Preparation method and application of pyrenyl imine covalent organic framework material

Abstract

The invention discloses a preparation method and application of a pyrenyl imine covalent organic framework material, and belongs to the technical field of materials. The preparation method comprises the following steps: dissolving 4, 4 ', 4', 4 ''-(pyrene-1, 3, 6, 8-tetrayl) tetraphenylamine and 3, 3 '-dimethoxy-[1, 1'-biphenyl]-4, 4 '-diformaldehyde in an organic solvent, fully mixing, and adding a catalyst to obtain a mixed solution; and freezing the mixed solution with liquid nitrogen, exhausting air, removing oxygen, carrying out a heating reaction, obtaining a yellow precipitate after the reaction is finished, and carrying out filtering, washing and vacuum drying treatment to obtain the pyrenyl imine covalent organic framework material. Pyrenyl and imine bonds on the pyrenyl imine covalent organic framework material structure prepared by the invention can provide a large number of binding sites bound with iodine, and the pyrenyl imine covalent organic framework material has the advantages of high crystallinity, large specific surface area, strong stability and the like, and can be used as a solid adsorption material for effective iodine vapor adsorption.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, and particularly relates to a method for preparing and applying a pyrene-imine covalent organic framework material. Background Technology

[0002] Nuclear energy, with its significant advantages of high energy density and low carbon emissions, has become a recognized key clean energy source in the global energy transition process, and has been widely used in power supply, industrial production, and other fields. It plays an irreplaceable strategic role in alleviating dependence on fossil fuels, reducing greenhouse gas emissions, helping to address global warming, and building a sustainable energy system.

[0003] However, nuclear fission inevitably produces large amounts of volatile radioactive isotope pollutants. These substances not only cause lasting damage to the ecological environment but also pose a serious and potential threat to human health. Among them, gaseous radioactive iodine, due to its extremely high environmental mobility and long half-life, can easily enter the food chain through atmospheric diffusion and water migration once leaked, causing long-term radioactive pollution risks. Its harmfulness is particularly prominent among various radioactive pollutants. Therefore, developing functional materials that can efficiently capture and stably fix volatile radioactive iodine has become a core requirement for ensuring nuclear safety, maintaining ecological stability, and protecting public health, and has crucial practical significance.

[0004] Covalent organic frameworks (COFs), a novel class of crystalline porous organic polymers formed by ordered covalent bonds, have shown broad application prospects in the field of radioactive iodine adsorption in recent years, attracting widespread attention from the scientific community due to their unique advantages such as highly regular internal structure, controllable porosity, excellent chemical stability, and high structural design flexibility. Existing research has clearly shown that the iodine adsorption performance of COFs mainly depends on the abundance of specific coordination sites in the material, such as functional groups containing heteroatoms (N) and electron-rich π-conjugated frameworks. These sites can form stable bonds with iodine molecules through electrostatic interactions and charge transfer interactions, thereby achieving efficient iodine capture.

[0005] To further enhance the iodine adsorption capacity of COFs, researchers typically employ post-modification or composite construction methods to functionalize them. This involves introducing complex framework monomers with specific binding capabilities into the COF system to strengthen the interaction between the material and iodine molecules. However, both methods have significant limitations: post-modification involves cumbersome synthesis steps, easily disrupting the integrity of the original crystal structure of the COFs during modification, leading to problems such as pore collapse and lattice defects. Furthermore, some modifying monomers exhibit poor bonding stability with the COF matrix, easily detaching during use and severely impacting the material's long-term adsorption performance. Composite construction methods face similar problems, including long synthesis cycles and easy monomer detachment. More importantly, the introduction of complex monomers may occupy the limited pore space within the COFs, actually reducing the material's adsorption capacity and failing to meet the demands of high-efficiency adsorption in practical applications.

[0006] Based on this, developing COFs materials with simple synthesis processes, abundant specific coordination sites, and excellent structural stability, and applying them to the efficient capture and stable storage of volatile radioactive iodine, can not only break through existing technological bottlenecks, but also has important practical significance and application value for promoting technological progress in fields such as nuclear waste treatment and nuclear facility safety protection. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a method for preparing and applying pyrene-imine covalent organic framework materials.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a pyrene-imine covalent organic framework material, the structural formula of which is shown in formula (I):

[0010]

[0011] (I).

[0012] This material has N-heteroatom imine bonds and pyrene group binding sites rich in conjugated π electrons. It has high crystallinity, large specific surface area, strong stability, and exhibits strong adsorption capacity for iodine vapor.

[0013] This invention provides a method for preparing the pyrene-imine covalent organic framework material, comprising the following steps:

[0014] 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde were dissolved in an organic solvent, thoroughly mixed, and then a catalyst was added to disperse the mixture to obtain a mixed solution.

[0015] The mixture was frozen with liquid nitrogen and then evacuated to remove oxygen. After heating and reaction, a yellow precipitate was obtained. After filtration, washing and vacuum drying, a pyrene-imine covalent organic framework material, abbreviated as PyTTA-BD(OMe)2, was obtained.

[0016] This invention uses pyrene-containing amines and methoxy-containing aldehydes as structural units to synthesize a pyrene-imine covalent organic framework material through a simple one-step reaction.

[0017] Furthermore, the molar ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde is 1:2.

[0018] Furthermore, the organic solvent is prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1.

[0019] Furthermore, the molar ratio of the catalyst to 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is 300:17.

[0020] Furthermore, the catalyst is acetic acid.

[0021] Furthermore, the heating reaction is carried out at a temperature of 120°C for 72 hours.

[0022] Furthermore, the washing is performed sequentially using acetone and tetrahydrofuran.

[0023] Furthermore, the vacuum drying process is carried out at a temperature of 80°C for 12-20 hours.

[0024] This invention also provides an application of pyrene-imine covalent organic framework materials in the field of iodine vapor adsorption.

[0025] When capturing radioactive iodine, the pyrene and imine bonds on the structure of the pyrene-imine covalent organic framework material prepared by this invention can provide a large number of binding sites for iodine. It also has the advantages of high crystallinity, large specific surface area and strong stability, and can be used as a solid adsorbent material for effective iodine vapor adsorption.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] This invention provides a pyrene-imine covalent organic framework material, which is obtained in a one-step reaction by pyrene-containing amines and methoxy-containing aldehydes as structural units, under an oxygen-free treatment in an organic solvent and with a catalyst. This preparation method is a novel strategy for designing and synthesizing pyrene-imine covalent organic framework materials, with advantages such as fewer steps, shorter cycle time, and higher efficiency. Furthermore, this material possesses N-heteroatom imine bonds and pyrene-group binding sites rich in conjugated π electrons, and exhibits advantages such as high crystallinity, large specific surface area, and strong stability. It can be used as a solid adsorbent for the effective adsorption of iodine vapor, and has significant practical significance and effective value. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 This is a process flow diagram for preparing pyrene-imine covalent organic framework materials in Example 1 of the present invention;

[0030] Figure 2 The infrared spectra of PyTTA and BD(OMe)2 in Example 1 and the prepared PyTTA-BD(OMe)2 are shown below.

[0031] Figure 3 Nitrogen adsorption-desorption curve (77K) of PyTTA-BD(OMe)2 prepared in Example 1;

[0032] Figure 4 The carbon NMR spectrum of PyTTA-BD(OMe)2 prepared in Example 1;

[0033] Figure 5 The X-ray powder diffraction pattern of PyTTA-BD(OMe)2 prepared in Example 1 is shown below.

[0034] Figure 6 The image shows a scanning electron microscope (SEM) image of PyTTA-BD(OMe)2 prepared in Example 1.

[0035] Figure 7 The image shows a transmission electron microscope (TEM) image of PyTTA-BD(OMe)2 prepared in Example 1.

[0036] Figure 8 The iodine vapor adsorption capacity-time curve of PyTTA-BD(OMe)2 prepared in Example 1 at 75°C;

[0037] Figure 9 The iodine retention rate of PyTTA-BD(OMe)2 prepared in Example 1 after adsorbing iodine vapor and being left at room temperature for 7 days is given. Detailed Implementation

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0041] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0042] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0043] The pyrene-imine covalent organic framework material provided by this invention has the structural formula shown in formula (I).

[0044]

[0045] (I).

[0046] Its molecular structure contains N-heteroatom imine bonds and pyrene group binding sites rich in conjugated π electrons, exhibiting high crystallinity, large specific surface area, and strong stability, and also demonstrating strong adsorption capacity for iodine vapor. This material is synthesized in a one-step reaction using pyrene-containing amines (4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine) and methoxy-containing aldehydes (3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde) as structural units. The synthetic route is shown in the figure below. Figure 1 As shown, the complete preparation experimental steps are as follows:

[0047] 1. Preparation before the experiment

[0048] Prepare the necessary raw materials, reagents, and equipment in advance: 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine, 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde (all with purity meeting synthesis requirements), o-dichlorobenzene (analytical grade), n-butanol (analytical grade), and acetic acid (analytical grade, used as a catalyst); experimental equipment includes a sealed reaction vessel, liquid nitrogen tank, vacuum pump, constant temperature water bath / oil bath heating equipment, sintered sand funnel (or filter device), vacuum drying oven, electronic balance (accuracy 0.0001g), pipettes, etc.

[0049] 2. Preparation of the mixture

[0050] 1) Weigh 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde separately using an electronic balance in a molar ratio of 1:2, and add the two monomers to a clean reaction vessel;

[0051] 2) Measure o-dichlorobenzene and n-butanol by volume ratio (1-4):(1-4) (exemplary, such as volume ratio 1:1, 1:4 or 4:1), and slowly add the mixed organic solvent to the reaction vessel containing the two monomers.

[0052] 3) After sealing the reaction vessel, place it on a magnetic stirrer and stir at room temperature to ensure that the monomer is fully dissolved in the organic solvent to form a homogeneous solution;

[0053] 4) Based on the ratio of "catalyst (acetic acid) to 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is 300:17", calculate and measure the required amount of acetic acid, slowly add the acetic acid dropwise to the above uniform solution, continue stirring to make the catalyst evenly dispersed, and finally obtain a clear and transparent mixture.

[0054] 3. Anaerobic reaction treatment

[0055] 1) Open the sealed lid of the reaction vessel, connect the vessel opening to the evacuation device, and then add liquid nitrogen to the liquid nitrogen bath surrounding the outside of the vessel to rapidly freeze the mixture to a solid state under the action of liquid nitrogen (ensure complete freezing and avoid residual oxygen in unfrozen areas).

[0056] 2) Start the vacuum device to vacuum the frozen reaction vessel and continue to evacuate to completely remove dissolved oxygen from the vessel and the mixture.

[0057] 3) Turn off the exhaust device, disconnect it from the reaction vessel, and quickly seal the reaction vessel to prevent air from re-entering; after the mixture in the reaction vessel has thawed naturally to room temperature, transfer it to a constant temperature water bath / oil bath.

[0058] 4. Heating reaction

[0059] Set the temperature of the constant temperature water bath / oil bath equipment to 120℃. After the temperature stabilizes, maintain the reaction vessel at this temperature for 72 hours (the state inside the vessel can be observed periodically during the reaction to avoid solvent evaporation or abnormal reaction due to poor sealing). In the later stage of the reaction, a yellow precipitate will gradually form in the vessel, indicating that the reaction is gradually completed.

[0060] 5. Product separation and washing

[0061] 1) After the reaction is complete, turn off the heating equipment and let the reaction vessel cool naturally to room temperature. Open the sealed lid and slowly transfer the reaction mixture (containing yellow precipitate and residual solvent) in the vessel to the microporous filter membrane of the sintered sand funnel. Start the suction filtration device to filter and collect the yellow solid precipitate on the microporous filter membrane.

[0062] 2) Use a pipette to measure an appropriate amount of acetone (analytical grade) and slowly rinse the yellow precipitate on the microporous filter membrane. After each rinse, continue to filter until no obvious liquid drips down. Repeat the rinsing to remove unreacted monomers and some residual solvents attached to the surface of the precipitate.

[0063] 3) Replace the microporous filter membrane (or clean the filter device), and transfer the yellow precipitate after washing with acetone back to the sand core funnel. Then, use tetrahydrofuran (analytical grade) to wash the precipitate in the same manner as above to further remove residual impurities and organic solvents from the precipitate and ensure product purity.

[0064] 6. Vacuum drying and product collection

[0065] 1) Transfer the washed yellow precipitate to a clean petri dish, spread it gently, and then place the petri dish in a vacuum drying oven;

[0066] 2) Set the temperature of the vacuum drying oven to 80℃, close the oven door and start the vacuum system. Under these conditions, continue drying for 12-20 hours (for example, drying time is 12 hours).

[0067] 3) After drying, first turn off the vacuum system, wait for the pressure inside the drying oven to return to normal pressure, then open the oven door, take out the petri dish, and cool it to room temperature to obtain a yellow powdery solid, which is the target product pyrene imine covalent organic framework material (abbreviated as PyTTA-BD(OMe)2). Transfer the product to a dry sample bottle, seal it and store it for later use.

[0068] The pyrene-imine covalent organic framework materials prepared above can be applied in the field of iodine vapor adsorption.

[0069] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃.

[0070] All raw materials used in this invention were purchased from the market.

[0071] The technical solution of the present invention will be further illustrated by the following embodiments.

[0072] Example 1

[0073] A method for preparing a pyrene-imine-based covalent organic framework material, comprising the following steps:

[0074] 1) Dissolve 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde (BD(OMe)2) in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1), mix thoroughly, and then add acetic acid to disperse, obtaining a mixed solution; wherein, 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde (BD(OMe)2) are dissolved in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1), and then disperse in acetic acid to obtain ... The molar ratio of 1,3,6,8-tetraphenyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde is 1:2; the molar ratio of acetic acid to 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine is 300:17; and the volume ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine to organic solvent is 193 mg:1 mL.

[0075] 2) The resulting mixture was frozen with liquid nitrogen and then evacuated to remove oxygen. It was then reacted at 120°C for 72 hours. After the reaction was completed, a yellow precipitate was obtained.

[0076] 3) The yellow precipitate was filtered, then washed with acetone and tetrahydrofuran in sequence, and finally dried under vacuum at 80°C for 12 h to obtain pyrene imine covalent organic framework material, abbreviated as PyTTA-BD(OMe)2.

[0077] Comparative Example 1

[0078] A method for preparing a pyrene-imine-based covalent organic framework material, comprising the following steps:

[0079] 1) Dissolve 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine (PyTTA) and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde (BD(OMe)2) in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:4), mix thoroughly, and then add acetic acid to disperse, obtaining a mixed solution; wherein, the molar ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde is 1:2. The molar ratio of acetic acid to 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is 300:17; the molar ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine to organic solvent is 193 mg:1 mL.

[0080] 2) The resulting mixture was frozen with liquid nitrogen and then evacuated to remove oxygen. It was then reacted at 120°C for 72 hours. After the reaction was completed, a yellow precipitate was obtained.

[0081] 3) The yellow precipitate was filtered, then washed with acetone and tetrahydrofuran in sequence, and finally dried under vacuum at 80°C for 12 h to obtain pyrene imine covalent organic framework material, abbreviated as PyTTA-BD(OMe)2.

[0082] Comparative Example 2

[0083] A method for preparing a pyrene-imine-based covalent organic framework material, comprising the following steps:

[0084] 1) Dissolve 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde (BD(OMe)2) in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 4:1), mix thoroughly, and then add acetic acid to disperse, obtaining a mixed solution; wherein, 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde (BD(OMe)2) The molar ratio of 1,3,6,8-tetraphenyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde is 1:2; the molar ratio of acetic acid to 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine is 300:17; and the volume ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine to organic solvent is 193 mg:1 mL.

[0085] 2) The resulting mixture was frozen with liquid nitrogen and then evacuated to remove oxygen. It was then reacted at 120°C for 72 hours. After the reaction was completed, a yellow precipitate was obtained.

[0086] 3) The yellow precipitate was filtered, then washed with acetone and tetrahydrofuran in sequence, and finally dried under vacuum at 80°C for 12 h to obtain pyrene imine covalent organic framework material, abbreviated as PyTTA-BD(OMe)2.

[0087] Comparative Example 3

[0088] 0.04 mmol of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine (PyTTA) and 0.02 mmol of 4',4'',4''',4''-(ethylene-1,1,2,2-tetramethyl)tetra(([1,1'-biphenyl]-3,5-dicarboxaldehyde)) (TPEE) were added to a 5 mL Pyrex tube, followed by 0.5 mL of toluene, 0.5 mL of benzyl alcohol, and 0.1 mL of acetic acid. The resulting mixture was frozen in liquid nitrogen and then degassed to remove oxygen. The reaction was carried out at 120 °C for 72 h. After the reaction was completed, the resulting yellow precipitate was extracted with tetrahydrofuran using a Soxhlet extractor for 24 h. Finally, it was dried under vacuum at 120 °C to obtain a deep yellow TPE-PyTTA-CMP.

[0089] Comparative Example 4

[0090] 1) Dissolve 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) and 2,7-dibenzaldehyde-benzothiadiazole in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1), mix thoroughly, and then add acetic acid to disperse, obtaining a mixed solution; wherein, 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) and 2,7-dibenzaldehyde-benzothiadiazole are dissolved in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1), and then disperse in acetic acid to obtain a mixed solution; wherein, 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (PyTTA) is dissolved in an organic solvent (prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:1), and then disperse in acetic acid to obtain a mixed solution. The molar ratio of 6,8-tetramethyl)tetraphenylamine and 2,7-dibenzaldehyde-benzothiadiazole is 1:2; the molar ratio of acetic acid to 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is 3:170; and the volume ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine to organic solvent is 193 mg:1 mL.

[0091] 2) The resulting mixture was frozen with liquid nitrogen and then evacuated to remove oxygen. It was then reacted at 120°C for 72 hours. After the reaction was completed, a yellow precipitate was obtained.

[0092] 3) The yellow precipitate was filtered, then washed sequentially with N,N-dimethylformamide and tetrahydrofuran, and finally dried under vacuum at 120°C for 12 h to obtain the target product.

[0093] Comparative Example 5

[0094] Similar to Example 1, the difference is that liquid nitrogen freezing and evacuation are not performed, and the mixture is directly heated, i.e., step 2) specifically: after the obtained mixture is sealed, it is reacted at 120°C for 72 hours.

[0095] Comparative Example 6

[0096] Granular activated carbon (Wuxi Xingzhiguang Activated Carbon Co., Ltd.)

[0097] Figure 2 The images show the infrared spectra of PyTTA and BD(OMe)2 from Example 1, as well as the prepared PyTTA-BD(OMe)2. As can be seen from the images, the NH absorption peak (3376 cm⁻¹) of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is present. -1 The C=O absorption peak (1681 cm⁻¹) of 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde is also present. -1 The absorption peak of the C=N bond disappeared, and the absorption peak of the C=N bond was observed in the synthesized pyrene imine covalent organic framework material; this indicates that the covalent bond was successfully formed.

[0098] Figure 3 The figure shows the nitrogen adsorption-desorption curve (77K) of PyTTA-BD(OMe)2 prepared in Example 1. As can be seen from the figure, the specific surface area of ​​this material is 1112 m². 2 / g.

[0099] Figure 4 The image shows the carbon NMR spectrum of PyTTA-BD(OMe)2 prepared in Example 1. As can be seen from the image, the peak at 158.59 ppm is a characteristic peak of C=N, and the peak at 52.85 ppm is a characteristic peak of -OCH3, indicating that the pyrene imine covalent organic framework material was successfully prepared.

[0100] Figure 5 The X-ray powder diffraction pattern of PyTTA-BD(OMe)2 prepared in Example 1 shows that the material exhibits two main peaks, which belong to the (100) and (300) crystal planes, respectively, confirming the crystallinity of the material.

[0101] Figure 6 The image shows a scanning electron microscope (SEM) image of PyTTA-BD(OMe)2 prepared in Example 1. As can be seen from the image, the morphology of this material is similar to that of a cauliflower.

[0102] Figure 7 The image shows a transmission electron microscope (TEM) image of PyTTA-BD(OMe)2 prepared in Example 1. As can be seen from the image, the material exhibits clear lattice fringes, indicating that the product has good crystallinity.

[0103] Figure 8 The figure shows the iodine vapor adsorption capacity-time curve of PyTTA-BD(OMe)2 prepared in Example 1 at 75℃. As can be seen from the figure, the material exhibits a rapid iodine vapor adsorption rate in the first 7.25 h, which gradually slows down, reaching adsorption equilibrium at 73 h, with a maximum adsorption capacity of 4.55 g / L. -1 .

[0104] Figure 9 The figure shows the iodine retention rate of PyTTA-BD(OMe)2 prepared in Example 1 after adsorbing iodine vapor and being left at room temperature for 7 days. As can be seen from the figure, the mass of the material after adsorption remained basically unchanged within 7 days.

[0105] The materials prepared in Example 1 and Comparative Examples 1-6 were used as iodine adsorbent materials for performance testing. The specific testing method was as follows: an open glass sample bottle containing 10 mg of adsorbent material was placed into a wide-mouth bottle containing excess iodine, the wide-mouth bottle was sealed, and then placed in a 75°C atmospheric pressure oven; the wide-mouth bottle was removed at regular intervals, cooled to room temperature, weighed, and the mass of the sample bottle was recorded until the mass stabilized. The iodine vapor adsorption capacity was calculated according to formula (1):

[0106]

[0107] Where, q t The adsorption amount of I2 at adsorption time t is m0 (mg), and the initial mass of the adsorbent is m. t The mass is the mass at adsorption time t.

[0108] The results are shown in Table 1.

[0109] Table 1. Performance test results of the materials prepared in Example 1 and Comparative Examples 1-6 as iodine adsorbents.

[0110] <![CDATA[Iodine adsorption capacity is (g g -1 ).]]> Example 1 4.55 Comparative Example 1 1.28 Comparative Example 2 1.64 Comparative Example 3 3.1 Comparative Example 4 3.97 Comparative Example 5 0.35 Comparative Example 6 0.80

[0111] The above experiments demonstrate that the pyrene imine covalent organic framework material prepared in the embodiments of the present invention exhibits good adsorption performance for iodine vapor.

[0112] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pyrene-imine-based covalent organic framework material, characterized in that, Its structural formula is shown in equation (Ⅰ): （Ⅰ）。 2. A method for preparing a pyrene-imine covalent organic framework material as described in claim 1, characterized in that, Includes the following steps: 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde were dissolved in an organic solvent, thoroughly mixed, and then a catalyst was added to disperse the mixture to obtain a mixed solution. The mixture was frozen with liquid nitrogen and then evacuated to remove oxygen. After heating and reaction, a yellow precipitate was obtained. After filtration, washing and vacuum drying, a pyrene-imine covalent organic framework material was obtained.

3. The preparation method according to claim 2, characterized in that, The molar ratio of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine and 3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-dicarboxaldehyde is 1:

2.

4. The preparation method according to claim 2, characterized in that, The organic solvent is prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 1:

1.

5. The preparation method according to claim 2, characterized in that, The molar ratio of the catalyst to 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is 300:

17.

6. The preparation method according to claim 5, characterized in that, The catalyst is acetic acid.

7. The preparation method according to claim 2, characterized in that, The heating reaction was carried out at a temperature of 120°C for 72 hours.

8. The preparation method according to claim 2, characterized in that, The washing process involves sequentially washing with acetone and tetrahydrofuran.

9. The preparation method according to claim 2, characterized in that, The vacuum drying process is carried out at a temperature of 80°C for 12-20 hours.

10. The application of a pyrene-imine covalent organic framework material as described in claim 1 in the field of iodine vapor adsorption.

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