阅读说明：本技术 一种共价有机框架材料及其制备方法和应用 (Covalent organic framework material and preparation method and application thereof ) 是由 赵冰 郑旺 阚伟 宋天舒 宋波 孙立 王秀文 于 2021-08-03 设计创作，主要内容包括：一种共价有机框架材料及其制备方法和应用,它涉及共价有机框架材料及其制备方法和应用。它是要解决现有的共价有机框架材料仅适用于碘蒸气的吸附、对碘的吸附平衡时间长的技术问题。本发明的共价有机框架材料的结构单元为：它是采用2-(4-氨基苯基)-1H-菲[9,10-d]咪唑-6,9-二胺和间苯二甲醛反应得到的,该共价有机框架材料用于吸附碘蒸气或有机溶剂Ⅲ中的碘。对碘蒸气的最大吸附量可达到为1.69g·g～(-1),30h时达到吸附平衡,对碘蒸气的去除率为169wt％；对100mg/L的环己烷-碘溶液的碘的吸附量为127.80mg·g～(-1)。可循环使用4次以上。可用于碘的去除领域。(A covalent organic framework material and a preparation method and application thereof relate to the covalent organic framework material and the preparation method and the application thereof. The covalent organic framework material is used for solving the technical problems that the existing covalent organic framework material is only suitable for adsorption of iodine vapor and has long adsorption equilibrium time for iodine. The covalent organic framework material of the invention has the structural units as follows: it is prepared from 2- (4-aminophenyl) -1H-phenanthrene [9,10-d]Imidazole-6, 9-diamine and m-phthalaldehyde, and the covalent organic framework material is used for adsorbing iodine vapor or iodine in an organic solvent III. The maximum adsorption capacity of the iodine vapor can reach 1.69 g.g ‑1 The adsorption balance is achieved at 30h, and the removal rate of iodine vapor is improved169 wt%; the iodine adsorption amount to a cyclohexane-iodine solution of 100mg/L was 127.80mg g ‑1 . Can be recycled for more than 4 times. Can be used in the field of iodine removal.)

1. A covalent organic framework material characterized in that the structural units of the covalent organic framework material are:

2. a method of preparing the covalent organic framework material of claim 1, characterized in that the method is carried out by the following steps:

firstly, according to the mass ratio of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and m-phthalaldehyde being 1: (1-5) weighing 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and m-phthalaldehyde, adding into a schlenk tube, adding an organic solvent I and an acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 100-200 ℃ and reacting for 1-7 days;

and fourthly, cooling to room temperature after the reaction is finished, carrying out suction filtration, repeatedly washing a filter cake by using an organic solvent II, and drying in vacuum to obtain the covalent organic framework material.

3. The method of claim 2, wherein the organic solvent I in step one is one or a combination of two of mesitylene, p-dichlorobenzene, N-dimethylformamide, dioxane and N-butanol.

4. The method according to claim 2 or 3, wherein the ratio of the mass of the 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine to the volume of the organic solvent I in step one is (0.1-0.2) g:1 mL.

5. The method according to claim 2 or 3, wherein the acid in step one is one of glacial acetic acid, trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid, concentrated hydrochloric acid with a concentration of 30-37% by mass, concentrated sulfuric acid with a concentration of 95-98% by mass, or a combination of any two of them.

6. The method for preparing the covalent organic framework material according to claim 2 or 3, wherein the ratio of the mass of the 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine to the volume of the acid in the step one is 1g (0.3-0.5) mL.

7. The method of claim 2 or 3, wherein the organic solvent II for washing filter cake in step four is one or a combination of any two of tetrahydrofuran, methanol, ethanol, ethyl acetate, acetone, dichloromethane and 1, 2-dichloroethane.

8. Use of a covalent organic framework material according to claim 1 for adsorbing iodine vapor or iodine in an organic solvent iii.

9. Use of a covalent organic framework material according to claim 8, characterized in that the organic solvent III is petroleum ether, n-hexane, cyclohexane or acetone.

Technical Field

The invention relates to a covalent organic framework material, a preparation method and application thereof.

Background

Radioactive iodine (A)¹²⁹I and¹³¹I) is a typical radioactive pollutant which can be rapidly diffused in the air and has great harm to the health of human bodies. The radiation effect of radioactive iodine can be up to 1000 ten thousand years, wherein¹²⁹The half-life of I is 1570 ten thousand years. Therefore, it is of great interest and extremely challenging to study materials that can effectively remove radioactive iodine. Materials such as zeolites, activated carbons, molecular sieves, Metal Organic Frameworks (MOFs), etc. have been studied and used for iodine removal, and the design of these materials is mainly based on the pore channels and the specific pore channel environmental forces. However, the factors such as the complex and irregular pore channels of the materials often cause the blockage of the pore channel joints in the adsorption process, and the limited adsorption capacity of the pore channels cannot achieve the expected adsorption effect.

Covalent Organic Frameworks (COFs), a class of crystalline porous organic polymers linked by strong Covalent bonds, have many advantages such as diverse and designable structures, high porosity, and good stability, and have become popular among researchers in recent years. At present, documents about covalent organic framework materials for iodine adsorption are reported successively, and a novel two-dimensional mesoporous covalent organic framework material which can be used for adsorbing iodine vapor for multiple cycles and keeps almost unchanged adsorption capacity is designed and synthesized in an article of a two-dimensional mesoporous covalent organic framework with high gaseous iodine adsorption on the 12 th college chemical newspaper of the No. 12 of 2020, 41, but the material cannot be used for adsorbing iodine in an organic solvent. A novel nitrogen-rich covalent organic framework material is designed and synthesized in 2019, namely an article 'research on synthesis of nitrogen-rich covalent organic framework materials and iodine adsorption performance thereof' on No. 1 'Chinese science' of volume 49, and has adsorption characteristics on iodine vapor. In addition, chinese patent publication No. CN109705049A discloses a schiff base cyclic compound applied to efficient iodine adsorption, which has excellent iodine adsorption and storage properties. However, the two materials can only be used for adsorbing iodine vapor, so that the application is limited, and the adsorption equilibrium time of iodine is long.

Disclosure of Invention

The invention provides a covalent organic framework material and a preparation method and application thereof, aiming at solving the technical problems that the existing covalent organic framework material is only suitable for adsorption of iodine vapor and has long adsorption equilibrium time on iodine. The covalent organic framework material can adsorb iodine vapor and iodine in an organic solvent at the same time, can quickly reach adsorption balance, and has good cyclic adsorption performance.

The covalent organic framework material of the invention has the structural units as follows:

denoted m-PICOF.

The covalent organic framework material is obtained by reacting 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and m-phthalaldehyde, and the specific preparation method is as follows:

firstly, according to the mass ratio of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and m-phthalaldehyde being 1: (1-5) weighing 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and m-phthalaldehyde, adding into a schlenk tube, adding an organic solvent I and an acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 100-200 ℃ and reacting for 1-7 days;

and fourthly, cooling to room temperature after the reaction is finished, carrying out suction filtration, repeatedly washing a filter cake by using an organic solvent II, and drying in vacuum to obtain the covalent organic framework material.

Further, the organic solvent I in the step one is one or a combination of any two of mesitylene, p-dichlorobenzene, N-dimethylformamide, dioxane and N-butanol;

furthermore, the ratio of the mass of the 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine to the volume of the organic solvent I in the step one is (0.1-0.2) g:1 mL;

0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.21g of m-phthalaldehyde were added to a schlenk tube, and 1.0mL of n-butanol and 0.05mL of glacial acetic acid were added thereto and mixed uniformly;

further, the acid in the step one is one or a combination of any two of glacial acetic acid, trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid, concentrated hydrochloric acid with the mass percentage concentration of 30% -37%, and concentrated sulfuric acid with the mass percentage concentration of 95% -98%;

furthermore, the ratio of the mass of the 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine to the volume of the acid in the step one is 1g (0.3-0.5) mL;

further, the organic solvent II for washing the filter cake in the fourth step is one or a combination of any two of tetrahydrofuran, methanol, ethanol, ethyl acetate, acetone, dichloromethane and 1, 2-dichloroethane.

The chemical reaction formula of the covalent organic framework material of the invention is as follows:

the covalent organic framework material is applied to adsorbing iodine vapor or iodine in an organic solvent III.

Further, the organic solvent III refers to petroleum ether, n-hexane, cyclohexane, or acetone.

And (3) soaking the covalent organic framework material adsorbed with iodine vapor or iodine in an organic solvent III by using an organic solvent IV, desorbing, and recycling, wherein the organic solvent IV is one or a mixture of any more of methanol, ethanol, n-butanol, ethyl acetate, dichloromethane and acetone.

The covalent organic framework material of the invention can effectively adsorb iodine due to the regular structure, ordered pore channels, large specific surface area and adjustability of the pore channel structure, and has strong iodine adsorption capacity, high adsorption speed and simple adsorption method. The maximum adsorption capacity of the covalent organic framework material to iodine vapor can reach 1.69 g.g^-1The adsorption balance is achieved in 30 hours, and the removal rate of iodine vapor is 169 wt%; the iodine adsorption amount to a cyclohexane-iodine solution of 100mg/L was 127.80mg g^-1. And the adsorption effect of the covalent organic framework material on iodine in the organic solvent can be realized by naked eye observation. The covalent organic framework material can be recycled for more than 4 times of adsorption of iodine. Can be used in the field of iodine removal.

Drawings

FIG. 1 is an infrared spectrum of a covalent organic framework material prepared in example 1;

FIG. 2 is a point line graph (343K) showing the change in the adsorption amount of iodine vapor with adsorption time of the covalent organic framework material prepared in example 1, with the abscissa representing time and the ordinate representing the adsorption amount of iodine vapor;

FIG. 3 is a point line graph (343K) of the removal rate of iodine vapor by the covalent organic framework material prepared in example 1 versus adsorption time, with time on the abscissa and iodine vapor removal rate on the ordinate;

FIG. 4 is a point-line graph of the adsorption amount of the covalent organic framework material prepared in example 1 to iodine in cyclohexane-iodine solution (100mg/L) as a function of adsorption time, with the abscissa representing time and the ordinate representing the adsorption amount of iodine.

Detailed Description

The following examples are used to demonstrate the beneficial effects of the present invention:

example 1: the preparation method of the covalent organic framework material of the embodiment comprises the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.21g of m-phthalaldehyde, adding into a schlenk tube, adding 1.0mL of n-butanol and 0.05mL of glacial acetic acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 115 ℃ and reacting for 5 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with methanol, and performing vacuum drying to obtain the covalent organic framework material, wherein the yield is as follows: 78 percent.

In this embodiment the schlenk tube is Schlenk

The covalent organic framework material of example 1 was structurally characterized by fourier spectroscopy, and the resulting ir spectrum is shown in fig. 1. At 3384cm^-1The absorption peak at N-H disappears at 1693cm^-1The absorption peak at C ═ O disappeared and was at 1610cm^-1The characteristic absorption peak of C ═ N appears, which indicates that the covalent organic framework material is successfully prepared.

The covalent organic framework material in this example 1 was used for solid iodine adsorption test, and the specific method was as follows:

firstly, 0.01g of covalent organic framework material is weighed and added into a material with the mass of M₀In bottle I, the total mass of the covalent organic framework material and bottle I was weighed and recorded as M₁；

Weighing 0.02g of iodine simple substance, adding the iodine simple substance into a screw bottle II, and weighing the total mass of the iodine simple substance and the screw bottle II;

thirdly, placing the open port of the bottle I into a screw bottle II, and sealing the screw port of the screw bottle II;

fourthly, the sealed screw bottle II is placed in an oven at the temperature of 70 ℃ for keeping, the bottle I is taken out of the sealed screw bottle II and weighed after the keeping time is 2h, 3h, 5h, 6h, 8h, 10h, 15h, 20h, 30h, 40h, 50h and 60h respectively, and the bottles are marked as M sequentially₂、M₃、M₄、……、M₁₁、M₁₂、M₁₃。

From the data comparison, M is known₂、M₃、M₄、……、M₁₁、M₁₂、M₁₃Are all greater than M₁It can be seen that the covalent organic framework material adsorbs iodine vapor.

According to formula 1: (M)_n－M_n－1) 0.01 calculating the adsorption amount of the covalent organic framework material to iodine vapor (wherein n is 2, 3, … …, 13), obtaining a point line graph (343K) of the change of the adsorption amount of the covalent organic framework material to iodine vapor with adsorption time as shown in FIG. 2, wherein as the adsorption time increases, the adsorption amount of the covalent organic framework material to iodine vapor gradually increases, the adsorption equilibrium is reached at 30h, and the maximum adsorption amount of the covalent organic framework material to iodine vapor at equilibrium is 1.69g^-1。

Then according to formula 2:calculating the removal rate alpha (wt%) of the covalent organic framework material to iodine vapor, wherein M₀Indicating the quality of the empty bottle I; m₁Represents the mass of covalent organic framework material to vial I; m_nThe mass of bottle I and the frame material of the organic solvent after the n-th adsorption is shown. The change curve of the removal rate of the covalent organic framework material to the iodine vapor along with the time is obtained, and as can be seen from fig. 3, the removal rate of the covalent organic framework material to the iodine gradually increases along with the increase of the time, the release rate of the iodine is extremely rapid within a time period of 0-30 h, the release rate of the iodine vapor tends to be gentle within 30h, and the removal rate is 169 wt%, which indicates that the covalent organic framework material can remove the iodine and the desorption efficiency is high.

Soaking the covalent organic framework material adsorbed with iodine vapor in ethanol, measuring the ultraviolet absorption spectrum of the ethanol solution every 10min, observing the absorbance at the absorption wavelength of 525nm, and when the absorbance is not increased any more, completely removing iodine, indicating that the desorption is finished. And (4) carrying out centrifugal separation to obtain the desorbed covalent organic framework material, and carrying out vacuum drying for 48 h. Repeatedly used for adsorbing iodine vapor, the maximum adsorption amount of the iodine vapor still reaches 1.60 g.g^-1The covalent organic framework material can be reused 4 times.

The covalent organic framework material prepared in example 1 is used for iodine adsorption test in cyclohexane-iodine solution, and the specific method is carried out according to the following steps:

firstly, preparing a cyclohexane-iodine solution A with the volume of 10mL and the concentration of 100mg/L₁；

Second, measurement of A₁The ultraviolet absorption spectrum of the solution has an absorption wavelength of 525nm and the absorbance is recorded as T₁；

Three directions of A₁Adding 0.003g of the covalent organic framework material prepared in example 1 into the solution, sealing and standing for 48 hours;

fourthly, filtering out the covalent organic framework material by using a filter membrane to obtain a solution A₂；

Fifth, measure A₂The ultraviolet absorption spectrum of the solution has an absorption wavelength of 525nm and the absorbance is recorded as T₂(ii) a The iodine concentration is detected to be C through the standard curve of the cyclohexane-iodine solution₂；

Sixthly, comparing T₁And T₂Discovery of T₁＞4T₂It was determined that the covalent organic framework adsorbed iodine in solution.

In addition, solution A₁Purple, solution A₂Is colorless, and thus it can be qualitatively determined that the covalent organic framework material adsorbs iodine in solution.

The covalent organic framework material prepared in example 1 is used for quantitative adsorption test of iodine in cyclohexane-iodine solution, and the specific method comprises the following steps:

firstly, preparing a cyclohexane-iodine solution A with the volume of 10mL and the concentration of 100mg/L₁；

Second, measurement of A₁The ultraviolet absorption spectrum of the solution has an absorption wavelength of 525nm and the absorbance is recorded as T₁；

Three directions of A₁The solution was added with 3mg of the covalent organic framework material prepared in example 1, sealed and allowed to stand, samples were taken at intervals, and the covalent organic framework material was filtered off with a filter to obtain solution A₂(ii) a Measurement A₂The ultraviolet absorption spectrum of the solution has an absorption wavelength of 525nm and the absorbance is recorded as T₂(ii) a The iodine concentration is detected to be C through the standard curve of the cyclohexane-iodine solution₂；

Fourthly, calculating the change of the adsorption quantity of the covalent organic framework material to the iodine in the cyclohexane-iodine solution along with the time to obtain the iodine in the cyclohexane-iodine solution of the covalent organic framework material prepared in the example 1The dot line graph of the change of the adsorption amount with time is shown in fig. 4. As can be seen from FIG. 4, the adsorption amount of the covalent organic frameworks prepared in example 1 to iodine gradually increased with time, the adsorption amount of iodine rapidly increased in 0-180 min, gradually decreased in 1000min, and saturated in 1440min, and the adsorption amount of the covalent organic frameworks to iodine in a 100mg/L cyclohexane-iodine solution was 127.80mg g^-1。

Example 2: the preparation method of the covalent organic framework material of the embodiment is carried out according to the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.17g of m-phthalaldehyde, adding the weighed materials into a schlenk tube, adding 1.0mL of N, N-dimethylformamide and 0.05mL of concentrated hydrochloric acid with the mass fraction of 37%, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 150 ℃ and reacting for 3 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with ethyl acetate, and performing vacuum drying to obtain the covalent organic framework material, wherein the yield is as follows: and 69 percent.

Example 3: the preparation method of the covalent organic framework material of the embodiment is carried out according to the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.05g of isophthalaldehyde, adding the 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.05g of isophthalaldehyde into a schlenk tube, then adding 0.5mL of LN, N-dimethylformamide, 0.5mL of dioxane and 0.05mL of concentrated sulfuric acid with the mass fraction of 98%, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 130 ℃ and reacting for 5 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with ethanol, and performing vacuum drying to obtain the covalent organic framework material, wherein the yield is as follows: 75 percent.

Example 4: the preparation method of the covalent organic framework material of the embodiment is carried out according to the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.27g of m-phthalaldehyde, adding the weighed materials into a schlenk tube, adding 0.8mL of mesitylene, 0.2mL of dioxane and 0.1mL of p-toluenesulfonic acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 160 ℃, and reacting for 4 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with acetone, and performing vacuum drying to obtain the covalent organic framework material, wherein the yield is as follows: 70 percent.

Example 5: the preparation method of the covalent organic framework material of the embodiment is carried out according to the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.16g of m-phthalaldehyde, adding the weighed materials into a schlenk tube, adding 0.8mL of p-dichlorobenzene, 0.2mL of dioxane and 0.05mL of benzenesulfonic acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 120 ℃ and reacting for 5 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with tetrahydrofuran, and performing vacuum drying to obtain the covalent organic framework material, wherein the yield is as follows: 60 percent.

Example 6: the preparation method of the covalent organic framework material of the embodiment is carried out according to the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.21g of m-phthalaldehyde, adding the weighed materials into a schlenk tube, adding 0.5mL of n-butyl alcohol, 0.5mL of dioxane and 0.1mL of glacial acetic acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 100 ℃ and reacting for 5 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with dichloromethane, and performing vacuum drying to obtain a covalent organic framework material, wherein the yield is as follows: 65 percent.

Example 7: the preparation method of the covalent organic framework material of the embodiment is carried out according to the following steps:

firstly, respectively weighing 0.14g of 2- (4-aminophenyl) -1H-phenanthrene [9,10-d ] imidazole-6, 9-diamine and 0.21g of m-phthalaldehyde, adding the weighed materials into a schlenk tube, then adding 0.5mL of mesitylene, 0.5mL of N, N-dimethylformamide and 0.1mL of p-toluenesulfonic acid, and uniformly mixing;

secondly, performing cycle operation of vacuumizing and filling nitrogen into the schlenk tube to keep the nitrogen environment in the schlenk tube;

thirdly, heating the schlenk tube to 160 ℃, and reacting for 5 days;

and fourthly, cooling to room temperature after the reaction is finished, performing suction filtration, repeatedly washing a filter cake with dichloromethane, and performing vacuum drying to obtain a covalent organic framework material, wherein the yield is as follows: 72 percent.