Preparation method and application of naphthalene bridged tetraurea macrocycle

Abstract

The invention provides a preparation method and application of a naphthalene bridged tetraurea macrocycle, and belongs to the technical field of adsorption material preparation. According to the invention, 4, 4 '-methylene bis (phenyl isocyanate) and 1, 5-diaminonaphthalene are used as raw materials to prepare the naphthalene bridged tetraurea macrocyclic material. The naphthalene bridged tetraurea macrocyclic material has a fluffy porous structure, can be used for adsorption separation of elemental iodine and iodide ion pollutants, shows excellent iodine adsorption capacity and rate, also shows extremely high adsorption kinetics rate and high interference resistance, and can be recycled for multiple times.

Description

Technical Field

[0001] This invention relates to the field of adsorption material preparation technology, specifically to a method for preparing a naphthalene-bridged tetraurea macrocycle and its application. Background Technology

[0002] Nuclear energy, as a safe, efficient, and high-quality clean energy source, boasts advantages such as no greenhouse gas emissions and stable and reliable operation. However, the operation of nuclear reactors inevitably produces volatile radioactive iodine (such as 129I and 131I), whose long half-life (129I has a half-life of up to 1.57 × 10⁷ years) and high mobility pose a long-term threat to the ecological environment and human health. Therefore, the efficient capture and fixation of radioactive gaseous iodine is one of the core challenges for the safe disposal of nuclear waste and the high-quality development of nuclear energy. Iodine adsorbers are currently important equipment used in nuclear power plant reprocessing plants to remove radioactive iodine pollutants from process exhaust gases. The adsorption materials used in iodine adsorbers in domestic nuclear power plants are mainly coal-based or coconut shell activated carbon impregnated with triethylenediamine (TEDA) and potassium iodide (KI). Utilizing activated carbon as a porous substrate, radioactive iodine pollutants are adsorbed and fixed within the pores of the impregnating activated carbon through a specific chemical reaction between the impregnating agent TEDA and iodine compounds. However, due to the low TEDA loading (<5%), the adsorption capacity of impregnated activated carbon is low. To meet the requirements, the amount of activated carbon in the iodine adsorber needs to be increased, which in turn significantly increases the operating cost of nuclear facilities and the amount of solid waste.

[0003] Traditional macrocyclic molecules such as crown ethers, cyclodextrins, and calixarnes have been extensively studied, but their structural uniformity and functional limitations restrict their application in complex separation systems and molecular recognition. This invention employs a strategy of integrating building blocks of different structures into the same macrocyclic framework to develop a novel hybrid macrocyclic host. This host not only achieves selective recognition through precise control of cavity size and shape but also introduces multiple binding sites, significantly enhancing its binding capacity and separation efficiency for specific guests. It exhibits unique advantages in the field of adsorption separation. Promoting the development of clean energy has become an important means to drive the transformation of the energy structure towards low carbon, replacing the high-cost and high-solid-waste iodine adsorbers used in existing technologies. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for preparing a naphthalene-bridged tetraurea macrocycle and its application. The naphthalene-bridged tetraurea macrocycle prepared by this invention further enhances the adsorption strength and effect of the adsorbent material for radioactive iodine pollutants, thus replacing the iodine adsorbers used in existing technologies, which are costly and generate large amounts of solid waste.

[0005] The technical solution of this invention is as follows: a method for preparing a naphthalene-bridged tetraurea macrocycle, the preparation method specifically includes the following steps: Preparation of S1,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent: 4,4'-methylenebis(phenyl isocyanate) was dissolved in anhydrous tetrahydrofuran solution at a ratio of 20-30 mg: 1 mL to obtain 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent for later use; S2. Synthesis of naphthalene-bridged tetraurea macrocyclic intermediate: 1,5-diaminonaphthalene was dissolved in anhydrous tetrahydrofuran at a ratio of 482 mg:15 mL. Then, 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent was slowly added at a ratio of 25 mg:1 mL. The reaction was stirred in an ice-water bath for 25-35 min. The solid was collected by centrifugation at 3600 rpm and washed 3-5 times with ether and acetone alternately, with 25-50 mL of ether and acetone used each time, until the solution was colorless. Unreacted raw materials were removed and the solution was dried under vacuum at 75-100 °C for 5-7 h to obtain the naphthalene-bridged tetraurea macrocyclic intermediate. S3. Preparation of naphthalene-bridged tetraurea macrocycle: Dissolve the naphthalene-bridged tetraurea macrocycle intermediate in 15-25 mL of anhydrous dimethyl sulfoxide. Under nitrogen protection, slowly add 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent and heat the reaction. The molar ratio of the naphthalene-bridged tetraurea macrocycle intermediate to 4,4'-methylenebis(phenyl isocyanate) is 1:1~1.2. Stir the mixture while adding the solvent. The reaction temperature is 80~120℃, and the reaction is continued for 3~5 h. After the reaction is completed, cool to room temperature and centrifuge at 3600 rpm to collect the solid. Wash the solid 3-5 times with tetrahydrofuran and acetone alternately. Each wash with tetrahydrofuran uses 25~50 mL of tetrahydrofuran and each wash with acetone uses 25~50 mL of acetone. Wash until the solution is colorless to obtain the naphthalene-bridged tetraurea macrocycle. The molecular structure of the naphthalene-bridged tetraurea macrocycle is as follows: ; The reaction equation is as follows: .

[0006] In step S1 above, the ratio of 4,4'-methylenebis(phenyl isocyanate) to anhydrous tetrahydrofuran is 25 mg: 1 mL.

[0007] In step S2 above, the molar ratio of 1,5-diaminonaphthalene and 4,4'-methylenebis(phenyl isocyanate) is 3.05:1.

[0008] In step S2 above, the reaction is stirred for 30 minutes in an ice-water bath.

[0009] In step S3 above, the molar ratio of the naphthalene-bridged tetraurea macrocyclic intermediate to 4,4'-methylenebis(phenyl isocyanate) is 1:1.

[0010] In step S3 above, the reaction temperature is 100℃, and the reaction is continuously stirred for 4 hours.

[0011] In step S3 above, the vacuum drying temperature is 80~100℃ and the drying time is 6h.

[0012] The aforementioned application of naphthalene-bridged tetraurea macrocycles for iodine adsorption involves the adsorption of iodine molecules from iodine vapor or aqueous iodine solution by the naphthalene-bridged tetraurea macrocycles saturated with iodine. The naphthalene-bridged tetraurea macrocycles can then desorb and release iodine molecules at a temperature of 100-120°C.

[0013] The aforementioned adsorption of iodine molecules from iodine vapor by a naphthalene-bridged tetraurea macrocyclic ring was carried out at 75°C for 4–7 hours.

[0014] The aforementioned naphthalene-bridged tetraurea macrocyclic adsorption of iodine molecules in an aqueous solution was carried out by stirring at 25°C for 12-20 minutes.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention combines an electron-rich I-π recognition site and a urea hydrogen-bonded assembly unit within a single molecule. Without any external template, the macrocycle spontaneously self-assembles into a robust, porous supramolecular structure where the binding sites are fully open and easily accessible. The resulting material rapidly, selectively, and reversibly captures iodine in steam and water media, unaffected by anions in water, achieving an adsorption capacity of 904 mg / g in iodine vapor, demonstrating ultrafast absorption kinetics and excellent cycling stability. This provides a general design blueprint for supramolecular adsorption separation systems, demonstrating how the intentional integration of recognition sites and self-assembly motifs eliminates the need for complex framework engineering while providing an active, accessible, and process-dependent adsorbent. Attached Figure Description

[0016] Figure 1 Example 1: Scanning electron microscope image of naphthalene-bridged tetraurea macrocyclic ring; Figure 2 Example 4 shows the surface energy dispersive spectroscopy (EDS) spectrum of iodine after naphthalene-bridged tetraurea macrocyclic adsorption, representing carbon (C), iodine (I), oxygen (O) and nitrogen (N), respectively. Figure 3 Example 5: The absorbance of iodine in aqueous solution after naphthalene-bridged tetraurea macrocyclic adsorption was measured over time using a UV-Vis spectrophotometer. Figure 4Examples 6, 7, and 8: Adsorption capacity of iodine by naphthalene-bridged tetraurea macrocycle at different molar ratios for iodine and Cl⁻, Br⁻, SO₄⁻, and NO₃⁻. Figure 5 Example 9: Adsorption capacity of iodine on naphthalene-bridged tetraurea macrocycle in a mixed anionic solution of I2:Cl⁻:Br⁻:SO4⁻:NO3⁻=1:1:1:1:1; Figure 6 Example 10: Adsorption capacity of iodine by naphthalene-bridged tetraurea macrocycle in a mixed anionic solution with a molar ratio of I2:Cl⁻:Br⁻:SO⁻:NO⁻=1:10:10:10:10; Figure 7 Example 11: Adsorption capacity of iodine by naphthalene-bridged tetraurea macrocycle in a mixed anionic solution with a molar ratio of I2:Cl⁻:Br⁻:SO⁻:NO⁻=1:100:100:100; Figure 8 Example 12: X-ray photoelectron spectra of naphthalene-bridged tetraurea macrocyclic ring before and after iodine desorption; Figure 9 Example 13: Adsorption and separation effect diagram of iodine vapor after cyclic use of naphthalene-bridged tetraurea macrocyclic adsorption; Figure 10 Example 14: Adsorption and separation effect of a cyclic naphthalene-bridged tetraurea macrocyclic adsorption of a mixed anion solution of I2:Cl⁻:Br⁻:SO4⁻:NO3⁻=1:100:100:100:100. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 Preparation of S1,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent: 375 mg (1.5 mmol) of 4,4'-methylenebis(phenyl isocyanate) was dissolved in 15 mL of anhydrous tetrahydrofuran solution to obtain 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent for later use; S2. Synthesis of the naphthalene-bridged tetraurea macrocyclic intermediate: 482 mg (3.05 mmol) of 1,5-diaminonaphthalene was dissolved in 15 mL of anhydrous tetrahydrofuran, and then 10 mL of 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent (equivalent to 1.0 mmol of 4,4'-methylenebis(phenyl isocyanate)) was slowly added dropwise. After stirring in an ice-water bath for 30 min, the solid was collected by centrifugation at 3600 rpm and washed 4 times alternately with ether and acetone, 30 mL of ether and 30 mL of acetone each time, until the solution was colorless. Unreacted raw materials were removed, and the solution was dried under vacuum at 80 °C for 6 h to obtain the naphthalene-bridged tetraurea macrocyclic intermediate. S3. Preparation of naphthalene-bridged tetraurea macrocycle: 283 mg (0.5 mmol) of the naphthalene-bridged tetraurea macrocycle intermediate was dissolved in 20 mL of anhydrous dimethyl sulfoxide. Under nitrogen protection, 5 mL of 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent (equivalent to 0.5 mmol of 4,4'-methylenebis(phenyl isocyanate)) was slowly added dropwise while heating and stirring. The reaction was carried out at 100 °C for 4 h. After the reaction was completed, the temperature was lowered to room temperature, and the solid was collected by centrifugation at 3600 rpm. The solid was washed four times alternately with tetrahydrofuran and acetone, 30 mL of tetrahydrofuran and 30 mL of acetone each time, until the solution was colorless, thus obtaining the naphthalene-bridged tetraurea macrocycle. The reaction equation is as follows: The characterization data of the product prepared in this embodiment are as follows: H-S1, 1H NMR (400MHz, DMSO-d6, 298K): δ [ppm] = 8.68(s, 2H), 8.45(s, 2H), 8.02(d, J=8.0 Hz, 4H), 7.90(d, J=8.0 Hz, 2H), 7.79(d, J=8.0 Hz, 4H), 7.49(d, J=8.0 Hz, 4H), 7.22(t, J=4 Hz, 4H), 6.65(d, J=4 Hz, 2H), 5.70(s, 4H), 3.80(s, 2H). High-resolution mass spectrometry value m / z: 589.2328, corresponding to [C35H30N6O2Na+].

[0019] H-S2, 1H NMR (400MHz, DMSO-d6, 298 K): δ [ppm] = 8.97 (d, J = 8.0 Hz, 4H), 8.48 (d, J = 8.0 Hz, 4H), 8.03 (d, J = 8.0 Hz, 4H), 7.80 (d, J = 8.0 Hz, 4H), 7.50 (t, J = 8.0 Hz, 4H), 7.28 (t, J = 8.0 Hz, 8H), 7.07 (d, J = 8.0 Hz, 8H), 3.80 (s, 4H). High-resolution mass spectrometry value m / z: 838.8386, corresponding to [C50H40N8O4Na+].

[0020] The naphthalene-bridged tetraurea macrocycle was characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 1 As shown, the naphthalene-bridged tetraurea macrocycle has a flocculent porous structure.

[0021] Example 2 Preparation of S1,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent: 375 mg (1.5 mmol) of 4,4'-methylenebis(phenyl isocyanate) was dissolved in 30 mL of anhydrous tetrahydrofuran solution to obtain 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent for later use; S2. Synthesis of the naphthalene-bridged tetraurea macrocyclic intermediate: 482 mg (3.05 mmol) of 1,5-diaminonaphthalene was dissolved in 20 mL of anhydrous tetrahydrofuran, and then 10 mL of 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent (equivalent to 1.0 mmol of 4,4'-methylenebis(phenyl isocyanate)) was slowly added dropwise. After stirring the reaction in an ice-water bath for 25 min, the solid was collected by centrifugation at 3600 rpm and washed 5 times alternately with 25 mL of ether and 25 mL of acetone each time until the solution was colorless. Unreacted starting material was removed, and the solution was dried under vacuum at 75 °C for 7 h to obtain the naphthalene-bridged tetraurea macrocyclic intermediate. S3. Preparation of naphthalene-bridged tetraurea macrocycle: 283 mg (0.5 mmol) of the naphthalene-bridged tetraurea macrocycle intermediate was dissolved in 25 mL of anhydrous dimethyl sulfoxide. Under nitrogen protection, 5 mL of 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent (equivalent to 0.5 mmol of 4,4'-methylenebis(phenyl isocyanate)) was slowly added dropwise while heating and stirring. The reaction temperature was 120 °C, and the stirring was continued for 3 h. After the reaction was completed, the temperature was lowered to room temperature, and the solid was collected by centrifugation at 3600 rpm. The solid was washed three times alternately with tetrahydrofuran and acetone, with 50 mL of tetrahydrofuran and 50 mL of acetone used each time, until the solution was colorless, thus obtaining the naphthalene-bridged tetraurea macrocycle.

[0022] Example 3 Preparation of S1,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent: 375 mg (1.5 mmol) of 4,4'-methylenebis(phenyl isocyanate) was dissolved in 10 mL of anhydrous tetrahydrofuran solution to obtain 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent for later use; S2. Synthesis of the naphthalene-bridged tetraurea macrocyclic intermediate: 482 mg (3.05 mmol) of 1,5-diaminonaphthalene was dissolved in 15 mL of anhydrous tetrahydrofuran, and then 10 mL of 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent (equivalent to 1.0 mmol of 4,4'-methylenebis(phenyl isocyanate)) was slowly added dropwise. After stirring the reaction in an ice-water bath for 35 min, the solid was collected by centrifugation at 3600 rpm and washed three times alternately with 50 mL of ether and 50 mL of acetone each time until the solution was colorless. Unreacted raw materials were removed, and the solution was dried under vacuum at 100 °C for 5 h to obtain the naphthalene-bridged tetraurea macrocyclic intermediate. S3. Preparation of naphthalene-bridged tetraurea macrocycle: 283 mg (0.5 mmol) of the naphthalene-bridged tetraurea macrocycle intermediate was dissolved in 15 mL of anhydrous dimethyl sulfoxide. Under nitrogen protection, 5 mL of 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent (equivalent to 0.5 mmol of 4,4'-methylenebis(phenyl isocyanate)) was slowly added dropwise while heating and stirring. The reaction temperature was 80 °C, and the reaction was continued for 5 h. After the reaction was completed, the temperature was lowered to room temperature, and the solid was collected by centrifugation at 3600 rpm. The solid was washed 5 times alternately with tetrahydrofuran and acetone, with 25 mL of tetrahydrofuran and 25 mL of acetone used for each wash, until the solution was colorless, thus obtaining the naphthalene-bridged tetraurea macrocycle.

[0023] Example 4 The adsorption of iodine vapor by the naphthalene-bridged tetraurea macrocycle prepared in Example 1: Take a 20 mL culture bottle, add 500 mg of iodine solid, weigh 20 mg of the naphthalene-bridged tetraurea macrocyclic material prepared in Example 1 and place it in a 5 mL open culture bottle, place the open 5 mL culture bottle in the above 20 mL culture bottle, seal the 20 mL culture bottle, and place it in a 75°C oven for 5 hours.

[0024] The naphthalene-bridged tetraurea macrocycle that adsorbed iodine vapor was analyzed by energy-dispersive spectroscopy (EDS), and the characterization data are as follows: Test results as follows Figure 2 As shown in the EDS spectrum, the surface of the naphthalene-bridged tetraurea macrocycle exhibits different colors, representing different elements: carbon (C), iodine (I), oxygen (O), and nitrogen (N). The results indicate that iodine is successfully adsorbed onto the surface of the naphthalene-bridged tetraurea macrocycle.

[0025] Example 5 The adsorption of iodine in aqueous solution by the naphthalene-bridged tetraurea macrocycle prepared in Example 1: Take a 20 mL culture bottle, add 10 mL of 1.2 mmol / L iodine solution, and place 10 mg of naphthalene-bridged tetraurea macrocycle into the culture bottle. Seal the 20 mL culture bottle and stir at 25°C. Quickly collect 3 mL of the supernatant at 0, 1, 2, 3, 4, 6, 8, 10, 12, 14, and 16 min for analysis using a UV-Vis spectrophotometer. After analysis, pour the supernatant back into the culture bottle.

[0026] The iodine aqueous solution after adsorption of naphthalene-bridged tetraurea macrocycle was analyzed by ultraviolet-visible spectroscopy (UV-Vis), and the characterization data are as follows: Test results as follows Figure 3 As shown in the UV-Vis spectrophotometer, the concentration of iodine in the aqueous solution continuously decreases over time, reaching adsorption equilibrium at 12 min. This demonstrates the rapid adsorption of iodine from the aqueous solution by the naphthalene-bridged tetraurea macrocycle.

[0027] Example 6 The naphthalene-bridged tetraurea macrocycle prepared in Example 1 adsorbs iodine in aqueous solution in the presence of other anions: Take four 20 mL inoculum bottles and add 10 mL of a 1:1 mixed aqueous solution to each bottle (I2:Cl⁻ = 1:1 aqueous solution, chloride ions provided by sodium chloride; I2:Br⁻ = 1:1, bromide ions provided by sodium bromide; I2:SO₄⁻ = 1:1 sulfate ions provided by sodium sulfate; I2:NO₃⁻ = 1:1, nitrate ions provided by sodium nitrate). Then, add 10 mg of naphthalene-bridged tetraurea macrocyclic compound to each inoculum bottle, seal the 20 mL bottles, and stir at 25°C for 20 min.

[0028] The iodine aqueous solution (containing anions) after adsorption of naphthalene-bridged tetraurea macrocyclic ring was subjected to UV-Vis detection, and the characterization data are as follows: Test results as follows Figure 4 As shown, the results indicate that when the molar ratio of iodine to anion is 1:1, the naphthalene-bridged tetraurea macrocycle can still adsorb iodine in aqueous solution, and the maximum adsorption amount remains essentially unchanged.

[0029] Example 7 Adsorption of iodine in aqueous solution by naphthalene-bridged tetraurea macrocycle in the presence of other anions: Take four 20 mL culture bottles and add 10 mL of a mixed aqueous solution with a molar ratio of 1:1 (I2:Cl⁻ = 1:10 aqueous solution, chloride ions provided by sodium chloride; I2:Br⁻ = 1:10, bromide ions provided by sodium bromide; I2:SO₄⁻ = 1:10, sulfate ions provided by sodium sulfate; I2:NO₃⁻ = 1:10, nitrate ions provided by sodium nitrate). Then add 10 mg of naphthalene-bridged tetraurea macrocycle to the culture bottle, seal the 20 mL culture bottle, and stir at 25 °C for 20 min.

[0030] The iodine aqueous solution (containing anions) after adsorption of naphthalene-bridged tetraurea macrocyclic ring was subjected to UV-Vis detection, and the characterization data are as follows: Test results as follows Figure 4 As shown, the results indicate that when the molar ratio of iodine to anion is 1:10, the naphthalene-bridged tetraurea macrocycle can still adsorb iodine in aqueous solution, and the maximum adsorption amount remains essentially unchanged.

[0031] Example 8 Adsorption of iodine in aqueous solution by naphthalene-bridged tetraurea macrocycle in the presence of other anions: Take four 20 mL culture bottles and add 10 mL of a mixed aqueous solution with a molar ratio of 1:1 (I2:Cl⁻=1:100 aqueous solution, chloride ions provided by sodium chloride; I2:Br⁻=1:100, bromide ions provided by sodium bromide; I2:SO₄⁻=1:100 sulfate ions provided by sodium sulfate; I2:NO₃⁻=1:100, nitrate ions provided by sodium nitrate). Then add 10 mg of naphthalene-bridged tetraurea macrocycle to the culture bottle, seal the 20 mL culture bottle, and stir at 25 °C for 20 min.

[0032] The iodine aqueous solution (containing anions) after adsorption of naphthalene-bridged tetraurea macrocyclic ring was subjected to UV-Vis detection, and the characterization data are as follows: Test results as follows Figure 4 As shown, the results indicate that when the molar ratio of iodine to anion is 1:100, the naphthalene-bridged tetraurea macrocycle can still adsorb iodine in aqueous solution, and the maximum adsorption amount remains essentially unchanged.

[0033] Example 9 Adsorption of iodine in aqueous solution by naphthalene-bridged tetraurea macrocycle in the presence of other anions: Take a 20 mL culture bottle and add 10 mL of a mixed aqueous solution (I₂:Cl⁻:Br⁻:SO₄⁻:NO₃⁻ = 1:1:1:1:1, where chloride ions are provided by sodium chloride; bromide ions by sodium bromide; sulfate ions by sodium sulfate; and nitrate ions by sodium nitrate). Then, add 10 mg of naphthalene-bridged tetraurea macrocycle to the culture bottle, seal the 20 mL culture bottle, and stir at 25 °C for 20 min.

[0034] The iodine aqueous solution (containing anions) after adsorption of naphthalene-bridged tetraurea macrocyclic ring was subjected to UV-Vis detection, and the characterization data are as follows: Test results as follows Figure 5 As shown, the results indicate that in a solution of iodine and mixed anions, the naphthalene-bridged tetraurea macrocycle can still adsorb iodine in the aqueous solution, and the maximum adsorption amount remains essentially unchanged.

[0035] Example 10 Adsorption of iodine in aqueous solution by naphthalene-bridged tetraurea macrocycle in the presence of other anions: Take a 20 mL culture bottle and add 10 mL of a mixed aqueous solution (I₂:Cl⁻:Br⁻:SO₄⁻:NO₃⁻ = 1:10:10:10:10, where chloride ions are provided by sodium chloride; bromide ions by sodium bromide; sulfate ions by sodium sulfate; and nitrate ions by sodium nitrate). Then, add 10 mg of naphthalene-bridged tetraurea macrocycle to the culture bottle, seal the 20 mL culture bottle, and stir at 25 °C for 20 min.

[0036] The iodine aqueous solution (containing anions) after adsorption of naphthalene-bridged tetraurea macrocyclic ring was subjected to UV-Vis detection, and the characterization data are as follows: Test results as follows Figure 6 As shown, the results indicate that in iodine and mixed anion solutions, naphthalene-bridged tetraurea macrocycles can still adsorb iodine in aqueous solution, and the maximum adsorption amount remains essentially unchanged. Example 11 Adsorption of iodine in aqueous solution by naphthalene-bridged tetraurea macrocycle in the presence of other anions: Take a 20 mL culture bottle and add 10 mL of a mixed aqueous solution (I₂:Cl⁻:Br⁻:SO₄⁻:NO⁻=1:100:100:100, where chloride ions are provided by sodium chloride; bromide ions by sodium bromide; sulfate ions by sodium sulfate; and nitrate ions by sodium nitrate). Then, add 10 mg of naphthalene-bridged tetraurea macrocycle to the culture bottle, seal the 20 mL culture bottle, and stir at 25 °C for 20 min.

[0037] The iodine aqueous solution (containing anions) after adsorption of naphthalene-bridged tetraurea macrocyclic ring was subjected to UV-Vis detection, and the characterization data are as follows: Test results as follows Figure 7 As shown, the results indicate that in a solution of iodine and mixed anions, the naphthalene-bridged tetraurea macrocycle can still adsorb iodine in the aqueous solution, and the maximum adsorption amount remains essentially unchanged.

[0038] Example 12 Regeneration of naphthalene-bridged tetraurea macrocyclic material: 100 mg of naphthalene-bridged tetraurea macrocyclic material saturated with iodine was heated in a vacuum oven at 100°C for 3 hours to obtain the regenerated naphthalene-bridged tetraurea macrocyclic material.

[0039] The regenerated naphthalene-bridged tetraurea macrocycle was subjected to X-ray photoelectron spectroscopy (XPS) analysis, and the characterization data are as follows: Test results as follows Figure 8 As shown, the characteristic peak signal corresponding to iodine has disappeared in the XPS spectrum, which indicates that the Q[6] crystal material has completed desorption and regeneration and all iodine molecules have been released.

[0040] Example 13 Reuse of naphthalene-bridged tetraurea macrocyclic material: 100 mg of the regenerated naphthalene-bridged tetraurea macrocyclic material was repeated in Example 4.

[0041] The results of ultraviolet-visible spectroscopic spectroscopy indicate that, Figure 9 As shown, the naphthalene-bridged tetraurea macrocyclic material can selectively adsorb iodine mixed solution, and its selectivity does not decrease after being reused 5 times. Furthermore, the adsorption capacity remains essentially unchanged.

[0042] Example 14 Reuse of naphthalene-bridged tetraurea macrocyclic material: 100 mg of the regenerated naphthalene-bridged tetraurea macrocyclic material was repeated in Example 11.

[0043] The results of ultraviolet-visible spectroscopic spectroscopy indicate that, Figure 10 As shown, the naphthalene-bridged tetraurea macrocyclic material can selectively adsorb iodine mixed solution, and its selectivity does not decrease after being reused 5 times. Furthermore, the adsorption capacity remains essentially unchanged.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a naphthalene-bridged tetraurea macrocycle, characterized in that: The preparation method specifically includes the following steps: Preparation of S1,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent: 4,4'-methylenebis(phenyl isocyanate) was dissolved in anhydrous tetrahydrofuran solution at a ratio of 25 mg: 1~2 mL to obtain 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent for later use; S2. Synthesis of naphthalene-bridged tetraurea macrocyclic intermediate: 1,5-diaminonaphthalene was dissolved in anhydrous tetrahydrofuran at a ratio of 482 mg: 15-20 mL. Then, 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent was slowly added at a ratio of 25 mg: 1-2 mL. The reaction was stirred in an ice-water bath for 25-35 min. The solid was collected by centrifugation at 3600 rpm and washed 3-5 times with ether and acetone alternately, with 25-50 mL of ether and acetone used each time, until the solution was colorless. Unreacted raw materials were removed and the solution was dried under vacuum at 75-100 °C for 5-7 h to obtain the naphthalene-bridged tetraurea macrocyclic intermediate. S3. Preparation of naphthalene-bridged tetraurea macrocycle: Dissolve the naphthalene-bridged tetraurea macrocycle intermediate in 15-25 mL of anhydrous dimethyl sulfoxide. Under nitrogen protection, slowly add 4,4'-methylenebis(phenyl isocyanate)-tetrahydrofuran solvent and heat the reaction. The molar ratio of the naphthalene-bridged tetraurea macrocycle intermediate to 4,4'-methylenebis(phenyl isocyanate) is 1:1~1.

2. Stir the mixture while adding the solvent. The reaction temperature is 80~120℃, and the reaction is continued for 3~5 h. After the reaction is completed, cool to room temperature and centrifuge at 3600 rpm to collect the solid. Wash the solid 3-5 times with tetrahydrofuran and acetone alternately. Each wash with tetrahydrofuran uses 25~50 mL of tetrahydrofuran and each wash with acetone uses 25~50 mL of acetone. Wash until the solution is colorless to obtain the naphthalene-bridged tetraurea macrocycle. The molecular structure of the naphthalene-bridged tetraurea macrocycle is as follows: ； The reaction equation for the preparation of the naphthalene-bridged tetraurea macrocycle is as follows: 。 2. The preparation method according to claim 1, characterized in that: In step S1, the ratio of 4,4'-methylenebis(phenyl isocyanate) to anhydrous tetrahydrofuran is 25 mg: 1 mL.

3. The preparation method according to claim 1, characterized in that: In step S2, the molar ratio of 1,5-diaminonaphthalene and 4,4'-methylenebis(phenyl isocyanate) is 3.05:

1.

4. The preparation method according to claim 1, characterized in that: In step S2, the reaction is carried out under an ice-water bath with stirring for 30 minutes.

5. The preparation method according to claim 1, characterized in that: In step S3, the molar ratio of the naphthalene-bridged tetraurea macrocyclic intermediate to 4,4'-methylenebis(phenyl isocyanate) is 1:

1.

6. The preparation method according to claim 1, characterized in that: In step S3, the reaction temperature is 100℃, and the reaction is continuously stirred for 4 hours.

7. The preparation method according to claim 1, characterized in that: In step S3, the vacuum drying temperature is 80~100℃ and the drying time is 6h.

8. The adsorption application of iodine by naphthalene-bridged tetraurea macrocycle according to claim 1, characterized in that: The naphthalene-bridged tetraurea macrocycle can be used to adsorb iodine molecules in iodine vapor or iodine aqueous solution. The naphthalene-bridged tetraurea macrocycle saturated with iodine can desorb and release iodine molecules at a temperature of 100-120℃.

9. The application according to claim 8, characterized in that: The adsorption of iodine molecules from iodine vapor by the naphthalene-bridged tetraurea macrocyclic ring was carried out at 75°C for 4-7 hours.

10. The application of the naphthalene-bridged tetraurea macrocycle in iodine adsorption according to claim 8, characterized in that: The iodine molecules in the aqueous solution of the naphthalene-bridged tetraurea macrocyclic adsorption were obtained by stirring at 25°C for 12-20 minutes.

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