Preparation method for crown ether covalent organic framework material, and use thereof in iodine adsorption

Abstract

Provided in the present invention are a preparation method for a crown ether covalent organic framework material, and the use thereof in iodine adsorption. In the present invention, an 18-crown-6-ether group is introduced into the structure of a covalent organic framework (COF) material for iodine adsorption work. The covalent organic framework material can form a one-dimensional pore channel structure in order, and the 18-crown-6-ether can be selectively complexed with iodine molecules, thereby achieving the purpose of efficient iodine adsorption. The material can perform specific iodine adsorption from high-temperature iodine steam, and the iodine steam adsorption capacity of the COF material is as high as 5.56 g / g. The COF material has a high adsorption capacity, is easy to prepare and simple to operate, has a high adsorption efficiency, and is particularly suitable for adsorbing and separating radioactive iodine in the nuclear industry.

Description

A method for preparing crown ether covalent organic framework materials and its application in iodine adsorption. (I) Technical Field

[0001] This invention relates to a method for preparing a novel covalent organic framework material with an 18-crown hexaether group, specifically for iodine adsorption, and belongs to the field of adsorption separation. (II) Background Technology

[0002] In recent years, waste products from the use of nuclear fuel have produced substances containing iodine isotopes ( 129 I and 131 Volatile radioactive compounds (I) must be removed from these exhaust gases before they are emitted. Compared to traditional treatment processes used to adsorb radioactive iodine and other iodine-containing compounds from exhaust gases, adsorption processes using porous solid adsorbents offer many advantages, including simple operation, low maintenance costs, and the elimination of the need for highly corrosive solutions. Currently, various adsorbents have been developed for iodine adsorption applications, including ceramics, zeolites, aerogels, metal-organic frameworks, and other materials. As an emerging adsorbent, covalent organic frameworks (COFs) are widely used due to their low density, high porosity, and excellent iodine adsorption capacity. Studies on iodine adsorption in COF materials have found that electron-rich adsorbents can effectively adsorb electron-deficient iodine by forming complexes. To prepare electron-rich adsorbents, various synthetic strategies have been developed, including constructing π-π conjugated bonds, doping with a large number of heteroatoms, and adding different heterocycles (such as triazine rings, pyrazine rings, etc.). Furthermore, N-containing functional groups (such as amines, imines, imidazoles, triazines, and pyridines) have been introduced into the framework structure to promote high iodine adsorption capacity.

[0003] Covalent organic frameworks (COFs) not only possess stable and tunable porous structures but also facilitate the design of functional group structures and properties. The crystallinity of COFs provides a well-defined, regular pore structure and the designability of active sites within the framework, which is beneficial for many applications in catalysis, adsorption, and separation, including iodine adsorption. In principle, by designing suitable monomers or through post-synthetic modification, COFs can possess the desired adsorption active sites for functionalization, thereby achieving high iodine adsorption capacity. Therefore, it is necessary to incorporate 18-crown-hexaenoic ether groups into the pore structure of COFs while maintaining high crystallinity and high porosity. This allows the COF material to simultaneously possess a one-dimensional pore structure and 18-crown-hexaenoic ether groups capable of complexing with iodine, significantly improving the iodine adsorption performance of the COF material. (III) Summary of the Invention

[0004] The application aims to provide a preparation method of a novel covalent organic framework material of an octadecacrown-6 ether group and iodine adsorption application thereof, and the COF-DB18C6 material is prepared in the application, and the prepared COF-DB18C6 has the performances of a large pore structure and strong force. The prepared COF-DB18C6 adsorbent has the advantages of high stability, simple preparation process, mild synthesis condition, high efficiency and the like, and the COF-DB18C6 material has very high adsorption performance and regeneration performance in iodine vapor.

[0005] The technical scheme of the application is as follows:

[0006] A novel COF-DB18C6 material of an octadecacrown-6 ether group is prepared according to the following method.

[0007] In a 100ml reaction kettle, 2,5-dimethylpyrazine (TT), 4,4',4'',4'''-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacyclooctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6), sodium hydroxide, mesitylene and methanol are put into the reaction kettle and ultrasonically dissolved for a period of time, then the reaction system is heated in an oven for a period of time, after the reaction is completed, the system is cooled and centrifuged, washed with DMF, THF, water and ethanol for several times, and vacuum dried at 100 DEG C to obtain a light yellow COF-DB18C6;

[0008] The mixed volume of the mesitylene and the methanol is 50-80ml;

[0009] The volume ratio of the mesitylene to the methanol is 1:0.5-10;

[0010] The molar ratio of the TT to the DB18C6 is 1:1-10;

[0011] The concentration of the DB18C6 dissolved in the mixed solution is 0.01-0.05mol / L;

[0012] The concentration of the sodium hydroxide in the mixed solution is 1-50mg / ml;

[0013] The reaction temperature is 80 DEG C-200 DEG C;

[0014] The reaction time is 0.5-7 days.

[0015] Compared with the prior art, the application has the following substantial advantages:

[0016] (1) The preparation process is simple and suitable for mass production;

[0017] (2) The synthesis condition is mild, and it is easy to prepare in a conventional synthesis environment;

[0018] (3) COF-DB18C6 has high chemical stability and thermal stability, and is suitable for iodine adsorption under different harsh conditions;

[0019] (4) COF-DB18C6 has high adsorption performance for iodine, and can deal with problems such as related radioactive accidents and environmental pollution. (IV) DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a BET schematic diagram of COF-DB18C6 in Example 1 of the present application;

[0021] Fig. 2 is an XRD schematic diagram of COF-DB18C6 in Example 1 of the present application;

[0022] Fig. 3 is a TGA schematic diagram of COF-DB18C6 in Example 1 of the present application;

[0023] Fig. 4 is an adsorption kinetics performance schematic diagram of COF-DB18C6 for iodine in Example 1 of the present application;

[0024] Fig. 5 is a cycle performance test diagram of COF-DB18C6 for iodine vapor in Comparative Example 1 of the present application; (V) PREFERRED EMBODIMENT

[0025] The present application will be described in detail below with specific examples, but the present application is not limited to the following examples, and variations of the embodiments should be included in the technical scope of the present application without departing from the content and scope of the present application.

[0026] Example 1: Preparation of COF-DB18C6

[0027] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4'',4'''-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacyclooctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (140 mg), mesitylene (30 ml) and methanol (30 ml) were put into the reaction kettle and ultrasonicated for a period of time until dissolved, and then the reaction system was reacted in an oven at 180°C for 4 days. After the reaction was completed, it was cooled and centrifuged, washed with DMF 3 times, THF 3 times, water 3 times, and ethanol 3 times, and dried at 100°C under vacuum to obtain a light yellow COF-DB18C6.

[0028] Example 2: Preparation of COF-DB18C6

[0029] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4",4"'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacloctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (140 mg), mesitylene (40 ml) and methanol (40 ml) were put into the reaction kettle and ultrasonic for a period of time to dissolve, then the reaction system was reacted in an oven at 180 °C for 4 days, after the reaction was completed, cooled and centrifuged, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, vacuum dried at 100 °C, to obtain a light yellow COF-DB18C6.

[0030] Example 3: Preparation of COF-DB18C6

[0031] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4",4"'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacloctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (140 mg), mesitylene (20 ml) and methanol (40 ml) were put into the reaction kettle and ultrasonic for a period of time to dissolve, then the reaction system was reacted in an oven at 180 °C for 4 days, after the reaction was completed, cooled and centrifuged, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, vacuum dried at 100 °C, to obtain a light yellow COF-DB18C6.

[0032] Example 4: Preparation of COF-DB18C6

[0033] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (0.5 mmol, 54.1 mg), 4,4',4",4"'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacloctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (140 mg), mesitylene (30 ml) and methanol (30 ml) were put into the reaction kettle and ultrasonic for a period of time to dissolve, then the reaction system was reacted in an oven at 180 °C for 4 days, after the reaction was completed, cooling and centrifugation, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, vacuum drying at 100 °C, a light yellow COF-DB18C6 was obtained.

[0034] Example 5: Preparation of COF-DB18C6

[0035] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4",4"'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacloctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (1 mmol, 620.4 mg), sodium hydroxide (140 mg), mesitylene (30 ml) and methanol (30 ml) were put into the reaction kettle and ultrasonic for a period of time to dissolve, then the reaction system was reacted in an oven at 180 °C for 4 days, after the reaction was completed, cooling and centrifugation, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, vacuum drying at 100 °C, a light yellow COF-DB18C6 was obtained.

[0036] Example 6: Preparation of COF-DB18C6

[0037] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4",4"'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacloctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (350 mg), mesitylene (30 ml) and methanol (30 ml) were put into the reaction kettle and ultrasonic for a period of time to dissolve, then the reaction system was reacted in an oven at 180 °C for 4 days, after the reaction was completed, cooling and centrifugation, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, vacuum drying at 100 °C, a light yellow COF-DB18C6 was obtained.

[0038] Example 7: Preparation of COF-DB18C6

[0039] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4",4"'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacloctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (140 mg), mesitylene (30 ml) and methanol (30 ml) were put into the reaction kettle and ultrasonic for a period of time to dissolve, then the reaction system was reacted in an oven at 150 °C for 4 days, after the reaction was completed, cooling and centrifugation, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, vacuum drying at 100 °C, a light yellow COF-DB18C6 was obtained.

[0040] Example 8: Preparation of COF-DB18C6

[0041] In a 100 ml reaction kettle, 2,5-dimethylpyrazine (TT) (1 mmol, 108.2 mg), 4,4',4”,4”'-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacyclooctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6) (0.5 mmol, 310.2 mg), sodium hydroxide (140 mg), mesitylene (30 ml) and methanol (30 ml) were placed in the reaction kettle and ultrasonicated for a period of time until dissolved, then the reaction system was reacted in an oven at 180°C for 2 days, after the reaction was completed, it was cooled and centrifuged, washed with DMF 3 times, THF 3 times, water 3 times, ethanol 3 times, and dried at 100°C under vacuum to obtain a light yellow COF-DB18C6.

[0042] Example 9: Adsorption of iodine vapor by COF-DB18C6

[0043] Before the experiment, all the COF-DB18C6 samples of examples 1-8 and the glass containers were fully vacuum degassed and dried, then 15 mg of COF-DB18C6 and excess iodine were added to two 20 ml sample bottles respectively, and the two sample bottles were placed in a sealable glass container at the same time, sealed and placed in a 75°C oven for heating, and taken out at certain time intervals, cooled to room temperature, and the mass change of COF-DB18C6 before and after iodine adsorption was measured.

[0044] Table 1: Iodine adsorption amount of COF-DB18C6 of examples 1-8

[0045] Example 10: Cycle performance test of regenerated COF-DB18C6 adsorbent for iodine vapor adsorption

[0046] After the iodine adsorption test of COF-DB18C6 of example 1 was selected, 200 mg of COF-DB18C6 after adsorbing iodine vapor (denoted as I2-COF-DB18C6) was stirred with 500 ml of ethanol at room temperature for 12 hours, washed 3 times, and filtered to obtain. Vacuum drying at 100°C, and measuring the weight percentage change of COF-DB18C6 before and after iodine desorption. The desorbed material was reused for iodine adsorption experiment, and the cycle was measured at least 5 times.

[0047] After 5 cycles of COF-DB18C6 in iodine vapor, the maximum adsorption capacity can still maintain more than 99% of the original maximum adsorption capacity.

[0048] Of course, the above specific embodiments are only to explain the corresponding technical solutions of the present application, and are not limited to the above embodiments. For those skilled in the art, various changes or modifications can still be made on the basis of the above embodiments. Here, all the embodiments are not listed, and all the changes or modifications derived from the similar principles or mechanisms are within the protection scope of the present application.

Claims

1. [Amended according to Rule 26 20.12.2024] A COF-DB18C6 material of a novel octadecacrown hexaether group, characterized by: The novel covalent organic framework material of the octa-crown ether group is prepared according to the following method: In a 100ml reaction kettle, 2,5-dimethylpyrazine (TT), 4,4',4'',4'''-(6,7,9,10,17,18,20,21-octahydrodibenzo[B,K][1,4,7,10,13,16]hexaoxacyclooctadecine-2,3,13,14-tetrayl) tetrakisbenzaldehyde (DB18C6), sodium hydroxide, trimethylbenzene and methanol are put into the reaction kettle and ultrasonic for a period of time until dissolved, then the reaction system is heated in an oven for a period of time, after the reaction is completed, it is cooled and centrifuged, washed with DMF, THF, water and ethanol for several times, and dried under vacuum at 100℃ to obtain a light yellow COF-DB18C6.

2. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The mixed volume of trimethylbenzene and methanol is 50-80ml.

3. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The volume ratio of trimethylbenzene and methanol is 1:0.5-10.

4. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The molar ratio of TT:DB18C6 is 1:1-10.

5. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The concentration of DB18C6 dissolved in the mixed solution is 0.01-0.05mol / L.

6. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The concentration of sodium hydroxide in the mixed solution is 1-50mg / ml.

7. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The reaction temperature is 80℃-200℃.

8. The COF-DB18C6 material of the novel octadecacrown hexaether group according to claim 1, characterized by: The reaction time is 0.5-7 days.

9. Use of the novel COF-DB18C6 material of the crown ether group of eighteen-crown-6 of claim 1 in iodine vapor adsorption performance, characterized by, The adsorption capacity of COF-DB18C6 for iodine vapor reaches 5.56g / g.

10. Use of the novel COF-DB18C6 material of the crown ether group of eighteen-crown-6 of claim 1 in the iodine vapor cyclic adsorption, characterized in that, After 5 cycles of adsorption in iodine vapor, the maximum adsorption capacity of COF-DB18C6 can still maintain more than 99% of the original maximum adsorption capacity.

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