Production process of pigment yellow 139
By using barbituric acid itself, the problems of low safety and raw material utilization in pigment yellow 139 production were solved, and the generation and cost of ammonium-free waste were achieved, improving the uniformity of pigment particles, and simplifying the pigmentation process.
Patent Information
- Application Number
- CN202510648565.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-08-15
AI Technical Summary
In the existing pigment yellow 139 production method, the introduction of organic or inorganic acids leads to poor reaction safety, low raw material utilization rate and ammonium salt waste.
The reaction is carried out by barbituric acid itself. By controlling the pH value to add 1,3-diiminoisoindoline to a supersaturated solution with a pH of ≤1.8, the additional introduction of acid solution is avoided. The ionization and weak acidity of barbituric acid are used to quickly neutralize the generated ammonia and barbituric acid to form a salt, reducing by-products, and the mother liquor is recovered by heating and decompression distillation.
It improves raw material utilization, avoids the generation of ammonium salt waste, reduces production costs, improves the uniformity and chromoluminescence properties of pigments, simplifies the pigmentation process, and improves economic benefits.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of pigment yellow 139 synthesis, and in particular relates to a production process of pigment yellow 139. Background Art
[0002] Pigment Yellow 139 is an organic pigment with the chemical name 2,6-dichloro-4-(4-sulfonatophenylazo)-5-(4-sulfonato-1-naphthylazo)-1,3,5-triazine-4'-sulfonic acid sodium salt (ternary form). It is a vibrant yellow pigment with good tinting strength. Its hue belongs to the bright yellow family and can produce a bright, pure yellow effect in various application systems.
[0003] This type of pigment contains imino and carbonyl groups in its molecules, which can form molecular hydrogen bonds, have obvious planarity, and have excellent heat resistance, light resistance, and solvent resistance.
[0004] Chinese Patent CN102585542 discloses a method for preparing CI Pigment Yellow 139. The method comprises: (1) preparing 1,3-diiminoisoindoline from phthalonitrile; (2) preparing crude CI Pigment Yellow 139 by reacting 1,3-diiminoisoindoline with barbituric acid; and (3) pigmenting the crude CI Pigment Yellow 139. The method is characterized in that aqueous ammonia or ammonia gas is added to the reaction described in step (1). This patent requires the introduction of an organic carboxylic acid and / or an inorganic acid for the reaction.
[0005] Chinese patent CN103013159 discloses a method for preparing an isoindoline pigment without water, comprising the steps of dissolving or suspending barbituric acid in an organic solvent A, adding an organic solvent B containing 1,3-diiminoisoindoline, reacting the solvent, fractionating the generated ammonia gas during the reaction, and collecting the isoindoline pigment from the reaction product. The patent also incorporates organic solvents such as amides, alcohols, dimethyl sulfoxide, or N-methylpyrrolidone into the reaction.
[0006] At present, the synthesis methods at home and abroad all use different inorganic or organic acids, or use organic solvents to promote the reaction, which has obvious disadvantages in reaction safety, raw material utilization and the generation of by-product ammonium salt waste. Summary of the Invention
[0007] The technical problem to be solved by the present invention is to provide a method for producing Pigment Yellow 139, which does not introduce organic or inorganic acids but utilizes the acidity of barbituric acid itself to carry out the reaction, thereby improving the utilization rate of raw materials and avoiding the generation of ammonium salt waste.
[0008] To achieve the above objectives, the present invention adopts the following technical solutions:
[0009] A production process for Pigment Yellow 139, comprising the following steps:
[0010] 1) adding barbituric acid to water and fully dissolving it at a temperature of 30-70° C., adjusting the pH to ≤1.8 to form a supersaturated solution, maintaining the temperature constant, and then adding 1,3-diiminoisoindoline solid or a mixture thereof with water in multiple additions, wherein the molar ratio of barbituric acid to 1,3-diiminoisoindoline is 2.5-4.5:1, maintaining the pH of the system <7 during the addition process, and then keeping the temperature at 40-70° C. for 0.5-4 hours;
[0011] 2) Crude product separation: After the heat preservation reaction is completed, the mixed solution in step 1) is kept at a temperature above 50°C and hot filtered to separate the crude pigment;
[0012] 3) Pigmentation: Add the crude pigment to water and heat at 105-130°C for pigmentation, which is completed within 4-10 hours to obtain Pigment Yellow 139 product;
[0013] 4) The filtrate obtained by hot filtration separation in step 2) is subjected to a temperature-elevated reduced-pressure distillation process to obtain a barbituric acid aqueous solution and aqueous ammonia.
[0014] Step 1) 1,3-diiminoisoindoline solid or a mixture thereof with water is added within 20 to 60 minutes.
[0015] Step 4) The filtrate is distilled at 60-65° C. and 0.05-1 MPa until the pH of the filtrate is less than 2.
[0016] Compared with the existing technology, the beneficial effects of the present invention are:
[0017] 1) The present invention utilizes the strong acidity generated by the dissolution of barbituric acid in warm water and its own ionization to ensure the acidity of the system, eliminating the need for the introduction of additional organic or inorganic acids. At temperatures between 30°C and 70°C, the degree of ionization of barbituric acid increases, leading to a higher solubility. Once a supersaturated solution is formed, the pH is ≤ 1.8, and the inherent acidity is sufficient to sustain the reaction, eliminating the need for the introduction of additional acid. As the reaction proceeds, the dissolved barbituric acid preferentially reacts with 1,3-diiminoisoindoline, resulting in a water-insoluble product that precipitates in the system. The ammonia released by the reaction rapidly reacts with the barbituric acid to form a salt through acid-base neutralization. During this process, the aqueous solution regains its solubility for barbituric acid, allowing the barbituric acid in the unsaturated solution to continue dissolving and reacting. The excess barbituric acid in the system replenishes the amount consumed during the reaction, maintaining a relatively stable reaction process until the added 1,3-diiminoisoindoline is completely consumed.
[0018] 2) The supersaturated barbituric acid solution of the present invention ensures that the mother liquor after the reaction is completed remains an aqueous solution of barbituric acid. Barbituric acid, due to its inherent acidity and the acidity generated when it is water-soluble, easily irreversibly forms a dimer. This dimer is adsorbed by the ammonia generated during the reaction, which also weakens its own acidity and suppresses side reactions. It also acts as a base, catalyzing the reaction, reducing the number of raw materials and by-products.
[0019] 3) The present invention utilizes the weak acidity of barbituric acid itself, combined with ammonia, to form a thermally unstable carboxylic acid weak base salt, exhibiting similar double hydrolysis properties. Barbituric acid maintains the reaction while remaining stable and capable of re-dissociation. The mother liquor after hot filtration is subjected to elevated temperature and reduced pressure distillation. The ammonia generated by hydrolysis is more likely to overflow the system at high temperature and low pressure. This overflow of ammonia further promotes the double hydrolysis reaction, leading to complete decomposition. This avoids the generation of ammonium salt waste and enhances environmental benefits.
[0020] 4) The solvent of the present invention is water only, devoid of alcohol or acid. The reaction temperature is kept at 60°C, and as the heat is maintained, the crude pigment particles can be slowly modified and homogenized under these conditions. The crude pigment, with its uneven particle size distribution and chaotically agglomerated surface, is slightly dissolved in water. Repeated dissolution and precipitation dissolves and modifies the surface of larger particles, causing them to become smaller. Smaller particles continue to grow, and the particles collide with each other until uniform, regular pigment particles are formed, exhibiting excellent color properties and hiding power. This replaces the partial pigmentation process, shortening the crude pigmentation process.
[0021] 5) The generated barbituric acid aqueous solution and ammonia water can be recycled as raw materials, thus saving raw materials, reducing production costs and raw material costs, and significantly improving economic benefits. DETAILED DESCRIPTION
[0022] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein in the specification of the application are for the purpose of describing specific embodiments only and are not intended to limit this application. Mentioning "embodiments" herein means that the specific features, structures or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.
[0023] A production process for Pigment Yellow 139, comprising the following steps:
[0024] 1) adding barbituric acid to water and fully dissolving it at a temperature of 30-70° C., adjusting the pH to ≤1.8 to form a supersaturated solution, maintaining the temperature constant, and then slowly adding 1,3-diiminoisoindoline solid or a mixture thereof with water in multiple portions, wherein the molar ratio of barbituric acid to 1,3-diiminoisoindoline is 2.5-4.5:1, maintaining the system pH <7 during the addition process, and then keeping the temperature at 40-70° C. for 0.5-4 hours;
[0025] The reaction equation is:
[0026]
[0027] 2) Crude product separation: After the heat preservation reaction is completed, the mixed solution in step 1) is kept at a temperature above 50°C and hot filtered to separate the crude pigment;
[0028] 3) Pigmentation: Add the crude pigment to water and heat at 105-130°C for pigmentation, which is completed within 4-10 hours to obtain Pigment Yellow 139 product;
[0029] 4) The filtrate obtained by hot filtration separation in step 2) is subjected to a temperature-elevated reduced-pressure distillation process to obtain a barbituric acid aqueous solution and aqueous ammonia.
[0030] Step 1) 1,3-diiminoisoindoline solid or a mixture thereof with water is added within 20 to 60 minutes.
[0031] Step 4) The filtrate is distilled at 60-65° C. and 0.05-1 MPa until the pH of the filtrate is less than 2.
[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.
[0033] Example 1:
[0034] A method for producing Pigment Yellow 139, comprising the following steps:
[0035] Mix 25.6 g of barbituric acid with 295 g of water, raise the temperature to 50° C., pH = 1.7, and prepare a supersaturated solution.
[0036] 8.5 g of 1,3-diiminoisoindoline solid was slowly added to the barbituric acid solution in several portions over 30 minutes to ensure that the pH of the system was less than 7. The molar ratio of 1,3-diiminoisoindoline to barbituric acid was 1:3.45.
[0037] The reaction system was then incubated at 60°C. After incubation, solid-liquid separation was performed at 60°C to obtain 230 g of mother liquor. The mother liquor was distilled at 0.5 MPa until its pH was less than 2. 150 g of water was added to the resulting filter cake and the mixture was incubated at 125°C for pigmentation to obtain Pigment Yellow 139.
[0038] After the addition of 1,3-diimidoisoindoline solid, the heat preservation reaction was started. The heat preservation time was recorded starting from 30 minutes. Sampling was carried out every 30 to 60 minutes. The barbituric acid conversion rate and pigment product particle size were tested. The results are shown in Table 1:
[0039] Table 1:
[0040]
[0041] Example 2:
[0042] A method for producing Pigment Yellow 139, comprising the following steps:
[0043] Mix 25.6 g of barbituric acid with 295 g of water, raise the temperature to 50° C., pH = 1.7, and prepare a supersaturated solution.
[0044] The solution of 8.5g of 1,3-diiminoisoindoline mixed with 30g of water was slowly added dropwise to the barbituric acid solution within 30 minutes to ensure that the pH of the system was less than 7. The molar ratio of 1,3-diiminoisoindoline to barbituric acid was 1:3.45.
[0045] After the addition was complete, the reaction system was incubated at 60°C. After incubation, solid-liquid separation was performed at 60°C to yield 252 g of mother liquor. The mother liquor was distilled at a gauge pressure of -0.05 MPa until its pH was <2. The filter cake was then added with 150 g of water and incubated at 125°C for pigmentation to yield Pigment Yellow 139.
[0046] After the addition of the 1,3-diimidoisoindoline aqueous solution was completed, the heat preservation reaction was started. The heat preservation time was recorded starting from 30 minutes. Sampling was carried out every 30 to 60 minutes. The barbituric acid conversion rate and pigment product particle size were tested. The results are shown in Table 2:
[0047] Table 2:
[0048]
[0049] Example 3:
[0050] Mix 25.6 g of barbituric acid with 150 g of water, raise the temperature to 65° C., pH = 1.6, and prepare a supersaturated barbituric acid solution.
[0051] A slurry obtained by mixing 8.5 g of 1,3-diiminoisoindoline solid with 50 g of water was slowly added dropwise to the barbituric acid solution. The addition was completed within 40 minutes to ensure that the pH of the system was less than 7.
[0052] After the addition was complete, the reaction system was incubated at 70°C. After incubation, solid-liquid separation was performed at 55°C to yield 215 g of mother liquor. The mother liquor was distilled at a gauge pressure of -0.08 MPa until its pH was <2. The filter cake was then added with 150 g of water and incubated at 125°C for pigmentation to yield Pigment Yellow 139.
[0053] After the addition of the 1,3-diimidoisoindoline aqueous solution was completed, the heat preservation reaction was started. The heat preservation time was recorded starting from 30 minutes. Sampling was carried out every 30 to 60 minutes. The barbituric acid conversion rate and pigment product particle size were tested. The test results are shown in Table 3:
[0054] Table 3:
[0055]
[0056] The data in the table above show that the reaction conversion is affected by barbituric acid and its concentration. Concentration and pH directly affect the reaction rate. Reaction with too high a concentration will lead to excessive product formation, and particle agglomeration will affect the pigmentation process.
[0057] Example 4:
[0058] 32.9 g of barbituric acid was mixed with 193 g of water, and the mixture was heated to 65° C. and pH=1.6 to prepare a supersaturated barbituric acid solution.
[0059] The slurry obtained by mixing 8.5g of 1,3-diiminoisoindoline solid with 50g of water was slowly added dropwise to the barbituric acid solution. The addition was completed within 40 minutes to ensure that the pH of the system was less than 7. The molar ratio of 1,3-diiminoisoindoline to barbituric acid was 1:4.5.
[0060] After the addition was complete, the reaction system was incubated at 70°C. After incubation, solid-liquid separation was performed at 55°C to yield 215 g of mother liquor. The mother liquor was distilled at a gauge pressure of -0.08 MPa until its pH was <2. The filter cake was then added with 150 g of water and incubated at 125°C for pigmentation to yield Pigment Yellow 139.
[0061] After the addition of the 1,3-diimidoisoindoline aqueous solution was completed, the heat preservation reaction was started. The heat preservation time was recorded starting from 30 minutes. Sampling was carried out every 30 to 60 minutes to test the conversion rate of barbituric acid and the particle size of the pigment product. The test results are shown in Table 4:
[0062] Table 4:
[0063]
[0064]
[0065] The data in the table above demonstrates that the reaction conversion rate is influenced by barbituric acid and its concentration. Concentration and pH directly impact the reaction rate. Excessively high concentrations can lead to rapid product formation and particle agglomeration, hindering pigmentation. The optimal reaction conditions are a barbituric acid to water mass ratio of 1:11.5 and a 1,3-diimidoisoindoline to barbituric acid molar ratio of 1:3.45, resulting in a faster reaction rate and more uniform particles.
[0066] Example 5:
[0067] Take 230g of the mother liquor after the reaction to test the barbituric acid concentration therein, and add barbituric acid and water until the concentration is equal to the concentration in step 1) of the embodiment. Add 8.5g of 1,3-diiminoisoindoline solid (slowly added multiple times), and then keep the reaction system at 65°C for reaction. After the insulation is completed, solid-liquid separation is carried out at 70°C to obtain 230g of mother liquor. The mother liquor is vacuum distilled at 0.5MPa until the mother liquor pH is less than 2. Add 150g of water to the obtained filter cake and keep it at 125°C for pigmentation to obtain Pigment Yellow 139 product.
[0068] After the addition of 1,3-diimidoisoindoline was completed, the heat preservation reaction was started. The heat preservation time was recorded starting from 30 minutes. Sampling was carried out every 30 to 60 minutes. The test results of the barbituric acid conversion rate and the pigment product particle size are shown in Table 4:
[0069] Table 4:
[0070]
[0071] From the data in the above table, it can be seen that the recycling of barbituric acid for reaction has a certain impact on the conversion rate and particle size, but has no effect on the reaction time and the formation of the final product.
[0072] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and basic spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A production process of Pigment Yellow 139, characterized in that: The specific steps include: 1) adding barbituric acid to water and fully dissolving it at a temperature of 30-70° C., adjusting the pH to ≤1.8 to form a supersaturated solution, maintaining the temperature constant, and then adding 1,3-diiminoisoindoline solid or a mixture thereof with water in multiple additions, wherein the molar ratio of barbituric acid to 1,3-diiminoisoindoline is 2.5-4.5:1, maintaining the pH of the system <7 during the addition process, and then keeping the temperature at 40-70° C. for 0.5-4 hours; 2) Crude product separation: After the heat preservation reaction is completed, the mixed solution in step 1) is kept at a temperature above 50°C and hot filtered to separate the crude pigment; 3) Pigmentation: Add the crude pigment to water and heat at 105-130°C for pigmentation, which is completed within 4-10 hours to obtain Pigment Yellow 139 product; 4) The filtrate obtained by hot filtration separation in step 2) is subjected to a temperature-elevated reduced-pressure distillation process to obtain a barbituric acid aqueous solution and aqueous ammonia.
2. The production process of Pigment Yellow 139 according to claim 1, characterized in that: Step 1) 1,3-diiminoisoindoline solid or a mixture thereof with water is added within 20 to 60 minutes.
3. The production process of Pigment Yellow 139 according to claim 1, characterized in that: Step 4) The filtrate is distilled at 60-65° C. and 0.05-1 MPa until the pH of the filtrate is less than 2.