Covalent organic framework material containing spiral monomer and preparation method and application thereof
By synthesizing covalent organic framework materials using hexahexene monomers and TPDA monomers, the problem of insufficient iodine adsorption performance of existing materials has been solved, achieving low electrochemical impedance and excellent iodine adsorption performance, thus expanding its application in the field of iodine adsorption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-30
- Publication Date
- 2026-04-14
AI Technical Summary
The application of existing covalent organic framework materials in the field of iodine adsorption has not been fully developed, especially the research on novel materials introduced through helical compounds, which leads to the need to improve adsorption and electrochemical performance.
Covalent organic framework materials were synthesized using hexaspirene monomers and TPDA monomers. Through a freeze-pump-thaw cycle degassing treatment and a heating crystallization reaction, covalent organic framework materials with excellent crystallinity and microporous channels were prepared for iodine adsorption.
It achieves low electrochemical impedance and good iodine adsorption and desorption properties, thus improving the material's efficiency in the field of iodine adsorption.
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Figure CN121851301A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to organic framework material preparation technology, and in particular to a covalent organic framework material containing helical monomers, its preparation method and application. Background Technology
[0002] With the continuous depletion of global energy, environmental pollution has become one of the most serious global problems facing humanity. Nuclear fusion, as a green and sustainable energy source, is considered one of the key new energy sources for solving the energy dilemma for human survival and development. However, the risk of radioactive pollution associated with nuclear energy cannot be ignored, as it may lead to damage to organisms and genetic mutations in offspring. Iodine, a common radioactive pollutant in nuclear power plants, has a long half-life and a significant impact on humans; therefore, the adsorption and sequestration of radioactive iodine is of great importance. In the past few decades, activated carbon, metallic hydrotalcite, and MOFs have been mainly used for iodine adsorption. In recent years, with continuous exploration in materials research, covalent organic frameworks (COFs) are now widely used in the field of iodine adsorption due to their diverse structures, tunable band gaps, large specific surface areas, and strong advantages in the optoelectronic field.
[0003] However, most of the reported COFs are synthesized by two-component or multi-component cocondensation polymerization of two planar monomers. Developing novel covalent organic framework materials and exploring their application in the field of iodine adsorption remains a research focus. This patent develops and explores a novel covalent organic framework that introduces helical compounds. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a covalent organic framework material containing helical monomers, its preparation method, and its application. The covalent organic framework is synthesized using hexahexene monomers and TPDA monomers, exhibiting excellent crystallinity and microporous channels, lower electrochemical impedance, and good iodine adsorption and desorption properties.
[0005] The first aspect of the present invention provides a covalent organic framework material containing helical monomers, which is a covalent organic framework material prepared from hexahexene monomers and TPDA monomers;
[0006] The chemical structural formula of the hexahexolene monomer is as follows: ;
[0007] The chemical structural formula of the TPDA monomer is: ;
[0008] The general chemical structural formula of covalent organic framework materials is:
[0009] ;
[0010] Wherein, R is methoxy, methyl, cyano, phenyl, fluorine, chlorine, or bromine.
[0011] A second aspect of this invention provides a method for preparing a covalent organic framework material containing helical monomers, comprising the following steps:
[0012] S1. Add hexahexene monomers and TPDA monomers to a Pyrex tube, add an organic solvent and disperse ultrasonically, then add a catalyst and continue dispersion to obtain a mixed solution;
[0013] S2. After the mixed solution is degassed by a freeze-pump-thaw cycle, it is sealed in a Pyrex tube and cooled to room temperature before undergoing a heating crystallization reaction. The product is extracted by Soxhlet extraction, and the extracted product is vacuum dried to obtain a covalent organic framework material.
[0014] Preferably, in step S1, the molar ratio of hexahexene monomer to TPDA monomer is 2:1.
[0015] Preferably, in step S1, the organic solvent is a mixture of o-dichlorobenzene and n-butanol, wherein the volume ratio of o-dichlorobenzene to n-butanol is (0.1-10):1.
[0016] Preferably, in step S1, the catalyst is a 0.005-0.5 mol / L aqueous solution of trifluoroacetic acid; the volume ratio of the aqueous solution of trifluoroacetic acid to the organic solvent is (0.1-1):1.
[0017] Preferably, in step S1, ultrasonic dispersion is performed at 20-30 kHz and 20-25°C for 30-40 min; the dispersion time is continued for 5-8 min.
[0018] Preferably, in step S2, the heating crystallization reaction is carried out by heating to 80-160°C and reacting for 24-120 h.
[0019] Preferably, in step S2, the solvent used for Soxhlet extraction is anhydrous tetrahydrofuran, anhydrous ethanol, or anhydrous methanol.
[0020] Preferably, in step S2, the temperature for vacuum drying is 60-150°C.
[0021] A third aspect of the present invention provides an application of a covalent organic framework material containing a helical monomer, wherein the covalent organic framework material is used as an adsorbent in iodine adsorption.
[0022] Advantages of the present invention: The present invention provides a covalent organic framework material containing helical monomers, its preparation method and application. The covalent organic framework is synthesized by using hexahexene monomers and TPDA monomers. It has excellent crystallinity and microporous channels, lower electrochemical impedance, and good iodine adsorption and desorption properties. Attached Figure Description
[0023] Figure 1 XRD pattern of the covalent organic framework material in the example;
[0024] Figure 2 FT-IR comparison of [6]-Helicene-OMe, TPDA, and covalent organic framework materials from the examples;
[0025] Figure 3 The N2 adsorption-desorption curves of the covalent organic framework material in the examples are shown.
[0026] Figure 4 A 5μm SEM image of the covalent organic framework material in the example;
[0027] Figure 5 A 20 nm TEM image of the covalent organic framework material used in this embodiment;
[0028] Figure 6 Electrochemical impedance spectroscopy comparison of [6]-Helicene-OMe and the covalent organic framework materials of the examples;
[0029] Figure 7 The diagram shows the iodine vapor adsorption of the covalent organic framework material in the example.
[0030] Figure 8 This is a standard curve diagram for iodine desorption.
[0031] Figure 9 The attached diagram shows the iodine removal process of the covalent organic framework material used in the embodiments. Detailed Implementation
[0032] To enhance understanding of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. These embodiments are only used to explain the invention and do not limit the scope of protection of the invention.
[0033] Among the following raw materials, the hexahexene monomer is denoted as [6]Helicene-R (R=OMe, F, Cl Br, Me, -CN, or -Ph), which is an existing compound. It can be synthesized by referring to the method reported in the literature Yin C , Ye X , Tao S , et al. Helicene Covalent Organic Frameworks for Robust Light Harvesting and Efficient Energy Transfers[J].AngewandteChemie,2024,136(45):e202411558-e202411558.DOI:10.1002 / ANGE.202411558. Unless otherwise specified, other raw material compounds such as TPDA were purchased from the market.
[0034] Example
[0035] This embodiment provides a covalent organic framework material containing helical monomers, and its preparation method is as follows:
[0036] S1. Add [6]-Helicene-OMe (13.3 mg, 0.03 mmol) and TPDA (15 mg, 0.015 mmol) to a 10 mL Pyrex tube, add o-dichlorobenzene (0.2 mL) and n-butanol (0.2 mL), sonicate at 30 kHz and 25 °C for 30 min, then add 0.2 mol / L trifluoroacetic acid aqueous solution (40 μL), and quickly freeze in liquid nitrogen to obtain a mixed solution;
[0037] S2. After degassing through three cycles of freezing-pumping-thawing, the Pyrex tube was sealed, and the mixture was cooled to room temperature. Then, it was heated in an oven at 120°C for 72 h to crystallize. The reaction product was extracted with anhydrous tetrahydrofuran. The extracted product was vacuum dried at 120°C to obtain a covalent organic framework material containing [6]-Helicene-OMe, denoted as [6]-Helicene-OMe-TPDA-COF.
[0038] The chemical structural formula of [6]-Helicene-OMe is as follows:
[0039] The chemical structural formula of TPDA is: ;
[0040] The general chemical structural formula of [6]-Helicene-OMe-TPDA-COF is:
[0041] .
[0042] The covalent organic framework materials of the examples were characterized by X-ray diffraction, and the results are as follows: Figure 1 As shown, the vertical axis represents intensity, and the horizontal axis represents the angle between the incident X-ray beam and the diffraction detector; from Figure 1 As can be seen from this embodiment, the covalent organic framework material [6]-Helicene-OMe-TPDA-COF was successfully synthesized.
[0043] The raw materials [6]-Helicene-OMe, TPDA, and [6]-Helicene-OMe-TPDA-COF prepared in the examples were characterized by Fourier transform infrared spectroscopy. The comparison results are as follows: Figure 2 As shown, the vertical axis represents transmittance, and the horizontal axis represents wavenumber; from Figure 2 As can be seen from the data, [6]-Helicene-OMe-TPDA-COF does not have stretching vibration peaks of C=O and -NH-, but has a stretching vibration peak of -C=N- at 1610 nm; this indicates that the [6]-Helicene-OMe-TPDA-COF covalent organic framework material has formed imine bonds.
[0044] The porosity of the covalent organic framework (COF) materials in the examples was analyzed by N2 adsorption-desorption tests at 77 K. The specific adsorption curves are shown below. Figure 3 As shown, the vertical axis represents the amount of N2 adsorbed, and the horizontal axis represents the relative pressure; according to IUPAC classification, Figure 3 The curve shows a typical Type I isotherm, and the specific surface area of [6]-Helicene-OMe-TPDA-COF is 38 m² calculated by the Brunauer-Emmett-Teller (BET) equation. 2 g -1 .
[0045] The covalent organic framework materials of the examples were characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 4 As shown; from Figure 4 It can be clearly observed that [6]-Helicene-OMe-TPDA-COF has a uniformly sized, sheet-like morphology that is aggregated together; the covalent organic framework material of the examples was characterized by transmission electron microscopy (TEM), and the results are as follows. Figure 5 As shown; from Figure 5 The well-organized lattice fringes are clearly visible. This is precisely because the covalent organic framework material of this embodiment exhibits excellent crystallinity and microporous channels.
[0046] Electrochemical impedance spectroscopy was performed on the raw material [6]-Helicene-OMe and the covalent organic framework material of the examples. The sample preparation method for electrochemical impedance spectroscopy was as follows: 5 mg of the ground test sample was added to a 10 mL glass bottle, 1 mL of anhydrous ethanol was added, and the sample was sonicated. Then, 50 μL of 5% Nafion reagent was added and sonicated again until the sample was completely dispersed to obtain a solution. A 6 mm diameter hole was drilled in the transparent tape and attached to the ITO conductive glass. The sonicated solution was dropped onto the ITO conductive glass with a pipette and dried. The sample preparation was completed. Sodium sulfate solution was used as the electrolyte, and the starting voltage was -0.5 V. The corresponding tests were performed. The test results are as follows: Figure 6 As shown; from Figure 6 It can be clearly observed that the covalent organic framework material of this embodiment has a smaller electrochemical impedance radius than the [6]-Helicene-OMe of the raw material, indicating that the covalent organic framework material of this embodiment has a smaller electrochemical impedance, a greater charge transport capacity, and is easier to react chemically than the [6]-Helicene-OMe monomer of the raw material.
[0047] Iodine adsorption test was performed on [6]-Helicene-OMe-TPDA-COF of Example 6. The specific method was as follows: 10 mg of [6]-Helicene-OMe-TPDA-COF and excess iodine were placed into two 5 mL airtight bottles, respectively. Then, the two 5 mL airtight bottles were placed into a 50 mL airtight bottle. The 50 mL airtight bottle was then sealed and transferred to a 75°C oven. The COF was removed and weighed periodically. The iodine absorption capacity of the COF was measured by calculating the weight change of the COF before and after iodine adsorption, and an adsorption curve was plotted accordingly. The adsorption curve is shown below. Figure 7 As shown, Figure 7 It can be seen that after 100 h, the mass of iodine adsorbed per gram of COF is 4.33 g.
[0048] The desorption performance of the iodine-loaded COF after the iodine adsorption test of [6]-Helicene-OMe-TPDA-COF in the aforementioned embodiment was tested. The specific method is as follows:
[0049] I. Establishing a Standard Curve: Based on the known concentrations of iodine in methanol solution (0.002 mg / L, 0.004 mg / L, 0.006 mg / L, 0.008 mg / L, 0.012 mg / L, 0.016 mg / L, 0.024 mg / L), UV absorption peaks at different concentrations were obtained through UV testing. The intensities of these UV absorption peaks were plotted and fitted to create a standard curve, as shown below. Figure 8As shown, the standard equation is: Y = 11.86842X + 0.01339, R 2 = 0.98977.
[0050] 2. Place 0.1 mg of iodine-loaded COF into a cuvette, then add 3 mL of methanol solution to immerse the iodine-loaded COF in methanol. Analyze the methanol solution of the iodine-loaded COF every three minutes using a UV spectrophotometer. The results are as follows: Figure 9 As shown; from Figure 9 It can be concluded that approximately 40% desorption occurs within one hour.
[0051] The above embodiments should not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent conversion fall within the protection scope of the present invention.
Claims
1. A covalent organic framework material containing helical monomers, characterized in that, It is a covalent organic framework material prepared from hexahexene monomers and TPDA monomers; The chemical structural formula of the hexahexolene monomer is as follows: ; The chemical structural formula of the TPDA monomer is: ; The general chemical formula for covalent organic framework materials is: ； Wherein, R is methoxy, methyl, cyano, phenyl, fluorine, chlorine, or bromine.
2. The method for preparing a covalent organic framework material containing helical monomers as described in claim 1, characterized in that, Includes the following steps: S1. Add hexahexene monomers and TPDA monomers to a Pyrex tube, add an organic solvent and disperse ultrasonically, then add a catalyst and continue dispersion to obtain a mixed solution; S2. After the mixed solution is degassed by a freeze-pump-thaw cycle, it is sealed in a Pyrex tube and cooled to room temperature before undergoing a heating crystallization reaction. The product is extracted by Soxhlet extraction, and the extracted product is vacuum dried to obtain a covalent organic framework material.
3. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S1, the molar ratio of hexahexene monomer to TPDA monomer is 2:
1.
4. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S1, the organic solvent is a mixture of o-dichlorobenzene and n-butanol, wherein the volume ratio of o-dichlorobenzene to n-butanol is (0.1-10):
1.
5. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S1, the catalyst is a 0.005-0.5 mol / L aqueous solution of trifluoroacetic acid; the volume ratio of the aqueous solution of trifluoroacetic acid to the organic solvent is (0.1-1):
1.
6. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S1, ultrasonic dispersion is performed at 20-30 kHz and 20-25℃ for 30-40 min; the dispersion time is continued for 5-8 min.
7. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S2, the heating crystallization reaction is carried out by heating to 80-160℃ and reacting for 24-120 h.
8. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S2, the solvent used for Soxhlet extraction is anhydrous tetrahydrofuran, anhydrous ethanol, or anhydrous methanol.
9. The method for preparing a covalent organic framework material containing helical monomers as described in claim 2, characterized in that, In step S2, the vacuum drying temperature is 60-150℃.
10. An application of a covalent organic framework material containing helical monomers, characterized in that, Application of the covalent organic framework material as described in claim 1 as an adsorbent in iodine adsorption.