Imidazolyl ionic porous organic polymer as well as preparation method and application thereof
By using ultrasound-assisted synthesis of imidazole-based ionic porous organic polymers, the problems of poor selectivity and high energy consumption in the separation of fluorocarbons by traditional porous organic polymers have been solved, achieving efficient separation of fluorocarbons and high-performance material preparation.
Patent Information
- Application Number
- CN202511892997.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional porous organic polymers exhibit poor selectivity when separating fluorocarbon systems with similar physical properties, and their synthesis is energy-intensive, making it difficult to meet industrial demands.
Imidazole-based ionic porous organic polymers were synthesized in a mixed solvent of acetic acid and water using ultrasound-assisted technology. Through the Debus–Radziszewski reaction, porous polymers with ionic structural units were prepared, which enhanced the polarity of the skeleton and regulated the charge distribution, thereby improving the ability to recognize and capture fluorocarbon molecules.
The selective adsorption performance and adsorption capacity for difluoromethane (HFC-32) and pentafluoroethane (HFC-125) were significantly improved under mild conditions, reducing synthesis energy consumption and providing a highly efficient separation material.
Smart Images
Figure CN121574366A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional polymer adsorption materials technology, and in particular to an imidazole-based ionic porous organic polymer, its preparation method, and its application. Background Technology
[0002] Fluorocarbons (FCCs) are widely used in air conditioning, cold chain transportation, automotive air conditioning, and foaming agents. Difluoromethane (HFC-32) and pentafluoroethane (HFC-125) are key components of mainstream mixed refrigerants such as R-410A and R-404A. However, because HFC-32 and HFC-125 are very similar in physical properties (e.g., their boiling points differ by only about 5 °C), traditional separation methods such as cryogenic distillation and extraction face technical bottlenecks such as high energy consumption, poor selectivity, and complex equipment, making it difficult to meet actual industrial needs. Therefore, developing novel adsorption separation materials has become a key breakthrough for improving the separation efficiency of FCs and reducing energy consumption.
[0003] Porous organic polymers (POPs) have shown great potential in the separation of small molecule gases due to their high specific surface area, tunable pore structure, and good physicochemical stability. However, for fluorocarbon systems with similar physical properties and subtle differences in molecular size, the recognition and differentiation capabilities of traditional POPs materials remain limited, and their separation selectivity is constrained by the precise construction of specific interactions between the framework and the target molecule. Furthermore, the synthesis of traditional POPs materials is mostly carried out under heating conditions, resulting in high energy consumption and long reaction times. Therefore, designing a simple method to synthesize a novel porous organic polymer framework capable of efficiently recognizing and separating fluorocarbon molecules is of significant research importance and application value. Summary of the Invention
[0004] To address the poor selectivity of porous organic polymers for separating fluorocarbon molecules in existing technologies, this invention proposes an imidazole-based ionic porous organic polymer, its preparation method, and its applications. It is particularly suitable for the efficient separation of fluorocarbons with similar physical properties, such as difluoromethane (HFC-32) and pentafluoroethane (HFC-125).
[0005] The technical solution of the present invention is as follows:
[0006] A method for preparing an imidazole-based ionic porous organic polymer includes the following steps: dissolving or uniformly dispersing a polyamine monomer in a mixed solution of acetic acid and water; dissolving formaldehyde and glyoxal in a mixed solution of acetic acid and water; mixing the two under ultrasonic conditions until the Debus–Radziszewski imidazole synthesis reaction is completed; washing and drying to obtain the polymer.
[0007] Preferably, the molar ratio of the polyamine monomer to formaldehyde and glyoxal is 1:8-9:8-9.
[0008] Preferably, the polyamine monomer is selected from one or more of tetra(4-aminophenyl)methane, 1,3,5-tris(4-aminophenyl)benzene, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 4,4',4''-(benzene-1,3,5-triyltri(oxy))triphenylamine, and tri(4-aminophenyl)thiophosphate.
[0009] Preferably, the molar ratio of the amine monomer to acetic acid is 1:145-300.
[0010] Preferably, the prepared imidazole-based ionic porous organic polymer has at least one chemical structural formula as described in any of formulas I-V.
[0011] , ,
[0012] , , .
[0013] Preferably, the power of the ultrasound is 100-150W.
[0014] Preferably, the ultrasound duration is 0.5-2 hours.
[0015] Preferably, the washing reagent is selected from one or more of tetrahydrofuran, acetone, N,N-dimethylformamide and water.
[0016] Preferably, the washing temperature is 30-55 ℃.
[0017] Preferably, the drying is freeze drying.
[0018] The present invention also provides the application of the imidazole-based ionic porous organic polymer prepared by the above-mentioned method as an adsorbent in the separation of difluoromethane and pentafluoroethane.
[0019] The principle of adsorbing HFC-32 using imidazole-based ionic porous organic polymers is based on the difference in adsorption performance caused by the difference in ion-dipole interactions between the nitrogen cations in the polymer and the fluorine atoms in the fluorocarbon gas molecules. Due to the difference in structural symmetry, HFC-32 has strong polarity and therefore strong polymer affinity.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] (1) This invention develops an imidazole-based ionic porous organic polymer that has a selective separation effect on HFC-32. By introducing ionic structural units, the polarity of the skeleton is enhanced and the degree of matching with the charge distribution of fluorine-containing molecules is adjusted, thereby improving the selective adsorption performance of HFC-32 and separating difluoromethane (HFC-32) and pentafluoroethane (HFC-125).
[0022] (2) The preparation method of this invention employs ultrasound-assisted technology to carry out the Debus–Radziszewski reaction using acetic acid and water as a green catalytic-solvent system. This method abandons the high-temperature and energy-consuming synthesis route of the traditional Debus–Radziszewski reaction, proceeding under mild conditions and significantly shortening the reaction time. More importantly, the ultrasound action generates more N2. + This significantly enhances its ability to recognize and capture fluorocarbon molecules. The resulting porous polymer exhibits adsorption capacity and selectivity far exceeding that of materials prepared by conventional methods in the separation of fluorocarbon mixed gases, providing a high-performance material and an efficient preparation route for its industrial application. Attached Figure Description
[0023] Figure 1 This is a schematic diagram illustrating the synthesis of the imidazole-based ionic porous organic polymer in this invention.
[0024] Figure 2 Optical images of imidazole-based ionic porous organic polymers.
[0025] Figure 3 The image shows the infrared spectrum of an imidazole-based ionic porous organic polymer.
[0026] Figure 4 Solid-state NMR of imidazole-based ionic porous organic polymers prepared under ultrasonic and room temperature conditions 13 C-spectrum, taking TAM-AcO as an example.
[0027] Figure 5 The XPS N 1s spectrum of TAM-AcO(RT) is shown.
[0028] Figure 6 The XPS N 1s spectrum of TAM-AcO(US).
[0029] Figure 7 N obtained by elemental analysis of TAM-AcO(RT) and TAM-AcO(US) + Content comparison chart.
[0030] Figure 8 Comparison of adsorption-desorption isotherms of HFC-32 by imidazole-based ionic porous organic polymers.
[0031] Figure 9 This is a comparison of adsorption-desorption isotherms of HFC-125 by imidazole-based ionic porous organic polymers.
[0032] Figure 10 A comparison of adsorption isotherms of ionic polymers prepared under ultrasonic and room temperature conditions for HFC-32 and HFC-125, with TAM-AcO as an example.
[0033] Figure 11 A comparative graph showing the IAST selectivity of different materials for HFC-32 / HFC-125 mixtures.
[0034] Figure 12 The adsorption cycle performance (298 K) of imidazole-based ionic porous organic polymers for HFC-32 is shown, taking TAM-AcO as an example. Detailed Implementation
[0035] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0037] It should be noted that the ionic porous organic polymers of this application are abbreviated as i-POPs, tetra(4-aminophenyl)methane is abbreviated as TAM, 1,3,5-tris(4-aminophenyl)benzene is abbreviated as TAPB, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is abbreviated as TAPT, 4,4',4''-(phenyl-1,3,5-triyltri(oxy))triphenylamine is abbreviated as TAPOB, tris(4-aminophenyl)thiophosphate is abbreviated as TAPTPhos, and the acetate counterion is abbreviated as AcO. The naming of the imidazole-based ionic porous organic polymers of this application will consist of the abbreviation of the amine monomer plus the abbreviation of the acetate counterion, for example, TAM-AcO. To make it easier to distinguish the samples during comparison, this application adds a suffix to the name: In this application, TAM-AcO(US) and its abbreviation TAM-AcO both refer to samples prepared under ultrasonic conditions; samples with the suffix RT, such as TAM-AcO(RT), refer to comparative samples prepared under non-ultrasonic conditions and with long-term stirring at room temperature.
[0038] Example 1: Preparation of TAM-AcO
[0039] TAM (0.6 mmol) was dissolved in a single-necked flask containing 8 mL of acetic acid (17.5 mol / L) and 8 mL of distilled water. Formaldehyde (37 wt% aqueous solution, 5.28 mmol) and glyoxal (39 wt% aqueous solution, 5.28 mmol) were dissolved in a centrifuge tube containing 1 mL of distilled water and 2 mL of acetic acid. The mixture from the centrifuge tube was then added to the single-necked flask, and the reaction was carried out under sonication (100 W) for 30 min. After the reaction, the product was washed three times with tetrahydrofuran, acetone, and distilled water, frozen, and lyophilized to obtain the product. The schematic diagram of the synthetic route is shown below. Figure 1 As shown. The prepared TAM-AcO is dark red ( Figure 2 ).
[0040] Example 2 Preparation of TAPB-AcO
[0041] The difference between this embodiment and Example 1 is that the amine monomer is replaced with TAPB, and the molar ratio of TAPB to formaldehyde and glyoxal is 1:8:8. The reaction is carried out under ultrasonic conditions (100 W) for 45 min, with other conditions the same as in Example 1, finally yielding TAPB-AcO. The prepared TAPB-AcO is purple-red (…). Figure 2 ).
[0042] Example 3 Preparation of TAPT-AcO
[0043] The difference between this embodiment and Example 1 is that the amine monomer is replaced with TAPT. The molar ratio of TAPT to formaldehyde and glyoxal is 1:9:9. The reaction is carried out under ultrasonic conditions (150 W) for 1 h. In the post-treatment, the sample is washed three times with tetrahydrofuran, acetone, N,N-dimethylformamide, and distilled water. Other conditions are the same as in Example 1, finally yielding TAPT-AcO. The prepared TAPT-AcO is yellow (…). Figure 2 ).
[0044] Example 4: Preparation of TAPOB-AcO
[0045] The difference between this embodiment and Example 1 is that the amine monomer is replaced with TAPOB, while other conditions are the same as in Example 1, ultimately yielding TAPOB-AcO. The prepared TAPOB-AcO is pale yellow (…). Figure 2 ).
[0046] Example 5 Preparation of TAPTPhos-AcO
[0047] The difference between this embodiment and Example 1 is that the amine monomer is replaced with TAPTPhos, while other conditions are the same as in Example 1, ultimately yielding TAPTPhos-AcO. The prepared TAPTPhos-AcO is light yellow (…). Figure 2 ).
[0048] Infrared spectra of the polymers prepared in Examples 1-5 Figure 3 All were displayed at 3200-3400 cm. -1 The disappearance of the characteristic peak belonging to -NH2 and the 1200-1350 cm⁻¹ -1 The presence of absorption peaks at the CN bond stretching vibrations confirms the successful preparation of imidazole i-POPs via the Debus–Radziszewski reaction.
[0049] Comparative Example 1: Preparation of TAM-AcO(RT)
[0050] The difference between this embodiment and Example 1 is that the reaction conditions are without ultrasound assistance and the reaction time is extended to 12 h. Other conditions are the same as in Example 1. The final result is TAM-AcO(RT) for comparison.
[0051] Solid-state NMR 13 C spectrum ( Figure 4 The results showed that TAM-AcO prepared by ultrasound did not have characteristic peaks of uncyclized byproducts in the range of 220-200 ppm. Figure 5 and Figure 6 The XPS N1s spectrum shows that it belongs to C=N + Peak area: TAM-AcO is greater than TAM-AcO(RT). Figure 7Elemental analysis results showed that the i-POP prepared with ultrasound assistance had higher N content. + content.
[0052] Test Example 1: Performance Test of HFC-32 Single Component
[0053] A: Weigh 50-100 mg of one of the above polymers and place it in a sample tube. Activate it at 100 °C under vacuum for 10 h, and then perform an isothermal adsorption-desorption test at 0 °C.
[0054] B: Weigh 50-100 mg of one of the above polymers and place it in a sample tube. Activate it at 100 °C under vacuum for 10 h, and then perform an isothermal adsorption-desorption test at 25 °C.
[0055] Test Example 2: HFC-125 Single-Component Performance Test
[0056] The difference between this test example and Test Example 1 is that the test gas is changed to HFC-125, while other conditions are the same as in Test Example 1. The isothermal adsorption-desorption curves of the i-POPs prepared in Examples 1-5 for HFC-32 and HFC-125 are shown below. Figure 8 and 9 As shown, the corresponding adsorption amounts are summarized in Table 1.
[0057] Table 1. Summary of adsorption capacity of ionic porous polymers for HFC-32 / HFC-125
[0058]
[0059] The isothermal adsorption-desorption curves of HFC-32 and HFC-125 of the two i-POPs prepared in Example 1 and Comparative Example 1 are as follows: Figure 10 As shown, i-POPs prepared with ultrasound assistance have a higher HFC-32 adsorption capacity.
[0060] Test Example 3: Theoretical Selectivity Calculation of an Ideal Adsorption Solution for a Mixture of HFC-32 / HFC-125 (1 / 1, v / v)
[0061]
[0062] This test case uses data obtained from Test Cases 1 and 2, and calculates IAST selectivity based on the above formula to evaluate the separation effect of the HFC-32 / HFC-125 mixture. The results are as follows: Figure 11As shown, the i-POPs prepared with ultrasound assistance exhibit higher selectivity for HFC-32 / HFC-125. TAM-AcO shows the best selectivity for HFC-32 / HFC-125, which may be because the selectivity of other polyamine monomers is reduced due to their topological structure, but they still have good adsorption effects on HFC-32. Although some polyamine monomers in the five polymers provided in this invention may exhibit relatively low adsorption selectivity in mixed gas adsorption due to their specific topological structure, experimental data confirm that these polymers still have significant and stable adsorption capacity for HFC-32. This characteristic not only reflects the targeted advantages of the materials in molecular recognition and adsorption performance, but also ensures their practical feasibility in related applications such as HFC-32 separation, recovery, or purification. Therefore, even with certain differences in selectivity, this series of polymers still has clear technical effects and industrial application value.
[0063] Test Example 4: Difluoromethane Cyclic Stability Test
[0064] This embodiment is based on Test Example 1, with multiple repeated tests under the same conditions. The cycle stability results are as follows. Figure 12 As shown, after 6 cycles of adsorption-desorption experiments, it can still maintain good adsorption effect.
[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, any combination of these technical features that does not contradict each other should be considered within the scope of this specification.
Claims
1. A method for preparing an imidazole-based ionic porous organic polymer, characterized in that, The process includes the following steps: dissolving or uniformly dispersing the polyamine monomer in a mixed solution of acetic acid and water; dissolving formaldehyde and glyoxal in a mixed solution of acetic acid and water; mixing the two under ultrasonic conditions until the Debus–Radziszewski imidazole synthesis reaction is complete; washing and drying to obtain the final product.
2. The preparation method according to claim 1, characterized in that, The molar ratio of the polyamine monomer to formaldehyde and glyoxal is 1:8-9:8-9.
3. The preparation method according to claim 1, characterized in that, The molar ratio of the polyamine monomer to acetic acid is 1:145-300.
4. The preparation method according to claim 1, characterized in that, The polyamine monomer is selected from one or more of tetra(4-aminophenyl)methane, 1,3,5-tris(4-aminophenyl)benzene, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 4,4',4''-(benzene-1,3,5-triyltri(oxy))triphenylamine, and tri(4-aminophenyl)thiophosphate.
5. The preparation method according to claim 1, characterized in that, The power of the ultrasound is 100-150W.
6. The preparation method according to claim 1, characterized in that, The duration of the ultrasound is 0.5-2 hours.
7. The preparation method according to claim 1, characterized in that, The washing reagent is selected from tetrahydrofuran, acetone, etc. N,N - Dimethylformamide and any one or more of the following in water.
8. The preparation method according to claim 7, characterized in that, The temperature of the washing solvent is 30-55 ℃.
9. The preparation method according to claim 1, characterized in that, The drying process is freeze-drying.
10. The application of the imidazole-based ionic porous organic polymer prepared by the preparation method according to any one of claims 1-9 as an adsorbent in the separation of difluoromethane and pentafluoroethane.