Multi-foot arylamine one-dimensional covalent organic framework material, preparation method thereof and application of multi-foot arylamine one-dimensional covalent organic framework material in photocatalytic preparation of hydrogen peroxide

Abstract

The invention discloses a multi-foot arylamine one-dimensional covalent organic framework material, a preparation method thereof and an application of the multi-foot arylamine one-dimensional covalent organic framework material in photocatalytic preparation of hydrogen peroxide, the material is constructed by a multi-foot arylamine amino monomer and 2, 9-bis [P-(formyl) phenyl]-1, 10-phenanthroline through a Schiff base reaction, and the material has a unique one-dimensional linear structure and can be used for preparing hydrogen peroxide. The preparation method comprises the following steps: dissolving a monomer in a mixed solvent according to a specific molar ratio, and carrying out solvothermal reaction under acid catalysis to synthesize. The material, as a photocatalyst, shows high catalytic activity, selectivity and cycling stability in a reaction of synthesizing hydrogen peroxide under the driving of visible light, and provides a new material basis for developing an efficient and stable photocatalytic system.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic preparation of hydrogen peroxide, specifically relating to a multi-legged aromatic amine-based one-dimensional covalent organic framework material, its preparation method, and its application in photocatalytic preparation of hydrogen peroxide. Background Technology

[0002] Hydrogen peroxide (H₂O₂) is an important green chemical product with widespread demand in papermaking, environmental protection, chemical synthesis, and energy sectors. However, the traditional anthraquinone process for production is complex, energy-intensive, and pollutes the environment. Photocatalysis technology, which utilizes solar energy to directly synthesize hydrogen peroxide from water and oxygen, is considered a highly promising clean alternative.

[0003] Covalent organic frameworks (COFs) are a new class of crystalline porous polymers whose structures can be pre-designed and whose functions can be precisely controlled, showing great promise for applications in photocatalysis. Currently, most photocatalytic COFs are two-dimensional topologies, with relatively fast recombination rates of photogenerated carriers, limiting further improvements in catalytic efficiency. Constructing one-dimensional linear COF structures is expected to provide more direct electron transport pathways, thereby significantly improving charge separation efficiency.

[0004] 2,9-Bis[P-(formyl)phenyl]-1,10-phenanthroline, as a linear dialdehyde monomer, is an ideal electron acceptor unit for constructing one-dimensional COFs. Tetra-(4-aminophenyl)ethylene and 4',5'-bis(4-aminophenyl)-[1,1':2',1''-triphenyl]-4,4''-diamine, as polypody aromatic amine monomers, possess multiple amino reaction sites and electron-rich properties, making them ideal electron donor units for constructing donor-acceptor type COFs. However, constructing COF materials with one-dimensional structures, high stability, and suitability for photocatalytic hydrogen peroxide preparation based on these polypody aromatic amine monomers and phenanthroline acceptors still faces challenges. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of this invention is to provide a one-dimensional covalent organic framework material with a polypody aromatic amine group, its preparation method, and its application in the photocatalytic preparation of hydrogen peroxide. This material is constructed by a Schiff base reaction of a polypody aromatic amine amino monomer and 2,9-bis[P-(formyl)phenyl]-1,10-phenanthroline to form a crystalline material with a one-dimensional π-stacked structure and well-defined channels. This material makes full use of the excellent light absorption ability and electron-rich properties of the polypody aromatic amine amino monomer to construct a highly efficient donor-acceptor system with the phenanthroline unit. In the photocatalytic preparation of hydrogen peroxide, it exhibits high activity, high selectivity, and excellent cycle stability, providing a novel and highly efficient catalyst for the solar-driven synthesis of hydrogen peroxide.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing a multi-legged aromatic amino-based one-dimensional covalent organic framework material includes the following steps: A poly-aryl amine amino monomer, 2,9-bis[p-(formyl)phenyl]-1,10-phenanthroline, acetic acid, o-dichlorobenzene, and n-butanol were added to a Pyrex tube. The mixture was sonicated, and then the Pyrex tube was placed in liquid nitrogen. After the liquid was completely frozen, a vacuum was drawn to remove the gas from the tube. Then, the vacuum valve was closed and the solvent was thawed. The above liquid nitrogen freezing-vacuuming-thawing cycle was repeated several times to remove the gas present in the ligands and solvent. Then, the Pyrex tube was completely sealed with a flame torch under vacuum conditions. The Pyrex tube was then placed in an oven at room temperature for drying. After drying, the material was cooled to room temperature, the precipitate was centrifuged, and repeatedly washed with N,N-dimethylformamide, tetrahydrofuran, and ethanol until the supernatant was clear. The washed precipitate was then dried. After drying, the covalent organic framework material to be prepared was obtained.

[0007] Furthermore, the polypody aromatic amine amino monomer is tetra-(4-aminophenyl)ethylene or 4',5'-bis(4-aminophenyl)-[1,1':2',1''-triphenyl]-4,4''-diamine.

[0008] Furthermore, the molar ratio of the polypodyroamine amino monomer to 2,9-bis[P-(formyl)phenyl]-1,10-phenanthroline is 1:1.5~2.5; the volume ratio of acetic acid to the mass ratio of the polypodyroamine amino monomer is 1:50~90, with volume in ml and mass in mg.

[0009] Furthermore, the volume ratio of acetic acid, o-dichlorobenzene and n-butanol is 1:5~7:5~7, wherein the concentration of acetic acid is 6 mol / L.

[0010] Furthermore, the Pyrex tubes were placed in an oven at room temperature and the reaction was carried out at 100-150°C for 72-120 h.

[0011] This invention proposes a method for preparing a multi-legged aromatic amine-based one-dimensional covalent organic framework material.

[0012] Furthermore, the chemical structural formula of this material is shown in Formula I below: Formula I.

[0013] Furthermore, the chemical structural formula of this material is shown in Formula II below: Formula II.

[0014] This invention also proposes an application of the aforementioned multi-legged aromatic amine-based one-dimensional covalent organic framework material in the photocatalytic preparation of hydrogen peroxide under water and oxygen conditions.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: Molecular design innovation: This invention uses polypody aromatic amine monomers as the core building blocks to successfully synthesize one-dimensional COF materials, making full use of the strong light-harvesting ability and electron-rich properties of polypody aromatic amines to provide a rich electron source for photocatalytic reactions; Synergistic effect: The combination of the polypody aromatic amine unit (strong electron donor) and the phenanthroline unit (strong electron acceptor) forms a highly efficient electron donor-acceptor structure on the COF backbone. Combined with the one-dimensional linear structure, it greatly promotes the separation and migration of photogenerated electron-hole pairs. Excellent performance: The material of this invention exhibits a yield far exceeding that of many traditional catalysts and superior cycle stability in the photocatalytic preparation of hydrogen peroxide. Simple preparation: The equipment and chemical reagents used in this invention are inexpensive and readily available, and the process is simple to operate, which can improve the utilization rate of solar energy and has research significance and application potential in the field of photocatalysis. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the synthesis process of the multi-legged aromatic amino one-dimensional covalent organic framework ETTA-BFp-COF of the present invention; Figure 2 The X-ray diffraction pattern of the multi-legged aromatic amino one-dimensional covalent organic framework ETTA-BFp-COF of this invention; Figure 3 This is a comparison of the Fourier transform infrared spectra of the multi-legged aromatic amino-based one-dimensional covalent organic framework ETTA-BFp-COF of this invention. Figure 4 This is the solid-state carbon NMR spectrum of the multi-legged aromatic amino one-dimensional covalent organic framework ETTA-BFp-COF of this invention; Figure 5 This is the nitrogen adsorption-desorption isotherm of the multi-legged aromatic amino one-dimensional covalent organic framework ETTA-BFp-COF of the present invention; Figure 6 This is a comparison image of the scanning electron microscope (SEM) of the multi-legged aromatic amino one-dimensional covalent organic framework ETTA-BFp-COF of the present invention; Figure 7 Thermogravimetric analysis curve of the multi-legged aromatic amino one-dimensional covalent organic framework ETTA-BFp-COF of this invention.

[0017] Figure 8 This is a graph showing the relationship between the yield of hydrogen peroxide produced by the photocatalytic oxidation of the multi-legged aromatic amine one-dimensional covalent organic framework ETTA-BFp-COF under an oxygen atmosphere and time. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the scope described. Example 1

[0019] 1) Synthesis of ETTA-BFp-COF Tetra-(4-aminophenyl)ethylene (ETTA) (0.08 mmol), 2,9-bis[p-(formyl)phenyl]-1,10-phenanthroline (BFp) (0.15 mmol), 0.4 mL acetic acid, 2.0 mL o-dichlorobenzene, and 2.0 mL n-butanol were added to a 10 mL Pyrex tube. The mixture was sonicated for 30 minutes, and then the Pyrex tube was placed in liquid nitrogen. After the liquid was completely frozen, the tube was evacuated to remove the gas. The evacuation valve was then closed, and the solvent was thawed. This liquid nitrogen freezing-evacuation-thawing cycle was repeated three times to remove the ligands and gases present in the solvent. The Pyrex tube was then completely sealed with a flame torch under vacuum and placed in an oven at 150 °C for 72 hours. After cooling to room temperature, the precipitate was centrifuged and washed repeatedly with N,N-dimethylformamide, tetrahydrofuran, and ethanol until the supernatant was clear. The mixture was then dried overnight in a vacuum oven at 80°C to obtain the corresponding ETTA-BFp-COF.

[0020] 2) Material characterization: Figure 1 This is a schematic diagram of the synthesis process of the covalent organic framework material ETTA-BFp-COF.

[0021] Depend on Figure 2 It can be seen that the material prepared in this embodiment is ETTA-BFp-COF.

[0022] Depend on Figure 3 This further verifies the bond structure and configuration within ETTA-BFp-COF. The FT-IR spectrum of ETTA-BFp-COF is at approximately 1620 cm⁻¹. -1 The region exhibits a characteristic vibrational peak, corresponding to the formation of C=N bonds. 3348 cm⁻¹ -1 The shoulder peak at that point corresponds to the NH bond of the secondary amine and 1699 cm⁻¹ -1 The strong peak at the point is attributed to the disappearance of the C=O bond in the imine bond, and these features together confirm the successful synthesis of ETTA-BFp-COF.

[0023] Depend on Figure 4 It can be seen that through solid-state 13 C-cross polarized magic angle rotating nuclear magnetic resonance (C-C) 13CCP-MAS NMR analysis confirmed the structural integrity of the material. The low-field signal at approximately 150 ppm corresponds to the imine bonds (C=N) in the covalent organic framework.

[0024] Depend on Figure 5 It can be seen that the specific surface area of ​​the material is confirmed to be 300m² through specific surface area testing and analysis. 2 g −1 above.

[0025] Depend on Figure 6 As can be seen, the morphology of ETTA-BFp-COF was clearly observed by scanning electron microscopy (SEM), and it exhibited a uniform spherical structure.

[0026] Depend on Figure 7 It can be seen that it can maintain good thermal stability under conditions not exceeding 500℃. Example 2

[0027] 5 mg of the target product obtained in Example 1 was added to a photocatalytic reactor, followed by 100 ml of deionized water. The reactor was sealed and sonicated for 30 min. Oxygen was introduced into the water through a needle while maintaining pressure balance inside the bottle. Oxygen was continuously introduced over 30 min to maintain an oxygen atmosphere inside the reactor. Next, the glass bottle was irradiated with a xenon lamp fitted with a 400 nm filter. Every hour, 1 ml of the sample was taken through a needle and filtered. 0.4 ml of the filtered liquid was mixed with 3.6 ml of cerium sulfate solution. After gentle shaking under light-protected conditions and standing for 30 min, the solution was analyzed using a liquid ultraviolet spectrophotometer and compared with a cerium sulfate standard solution. The amount of hydrogen peroxide produced was calculated using the correlation between peak value and concentration, and the reaction ratio in the chemical reaction equation. The results are as follows: Figure 8 . Example 3

[0028] The yield of hydrogen peroxide produced by ETTA-BFp-COF under different atmospheres was determined, and the photocatalytic performance for hydrogen peroxide production is shown in Table 1. This indicates that the catalyst exhibits the best hydrogen peroxide production performance under pure oxygen conditions.

[0029] Table 1. Effects of different atmospheres on the photocatalytic hydrogen peroxide production performance of ETTA-BFp-COF. Sequence Amount of photocatalyst (mg) Wavelength of light source (nm) Atmosphere <![CDATA[Hydrogen peroxide yield (mmol g -1 h -1 )]]> 1 5 >400 nm O2 3.2 2 5 >400 nm Air 2.3 4 5 >400 nm Ar 0.48 Example 4

[0030] The photocatalytic hydrogen peroxide production cycle performance of ETTA-BFp-COF was tested: 5 mg of photocatalyst was dispersed in oxygen-saturated water (100 mL) and irradiated at a wavelength > 400 nm for one hour. After the reaction was complete, the suspension was filtered, and the filtrate containing hydrogen peroxide was analyzed using the aforementioned method. ETTA-BFp-COF was washed with distilled water (100 mL) and dried under vacuum at 80 °C for subsequent cycle testing. The photocatalytic hydrogen peroxide production cycle performance is shown in Table 2. The performance of ETTA-BFp-COF remained stable over four consecutive cycles, highlighting its sustained photocatalytic activity.

[0031] Table 2. Photocatalytic hydrogen peroxide production cycle performance test Sequence Number of cycles Amount of photocatalyst (mg) Wavelength of light source (nm) Atmosphere Hydrogen peroxide rate (pmol / L) 1 First time 5 >400 nm O2 3.2 2 Second time 5 >400 nm O2 3.1 3 Third time 5 >400 nm O2 3.0 4 Fourth time 5 >400 nm O2 3.1

[0032] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a multi-legged aromatic amino-based one-dimensional covalent organic framework material, characterized in that... Includes the following steps: A poly-aryl amine amino monomer, 2,9-bis[p-(formyl)phenyl]-1,10-phenanthroline, acetic acid, o-dichlorobenzene, and n-butanol were added to a Pyrex tube. The mixture was sonicated, and then the Pyrex tube was placed in liquid nitrogen. After the liquid was completely frozen, a vacuum was drawn to remove the gas from the tube. Then, the vacuum valve was closed, and the solvent was thawed. The above liquid nitrogen freezing-vacuuming-thawing cycle was repeated several times to remove the gas present in the ligands and solvent. Then, the Pyrex tube was completely sealed with a flame torch under vacuum conditions. The Pyrex tube was then placed in an oven at room temperature for heating reaction. After the reaction was completed, the material was cooled to room temperature, the precipitate was centrifuged, and washed repeatedly with N,N-dimethylformamide, tetrahydrofuran, and ethanol until the supernatant was clear. The washed precipitate was then dried, and the desired covalent organic framework material was obtained after drying.

2. The method for preparing a multi-legged aromatic amino-based one-dimensional covalent organic framework material according to claim 1, characterized in that... The polypody aromatic amine amino monomer is tetra-(4-aminophenyl)ethylene or 4',5'-bis(4-aminophenyl)-[1,1':2',1''-triphenyl]-4,4''-diamine.

3. The method for preparing a multi-legged aromatic amino-based one-dimensional covalent organic framework material according to claim 1, characterized in that... The molar ratio of the polypodyroamine amino monomer to 2,9-bis[P-(formyl)phenyl]-1,10-phenanthroline is 1:1.5~2.5, and the volume ratio of acetic acid to the mass ratio of the polypodyroamine amino monomer is 1:50~90. The volume unit is ml, and the mass unit is mg.

4. The method for preparing a multi-legged aromatic amino-based one-dimensional covalent organic framework material according to claim 1, characterized in that... The volume ratio of acetic acid, o-dichlorobenzene and n-butanol is 1:5~7:5~7, and the concentration of acetic acid is 6 mol / L.

5. The method for preparing a multi-legged aromatic amino-based one-dimensional covalent organic framework material according to claim 1, characterized in that... The Pyrex tubes were placed in an oven at room temperature and the reaction was carried out at 100–150°C for 72–120 h.

6. A multi-legged aromatic amine-based one-dimensional covalent organic framework material prepared by the method according to any one of claims 1-5.

7. A one-dimensional covalent organic framework material with a polypody aromatic amine group according to claim 6, characterized in that... The chemical structural formula of the material is shown in Formula I below: Formula I.

8. A one-dimensional covalent organic framework material with a polypody aromatic amine group according to claim 6, characterized in that... The chemical structural formula of this material is shown in Formula II below: Formula II.

9. The application of the multi-legged aromatic amine-based one-dimensional covalent organic framework material as described in claim 6 in the photocatalytic preparation of hydrogen peroxide under water and oxygen conditions.

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