A boron-carbon-nitrogen photocatalytic material and its application in synthesis of fluorine-containing carboxylic compounds
By preparing boron, carbon, and nitrogen photocatalysts, the problems of difficult recovery and high cost of metal catalysts in existing technologies have been solved, enabling the efficient synthesis of fluorinated carboxylic acid compounds under visible light at room temperature, which has good prospects for industrial and agricultural applications.
Patent Information
- Application Number
- CN202410607202.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-16
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2044-05-16
AI Technical Summary
Existing technologies require the use of transition metal catalysts in the synthesis of fluorinated carboxylic acid compounds, which makes the catalysts difficult to recover and costly, and the reaction conditions are not green and environmentally friendly.
Boron carbon nitrogen (BCN) photocatalytic materials were prepared by the molten salt method to promote the reaction of indole or its derivatives with carbon dioxide and fluorine-containing free radical precursors at room temperature and under visible light conditions, generating fluorine-containing carboxylic acid compounds, thus avoiding the use of metal catalysts.
This method achieves high-yield synthesis of fluorinated carboxylic acid compounds, utilizes reusable catalysts, employs mild reaction conditions, is environmentally friendly, and is low-cost, making it suitable for industrial and agricultural applications.
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Figure CN118477674B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of photocatalytic organic synthesis, and in particular relates to a boron-carbon-nitrogen photocatalytic material and an application thereof in synthesizing fluorine-containing carboxylic acid compounds. Background Art
[0002] Fluorinated carboxylic acid compounds have wide applicability in various fields, such as the manufacture of water-absorbing polymers, food preservatives, fertilizers, cosmetics, soaps, detergents, rubber, dyes, animal feed, plastics, agricultural chemicals and pharmaceuticals. Therefore, the synthesis of fluorinated carboxylic acid compounds has attracted much attention. Sodium trifluoromethylsulfinate, as a stable, inexpensive, easy-to-store and easy-to-handle reagent, is widely used to incorporate CF3 groups into various skeletons. Significant progress has been made in the synthesis of trifluoromethyl-containing carboxylic acids using sodium trifluoromethylsulfinate as a free radical precursor and carbon dioxide as a carboxyl source. However, these methods generally require the use of transition metal catalysts such as iridium or ruthenium, or the use of organic dyes as photocatalysts. The use of these homogeneous catalysts is generally one-time and non-recyclable, and has disadvantages such as difficulty in separation and high cost, which limits their large-scale industrial use.
[0003] Solar-driven CO2 conversion is a green and effective way to address CO2 emissions and utilize it to synthesize high-value-added chemicals, which is more in line with green synthetic chemistry. Martin's group reported the photocatalytic difunctionalization of styrene with carbon dioxide and free radical precursors (Angew. Chem. Int. Ed. 2017, 56, 10915-10919.). Xi's group achieved the intermolecular trifluoromethyl dearylation reaction of indole and its analogs with carbon dioxide and fluorine-containing free radical precursors (Green Chemistry. 2022, 24 (20), 7894-7899.). However, the above methods still involve transition metals, and the catalysts cannot be recycled. Therefore, it is necessary to develop an innovative method with simple and easy-to-obtain catalysts, simple reaction operation, mild reaction conditions, green environmental protection and low cost to convert carbon dioxide to prepare fluorine-containing carboxylic acid derivatives. Summary of the Invention
[0004] In order to solve the above shortcomings and deficiencies in the prior art, the present invention provides a boron-carbon-nitrogen photocatalytic material and its application in the synthesis of fluorine-containing carboxylic acid compounds.
[0005] To achieve the above object, the present invention adopts the following technical solutions:
[0006] A boron carbon nitrogen (BCN) photocatalytic material is prepared by a molten salt method; the preparation steps are as follows:
[0007] (a) Grind boric acid, urea, and glucose in a mass ratio of (1-2):(1-4):(1-10) until uniform, then add potassium chloride as a molten salt and continue grinding until uniform;
[0008] (b) The mixed powder obtained by grinding in step (a) is transferred to a tube furnace, heated to 1000-1250°C in an ammonia atmosphere, calcined for 1-5 hours, then cooled to room temperature, ground, washed, and dried to obtain boron carbon nitrogen nanosheets.
[0009] Furthermore, the obtained boron carbon nitrogen nanosheets are rich in mesoporous structure and have a specific surface area of 400-600 m 2 / g, pore size is 5~15 nm, absorption band edge is 400-800 nm, and the shape is thin flakes.
[0010] The boron-carbon-nitrogen photocatalytic material can be used for the photocatalytic reaction of synthesizing fluorine-containing carboxylic acid compounds from carbon dioxide, that is, under the conditions of room temperature, normal pressure, and visible light illumination, using carbon dioxide as a carbon source, and utilizing the boron-carbon-nitrogen photocatalytic material to promote the dearomatization and carboxylation reaction of indole or its derivatives with a fluorine-containing free radical precursor to generate a fluorine-containing carboxylic acid compound; the reaction equation is as follows:
[0011] .
[0012] Furthermore, the application method includes the following steps:
[0013] 1) Add the boron-carbon-nitrogen material, base, fluorine-containing free radical precursor, and indole or its derivative directly into an organic solvent, inject carbon dioxide gas, and stir the reaction at room temperature, normal pressure, and visible light for 12-24 hours;
[0014] 2) After the reaction, the reaction solution is esterified with (trimethylsilyl)diazomethane (TMSCHN2), filtered, and extracted with ethyl acetate. The organic phases are combined, dried over anhydrous Na2SO4, filtered, and the solvent is distilled off under reduced pressure to obtain a crude product, which is finally purified by column chromatography to obtain a fluorine-containing carboxylic acid compound.
[0015] Furthermore, the indole derivatives used include any one of benzofuran and nitrogen heterocyclic indole.
[0016] Furthermore, the fluorine-containing free radical precursor is sodium trifluoromethanesulfinate.
[0017] Furthermore, the base is sodium carbonate.
[0018] Furthermore, the molar ratio of the boron carbon nitrogen material, the base, the fluorine-containing free radical precursor and the indole or its derivative used in step 1) is (1-5):(2-10):(2-5):(1-4).
[0019] Furthermore, the organic solvent used in step 1) is dimethyl sulfoxide.
[0020] Furthermore, in step 2), the esterification treatment temperature is 25° C. and the treatment time is 30 min.
[0021] Furthermore, in step 2), the column chromatography purification uses a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 50:1 to 10:1 as the eluent.
[0022] Nanosheet boron carbon nitride is a non-metallic semiconductor photocatalyst with a broad light absorption range (400-800 nm). It is inexpensive, readily available, chemically stable, highly adsorbable for organic matter, non-toxic, and has a wide band gap and well-positioned energy bands. Its activity is not affected by repeated recycling. This invention uses indole or its derivatives as a raw material and, under visible light, utilizes boron carbon nitride as a photocatalyst to achieve dearomatization and carboxylation of indole or its derivatives with carbon dioxide and free radical precursors.
[0023] The significant advantages of the present invention are:
[0024] 1. The synthesis method of the present invention avoids the use of metal-containing catalysts. The method is simple, easy to operate, mild in conditions, and green and safe.
[0025] 2. The synthesis method of the present invention does not require heating and can obtain a high yield under room temperature and visible light;
[0026] 3. The synthesis method of the present invention has high atom economy and mild reaction conditions, and has good application prospects in industry, agriculture and medicine;
[0027] 4. The catalyst used in the present invention is simple, easy to obtain, and reusable, green, environmentally friendly and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 The UV-visible absorption spectrum of the boron carbon nitride nanosheets prepared in Example 1 shows that the obtained BCN has good visible light absorption effect.
[0029] Figure 2 This is an electron microscope image of the boron carbon nitride nanosheets prepared in Example.
[0030] Figure 3 The pore size distribution of the boron carbon nitride nanosheets prepared in Example 1 is shown in the figure. As can be seen from the figure, the pore size of the obtained BCN is mainly distributed in the range of 5-10 nm.
[0031] Figure 4 The adsorption diagram of the boron carbon nitrogen nanosheet prepared in Example 1 is shown in the figure. As can be seen from the figure, the specific surface area of the obtained BCN is 517m 2 / g. DETAILED DESCRIPTION
[0032] A method for photocatalytically promoting the synthesis of fluorine-containing carboxylic acid compounds from carbon dioxide comprises the following steps:
[0033] 1) Boric acid, urea, and glucose were ground uniformly in a mass ratio of (1-2):(1-4):(1-10), and potassium chloride as a molten salt was added and continued to grind uniformly. The ground mixed powder was then transferred to a tube furnace and heated to 1000-1250°C in an ammonia atmosphere for calcination for 1-5 hours. The mixture was then cooled to room temperature and washed with purified water, anhydrous ethanol, and HCl in sequence, followed by drying to obtain boron carbon nitrogen nanosheets.
[0034] 2) The obtained boron carbon nitrogen nanosheets were used as a photocatalyst, and sodium carbonate, sodium trifluoromethanesulfinate, indole or its derivatives were directly added to dimethyl sulfoxide in a molar ratio of (1-5):(2-10):(2-5):(1-4). After the carbon dioxide gas was introduced, the reaction was stirred at room temperature, atmospheric pressure and visible light illumination for 12-24 hours;
[0035] 3) Step 3) After the reaction is completed, (trimethylsilyl)diazomethane (TMSCHN2) is added to the reaction solution and esterified at 25°C for 30 minutes. After filtration, the reaction solution is extracted with ethyl acetate, the organic phases are combined, dried over anhydrous Na2SO4, filtered, and the solvent is distilled off under reduced pressure to obtain a crude product. Finally, column chromatography is performed using a petroleum ether-ethyl acetate mixed solvent with a volume ratio of 50:1 to 10:1 as an eluent to obtain a fluorine-containing carboxylic acid compound.
[0036] The indole derivatives used include any one of benzofuran and nitrogen heterocyclic indole.
[0037] In order to make the contents of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation methods, but the present invention is not limited thereto. Example
[0038] Preparation of boron-carbon-nitrogen photocatalyst: Weigh 0.5 g of boric acid, 1 g of urea, and 3.5 g of glucose in an agate mortar and grind them evenly. Then add 4.5 g of potassium chloride and continue grinding evenly. Then transfer the ground mixed powder to a corundum boat and send it into a tube furnace. Heat it to 1250 ° C under an ammonia atmosphere and calcine it for 5 h. Then cool it to room temperature, take out the corundum boat, grind it, wash it with pure water, anhydrous ethanol and HCl in sequence, and dry it to obtain boron-carbon-nitrogen nanosheets with a catalytic yield of up to 62%.
[0039] Comparative Example
[0040] Preparation of boron-carbon-nitrogen photocatalyst: Weigh 0.5 g of boric acid, 1 g of urea, and 3.5 g of glucose in an agate mortar and grind them evenly. Then transfer the ground mixed powder to a corundum boat and send it into a tube furnace. Heat it to 1250°C under an ammonia atmosphere and calcine it for 5 h. Then cool it to room temperature, take out the corundum boat, grind it, wash it with pure water, anhydrous ethanol, and HCl in sequence, and then dry it to obtain boron-carbon-nitrogen nanosheets with a catalytic yield of only 23%.
[0041] Application Example 1
[0042] In a reactor filled with carbon dioxide, 27.5 mg of 1-Boc-6-ester indole, 10 mg of the boron carbon nitrogen photocatalyst prepared in Example 1, 26.5 mg of sodium carbonate, 39 mg of sodium trifluoromethylsulfinate, and 1 mL of dimethyl sulfoxide were added. The reaction was stirred at room temperature for 24 h under illumination. After the reaction, 2 equivalents of TMSCHN2 were added and esterified at 25°C for 30 min. The mixture was filtered and extracted with ethyl acetate. The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain a crude product, which was then purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 20:1 to obtain 25.0 mg of 1-(tert-butyl)-3,6-dimethyl 2-(trifluoromethyl)indoline-1,3,6-tricarboxylate ( ) to produce a yellow oily liquid with a yield of 62%.
[0043] 1 H NMR (600 MHz, Chloroform-d) δ 8.39 (s, 1H), 7.76 (dd, J =7.9, 1.5Hz, 1H), 7.46 (d, J = 7.9 Hz, 1H), 5.47 (s, 1H), 4.16 (s, 1H), 3.89 (s, 3H),3.77 (s, 3H), 1.58 (s, 9H). 13 C NMR (151 MHz, Chloroform-d) δ 169.11, 166.66,151.66, 142.47, 131.77, 125.52, 125.44, 123.73, 117.54,83.35, 62.13, 61.91,53.51, 52.40, 47.03, 28.22. 19 F NMR (565 MHz, Chloroform-d) δ -76.98.
[0044] Application Example 2
[0045] In a reactor filled with carbon dioxide, 24.2 mg of 1-Boc-6-cyanoindole, 10 mg of boron carbon nitrogen photocatalyst, 26.5 mg of sodium carbonate, 39 mg of sodium trifluoromethanesulfinate, and 1 mL of dimethyl sulfoxide were added. The reaction was stirred at room temperature under light for 24 h. After the reaction was completed, 2 equivalents of TMSCHN were added. 2， The mixture was esterified at 25°C for 30 min, filtered, and extracted with ethyl acetate. The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain a crude product, which was then purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 30:1 to obtain 15.2 mg of 1-(tert-butyl)-3-methyl-6-cyano-2-(trifluoromethyl)indoline-1,3-dicarboxylate ( ) was obtained as a yellow oily liquid with a yield of 41%.
[0046] 1 H NMR (600 MHz, Chloroform-d) δ 10.97 (d, J = 7.8 Hz, 1H), 10.82 (dd,J = 7.8, 1.5 Hz, 1H), 8.93 (d, J = 7.7 Hz, 1H), 7.65 (s, 1H), 7.26 (s,3H), 5.04 (s, 9H). 13 C NMR (151 MHz, Chloroform-d) δ 168.59, 151.28, 142.82,127.83, 126.41, 125.40, 119.72, 118.54, 113.58, 84.04, 62.05, 61.83,53.71,47.16, 28.18. 19 F NMR (565 MHz, Chloroform-d) δ -76.93.
[0047] Application Example 3
[0048] In a reactor filled with carbon dioxide, 28.6 mg of 1-Boc-5-trifluoromethyl-7-N heterocyclic indole, 10 mg of boron carbon nitrogen photocatalyst, 26.5 mg of sodium carbonate, 39 mg of sodium trifluoromethylsulfinate, and 1 mL of dimethyl sulfoxide were added. The reaction was stirred at room temperature under light for 24 h. After the reaction was completed, 2 equivalents of TMSCHN were added. 2，The mixture was esterified at 25°C for 30 min, filtered, and extracted with ethyl acetate. The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain a crude product, which was then purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 40:1 to obtain 22.7 mg of 1-(tert-butyl)-3-methyl-2,5-bis(trifluoromethyl)-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine-1,3-dicarboxylate ( ) to produce a yellow oily liquid with a yield of 55%.
[0049] 1 H NMR (600 MHz, Chloroform-d) δ 7.99 (d, J = 1.0 Hz, 1H), 7.26 (d, J= 1.3 Hz, 1H), 4.91 – 4.83 (m, 1H), 3.50 (d, J = 2.6 Hz, 1H), 3.17 (s, 3H),0.92 (s, 9H). 13 C NMR (151 MHz, Chloroform-d) δ 168.08, 158.17, 149.59, 147.22,147.19, 131.44,131.42, 129.72, 127.47, 125.23, 124.52, 123.35, 122.72,122.39, 122.16, 120.72, 84.35, 61.31, 61.09, 60.88, 60.66, 53.89, 44.45,28.02. 19 F NMR (565 MHz, Chloroform-d)δ-61.53, -77.09(d, J = 6.4 Hz).
[0050] Application Example 4
[0051] In a reactor filled with carbon dioxide, 25.2 mg of 1-Boc-6-chloro-5-N-heterocyclic indole, 10 mg of boron carbon nitrogen photocatalyst, 26.5 mg of sodium carbonate, 39 mg of sodium trifluoromethylsulfinate, and 1 mL of dimethyl sulfoxide were added and stirred at room temperature under light for 24 h. After the reaction, 2 equivalents of TMSCHN2 were added and esterified at 25°C for 30 min. The mixture was filtered and extracted with ethyl acetate. The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain a crude product, which was then purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 40:1 to obtain 12.2 mg of 1-(tert-butyl)-3-methyl-6-chloro-2-(trifluoromethyl)-2,3-dihydro-1H-pyrrolo[3,2-c]pyridine-1,3-dicarboxylate ( ) to produce a yellow liquid with a yield of 32%.
[0052] 1 H NMR (600 MHz, Chloroform-d) δ 8.32 (s, 1H), 7.68 (s, 1H), 5.63 –5.35 (m, 1H), 4.20 (d, J = 2.2 Hz, 1H), 3.81 (s, 3H), 1.58 (s, 10H). 13 C NMR(151 MHz, Chloroform-d) δ 168.59, 152.79, 150.55, 145.67, 111.38, 84.87,62.90, 62.68,53.84, 44.93, 28.10. 19 F NMR (565 MHz, Chloroform-d) δ -76.65.
[0053] Application Example 5
[0054] In a reactor filled with carbon dioxide, 14.3 mg of 5-cyanobenzofuran, 10 mg of boron carbon nitrogen photocatalyst, 35 mg of sodium carbonate, 39 mg of sodium trifluoromethylsulfinate, and 1 mL of dimethyl sulfoxide were added and stirred at room temperature for 24 h under light. After the reaction, 2 equivalents of TMSCHN2 were added and esterified at 25 ° C for 30 min. After filtration, the mixture was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain a crude product, which was then purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 50:1 to obtain 15.7 mg of 5-cyano-2-(trifluoromethyl)-2,3-dihydrobenzofuran-3-carboxylic acid methyl ester ( ) to a yellow solid with a yield of 58%.
[0055] 1 H NMR (600 MHz, Chloroform-d) δ 11.12 (t, J = 1.5 Hz, 1H), 10.97 (dd,J = 8.5, 1.0 Hz, 1H), 10.38 (d, J = 8.5 Hz, 1H), 9.04 – 8.92 (m, 1H),7.82 (dd, J = 5.5, 1.0 Hz, 1H), 7.26 (s, 3H). 13 C NMR (151 MHz, Chloroform-d) δ168.36, 161.73, 135.34, 130.00, 126.08, 124.22,123.88, 122.37, 118.64,111.62, 106.14, 80.86, 53.89, 47.50. 19 F NMR (565 MHz, Chloroform-d) δ -79.31(d, J = 6.5 Hz).
[0056] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.
Claims
1. Application of a boron-carbon-nitrogen photocatalytic material in the photocatalytic synthesis of fluorinated carboxylic acid compounds from carbon dioxide, characterized in that: At room temperature, normal pressure and visible light irradiation, carbon dioxide is used as a carbon source, and boron-carbon-nitrogen photocatalytic materials are used to promote the dearomatization and carboxylation reaction of indole or its derivatives with fluorine-containing free radical precursors to generate fluorine-containing carboxylic acid compounds; The preparation of the boron carbon nitrogen photocatalytic material comprises the following steps: (a) Grind boric acid, urea, and glucose in a mass ratio of (1-2):(1-4):(1-10) until uniform, then add potassium chloride as a molten salt and continue grinding until uniform; (b) The mixed powder obtained by grinding in step (a) is transferred to a tube furnace, heated to 1000-1250°C in an ammonia atmosphere, calcined for 1-5 hours, then cooled to room temperature, ground, washed, and dried to obtain boron carbon nitrogen nanosheets.
2. The use according to claim 1, wherein: The obtained boron carbon nitrogen nanosheets are rich in mesoporous structure and have a specific surface area of 400-600 m 2 / g, pore size is 5~15 nm, and absorption band edge is 400-800 nm.
3. The use according to claim 1, characterized in that: The indole derivatives used include any one of benzofuran and nitrogen heterocyclic indole.
4. The use according to claim 1, characterized in that: The fluorine-containing free radical precursor is sodium trifluoromethanesulfinate.
5. The use according to claim 1, characterized in that: The application method specifically includes the following steps: 1) Add the boron-carbon-nitrogen material, base, fluorine-containing free radical precursor, and indole or its derivative directly into an organic solvent, inject carbon dioxide gas, and stir the reaction at room temperature, normal pressure, and visible light for 12-24 hours; 2) After the reaction is completed, the reaction solution is esterified with (trimethylsilyl)diazomethane, filtered, and extracted with ethyl acetate. The organic phases are combined, dried over anhydrous sodium sulfate, filtered, and the solvent is distilled off under reduced pressure to obtain a crude product, which is finally purified by column chromatography to obtain a fluorine-containing carboxylic acid compound.
6. The use according to claim 5, characterized in that: The molar ratio of the boron carbon nitrogen material, base, fluorine-containing free radical precursor and indole or its derivative used in step 1) is (1-5):(2-10):(2-5):(1-4).
7. The use according to claim 5 or 6, characterized in that: The base is sodium carbonate.
8. The use according to claim 5, characterized in that: Step 2) The esterification treatment temperature is 25° C. and the treatment time is 30 min.
9. The use according to claim 5, characterized in that: Step 2) The column chromatography purification uses a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 50:1 to 10:1 as the eluent.