Carboxyl-functionalized triazinyl-based ionic polymer as well as preparation method and application thereof
By using carboxyl-functionalized triazine-based ionic polymer catalysts, the problem of synthesizing cyclic carbonates from carbon dioxide and epoxides under high temperature and pressure was solved, achieving efficient and low-cost catalytic effects and simplifying the process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies require high temperature and high pressure conditions in the catalytic synthesis of cyclic carbonates from carbon dioxide and epoxides, and the separation of products from catalysts is complex, making it difficult to meet industrial requirements.
Cyclic carbonates are synthesized using carboxyl-functionalized triazine-based ionic polymers as catalysts through a simple preparation method. The reaction conditions are mild and no co-catalysts or solvents are required, thus achieving highly efficient catalysis by utilizing their unique properties.
This method enables high-yield synthesis of cyclic carbonates, reduces catalyst costs, simplifies the process, and improves catalyst stability and ease of separation.
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Figure CN122037181A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of ionic polymers and chemical catalysis technology, specifically relating to a carboxyl-functionalized triazine-based ionic polymer, its preparation method, and its application. Background Technology
[0002] The rapid development of modern industry has led to the massive consumption of fossil fuels such as coal, oil, and natural gas in numerous sectors. However, the pollutants and carbon dioxide (CO2) emissions from the combustion of these fuels have caused serious impacts. It is worth noting that CO2 itself is an abundant, inexpensive, and non-toxic carbon resource on Earth. Utilizing CO2 as a raw material, it can be catalytically converted into various chemicals. Among these, the cycloaddition reaction of CO2 with epoxides to synthesize cyclic carbonates has become one of the most promising and few industrially feasible CO2 utilization methods due to its low raw material cost, 100% atom utilization rate, and compliance with the principles of "green chemistry" and "atom economy."
[0003] Currently, the industrial synthesis of this cycloaddition reaction mainly uses quaternary ammonium salt catalysts. Although the process is relatively mature, the reaction must be carried out under harsh conditions such as high temperature and high pressure, and the separation of the product from the catalyst after the reaction requires a series of complex steps.
[0004] Studies have shown that ionic liquid catalysts have attracted widespread attention due to their advantages such as simple preparation, tunable structure, low vapor pressure, low toxicity, high stability, unique solubility, easy separation, and non-flammability and non-explosiveness. However, with the deepening of ionic liquid research and application, conventional ionic liquids are no longer sufficient to meet higher demands. In recent years, ionic polymers (IPs) have developed rapidly, showing great application prospects in CO2 adsorption and conversion. IPs not only retain the special properties of ionic liquids but also possess good heterogeneity and thermal stability, giving them significant catalytic activity, ease of separation, and reusability, thus better meeting practical application needs. Summary of the Invention
[0005] The purpose of this invention is to provide a carboxyl-functionalized triazine-based ionic polymer, which has the advantages of high yield, strong activity, no need for co-catalysts and other solvents, mild reaction conditions, and high stability in the catalytic synthesis of cyclic carbonates from carbon dioxide and epoxides.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] The structural formula of a carboxyl-functionalized triazine-based ionic polymer is shown in (Ⅰ):
[0008] (I); where R = COOH or H.
[0009] The preparation method of the above-mentioned carboxyl-functionalized triazine-based ionic polymer includes the following steps:
[0010] 1) Imidazole, melamine and triethylamine were dissolved in an organic solvent and stirred to carry out the reaction. After the reaction was completed, the solvent was removed by rotary evaporator, and the product was washed and dried to obtain the precursor 2,4,6-tris(1H-imidazol-1-yl)-1,3,5-triazine.
[0011] 2) The precursor and hydrogen bond donor are mixed and heated to react. Then, after washing and drying, a carboxyl-functionalized triazine-based ionic polymer is obtained.
[0012] Furthermore, in the above preparation method, step 1), the reaction is carried out at 75°C for 4 hours.
[0013] Furthermore, in step 2) of the above preparation method, the hydrogen bond donor is 1,3-dibromopropane or 3-bromo-2-bromomethylpropionic acid.
[0014] Furthermore, in the above preparation method, in step 2), the molar ratio of the precursor to the hydrogen bond donor is 2:3.5.
[0015] Furthermore, in the above preparation method, step 2), the heating reaction is carried out at 75°C for 24 hours.
[0016] The above-mentioned carboxyl-functionalized triazine-based ionic polymers are used as catalysts in the catalytic synthesis of cyclic carbonates from epoxides.
[0017] Furthermore, in the above applications, the epoxy compound is epichlorohydrin, propylene oxide, butane oxide, 1,2-epoxyethylbenzene, or bromopropylidene oxide.
[0018] Furthermore, the above application method is as follows: 0.07 g to 0.11 g of a catalyst-functionalized triazine-based ionic polymer, carbon dioxide, and 2.7756 g of an epoxy compound are mixed and reacted at a pressure of 0.7 to 1.1 MPa and a temperature of 80 to 110 °C.
[0019] Furthermore, in the above application method, when the epoxy compound is epichlorohydrin, propylene oxide, butylene oxide, or bromopropylidene, the reaction time is 10-14 hours; when the epoxy compound is 1,2-epoxyethylbenzene, the reaction time is 24 hours.
[0020] The beneficial effects of this invention are: using carboxyl-functionalized triazine-based ionic polymers as catalysts in the cycloaddition reaction of epoxides with carbon dioxide to synthesize cyclic carbonates. Compared with traditional catalysts, the catalytic process of this invention is simple, the reaction system does not require solvents or co-catalysts, the reaction conditions are mild, and while ensuring the catalytic effect, the cost of the catalyst is greatly reduced, and the yield of cyclic carbonates is very high. Attached Figure Description
[0021] Figure 1 This is the 1H NMR spectrum of propylene carbonate obtained in Example 4.
[0022] Figure 2 This is the 1H NMR spectrum of styrene oxide ester obtained in Example 4.
[0023] Figure 3 This is the 1H NMR spectrum of chloropropylene carbonate obtained in Example 4.
[0024] Figure 4 This is the 1H NMR spectrum of butene carbonate obtained in Example 4.
[0025] Figure 5 This is the 1H NMR spectrum of bromopropylene carbonate obtained in Example 4.
[0026] Figure 6 This is a cyclic experiment diagram of the IPs-COOH catalyst obtained in Example 5. Detailed Implementation
[0027] Example 1: Preparation of carboxyl-functionalized triazine-based ionic polymers
[0028] (I) Preparation of carboxyl-functionalized triazine-based ionic polymers IPs-H
[0029] 2.04 g imidazole and 3.51 g triethylamine were dissolved in 35 mL tetrahydrofuran. Subsequently, 3.68 g melamine chloride was dissolved in 15 mL tetrahydrofuran. The two mixtures prepared above were reacted in an oil bath at 75 °C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, and the solvent was removed from the product by rotary evaporation. The product was then washed several times with water, and the washed product was vacuum dried for a period of time to obtain a pale yellow powder, which was the precursor 2,4,6-tris(1H-imidazol-1-yl)-1,3,5-triazine. Then, 4 mmol of the precursor was accurately weighed and dissolved in 50 mL acetonitrile. Then, 7 mmol of 1,3-dibromopropane was added to the mixture, and the mixture was reacted at 75 °C for 24 hours. After the reaction was completed, the mixture was washed several times with organic solvent, and then the ionomer was dried in a vacuum drying oven to obtain the final catalyst IPs-H, with the structural formula shown in (II).
[0030] (II).
[0031] (II) Preparation of carboxyl-functionalized triazine-based ionic polymers IPs-COOH
[0032] The method is the same as (I), except that 1,3-dibromopropane is replaced with 3-bromo-2-bromomethylpropionic acid to obtain the pure catalyst IPs-COOH, with the structural formula shown in (III).
[0033] (III).
[0034] Example 2: Carboxyl-functionalized triazine-based ionic polymer-catalyzed epoxide cycloaddition reaction
[0035] (a) Effect of temperature on reaction yield
[0036] In a 50 mL high-pressure reactor, the catalyst IPs-COOH and epichlorohydrin were added, mixed, and CO2 was introduced at 1.0 MPa. The reaction was carried out at the temperatures shown in Table 1 for 12 hours. The amount of catalyst added was 0.10 g, and the amount of epichlorohydrin added was 2.7756 g. After the reaction, the yield of cyclic carbonates was calculated, and the results are shown in Table 1.
[0037] Table 1. Yields of propylene chloride at different temperatures
[0038] Temperature / °C 110 100 95 90 80 Yield / % 98.83 98.32 93.82 90.19 82.60
[0039] (II) Effect of catalyst dosage on reaction yield
[0040] The method is the same as (I), but the temperature is 100℃. The amount of catalyst IPs-COOH added is changed as shown in Table 2, and the results are shown in Table 2.
[0041] Table 2. Yields of propylene chloride carbonate at different catalyst dosages
[0042] Catalyst dosage / g 0.11 0.10 0.09 0.08 0.07 Yield / % 98.81 98.32 96.63 95.37 94.62
[0043] (III) Effect of CO2 pressure on reaction yield
[0044] The method is the same as (I), but the temperature is 100℃. The pressure is changed as shown in Table 3, and the results are shown in Table 3.
[0045] Table 3. Yields of propylene chloride carbonate under different pressures
[0046] Pressure / MPa 1.1 1.0 0.9 0.8 0.7 Yield / % 98.36 98.32 97.39 96.09 95.79
[0047] (iv) Effect of reaction time on reaction yield
[0048] The method is the same as (I), the temperature is 100℃, the pressure is 1.0MPa, and the reaction time is changed as shown in Table 4. The results are shown in Table 4.
[0049] Table 4. Yields of propylene chloride carbonate at different reaction times
[0050] Time / h 14 12 10 8 6 Yield / % 98.51 98.32 96.02 84.78 73.90
[0051] In summary, considering the environmental and safety factors, and given the relatively small difference in the yield of chloropropylene carbonate, the optimal experimental conditions for the cycloaddition reaction of epoxides catalyzed by triazine-based ionic polymers with carboxyl functionalization were chosen as follows: In a 50 mL high-pressure reactor, the catalyst IPs-COOH and epichlorohydrin were added, mixed, and CO2 was introduced at 1.0 MPa. The reaction was carried out at 100 °C for 12 hours. The catalyst dosage was 0.10 g, and the epichlorohydrin dosage was 2.7756 g. The 1H NMR results are shown below. Figure 3 This is consistent with the reference (DOI:10.1016 / j.jece.2025.116247), proving that the pure target product, propylene chloride carbonate, was obtained.
[0052] Example 3: Carboxyl-functionalized triazine-based ionic polymer-catalyzed cycloaddition reaction of epoxide compounds
[0053] In a 50 mL high-pressure reactor, a catalyst (as shown in Table 5) and epichlorohydrin were added, mixed, and CO2 at 1.0 MPa was introduced. The reaction was carried out at 100 °C for 12 hours. The amount of catalyst added was 0.10 g, and the amount of epichlorohydrin added was 2.7756 g. After the reaction was completed, the yield of cyclic carbonates was calculated, and the results are shown in Table 5.
[0054] Table 5. Yields of propylene chloride carbonate under different catalysts under specific conditions.
[0055] Catalyst IPs-COOH IPs-H Yield / % 98.32 97.40
[0056] Example 4: Carboxyl-functionalized triazine-based ionic polymers catalyzing cycloaddition reactions of different epoxides
[0057] In a 50 mL high-pressure reactor, the catalyst IPs-COOH and the epoxide compound (Table 6) were added, mixed, and CO2 was introduced at 1.0 MPa. The reaction was carried out at 100 °C for 12 hours (24 hours for 1,2-epoxyethylbenzene). The amount of catalyst added was 0.07 g to 0.11 g. After the reaction, the yield of cyclic carbonates was calculated, and the results are shown in Table 6.
[0058] The results were obtained by 1H NMR spectroscopy, as shown in Table 6. Figures 1-5 As shown. Figure 1 : 1H NMR (300 MHz, CDCl3): δ4.91 (m, 1H), 4.58 (q, 1H), 4.05 (q, 1H), 1.50 (d, 3H); Figure 2 : 1 H NMR (300 MHz, CDCl3): δ 7.44 (m, 5H), 5.70 (t, 1H), 4.83 (t, 1H), 4.37 (q, 1H); Figure 3 : 1 H NMR (300 MHz, CDCl3): δ 5.00 (m, 1H), 4.55 (m, 1H), 4.40 (q, 1H), 3.76 (m, 2H); Figure 4 : 1 H NMR (300 MHz, CDCl3) δ 4.60 (dd, 1H), 4.51 (t, 1H), 4.14 (m, 1H), 1.84(m, 1H), 1.04 (dd, 3H); Figure 5 : 1 H NMR (300 MHz, CDCl3): δ 4.97 (m, 1H), 4.61 (t,1H), 4.40 (dd, 1H), 3.66 (m, 2H).
[0059] Table 6 Yields of different epoxide compounds
[0060]
[0061] Example 5: Cyclic Experiment of Carboxyl-functionalized Triazine-based Ionic Polymer Catalyzing Epoxides
[0062] In a 50 mL high-pressure reactor, catalyst IPs-COOH and epichlorohydrin (Table 7) were added, mixed, and CO2 was introduced at 1.0 MPa. The reaction was carried out at 100 °C for 12 hours. The amount of catalyst added was 0.10 g, and the amount of epichlorohydrin added was 2.7756 g. After the reaction, the yield of propylene chloride was calculated, and the results are shown in Table 7. The results show that the catalytic effect did not change significantly within five cycles, and the yield of propylene chloride was always higher than 97% (Table 7 and...). Figure 6 ).
[0063] Table 7 Cyclic Experiments of IPs-COOH Catalyst
[0064] Cycle 1 2 3 4 5 Yield % 98.32 98.24 97.94 97.60 97.21
Claims
1. A carboxyl-functionalized triazine-based ionic polymer, characterized in that, The structural formula of the carboxyl-functionalized triazine-based ionic polymer is shown in (Ⅰ): (I); where R = COOH or H.
2. The method for preparing a carboxyl-functionalized triazine-based ionic polymer according to claim 1, characterized in that, Includes the following steps: 1) Imidazole, melamine and triethylamine were dissolved in an organic solvent and stirred to carry out the reaction. After the reaction was completed, the solvent was removed by rotary evaporator, and the product was washed and dried to obtain the precursor 2,4,6-tris(1H-imidazol-1-yl)-1,3,5-triazine. 2) The precursor and hydrogen bond donor are mixed and heated to react. Then, after washing and drying, a carboxyl-functionalized triazine-based ionic polymer is obtained.
3. The preparation method according to claim 2, characterized in that, In step 1), the reaction is carried out at 75°C for 4 hours.
4. The preparation method according to claim 2, characterized in that, In step 2), the hydrogen bond donor is 1,3-dibromopropane or 3-bromo-2-bromomethylpropionic acid.
5. The preparation method according to claim 2, characterized in that, In step 2), the molar ratio of the precursor to the hydrogen bond donor is 2:3.
5.
6. The preparation method according to claim 2, characterized in that, In step 2), the heating reaction is carried out at 75°C for 24 hours.
7. The application of the carboxyl-functionalized triazine-based ionic polymer of claim 1 as a catalyst in the catalytic synthesis of cyclic carbonates from epoxides.
8. The application according to claim 7, characterized in that, The epoxy compound is epichlorohydrin, propylene oxide, butane oxide, 1,2-epoxyethylbenzene, or bromopropylidene oxide.
9. The application according to claim 8, characterized in that, The application method is as follows: Mix 0.07g~0.11g of a catalyst-functionalized triazine-based ionic polymer, carbon dioxide, and 2.7756g of an epoxy compound, and react them at a pressure of 0.7~1.1MPa and a temperature of 80~110℃.
10. The application according to claim 9, characterized in that, When the epoxy compound is epichlorohydrin, propylene oxide, butane oxide, or bromopropylidene oxide, the reaction time is 10-14 hours; when the epoxy compound is 1,2-epoxyethylbenzene, the reaction time is 24 hours.