High-catalytic-activity donor-receptor type covalent organic framework material and application thereof in synthesis of benzonitrile derivative
By designing the B-COF photocatalyst, the problems of low efficiency and poor stability of existing photocatalysts were solved, and the efficient catalytic production of benzonitrile derivatives was achieved with high selectivity and stability, making it suitable for the conversion and large-scale production of benzonitrile and its derivatives.
Patent Information
- Application Number
- CN202510893824.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-10-10
AI Technical Summary
Existing photocatalysts have problems in the degradation of organic pollutants and the conversion of renewable energy, such as narrow spectral response, high carrier recombination rate, poor stability and strong dependence on precious metals, resulting in low efficiency and high cost, making it difficult to meet the high efficiency and selectivity requirements of green chemistry and complex organic reactions.
A covalent organic framework material (B-COF) with donors and acceptors as building units was designed and synthesized by a solvothermal method. The push-pull electron effect was utilized to improve the efficiency of light absorption and charge separation, and the active sites were synergistically regulated to prepare an efficient COF photocatalyst.
The method achieves efficient catalysis for the production of benzonitrile and its derivatives, with high conversion rate, low by-product generation rate, high selectivity and good stability, and is suitable for large-scale production and wide application.
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Figure CN120757729A_ABST
Abstract
Description
Technical Field
[0001] This invention discloses a highly catalytically active donor-acceptor covalent organic framework (B-COF) and its application in the green synthesis of benzonitrile derivatives. This research addresses the interdisciplinary fields of catalytic chemistry, materials science, synthetic chemistry, biomedicine, environmental engineering, and green chemical engineering. Specifically, the invention involves the solvothermal synthesis of B-COF catalysts and their utilization of their photocatalytic properties in organic reactions, particularly in the degradation of organic pollutants, synthetic reactions, and other photocatalytic conversion processes. This technology can improve the efficiency and selectivity of photocatalytic reactions, promoting the development of sustainable chemical reactions. Background Art
[0002] Covalent organic frameworks (COFs) are a new class of crystalline porous materials composed of organic monomers covalently bonded to form an ordered porous network. Their structures offer high porosity, large surface area, and tunable pore size and porosity. COFs hold great promise for applications in optoelectronics, such as photocatalysis, proton conduction, gas storage, and energy storage.
[0003] In recent years, photocatalytic technology has attracted widespread attention due to its potential in the degradation of organic pollutants and the conversion of renewable energy. In the process of photocatalytic organic conversion, the performance of the catalyst directly affects the efficiency and selectivity of the reaction. Traditional photocatalysts generally suffer from problems such as narrow spectral response, high carrier recombination rate, poor stability, and strong dependence on precious metals. These problems lead to low efficiency and high cost, making it difficult to meet the high efficiency and selectivity requirements of green chemistry and complex organic reactions. To address these problems, researchers have begun to explore the design and synthesis of COF material photocatalysts, utilizing designable crystal structures and controllable active sites to improve the efficiency, selectivity, and stability of photocatalytic organic conversion. Therefore, it is crucial to develop photocatalysts with high thermal stability (>300°C) and no need for precious metals. The B-COF of the present invention can meet this demand.
[0004] B-COF, a novel COF material, possesses an ordered framework structure based on 2,4,6-triformylphloroglucinol (donor) and a benzidine derivative (acceptor). Its extended π-conjugated system effectively enhances light absorption and charge separation efficiency. Furthermore, the benzidine unit and the imine bond synergistically regulate the electronic environment of the active site, enabling selective adsorption and activation of specific reactants, thereby improving catalytic efficiency and activity. This invention aims to provide a method for preparing an efficient COF photocatalyst and explore its innovative applications in photocatalytic organic conversion, thereby promoting technological advancement and application development in this field. Summary of the Invention
[0005] The present invention aims to design donors and acceptors as building blocks, utilizing the push-pull electron effect to address the low efficiency of photocatalytic organic conversion and low visible light utilization in existing covalent organic frameworks. This approach also provides a method for preparing a highly efficient COF photocatalyst, resulting in excellent photocatalytic performance.
[0006] A technical purpose of the present invention is to provide a COF photocatalyst, wherein the catalyst includes a strong small-angle peak at 2θ=3.46° and is marked as a 100 crystal plane.
[0007] In order to identify the product of this case, the present invention conducted infrared detection and found that the catalyst had peaks at characteristic positions of 1140 cm-1, 1251 cm-1, 1260 cm-1, and 1570 cm-1.
[0008] To further identify the product of this case, the present invention conducted solid-state nuclear magnetic resonance carbon spectrum analysis, and the catalyst included characteristic signal peaks at 193.9, 148.5, 137.7, 127.1, 119.5, 115.2, 107.1, and 101.1 ppm.
[0009] Another technical purpose of the present invention is to provide a method for preparing an efficient COF photocatalyst, which mainly includes the following steps: (1) Weigh a certain amount of 2,4,6-triformaldehyde benzidine and benzidine, place them in a 25 ml Schlenk tube, and ensure that the two are fully mixed. Subsequently, add two or more organic solvents to the reaction system, mix thoroughly and shake until the solution reaches a uniform state. After that, add an appropriate amount of acid solution, and after a freeze-evacuation-thaw cycle, seal the Schlenk tube, place the sealed Schlenk tube in an oven, heat the temperature to the specified reaction temperature, and maintain it for a period of time to ensure that the reaction is fully carried out. After the reaction is completed, the solid product obtained needs to be washed and filtered multiple times in different solvents to remove impurities. Subsequently, the washed solid product is placed in a vacuum drying oven at a set temperature and dried for several hours to obtain the final target product.
[0010] In the step (1), the molar ratio of 2,4,6-triformylphloroglucinol to benzidine is 1-3:1-3, preferably 2:3.
[0011] The organic solvent in step (1) is a mixture of two or more of mesitylene, 1,4-dioxane, o-dichlorobenzene, dimethyl sulfoxide, and N-methylpyrrolidone.
[0012] In some preferred cases, the mixed solvent is preferably: mesitylene, 1,4-dioxane; The volume ratio of the mixed solvent is 1-3:1-3, preferably 1:1; the crystallinity is best when it is 1:1.
[0013] The acid solution in step (1) is any one of nitric acid, hydrochloric acid, sulfuric acid, and acetic acid, preferably acetic acid.
[0014] The concentration of acetic acid is 1-12 M, preferably 1 M, 3 M, 6 M, 12 M; more preferably 6 M.
[0015] In the step (1), the temperature is heated to a specified reaction temperature of 80-140°C and maintained for 3-4 days, preferably 120°C; the reaction time is 3 days.
[0016] The washing step in step (1) is to sequentially wash with ethanol, anhydrous N,N-dimethylformamide, and acetone, respectively, and repeat 3-5 times, preferably 3 times.
[0017] The product in step (1) is dried in a vacuum drying oven at a temperature of 50-100°C, preferably 60°C, for not less than 12 hours.
[0018] Another object of the present invention is to provide a catalyst for converting aromatic aldehyde oxime to nitrile, wherein the catalyst is the B-COF photocatalyst or the B-COF photocatalyst prepared by the preparation method, and the aromatic aldehyde oxime can also be an aromatic aldehyde oxime derivative.
[0019] The aromatic aldoxime derivatives include 4-methylbenzaldehyde oxime, 4-fluorobenzaldehyde oxime, 4-chlorobenzaldehyde oxime, and 4-bromobenzaldehyde oxime.
[0020] A method for converting aromatic aldehyde oxime into nitrile by B-COF photocatalyst comprises the following steps: First, weigh a certain amount of aromatic aldehyde oxime or aromatic aldehyde oxime derivative, photocatalyst and reaction additives, measure a certain volume of organic solvent, and place it in a light-transmitting glass bottle. Fully dissolve to ensure uniform dispersion. Then, pass a certain volume of gas to keep the reaction conditions stable. Place the glass bottle under a light source and continuously stir the suspension to promote the reaction. At a certain temperature, irradiate for a certain time to carry out the catalytic reaction. After the experiment is completed, process the reaction system, collect the product and analyze it to confirm the success of the reaction and the catalytic effect of the photocatalyst. The reaction formula is as follows:
[0021] R is an alkyl group or a halogen group.
[0022] The alkyl group is a C1-C10 straight-chain alkyl group or a branched-chain alkane, and the halogen group includes any one of F, Cl, and Br.
[0023] The reactant is an aromatic aldehyde oxime or an aromatic aldehyde oxime derivative, the catalyst is B-COF, and the reaction additives include NH4SCN, KSCN, and NaSCN, preferably NH4SCN. The ratio of the three is 0.1-0.3 mmol: 3-5 mg: 0.1-0.5 mmol, preferably 0.2 mmol: 4 mg: 0.3 mmol.
[0024] The solvent includes any one or more of methanol, ethanol, acetonitrile, ethyl acetate, and dichloromethane, preferably acetonitrile.
[0025] The reaction temperature is room temperature and is maintained for 12-18 hours, preferably 25°C; the reaction time is 15 hours.
[0026] The introduced gas is one of oxygen, air or other reagents that can release oxygen.
[0027] The light source is ultraviolet light or visible light source (blue light, white light, orange light, green light, etc.), and the power of the light source is 5 W-70 W; preferably a 40 W blue light source.
[0028] Patent beneficial effects The B-COF photocatalyst of the present invention exhibits the following advantages in the field of photocatalytic organic conversion: 1. High catalytic activity and selectivity: The catalyst can efficiently catalyze the formation of benzonitrile and its derivatives with high conversion rate, low by-product generation rate, high selectivity, and excellent photocatalytic performance.
[0029] 2. Simple preparation and broad application potential: The B-COF photocatalyst was synthesized via a solvothermal method under mild conditions, which is simple and amenable to large-scale production. The catalyst exhibits good substrate compatibility in the conversion of benzonitrile and its derivatives, offering the dual advantages of simple preparation and wide application.
[0030] 3. Products with high added value: The diversity and reactivity of nitrile compounds also make them extremely important in chemical synthesis. They often serve as intermediates in the synthesis of other complex organic molecules. They add fragrance to foods, cosmetics, and perfumes. In materials science, they serve as polymerization monomers, facilitating the synthesis of high-performance polymer materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 This is the technical roadmap for the preparation of B-COF.
[0032] Figure 2The Fourier transform infrared spectra of B-COF, 2,4,6-triformylphloroglucinol and benzidine.
[0033] Figure 3 is the X-ray powder diffraction spectrum of B-COF.
[0034] Figure 4 This is the solid-state NMR carbon spectrum of B-COF.
[0035] Figure 5 Schematic diagram of thermogravimetric analysis of B-COF.
[0036] Figure 6 This is the H NMR spectrum of 4-methylbenzonitrile.
[0037] Figure 7 This is the H NMR spectrum of 4-fluorobenzonitrile.
[0038] Figure 8 This is the H NMR spectrum of 4-chlorobenzonitrile.
[0039] Figure 9 This is the H NMR spectrum of 4-bromobenzonitrile. DETAILED DESCRIPTION
[0040] The present invention will be further described below with reference to the examples, but the present invention is not limited to the following examples.
[0041] Example 1 Synthesis of B-COF materials: First, 0.1 mmol of 2,4,6-triformylphloroglucinol (21.1 mg) and 0.15 mmol of benzidine (27.7 mg) were weighed into a Schlenk tube. Mesitylene (2 mL) and 1,4-dioxane (2 mL) were then added and mixed thoroughly with vortexing until the solution reached a homogeneous state. Acetic acid (0.5 mL, 6 M) was then added. After a freeze-evacuation-thaw cycle, the Schlenk tube was sealed and placed in an oven at 120°C, where it was kept warm for 3 days. After completion of the reaction, the system was naturally cooled to room temperature to obtain a yellow solid product. The solid was then washed repeatedly with ethanol, anhydrous N,N-dimethylformamide, and acetone to completely remove unreacted monomers and organic byproducts. The product was then dried in a vacuum oven at 60°C for 15 hours to obtain a high-purity yellow powder of B-COF.
[0042] Figure 1 This is the synthetic technology route for preparing B-COF in Example 1.
[0043] Figure 2The Fourier transform infrared spectra of B-COF, 2,4,6-triformylphloroglucinol, and benzidine are shown. The –NH stretching vibration of the amine precursor (3100-3400 cm -1 ) and the C=O stretching vibration of the aldehyde group (1638 cm -1 and 1686 cm -1 ) completely disappears in the COFs spectrum, proving that the precursor is consumed by the condensation reaction. 1570 cm -1 The absorption peak at 1260 cm is attributed to the symmetrical stretching vibration of the C=N bond generated by the Schiff base condensation, while the absorption peak at 1260 cm -1 、1251 cm -1 The peak at corresponds to the stretching vibration peak of the C–N bond, and the two together indicate the successful formation of the imine bond; no residual peaks of the precursor (such as –NH or aldehyde group) were observed, further verifying the high efficiency of the condensation reaction and the integrity of the framework structure.
[0044] Figure 3 The X-ray powder diffraction spectrum of B-COF is shown in Figure 2. The PXRD pattern of B-COF has a strong 2θ angle peak at 3.46°, and a significant diffraction peak can be observed, corresponding to the reflection from the
[100] crystal plane.
[0045] Figure 4 Solid-state carbon nuclear magnetic resonance spectrum of B-COF prepared in Example 1: 13C NMR (101 MHz) δ 193.9, 148.5, 137.7, 127.1, 119.5, 115.2, 107.1, 101.1.
[0046] Example 1-1 Synthesis of B-COF crystals: The Schlenk tube was sealed and placed in an oven. The temperature was raised to 100°C using a precise programmable temperature control system and maintained for 4 days. The remaining synthesis steps were the same as in Example 1, ultimately producing B-COF crystals.
[0047] Example 1-2 Synthesis of B-COF crystals: After the reaction substrates were mixed evenly, 2 mL of mesitylene and 2 mL of o-dichlorobenzene were added to carry out the reaction. The other synthesis steps were the same as those in Example 1, and B-COF crystals were finally prepared.
[0048] Examples 1-3 Synthesis of B-COF crystals: After the reaction substrates were mixed evenly, a mixed solvent (mesitylene:1,4-dioxane) was added, followed by acetic acid (1 mL, 3 M). The remaining synthesis steps were the same as in Example 1, ultimately producing B-COF crystals.
[0049] The other synthesis steps are the same as those in Example 1.
[0050] Example 2 Synthesis of 4-methylbenzonitrile:
[0051] 0.2 mmol of 4-methylbenzaldehyde oxime (27.1 mg), 0.3 mmol of NH₄SCN (22.9 mg), and 4 mg of the B-COF photocatalyst (B-COF described in Example 1) were weighed into a glass vial and 2 mL of CH₃CN was added. O₂ was then continuously bubbled through the vial for a specified time. The vial was placed in a 40 W blue LED reactor, and the suspension was stirred at an appropriate rate and irradiated at room temperature for 15 hours. After the reaction was complete, the mixture was concentrated to obtain a crude product, which was further purified by flash chromatography to yield the desired product, 4-methylbenzonitrile, in a 91% yield.
[0052] Example 2-1 4-Fluorobenzonitrile
[0053] 0.2 mmol of 4-fluorobenzaldehyde oxime (27.9 mg), 0.3 mmol of NH₄SCN (22.6 mg), and 4 mg of the B-COF photocatalyst (B-COF described in Example 1) were weighed into a glass vial and 2 mL of CH₃CN was added. O₂ was then continuously bubbled through the vial for a specified time. The vial was placed in a 40 W blue LED reactor, and the suspension was stirred at an appropriate rate and irradiated at room temperature for 15 hours. After the reaction was complete, the mixture was concentrated to obtain a crude product, which was further purified by flash chromatography to obtain the desired product, 4-fluorobenzonitrile, in a 79% yield.
[0054] Example 2-2 4-Chlorobenzonitrile
[0055] 0.2 mmol of 4-chlorobenzaldehyde oxime (31.5 mg), 0.3 mmol of NH₄SCN (22.5 mg), and 4 mg of the B-COF photocatalyst (B-COF described in Example 1) were weighed into a glass vial and 2 mL of CH₃CN was added. O₂ was then continuously bubbled through the vial for a specified time. The vial was placed in a 40 W blue LED reactor, and the suspension was stirred at an appropriate rate and irradiated at room temperature for 15 hours. After completion of the reaction, the mixture was concentrated to obtain a crude product, which was further purified by flash chromatography to yield the desired product, 4-chlorobenzonitrile, in an 83% yield.
[0056] Example 2-3 4-bromobenzonitrile
[0057] A 0.2 mmol of 4-bromobenzaldoxime (40.6 mg) and 0.3 mmol of NH4SCN (22.8 mg) and 4 mg of B-COF photocatalyst (B-COF described in Example 1) were weighed in a glass bottle, and 2 mL of CH3CN was added. Then, the glass bottle was placed in a 40 W blue light LED reactor, and the suspension was stirred at an appropriate speed and irradiated at room temperature for 15 h while continuously passing O2. After the reaction was completed, the mixture was concentrated to obtain a crude product, and the crude product was further purified by flash chromatography to obtain the target product 4-bromobenzonitrile with a yield of 89%.
[0058] Example 3 Synthesis of white light photocatalytic 4-methylbenzonitrile: The photocatalyst for preparing 4-methylbenzonitrile was B-COF described in Example 1, and the amount was 5 mg. Other operation steps were the same as in Example 2. The glass bottle was placed in a 40 W white light LED reactor, and the suspension was stirred at an appropriate speed and irradiated at room temperature for 15 h. After the reaction was completed, the mixture was concentrated to obtain a crude product, and the crude product was further purified by flash chromatography to obtain the target product 4-methylbenzonitrile with a yield of 80%.
[0059] Figure 5 The thermal stability test and analysis of the B-COF prepared in Example 1 were performed. The results showed that the B-COF crystal started to collapse when heated to 369 ℃ in an air atmosphere, proving that the B-COF crystal has good thermal stability.
[0060] Figure 6 The 1H NMR spectrum of 4-methylbenzonitrile is: 1H NMR (400 MHz, Chloroform-d) δ 7.54 (d, J = 8.2 Hz, 2H), 7.28 (s, 2H), 2.42 (s, 3H); as can be seen from the figure, 4-methylbenzaldoxime is successfully oxidized to synthesize 4-methylbenzonitrile.
[0061] Figure 7 The 1H NMR spectrum of 4-fluorobenzonitrile is: 1H NMR (400 MHz, Chloroform-d) δ 7.72-7.63 (m, 2H), 7.22-7.13 (m, 2H); as can be seen from the figure, 4-fluorobenzaldoxime is successfully oxidized to synthesize 4-fluorobenzonitrile.
[0062] Figure 8The H NMR spectrum of 4-chlorobenzonitrile is: 1H NMR (400 MHz, Chloroform-d) δ 7.64–7.56 (m, 2H), 7.50–7.43 (m, 2H); the figure shows that 4-chlorobenzonitrile was successfully synthesized by oxidation of 4-chlorobenzaldehyde oxime.
[0063] Figure 9 The H NMR spectrum of 4-bromobenzonitrile is: 1H NMR (400 MHz, Chloroform-d) δ 7.64 (d, J= 8.4 Hz, 2H), 7.53 (d, J= 8.5 Hz, 2H); the figure shows that 4-bromobenzonitrile was successfully synthesized by oxidation of 4-bromobenzaldehyde oxime.
[0064] In summary, this protocol provides a novel method for the preparation of a highly efficient B-COF photocatalyst and its innovative application in photocatalytic organic conversion. The prepared B-COF photocatalyst was applied to the organic conversion of aromatic aldehyde oximes to benzonitrile and its derivatives. The catalyst exhibited excellent photocatalytic performance, good stability, and the advantages of simple preparation and wide application.
[0065] The above content is only a preferred embodiment of the present invention, but the present invention should not be limited to the content disclosed in this embodiment. Therefore, any equivalent or modified content that does not depart from the spirit disclosed in the present invention shall fall within the scope of protection of the present invention.
Claims
1. A donor-acceptor covalent organic framework material B-COF photocatalyst, characterized in that: The catalyst was subjected to polycrystalline powder X-ray diffraction analysis, which showed a strong small-angle peak at 2θ=3.46°, which was marked as the 100 crystal plane.
2. The B-COF photocatalyst according to claim 1, characterized in that The catalyst included in the Fourier infrared test analysis, which was at 1140 cm -1 、1251 cm -1 , 1260 cm -1 、1570 cm -1 Characteristic absorption peaks appear at the positions, and the catalyst has characteristic signal peaks at 193.9, 148.5, 137.7, 127.1, 119.5, 115.2, 107.1, and 101.1 ppm in solid-state nuclear magnetic carbon spectrum analysis.
3. The method for preparing the B-COF photocatalyst according to claim 1 or 2, characterized in that: The steps include: A certain mass of 2,4,6-triformylphloroglucinol and benzidine were weighed and thoroughly mixed, and then an organic solvent was added. Subsequently, a certain amount of acidic solution was added, and gas exchange was performed. In a closed environment, a hot bath reaction was carried out at a set temperature. After the reaction was completed, a B-COF photocatalyst was obtained.
4. The method for preparing the B-COF photocatalyst according to claim 3, wherein: The reaction molar ratio of 2,4,6-triformylphloroglucinol to benzidine is 1-3:1-3, preferably 2:
3.
5. The method for preparing the B-COF photocatalyst according to claim 3, wherein: The organic solvent is a mixture of two or more of mesitylene, 1,4-dioxane, o-dichlorobenzene, dimethyl sulfoxide, and N-methylpyrrolidone; the mixed solvent is preferably mesitylene and 1,4-dioxane.
6. The method for preparing the B-COF photocatalyst according to claim 3, wherein: The acid solution is any one of nitric acid, hydrochloric acid, sulfuric acid, and acetic acid, preferably acetic acid; The concentration of acetic acid is 1 M to 12 M; preferably 6 M.
7. The method for preparing the B-COF photocatalyst according to claim 3, wherein: The temperature is heated to a specified reaction temperature of 80-140°C and maintained for 3-4 days, preferably the reaction temperature is 120°C; the reaction time is 3 days.
8. A photochemical reaction catalyst for converting aromatic aldehyde oxime or aromatic aldehyde oxime derivatives into nitrile and its derivatives, characterized in that: The catalyst is the B-COF photocatalyst according to claim 1 or 2, or the B-COF photocatalyst prepared by the preparation method according to any one of claims 3 to 7.
9. A method for catalyzing the conversion of aromatic aldehyde oxime to nitrile using a B-COF photocatalyst, characterized in that: The steps include: Add aromatic aldehyde oxime or an aromatic aldehyde oxime derivative to a glass reaction bottle, add a certain organic solvent, then add the B-COF photocatalyst according to claim 1 or 2, or the B-COF photocatalyst prepared by the preparation method according to any one of claims 3 to 7, then add the reaction substrate and additives, and react under light, after introducing gas, at a certain temperature to obtain the target product. The reaction formula is as follows: R is alkyl or halogen; The alkyl group is a C1-C10 straight-chain alkyl group or a branched-chain alkane, and the halogen group includes any one of F, Cl, and Br.
10. The method for converting aromatic aldehyde oxime into nitrile using a B-COF photocatalyst according to claim 9, characterized in that: The reactant is an aromatic aldoxime or an aromatic aldoxime derivative, and the additive includes NH4SCN, KSCN or NaSCN; The light source is an ultraviolet light or visible light source, and the power of the light source is 5W-70W.