5-arylazobarbituric acid derivative salt, and preparation method and application thereof

Abstract

The application discloses a 5-aryl azobabitaric acid derivative salt and a preparation method and application thereof, and a structure is shown in a general formula (I), wherein R1, R2, R 3、 R4, R5 are independently selected from H, ionizable hydroxyl, carboxyl, sulfonic acid group, C1-C4 alkyl carboxyl; M is one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Zn, Al, Fe, Cu, Mn. As a dispersant, through the interaction between the planar 5-phenyl azobabitaric acid structure and the pigment yellow 150 molecules, it is anchored to the surface of the pigment particles, and through the ionized hydrophilic groups on the benzene ring, a hydration layer is formed on the surface of the pigment particles, so that a pigment product with excellent dispersibility, high transparency and excellent coloring strength is obtained.

Description

Technical Field

[0001] This invention relates to the field of pigment production technology, and in particular to a 5-aryl azobarbituric acid derivative salt, its preparation method, and its application. Background Technology

[0002] Pigment Yellow 150 is a heterocyclic azo nickel complex containing a pyrimidine ring, with its main component being a nickel 5,5'-azobisbarbiturate complex. It exhibits a dark, neutral yellow color, excellent lightfastness, and good tinting strength. However, due to its planar molecular structure and strong intermolecular π-π stacking, it easily forms a highly ordered lattice during synthesis. While this imparts excellent heat resistance and weather stability, the pigment particles are prone to agglomeration, affecting the product's transparency and tinting strength. Studies have shown that particle size is a key factor affecting pigment tinting strength; smaller and more uniform particle size results in stronger tinting strength. In applications such as high-end inks, inkjet inks, and color photoresists, where pigment requirements are high, traditionally prepared Pigment Yellow 150 dispersions cannot fully meet practical needs.

[0003] Pigment derivatives have been widely used to increase solid content and reduce viscosity in pigment dispersion. For example, patent CN101663361A describes an azo-type pigment dispersant prepared based on the pigment structure. This dispersant is mixed with organic pigments during pigment post-processing (such as grinding and dispersion), and the surface of the pigment particles is modified through physical adsorption. This synergistic dispersion with commercial dispersants reduces the particle size and increases pigment concentration. However, the particle size is primarily above 120 nm, which cannot truly achieve a nano-pigment dispersion. Currently, even with commercial dispersants and the addition of small amounts of pigment derivatives as synergists, the dispersion of pigments cannot meet the requirements for color strength and transparency of nano-pigments in high-end inks, inkjet inks, and color photoresists. Therefore, the traditional dispersion process for Pigment Yellow 150 dispersion suffers from large particle size, poor dispersion stability, and cumbersome processing under industrial-scale production conditions, requiring further solutions. Summary of the Invention

[0004] To address the aforementioned problems in existing technologies, this invention proposes a 5-aryl azobarbituric acid derivative salt, its preparation method, and its applications. This invention synthesizes a 5-aryl azobarbituric acid derivative salt with polar groups, which is used as a dispersant. Through the interaction between its planar 5-phenyl azobarbituric acid structure and Pigment Yellow 150 molecules, it anchors itself to the surface of pigment particles. Furthermore, the ionized hydrophilic groups on the benzene ring form a hydration layer on the surface of the pigment particles, thereby obtaining a pigment product with excellent dispersibility, high transparency, and superior coloring strength.

[0005] The technical solution of the present invention is as follows: The first objective of this invention is to provide a 5-aryl azobarbituric acid derivative salt with the structure shown in general formula (I):

[0006] Among them, R1, R2, R 3、 R4 and R5 are each independently selected from one of H, ionizable hydroxyl, carboxyl, sulfonic acid, and C1-C4 alkyl carboxyl groups; M is one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Zn, Al, Fe, Cu, and Mn.

[0007] In one embodiment of the present invention, the C1-C4 alkyl carboxyl group is one of carboxymethyl, carboxyethyl, carboxypropyl, and carboxybutyl.

[0008] In one embodiment of the present invention, R1, R2, and R3 are each independently selected from H, ionized hydroxyl groups, carboxyl groups, and sulfonic acid groups.

[0009] In one embodiment of the present invention, two of R1, R2, and R3 are hydrogen atoms, and the other is one of an ionized hydroxyl group, carboxyl group, or sulfonic acid group.

[0010] In one embodiment of the present invention, M is one or more of Li, Na, and K.

[0011] In general formula (Ⅰ), + and - only indicate the type of charge, and do not limit the number of charges.

[0012] A second objective of this invention is to provide a method for preparing the above-mentioned 5-aryl azobarbituric acid derivative salt, comprising the following steps: The aromatic amine compound represented by general formula (II) is subjected to a diazotization reaction to obtain a diazonium salt; The obtained diazonium salt was coupled with barbituric acid to obtain the barbituric acid derivative salt. ; Among them, R1, R2, R3, R4, and R5 are independently selected from H, hydroxyl, carboxyl, sulfonic acid, and C1-C4 alkyl carboxyl groups, respectively.

[0013] In one embodiment of the present invention, the diazotization reaction is as follows: an aromatic amine compound is added to water, an HCl solution is added, the mixture is cooled to 0-15°C, a sodium nitrite solution is added dropwise, and the reaction is carried out for 20-60 minutes.

[0014] In one embodiment of the present invention, the molar ratio of the aromatic amine compound to HCl is 1:1 to 3.5, and the amount of sodium nitrite is 1.0 to 1.2 times (e.g., 1.0 times, 1.1 times, or 1.2 times) of the molar amount of the aromatic amine compound.

[0015] In one embodiment of the present invention, the concentration of the HCl solution is 12 mol / L.

[0016] In one embodiment of the present invention, the aromatic amine compound is one or more of 4-aminobenzenesulfonic acid, 4-aminobenzoic acid, 4-aminophenylacetic acid, 4-aminophenylbutyric acid, and 4-aminophenol.

[0017] In one embodiment of the present invention, the diazotization reaction is as follows: an aromatic amine compound is added to water, an HCl solution is added, the mixture is cooled to 0-15°C (e.g., 5°C), a sodium nitrite solution is added dropwise, and the reaction is carried out for 20-60 minutes (e.g., 20 minutes, 30 minutes, or 40 minutes).

[0018] In one embodiment of the present invention, the coupling reaction is as follows: a diazonium salt is gradually added to an alkaline solution of barbituric acid at a reaction temperature of 0-10°C (e.g., 5°C). After the reaction, the pH is adjusted to 5-7 (e.g., pH=6), filtered, washed, and dried to obtain a 5-aryl azobarbituric acid product. The product is then mixed with an alkaline solution at a molar ratio of 1:1 to 1:3 to obtain a 5-aryl azobarbituric acid derivative salt solution.

[0019] In one embodiment of the present invention, the strong alkali is KOH, NaOH, Ba(OH)2, LiOH, etc. A third objective of this invention is to provide an application of the above-mentioned 5-aryl azobarbituric acid derivative salt as a dispersant in the preparation of an ultrafine nano pigment yellow 150 dispersion.

[0020] In one embodiment of the present invention, a 5-aryl azobarbituric acid derivative salt is dispersed in an aqueous system by grinding, ultrasonication or sand milling to obtain a dispersant solution, and then pigment yellow 150 powder is added. The amount of 5-aryl azobarbituric acid derivative salt used is 0.1-20% of the mass of Pigment Yellow 150 powder.

[0021] The fourth objective of this invention is to provide an ultrafine nano-pigment yellow 150 dispersion, the preparation method of which is as follows: The 5-aryl azobarbituric acid derivative salt is dispersed in an aqueous system by grinding, ultrasonication, sand milling, etc., to improve the application performance of the pigment.

[0022] Furthermore, after the 5-aryl azobarbituric acid derivative salt dispersant is prepared into a dispersant solution, Pigment Yellow 150 powder is added.

[0023] Furthermore, the 5-aryl azobarbituric acid derivative salt dispersant corresponds to 0.1%~20% of the mass of Pigment Yellow 150 powder.

[0024] Furthermore, the pigment accounts for 1% to 30% of the total solid content of the dispersion.

[0025] Furthermore, the ultrafine nano pigment yellow 150 dispersion is prepared by sonication for 5-60 minutes using a cell disruptor.

[0026] In one embodiment of the present invention, Pigment Yellow 150 powder is added to a 5-aryl azobarbituric acid derivative salt solution, and ultrafine nano Pigment Yellow 150 dispersion is obtained by treating it with a cell disperser for 30 minutes.

[0027] The amount of the 5-aryl azobarbituric acid derivative salt solid used can be adjusted according to actual needs. Preferably, its usage accounts for 0.5% to 10% of the mass of Pigment Yellow 150 powder. Pigment Yellow 150 prepared by the above method has small and uniformly distributed pigment particles, reaching the nanoscale. This product has excellent dispersibility, high transparency, high coloring strength, low viscosity, and good flowability.

[0028] This new ultrafine pigment yellow 150 dispersion can be widely used in high-end applications such as pigment printing, inkjet printing, and painting inks, and can meet the stringent requirements of high-end applications for pigment performance.

[0029] Beneficial effects: The 5-aryl azobarbituric acid derivative salt of this invention is produced by introducing an aromatic ring with polar groups (such as hydroxyl, carboxyl, sulfonic acid, etc.) through a diazotization-coupling reaction using barbituric acid as a raw material, forming a target product containing 5-arylphenylazobarbituric acid. This molecular structure is highly similar to the main structure of Pigment Yellow 150, both possessing a planar π-conjugated system, and their side chains carry polar groups with steric hindrance and electrostatic repulsion effects.

[0030] When this small-molecule dispersant is applied to the dispersion of Pigment Yellow 150, due to its similar structure to the pigment matrix, it can rapidly move and stably adsorb onto the surface of pigment particles through π-π stacking and intermolecular recognition, thereby increasing the hydrophilicity of the pigment particle surface. The ionized hydrophilic groups (such as hydroxyl, carboxyl, and sulfonic acid groups) introduced onto the dispersant generate a significant electrostatic repulsion effect on the pigment particle surface, effectively preventing the pigment particles from approaching each other in water, thus inhibiting the aggregation of pigment particles and achieving ultrafine nano-dispersion of Pigment Yellow 150.

[0031] Through the above mechanism, this invention achieves highly efficient dispersion of Pigment Yellow 150, precisely anchoring pigment particles to obtain uniformly distributed pigment particles with nanoscale particle sizes, thereby improving the product's transparency and color strength. Compared to traditional processes that require tedious kneading and prolonged grinding to reduce particle size, this invention directly enhances the anchoring effect of the dispersant on pigment particles through 5-aryl azobarbituric acid. The rapid movement of the small molecule dispersant improves the dispersion efficiency of Pigment Yellow 150, while reducing the amount of dispersant used and lowering energy consumption during dispersion.

[0032] The nano-pigment yellow 150 dispersion prepared from 5-aryl azobarbituric acid derivative salts not only has small particle size, low PDI, low viscosity, and high surface tension, but also meets the requirements of high-end inks, inkjet inks, color photoresists, and other applications with extremely high pigment performance requirements. Attached Figure Description

[0033] Figure 1 The mass spectrum of 5-[(4-carboxyphenyl)azo]barbituric acid prepared in Example 1 of this invention.

[0034] Figure 2 This is a particle size distribution diagram of the ultrafine nano pigment yellow 150 dispersion prepared in Example 1 of the present invention.

[0035] Figure 3 This is a particle size distribution diagram of the Pigment Yellow 150 dispersion prepared in Comparative Example 1 of the present invention.

[0036] Figure 4 This is a particle size distribution diagram of the Pigment Yellow 150 dispersion prepared in Comparative Example 3 of the present invention.

[0037] Figure 5 This is a particle size distribution diagram of the Pigment Yellow 150 dispersion prepared in Comparative Example 4 of the present invention. Detailed Implementation

[0038] Example 1 (1) Preparation of potassium salt solution of 5-[(4-carboxylic acid phenyl)azo]barbiturate 0.1 mol of 4-aminobenzoic acid was added to water, followed by an HCl solution containing 0.1 mol of HCl. The mixture was cooled to 5°C, and sodium nitrite solution at 5°C was gradually added dropwise over 20 minutes, reacting for 30 minutes. The product was then gradually added to a 0.1 mol alkaline solution of barbituric acid, and a small molecule barbituric acid was prepared via a coupling reaction at 5°C. The pH was adjusted to 6, and the product was filtered, washed, and dried to obtain 5-[(4-carboxyphenyl)azo]barbituric acid. A 5% potassium salt solution of 5-[(4-carboxyphenyl)azo]barbituric acid was prepared at a molar ratio of 1:1 with KOH.

[0039] (2) Preparation of ultrafine nano pigment yellow 150 dispersion 10g of Pigment Yellow 150 powder, 15ml of the above-mentioned potassium 5-[(4-carboxylic acid phenyl)azo]barbiturate solution, and 75g of water were mixed and then sonicated in a cell disruptor for 30min to obtain an ultrafine nano Pigment Yellow 150 dispersion.

[0040] Figure 1 This is the mass spectrum of barbituric acid azobenzoic acid from Example 1. Figure 1 It can be seen that the theoretical molecular weight of the target product is 276.21, and the main peak at 275 can be attributed to the [M+H] mode in negative ion mode. － The peaks on the right side are molecular fragments, while 551 on the right side is a dimer, indicating that the synthesis of barbituric acid azobenzoic acid was successful. Figure 2 The particle size distribution of the ultrafine nano pigment Yellow 150 dispersion prepared using potassium azobenzoate barbiturate dispersant solution is shown. The particle size distribution is single-peaked, with the main peak located within 100 nm. The peak shape is narrow, and the particle size distribution is concentrated. There are no obvious large particle peaks in the range of hundreds of nanometers to hundreds of micrometers, indicating that there are no obvious agglomerates or undispersed large pigment particles in the system.

[0041] Example 2 (1) Preparation of potassium salt solution of 5-[(4-carboxylic acid phenyl)azo]barbiturate 0.1 mol of 4-aminobenzoic acid was added to water, followed by an HCl solution containing 0.1 mol of HCl. The mixture was cooled to 5°C, and sodium nitrite solution at 5°C was gradually added dropwise over 20 minutes, reacting for 30 minutes. The product was then gradually added to a 0.1 mol alkaline solution of barbituric acid, and a small molecule barbituric acid was prepared via a coupling reaction at 5°C. The pH was adjusted to 6, and the product was filtered, washed, and dried to obtain 5-[(4-carboxyphenyl)azo]barbituric acid. A 5% potassium salt solution of 5-[(4-carboxyphenyl)azo]barbituric acid was prepared at a molar ratio of 1:1 with KOH.

[0042] (2) Preparation of ultrafine nano pigment yellow 150 dispersion 10g of Pigment Yellow 150 powder, 10ml of the above-mentioned potassium 5-[(4-carboxylic acid phenyl)azo]barbiturate dispersant solution, and 80g of water were mixed and then sonicated in a cell disruptor for 30min to obtain an ultrafine nano Pigment Yellow 150 dispersion.

[0043] Example 3 (1) Preparation of potassium salt solution of 5-[(4-sulfonophenyl)azo]barbiturate 0.1 mol of 4-aminobenzenesulfonic acid was added to water, followed by an HCl solution containing 0.1 mol of HCl. The mixture was cooled to 5°C, and sodium nitrite solution at 5°C was gradually added dropwise over 20 minutes, reacting for 30 minutes. The product was then gradually added to a 0.1 mol alkaline solution of barbituric acid, and a small molecule barbituric acid was prepared via a coupling reaction at 5°C. The pH was adjusted to 6, and the product was filtered, washed, and dried to obtain 5-[(4-sulfonic acid phenyl)azo]barbituric acid. A 5% potassium salt solution of 5-[(4-sulfonic acid phenyl)azo]barbituric acid was prepared at a molar ratio of 1:1 with KOH.

[0044] (2) Preparation of ultrafine nano pigment yellow 150 dispersion 10g of Pigment Yellow 150 powder, 15ml of the above-mentioned potassium 5-[(4-sulfonylphenyl)azo]barbiturate dispersant solution, and 75g of water were mixed and then sonicated in a cell disruptor for 30min to obtain an ultrafine nano Pigment Yellow 150 dispersion.

[0045] Example 4 (1) Preparation of potassium salt solution of 5-[(4-hydroxyphenyl)azo]barbiturate 0.1 mol of 4-aminophenol was added to water, followed by an HCl solution containing 0.1 mol of HCl. The mixture was cooled to 5°C, and a sodium nitrite solution at 5°C was gradually added dropwise over 20 minutes. The reaction was allowed to proceed for 30 minutes. The product was then gradually added to a 0.1 mol alkaline solution of barbituric acid. A small molecule barbituric acid was prepared via a coupling reaction at 5°C. The pH was adjusted to 6, and the product was filtered, washed, and dried to obtain 5-[(4-hydroxyphenyl)azo]barbituric acid. A 5% potassium salt solution of 5-[(4-hydroxyphenyl)azo]barbituric acid was prepared at a molar ratio of 1:1 with KOH.

[0046] (2) Preparation of ultrafine nano pigment yellow 150 dispersion 10g of Pigment Yellow 150 powder, 15ml of the above-mentioned potassium 5-[(4-hydroxyphenyl)azo]barbiturate dispersant solution, and 75g of water were mixed and then sonicated in a cell disruptor for 30min to obtain an ultrafine nano Pigment Yellow 150 dispersion.

[0047] Comparative Example 1 Preparation of ultrafine nano-pigment yellow 150 dispersion 10g of Pigment Yellow 150 powder, 6g of BYK-190 dispersant, and 84g of water were mixed and then sonicated in a cell disruptor for 30 minutes to obtain a Pigment Yellow 150 dispersion. Figure 3 This is a particle size distribution diagram of the dispersion.

[0048] Comparative Example 2 Preparation of ultrafine nano-pigment yellow 150 dispersion 10g of Pigment Yellow 150 powder, 1g of sodium dodecylbenzenesulfonate, and 89g of water were mixed and then sonicated in a cell disruptor for 30 minutes to obtain a Pigment Yellow 150 dispersion.

[0049] Comparative Example 3 (1) Preparation of 5-[(4-nitrophenyl)azo]barbituric acid solution 0.1 mol of 4-nitrophenylamine was added to water, and an HCl solution containing 0.1 mol of HCl was added. The mixture was cooled to 5°C, and a sodium nitrite solution at 5°C was added dropwise over 20 min. The mixture was allowed to react for 30 min. The product was then gradually added to an alkaline solution of 0.1 mol of barbituric acid. The barbituric acid molecules were prepared by coupling reaction at 5°C. The pH was adjusted to 6, and the mixture was filtered, washed, and dried to obtain 5-[(4-nitrophenyl)azo]barbituric acid.

[0050] (2) Preparation of Pigment Yellow 150 Dispersion 10g of Pigment Yellow 150 powder, 0.75g of the above-mentioned 5-[(4-nitrophenyl)azo]barbituric acid, and 89.25g of water were mixed and then sonicated in a cell disruptor for 30 minutes to obtain a Pigment Yellow 150 dispersion. Figure 4 This is a particle size distribution diagram of the dispersion.

[0051] Comparative Example 4 (1) Preparation of 5-[(4-hydroxyphenyl)azo]barbituric acid solution 0.1 mol of 4-nitrophenol was added to water, and an HCl solution containing 0.1 mol of HCl was added. The mixture was cooled to 5°C, and a sodium nitrite solution at 5°C was added dropwise over 20 min. The mixture was allowed to react for 30 min. The product was then gradually added to an alkaline solution of 0.1 mol of barbituric acid. The barbituric acid was prepared by coupling reaction at 5°C. The pH was adjusted to 6, and the mixture was filtered, washed, and dried to obtain 5-[(4-hydroxyphenyl)azo]barbituric acid.

[0052] (2) Preparation of Pigment Yellow 150 Dispersion 10g of Pigment Yellow 150 powder, 0.75g of the above-mentioned 5-[(4-hydroxyphenyl)azo]barbituric acid, and 89.25g of water were mixed and then sonicated in a cell disruptor for 30 minutes to obtain a Pigment Yellow 150 dispersion. Figure 5 This is a particle size distribution diagram of the dispersion.

[0053] The average dispersed particle size of the pigment samples in Examples 1-4 and Comparative Examples 1-2 is shown in Table 1.

[0054] Table 1

[0055] As is evident from Table 1, the addition of appropriate 5-aryl azobarbituric acid derivative salts in Examples 1-4 significantly reduced the dispersion of Pigment Yellow 150 to below 100 nm, with Example 1 showing a reduction of 67.4% and 78.6% compared to Comparative Examples 1 and 2, respectively. In Comparative Examples 3 and 4, the substituents, i.e., the R3 portion of formula (Ⅰ), were either nitro or hydroxyl groups. Without salt formation, these groups showed no significant dispersing effect; the pigment agglomerated and stratified in water, and the particle size distribution of the dispersion exhibited multi-peaks and large particle agglomeration. This indicates that the 5-aryl azobarbituric acid derivative salt dispersant, compared to traditional dispersants and surfactants, can significantly and effectively reduce the dispersed particle size of Pigment Yellow 150 in aqueous systems.

[0056] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A 5-aryl azobarbituric acid derivative salt, characterized in that, The structure is shown in general formula (Ⅰ): Among them, R1, R2, R 3、 R4 and R5 are each independently selected from one of H, ionizable hydroxyl, carboxyl, sulfonic acid, and C1-C4 alkyl carboxyl groups; M is one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Zn, Al, Fe, Cu, and Mn.

2. The 5-aryl azobarbituric acid derivative salt according to claim 1, characterized in that, R1, R2, and R3 are each independently selected from one of H, ionized hydroxyl, carboxyl, or sulfonic acid groups.

3. The 5-aryl azobarbituric acid derivative salt according to claim 1, characterized in that, Two of R1, R2, and R3 are hydrogen atoms, and the other is one of an ionized hydroxyl, carboxyl, or sulfonic acid group.

4. The 5-aryl azobarbituric acid derivative salt according to claim 1, characterized in that, M can be one or more of Li, Na, and K.

5. A method for preparing the 5-aryl azobarbituric acid derivative salt according to any one of claims 1-4, characterized in that, Includes the following steps: The aromatic amine compound represented by general formula (II) is subjected to a diazotization reaction to obtain a diazonium salt; The obtained diazonium salt was coupled with barbituric acid to obtain the barbituric acid derivative salt. ； Among them, R1, R2, R3, R4, and R5 are independently selected from H, hydroxyl, carboxyl, sulfonic acid, and C1-C4 alkyl carboxyl groups, respectively.

6. The preparation method according to claim 5, characterized in that, The diazotization reaction is as follows: add the aromatic amine compound to water, add HCl solution, cool to 0~15℃, add sodium nitrite solution dropwise, and react for 20~60 minutes.

7. The preparation method according to claim 6, characterized in that, The molar ratio of the aromatic amine compound to concentrated hydrochloric acid is 1:1 to 3.5, and the amount of sodium nitrite used is 1.0 to 1.2 times the molar amount of the aromatic amine compound.

8. The preparation method according to claim 5, characterized in that, The coupling reaction is as follows: the diazonium salt is gradually added to the alkaline solution of barbituric acid at a reaction temperature of 0-10℃. After the reaction, the pH is adjusted to 5-7, filtered, washed, and dried to obtain the 5-aryl azobarbituric acid product. The product is then mixed with the alkaline solution at a molar ratio of 1:1 to 1:3 to obtain a 5-aryl azobarbituric acid derivative salt solution.

9. The application of a 5-aryl azobarbituric acid derivative salt according to any one of claims 1-4, characterized in that, Used as a dispersant in the preparation of ultrafine nano pigment yellow 150 dispersion.

10. The application according to claim 9, characterized in that, 5-Arylazobarbituric acid derivative salts are dispersed in an aqueous system by grinding, ultrasonication or sand milling to prepare a dispersant solution, and then Pigment Yellow 150 powder is added. The amount of 5-aryl azobarbituric acid derivative salt used is 0.1-20% of the mass of Pigment Yellow 150 powder.

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