90-150℃ for 2-12 hours to remove solvent and salt, and then dried to obtain the azo pigment.

5. The method according to claim 1 or 2, characterized in that, When synthesizing azo condensation series pigments, In step one, the raw materials include 2-hydroxy-3-naphthoic acid, aromatic amine, diazo reagent, sulfoxide, and aromatic diamine. In step two, 2-hydroxy-3-naphthoic acid is added to a small amount of high-boiling-point benzene solvent, aromatic amine is added, and forced mixing is performed. Then, under controlled conditions, a diazo reagent is added to carry out the intermediate dye reaction. The molar ratio of 2-hydroxy-3-naphthoic acid to aromatic amine is 1:1-1.

1.

6. The method according to claim 5, characterized in that, A monoazo dye undergoes acylation. Sulfoxide is added to the intermediate dye system to initiate the acylation reaction, generating a carboxylic acid acylate. The molar ratio of the intermediate to sulfoxide is 1:1-1.

2. The carboxylic acid acyl chloride is then amidated by heating the acyl chloride to 60-110°C. An aromatic diamine is then added to the system, and the reaction is continued at a higher temperature to obtain a reaction solution containing an azo condensation pigment. After the reaction is complete, the reaction solution containing the azo condensation pigment is heated to evaporate the solvent and obtain the azo condensation pigment.

7. The method according to claim 1 or 2, characterized in that, When synthesizing pyrrolopyrroledione series pigments, In step one, the raw materials include sodium alkoxide, benzonitrile compounds, and succinate diester compounds, wherein the benzonitrile compounds include 4-chlorobenzonitrile, benzonitrile, 4-methylbenzonitrile, and 4-phenylbenzonitrile. Sodium alkoxide is prepared by reacting sodium metal with an alcohol under reflux / pressure, wherein the alcohol is anhydrous tert-amyl alcohol, and the mass ratio of sodium metal to tert-amyl alcohol is 1:3.9-5.

5.

8. The method according to claim 7, characterized in that, In step two, A benzonitrile compound is premixed with a succinate diester compound selected from diisopropyl succinate, di-tert-amyl succinate, and / or dicyclohexyl succinate. The mixture is heated to 80-120°C and then added dropwise to sodium alkoxide. The reaction is then carried out at 80-150°C. After the reaction is completed, the remaining solvent is evaporated to obtain a powdered sodium salt.

9. The method according to claim 8, characterized in that, In step two, some solvent substances are extracted and recovered during the condensation reaction, with solvents with boiling points below 90-100℃ continuously being extracted. The molar ratio of sodium metal to benzonitrile compounds is 1.01~2.50:1; the molar ratio of benzonitrile compounds to succinate diester compounds is 1.50~2.02:

1.

10. The method according to claim 7, characterized in that, In step three, Sodium salt powder is protonated in water or a certain concentration of alcohol water to obtain pyrrolopyrrole dione series pigments. The hydrolysis is carried out at an elevated temperature. The powder is added to water at 45-50°C for the hydrolysis reaction, followed by filtration, washing, and drying.

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