Covalent organic framework material with conjugated structure as well as preparation method and application of covalent organic framework material

Abstract

The invention provides a covalent organic framework material with a conjugated structure as well as a preparation method and application thereof, and relates to the field of covalent organic framework materials. The covalent organic framework material is Cz-TA-COF, the novel conjugated covalent organic framework material containing a dicarbazole structural unit and a porphyrin structural unit is simply synthesized by adopting a solvothermal polymerization method, and the material has the characteristics of high specific surface area, high thermal stability, high chemical stability and the like, can be used as a solid adsorbent, and can be applied to the field of organic adsorption. The adsorption effect on the iodine steam is better.

Description

Technical Field

[0001] The present invention relates to the field of covalent organic framework (COF) materials, and specifically to a covalent organic framework material with a conjugated structure, its preparation method and application. Background Art

[0002] At present, the electricity generated by nuclear power plants accounts for 11% of the total global electricity generation. Nuclear power plants can emit some harmful substances. Radioactive iodine is a gaseous by-product generated during nuclear fission and is a dangerous radioactive pollutant. Due to its extremely long radioactive half-life ( 129 I, with a half-life of 1.57 million years) and extremely strong radiation toxicity ( 131 I) as well as the tendency of bioaccumulation, radioactive iodine poses a major threat to both the ecological environment and human health. Therefore, it is of crucial significance to develop safe, efficient and economical iodine waste treatment materials.

[0003] Covalent Organic Frameworks (COFs for short) are porous crystalline polymers linked by covalent bonds, generally composed of elements such as C, H, N, O, B, etc. They have significant advantages such as low density, large specific surface area, high thermal stability and chemical stability. In recent years, COFs materials have broad application prospects in the fields of gas storage, fluorescence detection and catalysis.

[0004] N atoms have a relatively high electronegativity, and they can attract iodine molecules through electrostatic interaction. Therefore, framework materials containing N-rich groups (such as NH2, N═C, etc.) have good adsorption ability for iodine molecules. The new framework structure prepared in the present invention contains carbazole, porphyrin structural units and Schiff base structures, increasing the binding sites between iodine molecules and the framework structure, thus increasing the adsorption ability of this material for iodine vapor.

[0005] The Schiff base condensation reaction is a chemical reaction in which an amine compound condenses with an aldehyde or a ketone to form a Schiff base with an imine structure. Since the reaction requires mild conditions and has a high yield, it is widely used in material synthesis and chemical reagent synthesis. Summary of the Invention

[0006] The purpose of the present disclosure is to provide a covalent organic framework material with a conjugated structure, its preparation method and application. By using the Schiff base condensation reaction, a new type of covalent organic framework material containing carbazole and porphyrin structural units is simply synthesized. This material has a large specific surface area, high thermal stability and chemical stability, and has strong adsorption ability for iodine vapor.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] The present invention first provides a covalent organic framework material (Cz-TA-COF) with a conjugated structure, as shown in Formula 1:

[0009]

[0010] The present invention also provides a preparation method of a covalent organic framework material (Cz-TA-COF) with a conjugated structure, comprising:

[0011] Disperse 3,3',6,6'-tetraformyl-9,9'-bicarbazole (Cz) and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (TA) in a reaction solvent, add a catalyst and react. After cooling to room temperature, filter, wash, and obtain a covalent organic framework material with a conjugated structure after vacuum drying.

[0012] Preferably, the molar ratio of 3,3',6,6'-tetraformyl-9,9'-bicarbazole to 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is 1:1.

[0013] Preferably, the reaction solvent is selected from one or more of 1,4-dioxane, mesitylene, o-dichlorobenzene, n-butanol, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide.

[0014] Preferably, the reaction solvent is a mixture of o-dichlorobenzene and n-butanol, wherein the volume ratio of o-dichlorobenzene to n-butanol is 1:5.

[0015] Preferably, the total concentration of 3,3',6,6'-tetraformyl-9,9'-bicarbazole and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is 10-50 mg / ml.

[0016] Preferably, the catalyst is selected from one of sulfuric acid, trifluoroacetic acid, phosphoric acid, or acetic acid aqueous solution.

[0017] Preferably, the content of the catalyst accounts for 0.1%-10% of the total volume.

[0018] Preferably, the reaction temperature is 25-280 °C, and the reaction time is 24-168 h.

[0019] The present invention also provides the application of the above covalent organic framework material with a conjugated structure in iodine vapor adsorption.

[0020] Advantages of the present invention

[0021] (1) A porous organic polymer with carbazole and porphyrin structural units was synthesized through Schiff base reaction, which has the characteristics of simplicity, greenness and high efficiency, enriching the construction methods and diversity of covalent organic framework materials.

[0022] (2) The covalent organic framework material obtained by the above method has the advantages of good crystallization, low density, large specific surface area, rich heteroatoms on the framework, high thermal stability and chemical stability, etc., and has advantages in the application field of iodine vapor adsorption. Description of the Drawings

[0023] The drawings of the specification that form a part of the present disclosure are used to provide a further understanding of the present disclosure. The schematic embodiments and descriptions thereof of the present disclosure are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure.

[0024] Figure 1 It is the nitrogen isothermal adsorption and desorption curve (77K) of Cz-TA-COF in Example 1 of the present disclosure;

[0025] Figure 2 It is the infrared spectrum of Cz-TA-COF in Example 1 of the present disclosure;

[0026] Figure 3 It is the solid-state nuclear magnetic resonance carbon spectrum of Cz-TA-COF in Example 1 of the present disclosure;

[0027] Figure 4 It is the PXRD spectrum of Cz-TA-COF in Example 1 of the present disclosure;

[0028] Figure 5 It is the scanning electron microscope image of Cz-TA-COF in Example 1 of the present disclosure;

[0029] Figure 6 It is the transmission electron microscope image of Cz-TA-COF in Example 1 of the present disclosure;

[0030] Figure 7 It is the nitrogen isothermal adsorption and desorption curve (77K) of Cz-TA-COF in Example 2 of the present disclosure;

[0031] Figure 8 It is the infrared spectrum of Cz-TA-COF in Example 2 of the present disclosure;

[0032] Figure 9 It is the nitrogen isothermal adsorption and desorption curve (77K) of Cz-TA-COF in Example 3 of the present disclosure;

[0033] Figure 10 It is the infrared spectrum of Cz-TA-COF in Example 3 of the present disclosure;

[0034] Figure 11This is the iodine adsorption-time curve of Cz-TA-COF in Example 1Cz-TA-COF of the present disclosure at 75 °C. Detailed implementation mode

[0035] The present invention first provides a covalent organic framework material (Cz-TA-COF) with a conjugated structure, as shown in Formula 1:

[0036]

[0037] The present invention also provides a preparation method of a covalent organic framework material (Cz-TA-COF) with a conjugated structure, including:

[0038] Disperse 3,3’6,6’-tetraformyl-9,9'-bicarbazole (Cz) and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (TA) in a reaction solvent, add a catalyst. Before the reaction, it is preferred to first ultrasonically treat the mixture in an ultrasonic cleaner. The ultrasonic treatment time is preferably 20 minutes, then bubble with nitrogen for 20 minutes, then seal the reaction kettle and react. After cooling to room temperature, filter, and wash the solid product successively with tetrahydrofuran and acetone, and obtain the covalent organic framework material Cz-TA-COF with a conjugated structure after vacuum drying. The specific reaction route is as follows:

[0039]

[0040] According to the present invention, the molar ratio of 3,3’6,6’-tetraformyl-9,9'-bicarbazole to 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is preferably 1:1. The total concentration of 3,3’6,6’-tetraformyl-9,9'-bicarbazole and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is preferably 10-50 mg / ml.

[0041] According to the present invention, the reaction solvent is preferably selected from one or more of 1,4-dioxane, mesitylene, o-dichlorobenzene, n-butanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide; more preferably one or a binary mixture of o-dichlorobenzene and n-butanol; most preferably o-dichlorobenzene / n-butanol (1:5 / mL:mL).

[0042] According to the present invention, the catalyst is preferably selected from one of sulfuric acid, trifluoroacetic acid, phosphoric acid or acetic acid aqueous solution, and more preferably 6M acetic acid aqueous solution. The content of the catalyst preferably accounts for 0.1%-10% of the total volume, and more preferably 6%.

[0043] According to the present invention, the reaction temperature is preferably 25 - 280 °C, more preferably 120 °C. The reaction time is preferably 24 - 168 h, more preferably 72 h.

[0044] The following is a further elaboration of the present disclosure in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present disclosure and not to limit the scope of the present disclosure. The experimental methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0045] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be obtained through conventional channels or synthesized by themselves according to the methods reported in the existing literature. Unless otherwise specified, the reagents or raw materials used in the present invention are used in the conventional manner in the art or according to the product instructions. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention. The preferred implementation methods and materials described in the text are only for demonstration purposes.

[0046] Example 1

[0047] 67.4 mg (0.1 mmol) of TA and 44.4 mg (0.1 mmol) of Cz were added to a 20 mL hydrothermal reaction kettle. 1 mL of o-dichlorobenzene and 5 mL of n-butanol were added, and then 0.4 mL of 6 M hydrochloric acid was added. The mixture was ultrasonicated in an ultrasonic cleaner for 20 minutes and then bubbled with nitrogen for 20 minutes. The reaction kettle was sealed and heated at 120 °C for 72 hours. After cooling to room temperature, it was filtered. The solid product was washed 3 times with tetrahydrofuran and acetone respectively and vacuum dried at 120 °C for 12 hours to obtain Cz-TA-COF.

[0048] The nitrogen adsorption and desorption curve of the product of Example 1 is as shown in the appendix Figure 1 It can be seen that the BET specific surface area of the product is 576 m 2 g -1 .

[0049] The infrared spectrum of the product of Example 1 is as shown in the appendix Figure 2 The solid nuclear magnetic resonance is as shown in the appendix Figure 3 The PXRD spectrum is as shown in the appendix Figure 4 indicating that the Cz-TA-COF was successfully prepared according to the present invention.

[0050] The scanning electron microscope (SEM) image of the product of Example 1 is as shown in the appendix Figure 5 It can be seen that the morphology of the product is a rod-like structure, with a diameter of about 0.1 - 0.3 microns and a length of about 0.5 - 2 microns. The transmission electron microscope (TEM) image is as shown in the appendix Figure 6As shown, obvious lattice fringes can be seen, indicating that the crystallinity of the product is very good.

[0051] Example 2

[0052] 67.4 mg (0.1 mmol) of TA and 44.4 mg (0.1 mmol) of Cz were added to a 20 mL hydrothermal reactor. 1 mL of o-dichlorobenzene and 1 mL of n-butanol were added, and then 0.4 mL of 6 M hydrochloric acid was added. The mixture was sonicated in an ultrasonic cleaner for 20 minutes and then bubbled with nitrogen for 20 minutes. The reactor was sealed and heated at 120 °C for 72 hours. After cooling to room temperature, the mixture was filtered, and the solid product was washed three times with tetrahydrofuran and acetone each, and vacuum dried at 120 °C for 12 hours to obtain Cz-TA-COF.

[0053] The nitrogen adsorption-desorption isotherm of the product of Example 2 is as shown in Figure 7 As shown, it can be seen that the BET specific surface area of the product is 344 m 2 g -1 . The infrared spectrum of the product of Example 2 is as shown in Figure 8 As shown.

[0054] Example 3

[0055] 67.4 mg (0.1 mmol) of TA and 44.4 mg (0.1 mmol) of Cz were added to a 20 mL hydrothermal reactor. 5 mL of o-dichlorobenzene and 1 mL of n-butanol were added, and then 0.6 mL of 6 M hydrochloric acid was added. The mixture was sonicated in an ultrasonic cleaner for 20 minutes and then bubbled with nitrogen for 20 minutes. The reactor was sealed and heated at 120 °C for 72 hours. After cooling to room temperature, the mixture was filtered, and the solid product was washed three times with tetrahydrofuran and acetone each, and vacuum dried at 120 °C for 12 hours to obtain Cz-TA-COF.

[0056] The nitrogen adsorption-desorption isotherm of the product of Example 3 is as shown in Figure 9 As shown, it can be seen that the BET specific surface area of the product is 213 m 2 g -1 . The infrared spectrum of the product of Example 2 is as shown in Figure 10 As shown.

[0057] Example 4

[0058] 20.3 mg of the Cz-TA-COF material prepared in Example 1 above was placed in a small glass bottle and weighed, and then the bottle was placed in a large glass bottle containing solid iodine. The large glass bottle was sealed and then placed in an oven. The oven was heated to 75 °C and kept at a constant temperature. The small glass bottle was taken out and weighed at regular intervals, and the time and mass were recorded. When the mass of the small glass bottle no longer increased, the measurement was stopped.

[0059] The iodine adsorption-time curve of the product of Example 1 at 75 °C is as shown in the appendix Figure 11 It can be seen that the adsorption rate of the material for iodine vapor is very fast in the first 500 minutes, and then gradually slows down, reaching the adsorption-desorption equilibrium at 3380 minutes, with the highest adsorption capacity of 2.37 g g -1 .

Claims

1. A covalent organic framework material with a conjugated structure, characterized in that, As shown in Formula 1:

2. The preparation method of a covalent organic framework material with a conjugated structure according to claim 1, characterized in that, Including: Disperse 3,3’6,6’-tetraformyl-9,9'-bicarbazole and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin in a reaction solvent, add a catalyst and react. After cooling to room temperature, filter, wash, and obtain a covalently organic framework material with a conjugated structure after vacuum drying.

3. The preparation method of a covalent organic framework material with a conjugated structure according to claim 2, characterized in that, The molar ratio of the described 3,3’6,6’-tetraformyl-9,9'-bicarbazole to 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is 1:

1.

4. The preparation method of a covalent organic framework material with a conjugated structure according to claim 2, characterized in that, The described reaction solvent is selected from one or more of 1,4-dioxane, mesitylene, o-dichlorobenzene, n-butanol, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide.

5. The preparation method of a covalent organic framework material with a conjugated structure according to claim 4, characterized in that, The described reaction solvent is a mixture of o-dichlorobenzene and n-butanol, where the volume ratio of o-dichlorobenzene to n-butanol is 1:

5.

6. The preparation method of a covalent organic framework material with a conjugated structure according to claim 2, characterized in that, The total concentration of the described 3,3’6,6’-tetraformyl-9,9'-bicarbazole and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is 10 - 50 mg / ml.

7. The preparation method of a covalent organic framework material with a conjugated structure according to claim 2, characterized in that, The described catalyst is selected from one of sulfuric acid, trifluoroacetic acid, phosphoric acid, or an aqueous acetic acid solution.

8. The preparation method of a covalent organic framework material with a conjugated structure according to claim 2, characterized in that, The content of the described catalyst accounts for 0.1% - 10% of the total volume.

9. The preparation method of a covalent organic framework material with a conjugated structure according to claim 2, characterized in that, The described reaction temperature is 25 - 280 °C, and the reaction time is 24 - 168 h.

10. Use of the covalently organic framework material with a conjugated structure described in claim 1 in iodine vapor adsorption.

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