Three-dimensional network imino covalent organic framework material as well as preparation method and application thereof

Abstract

The invention discloses a three-dimensional network imino covalent organic framework material as well as a preparation method and application thereof, and belongs to the field of materials. A specific number of multi-aldehyde benzene series and multi-amino benzene series are subjected to a Schiff base reaction, in the preparation process, a mode of combining ultrasonic dispersion and mechanical oscillation is adopted to ensure that reactants are uniformly mixed, and efficient polymerization can be realized at room temperature in cooperation with the synergistic catalysis of acetic acid or cesium carbonate and aniline or benzaldehyde; reaction conditions are mild and easy to control, damage of high temperature and high pressure to a material structure is avoided, meanwhile, directional assembly of a covalent organic framework is promoted through a solvent in a specific proportion and solvent types, formed imine bonds are stably combined, functional groups in a molecular structure endow the material with good chemical activity, and the covalent organic framework material is prepared. The accurate reaction of the multi-aldehyde benzene series and the multi-amino benzene series successfully constructs a three-dimensional network spherical structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of materials, in particular to a three-dimensional reticular imine-based covalent organic framework material and a preparation method and application thereof. BACKGROUND

[0002] With the continuous development of science and technology, the spheroidization shaping technology in powder technology is more and more valued by the development of industry. Since the spherical powder has the advantages of large specific surface area, good fluidity and other advantages that general powder does not have, it is widely used in catalysis, battery, chemical industry and other fields, and gradually becomes a new material that cannot be replaced. The preparation of spherical catalyst carrier for efficient catalyst loading has always been the focus and difficulty of the industry. For example, single-atom catalysts, although they have high activity, they are generally prone to agglomeration. Therefore, the preparation of high-density dispersion has always been a great challenge today. Therefore, the preparation of uniform spherical catalyst carrier is expected to overcome this technical difficulty.

[0003] Covalent organic framework materials are internal structures with uniformly distributed pores connected by light elements through covalent bonds. Compared with traditional materials, covalent organic frameworks have the advantages of large specific surface area, adjustable pore size, easy functional design, good chemical stability, and are widely used in gas storage and separation, catalysis, optoelectronic materials, environment, biomedicine and other fields. With these advantages, combined with the high stability of covalent organic framework materials, they have gradually attracted great attention in the field of environmental applications.

[0004] CN109320734A discloses a spherical covalent organic framework material and a preparation method and application thereof. Two covalent organic framework building blocks containing amino and aldehyde groups respectively are dissolved in an organic solvent, ultrasonic dispersion is carried out, a catalyst is quickly added, a Schiff base reaction occurs at a certain temperature, and the spherical covalent organic framework material is synthesized.

[0005] Wang et al. published a paper entitled "Highly Efficient Silver Catalyst Supported by a Spherical Covalent Organic Framework for the Continuous Reduction of 4-Nitrophenol" in ACS Applied Materials & Interfaces , which discloses that silver nanoparticles (AgNPs) are loaded onto a nitrogen-containing covalent organic framework material and exhibit good selectivity in catalyzing the reduction of 4-nitrophenol (4-NP). However, the existing preparation process of spherical covalent organic framework materials is complex, and the material performance is not stable.

[0006] In summary, covalent organic frameworks are widely used in catalysis, optoelectronics, environment and biomedicine, but the preparation process of covalent organic framework materials is complex, and the unstable material performance is still a problem to be solved. SUMMARY

[0007] In view of the above problems, the present application provides a kind of three-dimensional network imine-based covalent organic framework material and preparation method and application, through specific polyaldehyde benzene and polyamino benzene under the action of catalyst and control agent, spherical covalent organic structure is stably prepared, and active site is rich.

[0008] The present application provides a kind of three-dimensional network imine-based covalent organic framework material, the imine-based covalent organic framework material is spherical structure with three-dimensional network, average particle size is 0.2-0.7 μm, the imine-based covalent organic framework material is prepared by forming imine from polyaldehyde benzene and polyamino benzene under the action of catalyst and control agent; The number of aldehyde groups in the polyaldehyde benzene is 3, the number of amino groups in the polyamino benzene is 2, and the polyamino benzene has a-S-structure; The catalyst is acetic acid or cesium carbonate; The control agent is aniline or benzaldehyde.

[0009] Further, the structural general formula of the polyaldehyde benzene is Or Wherein, R1 is at least N or Or Or Or .

[0010] Further, the structural general formula of the polyamino benzene is Or Wherein, R2 and R3 are at least S-CH3 or S-H.

[0011] The present application also provides a preparation method of the three-dimensional network imine-based covalent organic framework material, comprising the following steps: Step 1, ultrasonic dispersion of polyaldehyde benzene and polyamino benzene in organic solvent to obtain a mixed solution; Step 2, adding catalyst and control agent to the mixed solution and mechanically oscillating, sealing and standing at room temperature for polymerization, centrifuging to obtain solid product, washing and drying the solid product to obtain the three-dimensional network imine-based covalent organic framework material.

[0012] Further, the molar ratio of the polyaldehyde benzene to the polyamino benzene in step 1 is (2:3)-(3:2).

[0013] Further, the mass of the polyaldehyde-based benzene series and the polyamino-based benzene series in the step 1 and the mass of the organic solvent are in a ratio of (2.5:1) to (3:1), wherein the unit of mass is mg and the unit of volume is mL.

[0014] Further, the number of aldehyde groups in the polyaldehyde-based benzene series in the step 1 is 3.

[0015] Further, the polyaldehyde-based benzene series is one or more of tris(4-formylphenyl)amine, tris(4-aldehyde biphenyl)amine, 1,3,5-tris(p-formylphenyl)benzene, 1,3,5-tris(4'-aldehyde[1,1'-biphenyl]-4-yl)benzene, and tris(3-aldehyde phenyl)benzene.

[0016] Further, the number of amino groups in the polyamino-based benzene series in the step 1 is 2.

[0017] Further, the polyamino-based benzene series is one or more of 2,5-dimercaptobenzene-1,4-diamine, 2,5-bis-methyl-mercaptobenzene-1,4-diamine, and 3,3'-dimercaptobiphenylamine.

[0018] Further, the organic solvent in the step 1 is a mixed solvent of mesitylene and 1,4-dioxane, wherein the volume ratio of the mesitylene and the 1,4-dioxane is 1:1.

[0019] Further, the time of the ultrasonic in the step 1 is 10-20 min.

[0020] Further, the concentration of the catalyst in the mixed solution in the step 2 is 0.15-0.3 mmol / mL.

[0021] Further, the catalyst in the step 2 is acetic acid or cesium carbonate.

[0022] Further, the volume ratio of the regulator to the mixed solution in the step 2 is (0.025-0.05):1.

[0023] Further, the regulator in the step 2 is aniline or benzaldehyde.

[0024] Further, the time of the mechanical oscillation in the step 2 is 3-5 min. Further, the time of the standing in the step 2 is 3-5 d.

[0025] Further, the speed of the centrifugation in the step 2 is 5000-10000 rpm, and the time of the centrifugation is 5-10 min.

[0026] Furthermore, the washing method in step 2 is as follows: the solid product is soaked in the washing liquid and then filtered to complete the washing.

[0027] Furthermore, the washing liquid is acetone.

[0028] Furthermore, the soaking time is 5-10 minutes.

[0029] Furthermore, the drying temperature in step 2 is 80-120℃, and the drying time is 12-24h.

[0030] This invention provides a heavy metal adsorbent, wherein the heavy metal adsorbent is the three-dimensional network imine-based covalent organic framework material.

[0031] Furthermore, the method for the heavy metal adsorbent to adsorb heavy metals is as follows: To contain Cu 2+ Hg 2+ Pb 2+ Cd 2+ The heavy metal adsorbent is added to the wastewater and stirred to carry out adsorption.

[0032] Furthermore, the pH of the wastewater is 6-7.

[0033] Furthermore, the mass-to-volume ratio of the heavy metal adsorbent to the wastewater is (0.1-0.5):(50-150), where mass is measured in g and volume in mL.

[0034] Furthermore, the Cu 2+ Hg 2+ Pb 2+ Cd 2+ The concentrations were all 0.2-0.5 mol / L.

[0035] Furthermore, the stirring speed is 300-500 rpm, and the adsorption time is 10-30 min.

[0036] Furthermore, the heavy metal adsorbent has a positive effect on Cu. 2+ Hg 2+ Pb 2+ Cd 2+ The adsorption molar percentages were 98-99.9%, 90-99.9%, 99-99.9%, and 95-99.9%, respectively.

[0037] The beneficial effects of this invention are: This invention utilizes a Schiff base reaction involving specific quantities of polyaldehyde-based benzene compounds and polyamino-based benzene compounds. During preparation, a combination of ultrasonic dispersion and mechanical oscillation ensures uniform mixing of the reactants. The synergistic catalytic effect of acetic acid or cesium carbonate with aniline or benzaldehyde enables efficient polymerization at room temperature. The reaction conditions are mild and easily controlled, avoiding the structural damage caused by high temperature and pressure. Simultaneously, purification steps including centrifugation and acetone washing effectively remove impurities, and an 80°C drying process further ensures material stability. Specific solvent ratios and types promote the directional assembly of the covalent organic framework, resulting in stable imine bonds. The thiol functional groups in the molecular structure endow the material with excellent chemical activity. The precise reaction of the polyaldehyde-based benzene compounds and polyamino-based benzene compounds successfully constructs a three-dimensional network spherical structure. Scanning electron microscopy confirms the uniform size and excellent dispersibility of the spheres. This well-ordered structure provides a large specific surface area and abundant pores, enhancing its application potential in adsorption, catalysis, and other fields. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the three-dimensional network imine-based covalent organic framework material structure described in Example 1. Figure 2 This is a scanning electron microscope image of the three-dimensional network imine-based covalent organic framework material described in Example 1. Figure 3 Scanning electron microscope (SEM) images of the three-dimensional network imine-based covalent organic framework materials described in Comparative Examples 1-3. Detailed Implementation

[0039] The invention will be described in detail below with reference to the embodiments: This invention provides a three-dimensional network imine-based covalent organic framework material. Through a simple preparation method, and with specific ratios and raw materials, the covalent organic framework material is prepared, which effectively improves the active sites of the material.

[0040] Example 1 This embodiment provides a three-dimensional network imine-based covalent organic framework material. The imine-based covalent organic framework material has a three-dimensional network spherical structure with an average particle size of 0.5 μm. The imine-based covalent organic framework material is prepared by forming imine groups from tris(4-formylphenyl)amine and 2,5-dimercaptophenyl-1,4-diamine under the action of acetic acid and aniline. The structural formula of the polyaldehyde benzene series compound is as follows: ; The structural formula of the polyaminobenzene compound is as follows: .

[0041] This embodiment also provides a method for preparing the three-dimensional network imine-based covalent organic framework material, including the following steps: Step 1: Disperse 6.59 mg (0.02 mmol) of tris(4-formylphenyl)amine and 5.17 mg (0.03 mmol) of 2,5-dimercaptophenyl-1,4-diamine by sonication for 10 min in 2 mL of mesitylene and 2 mL of 1,4-dioxane to obtain a mixed solution; Step 2: Add 0.036 g (0.6 mmol) acetic acid and 0.1 mL aniline to the mixed solution and mechanically shake for 3 min. After sealing, let it stand at room temperature for 3 days for polymerization. After polymerization, centrifuge at 8000 rpm for 7 min to obtain a solid product. Soak the solid product in acetone for 5 min and shake and wash. After filtration, dry at 80 °C for 24 h to obtain the three-dimensional network imine covalent organic framework material.

[0042] This embodiment provides a heavy metal adsorbent, wherein the heavy metal adsorbent is the three-dimensional network imine-based covalent organic framework material; The method for adsorbing heavy metals by the heavy metal adsorbent is as follows: Add 0.02 mol Cu to 100 mL of solution with a pH of 7. 2+ 0.02 mol Hg 2+ 0.02 mol Pb 2+ 0.02 mol Cd 2+ Add 0.1g of the heavy metal adsorbent to the wastewater and stir at 300rpm for 30min to carry out adsorption; The heavy metal adsorbent for Cu 2+ Hg 2+ Pb 2+ Cd 2+ The adsorption molar percentages were 98.11%, 90.26%, 99.49%, and 95.36%, respectively.

[0043] like Figure 1 This is a schematic diagram of the three-dimensional network imine-based covalent organic framework material structure described in Example 1.

[0044] like Figure 2 The image shows a scanning electron microscope (SEM) image of the three-dimensional network imine-based covalent organic framework material described in Example 1. As can be seen from the image, the spherical structures of the three-dimensional network imine-based covalent organic framework material are uniform in size and evenly dispersed.

[0045] Example 2 This embodiment provides a three-dimensional network imine-based covalent organic framework material. The imine-based covalent organic framework material has a three-dimensional network spherical structure with an average particle size of 0.7 μm. The imine-based covalent organic framework material is prepared by forming imine groups with tris(4-aldehyde biphenyl)amine and 2,5-dimethyl mercaptophenyl-1,4-diamine under the action of cesium carbonate and benzaldehyde. The structural formula of the polyaldehyde benzene series compound is as follows: ; The structural formula of the polyaminobenzene compound is as follows: .

[0046] This embodiment also provides a method for preparing the three-dimensional network imine-based covalent organic framework material, including the following steps: Step 1: Disperse 16.72 mg (0.03 mmol) of tris(4-aldehyde biphenyl)amine and 4.00 mg (0.02 mmol) of 2,5-dimethyl mercaptophenyl-1,4-diamine by sonication for 20 min in 4 mL of mesitylene and 4 mL of 1,4-dioxane to obtain a mixed solution; Step 2: Add 0.78 g (2.4 mmol) of cesium carbonate and 0.4 mL of benzaldehyde to the mixed solution and mechanically shake for 5 min. After sealing, let it stand at room temperature for 5 days for polymerization. After polymerization, centrifuge at 5000 rpm for 10 min to obtain a solid product. Soak the solid product in acetone for 10 min and shake and wash. After filtration, dry at 80 °C for 18 h to obtain the three-dimensional network imine covalent organic framework material.

[0047] This embodiment provides a heavy metal adsorbent, wherein the heavy metal adsorbent is the three-dimensional network imine-based covalent organic framework material; The method for adsorbing heavy metals by the heavy metal adsorbent is as follows: Add 0.02 mol Cu to 100 mL of solution with a pH of 6. 2+ 0.02 mol Hg 2+ 0.02 mol Pb 2+ 0.02 mol Cd 2+ Add 0.15g of the heavy metal adsorbent to the wastewater and stir at 300rpm for 30min to carry out adsorption; The heavy metal adsorbent for Cu 2+ Hg 2+ Pb 2+ Cd 2+ The adsorption molar percentages were 99.04%, 93.37%, 98.12%, and 97.97%, respectively.

[0048] Example 3 This embodiment provides a three-dimensional network imine-based covalent organic framework material. The imine-based covalent organic framework material has a three-dimensional network spherical structure with an average particle size of 0.6 μm. The imine-based covalent organic framework material is prepared by forming imine groups from 1,3,5-tris(p-formylphenyl)benzene and 3,3'-dimercaptobenzidine under the action of acetic acid and aniline. The structural formula of the polyaldehyde benzene series compound is as follows: ; The structural formula of the polyaminobenzene compound is as follows: .

[0049] This embodiment also provides a method for preparing the three-dimensional network imine-based covalent organic framework material, including the following steps: Step 1: Disperse 7.81 mg (0.02 mmol) of 1,3,5-tris(p-formylphenyl)benzene and 7.45 mg (0.03 mmol) of 3,3'-dimercaptobenzidine by sonication for 15 min in 3 mL of mesitylene and 3 mL of 1,4-dioxane to obtain a mixed solution; Step 2: Add 0.091 g (1.5 mmol) acetic acid and 0.18 mL aniline to the mixed solution and mechanically shake for 4 min. After sealing, let it stand at room temperature for 4 days for polymerization. After polymerization, centrifuge at 10000 rpm for 5 min to obtain a solid product. Soak the solid product in acetone for 5 min and shake and wash. After filtration, dry at 120 °C for 12 h to obtain the three-dimensional network imine covalent organic framework material.

[0050] Comparative Example 1 This comparative example provides a three-dimensional network imine-based covalent organic framework material with an average particle size of 0.5 μm. The imine-based covalent organic framework material is prepared by forming imine groups with tris(4-formylphenyl)amine and 2,5-dimercaptophenyl-1,4-diamine under the action of acetic acid and aniline.

[0051] This comparative example also provides a method for preparing the three-dimensional network imine-based covalent organic framework material, comprising the following steps: Step 1: Disperse 6.59 mg (0.02 mmol) of tris(4-formylphenyl)amine and 5.17 mg (0.03 mmol) of 2,5-dimercaptophenyl-1,4-diamine by sonication for 10 min in 1.2 mL of mesitylene and 2.8 mL of 1,4-dioxane to obtain a mixed solution; Step 2: Add 0.036 g (0.6 mmol) acetic acid and 0.1 mL aniline to the mixed solution and mechanically shake for 3 min. After sealing, let it stand at room temperature for 3 days for polymerization. After polymerization, centrifuge at 8000 rpm for 7 min to obtain a solid product. Soak the solid product in acetone for 5 min and shake and wash. After filtration, dry at 80 °C for 24 h to obtain the three-dimensional network imine covalent organic framework material.

[0052] Comparative Example 2 This comparative example provides a three-dimensional network imine-based covalent organic framework material with an average particle size of 0.5 μm. The imine-based covalent organic framework material is prepared by forming imine groups with tris(4-formylphenyl)amine and 2,5-dimercaptophenyl-1,4-diamine under the action of acetic acid and aniline.

[0053] This comparative example also provides a method for preparing the three-dimensional network imine-based covalent organic framework material, comprising the following steps: Step 1: Disperse 6.59 mg (0.02 mmol) of tris(4-formylphenyl)amine and 5.17 mg (0.03 mmol) of 2,5-dimercaptophenyl-1,4-diamine by sonication for 10 min in 1.5 mL of mesitylene and 2.5 mL of 1,4-dioxane to obtain a mixed solution; Step 2: Add 0.036 g (0.6 mmol) acetic acid and 0.1 mL aniline to the mixed solution and mechanically shake for 3 min. After sealing, let it stand at room temperature for 3 days for polymerization. After polymerization, centrifuge at 8000 rpm for 7 min to obtain a solid product. Soak the solid product in acetone for 5 min and shake and wash. After filtration, dry at 80 °C for 24 h to obtain the three-dimensional network imine covalent organic framework material.

[0054] Comparative Example 3 This comparative example provides a three-dimensional network imine-based covalent organic framework material with an average particle size of 0.5 μm. The imine-based covalent organic framework material is prepared by forming imine groups with tris(4-formylphenyl)amine and 2,5-dimercaptophenyl-1,4-diamine under the action of acetic acid and aniline.

[0055] This comparative example also provides a method for preparing the three-dimensional network imine-based covalent organic framework material, comprising the following steps: Step 1: Disperse 6.59 mg (0.02 mmol) of tris(4-formylphenyl)amine and 5.17 mg (0.03 mmol) of 2,5-dimercaptophenyl-1,4-diamine by sonication for 10 min in 2.8 mL of mesitylene and 1.2 mL of 1,4-dioxane to obtain a mixed solution; Step 2: Add 0.036 g (0.6 mmol) acetic acid and 0.1 mL aniline to the mixed solution and mechanically shake for 3 min. After sealing, let it stand at room temperature for 3 days for polymerization. After polymerization, centrifuge at 8000 rpm for 7 min to obtain a solid product. Soak the solid product in acetone for 5 min and shake and wash. After filtration, dry at 80 °C for 24 h to obtain the three-dimensional network imine covalent organic framework material.

[0056] like Figure 3 The images shown are scanning electron microscope (SEM) images of the three-dimensional network imine-based covalent organic framework materials described in Comparative Examples 1-3. a, b, and c are the irregular shapes of the materials in Comparative Examples 1, 2, and 3, respectively.

[0057] As can be seen from the above, the three-dimensional network imine-based covalent organic framework material of the present invention has a wide range of applications, low cost, and extremely high market prospects.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A three-dimensional network imine-based covalent organic framework material, characterized in that, The imine-based covalent organic framework material has a three-dimensional network spherical structure with an average particle size of 0.2-0.7 μm. The imine-based covalent organic framework material is prepared by forming imine groups from polyaldehyde benzene compounds and polyamino benzene compounds under the action of catalysts and regulators. The polyaldehyde benzene compound has 3 aldehyde groups, the polyamino benzene compound has 2 amino groups, and the polyamino benzene compound has a -S- structure. The catalyst is acetic acid or cesium carbonate; The regulator is aniline or benzaldehyde.

2. The three-dimensional network imine-based covalent organic framework material according to claim 1, characterized in that, The general structural formula of the polyaldehyde benzene series compounds is: or Where R1 is at least N or or or or .

3. The three-dimensional network imine-based covalent organic framework material according to claim 1, characterized in that, The general structural formula of the polyaminobenzene compound is: or Among them, R2 and R3 are at least S-CH3 or SH.

4. A method for preparing the three-dimensional network imine-based covalent organic framework material according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Disperse the polyaldehyde benzene series and the polyamino benzene series in an organic solvent by ultrasonication to obtain a mixed solution; Step 2: Add catalyst and regulator to the mixed solution and mechanically vibrate. After sealing, allow it to stand at room temperature for polymerization. After polymerization, centrifuge to obtain solid product. Wash the solid product and dry it to obtain the three-dimensional network imine covalent organic framework material.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the polyaldehyde benzene series and the polyamino benzene series in step 1 is (2:3)-(3:2).

6. The preparation method according to claim 4, characterized in that, The organic solvent in step 1 is a mixture of mesitylene and 1,4-dioxane, wherein the volume ratio of mesitylene to 1,4-dioxane is 1:

1.

7. The preparation method according to claim 4, characterized in that, The concentration of the catalyst in the mixed solution in step 2 is 0.15-0.3 mmol / mL.

8. The preparation method according to claim 4, characterized in that, In step 2, the volume ratio of the regulator to the mixed solution is (0.025-0.05):

1.

9. The preparation method according to claim 4, characterized in that, The drying temperature in step 2 is 80-120℃, and the drying time is 12-24h.

10. A heavy metal adsorbent, characterized in that, The heavy metal adsorbent is the three-dimensional network imine-based covalent organic framework material according to any one of claims 1-3.

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