Green synthesis method of electronic-grade 2, 3, 4-trihydroxybenzophenone

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a green synthesis method of electronic-grade 2, 3, 4-trihydroxy benzophenone. The method comprises the following steps: catalytic reaction: taking water as a solvent, uniformly mixing water and a catalyst, adding pyrogallic acid, heating the system to 40-50 DEG C, continuously adding trichlorotoluene, carrying out heat preservation reaction, cooling to 10-15 DEG C after the reaction is completed, crystallizing, separating out and filtering to obtain a crude wet product; and purification treatment: removing impurities from the crude wet product to obtain the high-purity 2, 3, 4-trihydroxy benzophenone. The method does not need reaction in an organic solvent system, is green and environment-friendly, does not need nitrogen protection and is low in production cost, and the prepared 2, 3, 4-trihydroxy benzophenone is high in purity and yield and suitable for industrial processing production.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone. Background Technology

[0002] 2,3,4-Trihydroxybenzophenone (3HBP), a polyfunctional aromatic ketone compound, exhibits excellent ultraviolet light absorption, metal chelating ability, and reactivity due to the simultaneous presence of phenolic hydroxyl and benzophenone structures in its molecule. It has become an important organic intermediate in the fine chemical industry. In semiconductor photoresists, it serves as a photosensitive component, effectively regulating the solubility of the exposed area; in polymer materials, it acts as an ultraviolet stabilizer, delaying material aging; furthermore, it has wide applications in pharmaceutical synthesis, dyes, and functional auxiliaries.

[0003] Extensive research has been conducted on the synthesis of 2,3,4-trihydroxybenzophenone in the prior art. For example, Japanese Patent JPH06172252A uses pyrogallol and benzoic acid as raw materials, tin chloride as a catalyst, and phosphorus oxychloride to synthesize 2,3,4-trihydroxybenzophenone. German Patent DE50415 uses benzoyl chloride and pyrogallol to synthesize 2,3,4-trihydroxybenzophenone in the presence of zinc chloride. Chinese Patent CN111217685A uses pyrogallol and benzoic acid as raw materials and macroporous strong acid styrene-based cation exchange resin as a catalyst for preparation. Chinese patent CN 1313272A describes the use of pyrogallol as a starting material, reacting it with trichlorotoluene in a binary mixed solvent under inert gas protection and with Lewis acid as a catalyst. After post-treatment with an aromatic hydrocarbon solvent, 2,3,4-trihydroxybenzophenone is obtained.

[0004] However, these existing technologies have the following drawbacks: First, the use of organic solvents leads to serious environmental and safety problems. Solvents such as methanol and toluene are highly toxic, volatile, and flammable, posing a threat to the health of production operators. Furthermore, after the reaction, a large amount of wastewater and waste gas containing organic solvents is generated, which is difficult and costly to treat. Residual solvents are difficult to remove completely, easily causing environmental pollution and exceeding solvent residue limits in the product. Second, existing processes produce many reaction byproducts, resulting in generally low yields. In addition, the polarity and solubility of the solvent significantly affect the reaction equilibrium and product precipitation behavior, often leading to incomplete product precipitation or impurity encapsulation, reducing the effective yield. Moreover, the purity of products obtained by existing technologies is insufficient, especially with high levels of metal ion impurities, failing to meet the requirements of high-end semiconductor applications. Furthermore, existing purification processes are complex and costly. To obtain high-purity products, multiple recrystallizations, column chromatography, or high-temperature vacuum sublimation are often required. These processes are not only cumbersome and time-consuming but also consume large amounts of solvent and result in significant product loss, hindering large-scale production.

[0005] In conclusion, developing a green, environmentally friendly, easy-to-operate synthesis method with high product yield and semiconductor-grade purity is of great significance and is also an urgent need for technological development in this field. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a green, environmentally friendly, easy-to-operate, high-purity product synthesis method suitable for industrial production of high-purity 2,3,4-trihydroxybenzophenone.

[0007] The technical problem solved by this invention is achieved by the following technical solution: A green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone includes the following steps: Catalytic reaction: Using water as a solvent, water and catalyst are mixed evenly, then pyrogallol is added, the system is heated to 40~50℃, trichlorotoluene is added, and the reaction is carried out under heat. After the reaction is completed, the temperature is lowered to 10~15℃, crystallization occurs, and then the crude wet product is obtained by filtration. Purification process: The crude wet product is purified to obtain the high-purity 2,3,4-trihydroxybenzophenone.

[0008] Furthermore, in the catalytic reaction, the catalyst includes N-N-dimethylformamide or N-methylpyrrolidone.

[0009] Furthermore, in the catalytic reaction, the mass-to-volume ratio of the pyrogallic acid to the solvent is 2-3 g: 10 ml; the volume ratio of the trichlorotoluene to the solvent is 5-7: 20; and the volume ratio of the catalyst to the solvent is 2-8: 100.

[0010] Furthermore, in the catalytic reaction, trichlorotoluene is added dropwise while the system is under stirring, and the reaction time is maintained at the temperature for 0.5~1.5h after the addition is completed.

[0011] Furthermore, in the catalytic reaction, the filter residue obtained after crystallization and filtration is washed to obtain a crude wet product.

[0012] Furthermore, in the purification process, the impurity removal includes a primary impurity removal process by mixing the wet crude product with a decolorizing solvent, activated carbon, and a metal ion impurity removal agent; and a secondary impurity removal process by mixing the dried crude product obtained after filtration and concentration following the primary impurity removal process with an ethanol solution and a metal ion impurity removal agent.

[0013] Furthermore, in the first purification step, the mass-to-volume ratio of the wet crude product to the decolorizing solvent is 2-3 g: 12 ml; the mass ratio of the wet crude product to activated carbon and metal ion purification agent is 100-150: 4-8: 2-6; the purification temperature is 55-75℃; and the purification time is 1-3 h.

[0014] Preferably, the decolorizing solvent is methyl tert-butyl ether, or methyl tert-amyl ether, or ethylene glycol dimethyl ether, or a mixed solvent of n-heptane and ethyl acetate, or a mixed solvent of n-heptane and dimethyl carbonate, or a mixed solvent of hexane and ethyl acetate, or a mixed solvent of hexane and dimethyl carbonate, or a mixed solvent of petroleum ether and ethyl acetate, or a mixed solvent of petroleum ether and dimethyl carbonate.

[0015] Furthermore, in the secondary impurity removal process, the concentration of the ethanol solution is 30-50%, the volume-to-mass ratio of the ethanol solution to the wet crude product is 10-20 ml: 2 g; the mass ratio of the metal ion impurity remover to the wet crude product is 2-6: 100-150; the impurity removal temperature is 6-10℃, and the impurity removal time is 6-16 h.

[0016] Furthermore, the metal ion impurity removers used in the primary and secondary impurity removal processes include oxalic acid, tartaric acid, cationic resin, or citric acid or ethylenediaminetetraacetic acid.

[0017] A high-purity 2,3,4-trihydroxybenzophenone is prepared by the method described above, wherein the yield of the 2,3,4-trihydroxybenzophenone is not less than 92%, and the purity of the 2,3,4-trihydroxybenzophenone is not less than 99%.

[0018] Beneficial effects: The green synthesis method of electronic grade 2,3,4-trihydroxybenzophenone described in this invention uses water as the reaction solvent for the catalytic reaction, eliminating the need for reaction in an organic solvent system. It is green, environmentally friendly, simple, readily available, and has high production safety. The purified product has high purity, high yield, and low content of metal ion impurities, which can better meet the requirements for use in semiconductor materials.

[0019] The present invention discloses a green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone, which does not require nitrogen protection during the reaction, has a low reaction temperature, uses an aqueous solvent, and the product precipitates in water immediately after the reaction. The preparation process involves minimal oxidation of raw materials, and the purification process employs a two-stage impurity removal method, resulting in a product with a purity of not less than 99%, a yield of not less than 92%, and metal ion impurities below 50 ppb. Furthermore, the purification method is simple, and the solvent used in the purification process can be recycled, reducing losses and costs, which is beneficial for industrial production. Attached Figure Description

[0020] Figure 1 The 2,3,4-trihydroxybenzophenone product obtained in Example 1 1 H-NMR spectrum.

[0021] Figure 2 The image shows the HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in Example 1.

[0022] Figure 3 The image shows the HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in Example 2.

[0023] Figure 4 The image shows the HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in Example 3.

[0024] Figure 5 The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained from Comparative Example 1 is shown.

[0025] Figure 6 The image shows the HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in Comparative Example 2.

[0026] Figure 7 The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained from Comparative Example 3 is shown.

[0027] Figure 8 The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in Comparative Example 4 is shown.

[0028] Figure 9 The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in Comparative Example 5 is shown. Detailed Implementation

[0029] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0030] Example 1 The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone described in this embodiment includes the following steps: Catalytic reaction: Using 200ml of water as solvent, 4mL of DMF (NN-dimethylformamide) was added to the water and mixed evenly. 50g of pyrogallic acid was added, and the system was heated to 45℃. The system was kept under stirring, and then trichlorotoluene was added to the system dropwise. The amount of trichlorotoluene added was 60ml. After the addition was completed, the reaction was carried out for 1h. The temperature was lowered to 12℃, crystals were precipitated, and then filtered. The obtained filter residue was washed with 50℃ warm water and dried to obtain 130g of wet crude product.

[0031] Purification process: The crude wet product was subjected to a first and a second purification process. The first purification process involved adding 130g of the wet crude product to 600ml of n-heptane, then adding 6g of activated carbon and 4g of oxalic acid, heating to 70℃ for 1.5h for decolorization and purification, followed by filtration. The filtrate was then concentrated to dryness to obtain the dry crude product. The second purification process involved mixing the dry crude product with 600mL of 40% ethanol, dissolving it at 70℃, then adding 4g of oxalic acid, mixing thoroughly, and allowing it to stand at 8℃ for 12h. The mixture was then filtered to obtain the wet purified product. The wet purified product was dried to obtain 86g of yellow powder, which is the 2,3,4-trihydroxybenzophenone product.

[0032] The NMR spectrum of the 2,3,4-trihydroxybenzophenone product obtained in this embodiment is as follows: Figure 1 As shown, 1 H NMR(400MHz.Chloroform-d)12.70(s,1H),7.70-7.63(m,2H),7.62-7.54(m,1H).7.54-7.43(m, 2H),7.15(d,J=8.9Hz.1H),6.51(d,J=8.9Hz.1H).6.21(d,J=3.5Hz.1HI),5.87(d,J=3.5Hz.1H).

[0033] The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in this embodiment is shown below. Figure 2 As shown.

[0034] Example 2 The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone described in this embodiment includes the following steps: Catalytic reaction: Using 200 ml of water as a solvent, 6 mL of N-methylpyrrolidone was added to the water and mixed evenly. 50 g of pyrogallol was added, and the system was heated to 50 °C. The system was kept under stirring, and then trichlorotoluene was added to the system dropwise. The amount of trichlorotoluene added was 70 ml. After the addition was completed, the reaction was carried out for 1 h. The temperature was lowered to 15 °C, crystals were precipitated, and then filtered. The obtained filter residue was washed with 50 °C warm water and dried to obtain 128 g of wet crude product.

[0035] Purification process: The crude wet product was subjected to a first and a second purification process. The first purification process involved adding 128g of the wet crude product to 600ml of n-heptane, then adding 7g of activated carbon and 4g of citric acid, heating to 55℃ for 1.5h for decolorization and purification, followed by filtration. The filtrate was then concentrated to dryness to obtain the dry crude product. The second purification process involved mixing the dry crude product with 600mL of 40% ethanol, dissolving it at 70℃, then adding 4g of citric acid, mixing thoroughly, and allowing it to stand at 8℃ for 12h. The mixture was then filtered to obtain the wet purified product. The wet purified product was dried to obtain 84g of yellow powder, which is the 2,3,4-trihydroxybenzophenone product.

[0036] The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in this embodiment is shown below. Figure 3 As shown.

[0037] Example 3 The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone described in this embodiment includes the following steps: Catalytic reaction: Using 200 ml of water as solvent, 6 mL of DMF (NN-dimethylformamide) was added to the water and mixed evenly. 50 g of pyrogallic acid was added, and the system was heated to 45 °C. The system was kept under stirring, and then trichlorotoluene was added to the system dropwise at a rate of 60 ml. After the addition was complete, the reaction was carried out for 1 h. The temperature was then lowered to 12 °C, and crystals were precipitated. The crystals were then filtered, and the resulting residue was washed with 50 °C warm water and dried to obtain 132 g of wet crude product.

[0038] Purification process: The crude wet product was subjected to a first and a second purification process. The first purification process involved adding 132g of the wet crude product to 700ml of n-heptane, then adding 6g of activated carbon and 8g of tartaric acid, heating to 65℃ for 1.5h to remove color and impurities, then filtering, and concentrating the filtrate to dryness to obtain the dry crude product. The second purification process involved mixing the dry crude product with 600mL of 40% ethanol, dissolving it at 70℃, then adding 4g of tartaric acid, mixing thoroughly, and allowing it to stand at 10℃ for 12h, then filtering to obtain the wet purified product. The wet purified product was dried to obtain 85g of yellow powder, which is the 2,3,4-trihydroxybenzophenone product.

[0039] The HPLC chromatogram of the 2,3,4-trihydroxybenzophenone product obtained in this embodiment is shown below. Figure 4 As shown.

[0040] Compare with Example 1 In this comparative example, nitrogen protection was used during the catalytic reaction; in the purification step, decolorization and impurity removal were not performed, and the crude wet product was directly subjected to a secondary impurity removal treatment. The rest was the same as in Example 1, yielding 84g of yellow powder. The HPLC chromatogram of the product obtained in this comparative example is shown below. Figure 5 As shown.

[0041] Compare with Example 2 In this comparative example, no DMF catalyst was added during the catalytic reaction; all other steps were the same as in Example 1, yielding 75g of a yellow powder. The HPLC chromatogram of the product obtained in this comparative example is shown below. Figure 6 As shown.

[0042] Compare with Example 3 In this comparative example, no metal ion impurity remover was added during purification. The secondary impurity removal was performed by mixing the dried crude product with 200 mL of 40% ethanol, with the remaining steps the same as in Example 3. 83 g of a yellow powder was obtained. The HPLC chromatogram of the product obtained in this comparative example is shown below. Figure 7 As shown.

[0043] Compare with Example 4 In this comparative example, the reaction temperature was 60°C, and the rest of the reaction was the same as in Example 1, yielding 70g of a brownish-yellow powder. The HPLC chromatogram of the product obtained in this comparative example is shown below. Figure 8 As shown.

[0044] Compare with Example 5 In this comparative example, the ethanol concentration was 60% during purification, and the rest was the same as in Example 3. 85g of a yellow powder was obtained. The HPLC chromatogram of the product obtained in this comparative example is shown below. Figure 9 As shown.

[0045] The liquid chromatograms of the 2,3,4-trihydroxybenzophenone products prepared in Examples 1-3 and Comparative Examples 1-5 are shown below. Figures 2-9 As shown.

[0046] The yields and purities of the 2,3,4-trihydroxybenzophenone products prepared in Examples 1-3 and Comparative Examples 1-5 are shown in Table 1. The 26 metal ion impurities were detected by ICP-MS, and the results are shown in Table 2.

[0047] Table 1. Statistical table of yield and purity of 2,3,4-trihydroxybenzophenone products in each example and control example. project Appearance Yield (%) purity(%) Example 1 Yellow crystalline powder 94.17% 99.95% Example 2 Yellow crystalline powder 92.00% 99.97% Example 3 Yellow crystalline powder 93.09% 99.99% Compare with Example 1 Brownish-red crystalline powder 90.97% 98.85% Compare with Example 2 Brownish-yellow crystalline powder 73.63% 89.61% Compare with Example 3 Brownish-yellow crystalline powder 89.50% 98.43% Compare with Example 4 Brownish-yellow crystalline powder 70.96% 92.53% Compare with Example 5 Brownish-yellow crystalline powder 86.61% 93.01% Table 2. Detection of Metal Impurities in 2,3,4-Trihydroxybenzophenone Products in Each Example and Comparative Example. (Unit: ppb)

[0048] As shown in the accompanying drawings and Tables 1 and 2, the 2,3,4-trihydroxybenzophenone prepared using the technology of this invention has high purity, high yield, and low metal ion impurity content, which is far superior to existing technologies and has great value for large-scale production and promotion. Furthermore, in this invention, the selection of catalyst type, the ratio of catalyst to raw materials, the control of catalytic reaction conditions, and purification treatment are all crucial; improper control will result in unsatisfactory results. In addition, as shown in Comparative Example 1, the reaction results under nitrogen protection are not significantly different, indicating that this invention does not require nitrogen protection, making the actual operation simpler and the production cost lower.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone, characterized in that, Includes the following steps: Catalytic reaction: Using water as a solvent, water and catalyst are mixed evenly, then pyrogallol is added, the system is heated to 40~50℃, trichlorotoluene is added, and the reaction is carried out under heat. After the reaction is completed, the temperature is lowered to 10~15℃, crystallization occurs, and then the crude wet product is obtained by filtration. Purification process: The crude wet product is subjected to impurity removal, which includes a primary impurity removal process by mixing the wet crude product with a decolorizing solvent, activated carbon and a metal ion impurity removal agent; and a secondary impurity removal process by mixing the dry crude product obtained by filtration and concentration after the primary impurity removal process with an ethanol solution and a metal ion impurity removal agent; to obtain high-purity 2,3,4-trihydroxybenzophenone.

2. The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, In the catalytic reaction, the catalyst includes N-N-dimethylformamide or N-methylpyrrolidone.

3. The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, In the catalytic reaction, the mass-to-volume ratio of the pyrogallic acid to the solvent is 2-3 g: 10 ml; the volume ratio of the trichlorotoluene to the solvent is 5-7: 20; and the volume ratio of the catalyst to the solvent is 2-8:

100.

4. The green synthesis method of electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, In the catalytic reaction, trichlorotoluene was added dropwise while the system was under stirring. After the addition was completed, the reaction was kept at the temperature for 0.5 to 1.5 hours.

5. The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, In the catalytic reaction, the filter residue obtained after crystallization and filtration is washed to obtain the crude wet product.

6. The green synthesis method of electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, In one purification process, the mass-to-volume ratio of the wet crude product to the decolorizing solvent is 2-3 g: 12 ml; the mass ratio of the wet crude product to activated carbon and metal ion purification agent is 100-150: 4-8: 2-6; the purification temperature is 55-75℃; and the purification time is 1-3 h.

7. The green synthesis method for electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, In the secondary impurity removal process, the concentration of the ethanol solution is 30-50%, and the volume-to-mass ratio of the ethanol solution to the wet crude product is 10-20 ml: 2 g; the mass ratio of the metal ion impurity remover to the wet crude product is 2-6: 100-150; the impurity removal temperature is 6-10℃, and the impurity removal time is 6-16 h.

8. The green synthesis method of electronic-grade 2,3,4-trihydroxybenzophenone according to claim 1, characterized in that, The metal ion impurity removal agents used in primary and secondary impurity removal include oxalic acid, tartaric acid, cationic resin, or citric acid, ethylenediaminetetraacetic acid, or disodium ethylenediaminetetraacetic acid.

9. A high-purity 2,3,4-trihydroxybenzophenone, characterized in that, The 2,3,4-trihydroxybenzophenone is prepared by the method described in any one of claims 1 to 8, wherein the yield of the 2,3,4-trihydroxybenzophenone is not less than 92%, and the purity of the 2,3,4-trihydroxybenzophenone is not less than 99%.

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