Ureido-functionalized imidazole polyionic liquid as well as preparation method and application thereof

Abstract

The invention provides ureido-functionalized imidazole polyionic liquid as well as a preparation method and application thereof, and belongs to the technical field of catalysts containing polymers. The ureido-functionalized imidazole polyionic liquid is obtained by carrying out condensation reaction on simple polyvinyl imidazole and isocyanate containing triazine. The high-density ureido in the main body skeleton is used as a hydrogen bond donor to activate the epoxide and CO2, and the charge-balanced bromine negative ions are used as a nucleophilic reagent to meet with the epoxide of carbon atoms with small steric hindrance, so that ring opening of the epoxide is promoted synergistically. Under a mild condition, the carbamido-functionalized imidazole polyionic liquid shows excellent catalytic activity in the cycloaddition reaction of CO2.

Description

Technical Field

[0001] The present application relates to a urea-functionalized imidazole polyionic liquid and a preparation method and application thereof, belonging to the technical field of catalysts containing polymers. Background Art

[0002] Carbon dioxide (CO 2 ) has caused various disasters and environmental problems. 2 Resource recycling methods are imminent, and the coupling reaction of carbon dioxide and epoxides to form cyclic carbonates meets the above requirements. 2 Due to the chemical inertness of epoxides, scientists have devoted a lot of time and energy to design and synthesize many catalysts over the years. The design and synthesis of these catalysts have gradually developed in the direction of simpler synthesis processes, milder catalytic reaction conditions, more convenient reuse and more stable catalysts. Some of these catalysts may cause corrosive metal ions to leach into the solution and cause inevitable harm to the environment due to the use of metals, which does not meet the requirements of green chemistry; other heterogeneous catalysts are rarely paid attention to by researchers because they are not conducive to reuse. 2 ) into useful chemicals is one of the effective ways to reduce global warming and energy crisis. Developing heterogeneous catalytic systems with specific active sites is an important way to achieve CO 2 The key to chemical transformation. Summary of the invention

[0003] In view of this, the present application first provides a urea-functionalized imidazole polyionic liquid, in which a urea group is introduced into the structure as a hydrogen bond donor. The two secondary amine (NH) groups in the urea group can form double hydrogen bonds with epoxides, thereby better activating the CO bonds in the epoxides and improving the catalytic activity.

[0004] Specifically, the present application is implemented through the following scheme:

[0005] A urea-functionalized imidazole polyionic liquid, wherein the urea-functionalized imidazole polyionic liquid satisfies the following structural formula: Among them, a is 1 to 100, and b is 1 to 600.

[0006] Further, preferably, the urea-functionalized imidazole polyionic liquid satisfies the following structural formula:

[0007]

[0008] The urea-functionalized imidazole polyionic liquid (CTF-UI-PIL-X) has a high density of urea groups in the main skeleton as hydrogen bond donors to activate epoxides and CO2 The charge-balanced bromide anion acts as a nucleophile to meet the epoxide with a less sterically hindered carbon atom, and they synergistically promote the ring opening of the epoxide, which can be used for metal-free, solvent-free, and additive-free CO under mild conditions. 2 Converted into cyclic carbonate in CO 2 It exhibits excellent catalytic activity in the cycloaddition reaction.

[0009] The second object of the applicant is to provide a method for preparing a urea-functionalized imidazole polyionic liquid having the above structure, wherein the specific process is: condensing an amino-modified polyvinyl imidazole with an isocyanate containing triazine to obtain the polyvinyl imidazole, wherein the amino-modified polyvinyl imidazole has the structural formula: The structural formula of triazine-containing isocyanate is The added molar ratio of the triazine-containing isocyanate to the amino-modified polyvinylimidazole is 1:3 to 1:7.

[0010] Further, as a preference:

[0011] The condensation reaction temperature is 90-110°C, preferably 100°C.

[0012] The molar ratio of the triazine-containing isocyanate to the amino-modified polyvinylimidazole is 1:3 to 1:7.

[0013] In the condensation reaction, amino-modified polyvinyl imidazole and triazine-containing isocyanate are dissolved in anhydrous DMF to form an amino-modified polyvinyl imidazole solution and a triazine-containing isocyanate solution, which are added in the form of solutions and reacted.

[0014] The preparation method of the amino-modified polyvinyl imidazole is as follows: adding anhydrous ethanol and BHT to N-vinyl imidazole, evacuating the mixture and passing nitrogen gas, and 2 An ethanol solution of 2-bromoethylamine hydrobromide is added under air flow, and after reflux reaction, the mixture is cooled to room temperature, filtered to recover the crude product, washed with ethanol to remove unreacted monomers, and then vacuum dried overnight to obtain amino-modified imidazolium ionic liquid; the amino-modified imidazolium ionic liquid is dissolved in an appropriate amount of methanol solution, AIBN is added, the mixture is refluxed to react, cooled to room temperature, filtered to separate the solid polymer, eluted with methanol, the solid is collected and vacuum dried overnight, deprotonated, and then dried to obtain amino-modified polyvinyl imidazole.

[0015] The preparation method of the triazine-containing isocyanate is as follows: 4-aminobenzonitrile is dissolved in CHCl 3 , add dropwise to the mixed solution of chloroform and TfOH at 0-20℃. After the reaction is completed, dilute with distilled water and neutralize to neutral. Filter the solution and CHCl 3The product obtained by washing and vacuum drying and triphosgene were dissolved in anhydrous THF to obtain TATZ solution and triphosgene solution respectively. The TATZ solution was added dropwise to the triphosgene solution in an ice-water bath. After the reaction was completed, the mixture was refluxed and THF was removed by rotary evaporation. Anhydrous CH 2 Cl 2 Ultrasonic dispersion, filtration and vacuum drying are performed to obtain isocyanate containing triazine.

[0016] The third object of the applicant is to provide an application of a urea-functionalized imidazole polyionic liquid having the above structure, wherein the urea-functionalized imidazole polyionic liquid is used for reacting an epoxy substrate with CO 2 The cycloaddition reaction is carried out under normal pressure, in the absence of solvent and co-catalyst.

[0017] The epoxy substrate is any one of the following structures: epichlorohydrin,

[0018] The amino-functionalized imidazole polyionic liquid and the isocyanate precursor containing triazine form a urea-based cross-linked polymer, which catalyzes the CO conversion through the synergistic action of the nucleophilic halogen anion and the hydrogen bond donor. 2 Cycloaddition reactions with epoxides. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is the solid-state carbon NMR spectrum of the polymer obtained in Example 1;

[0021] Figure 2 is the infrared spectrum of each sample in Example 1,

[0022] (a) BTC, TITZ and TATZ, (b) TITZ, CTF-UI-PIL-5 and PAVIm NH 2 ;

[0023] Figure 3 For TITZ, PAVIm NH 2 and thermogravimetric analysis spectra of CTF-UI-PIL-5;

[0024] Figure 4 For CTF-UI-PIL-5 catalyst, N 2 Adsorption-desorption curves and pore size distribution. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application clearer, the technical solutions in the embodiments of this application will be further described in detail below in conjunction with the drawings in the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit the technical solutions of this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] The experimental instruments and reagents used in the following examples are shown in Table 1 and Table 2.

[0027] Table 1: Characterization and testing instruments used in this application

[0028] name model factory Oil bath pot DF-101S Zhengzhou Great Wall Science, Industry and Trade Co., Ltd. Vacuum drying oven DZF-150 Zhengzhou Great Wall Science, Industry and Trade Co., Ltd. Analytical Balance YP402N Shanghai Precision Scientific Instrument Co., Ltd. Nuclear Magnetic Resonance Spectrometer WNMR-I 400 Wuhan Zhongke Oxford Pop Technology Co., Ltd. XPS Thermo ESCALAB 250 Thermo Fisher Scientific Fourier Transform Infrared Spectrometer Nicolet 6700 Thermo Fisher Scientific Thermogravimetric Analyzer TG 209F3 NETZSCH, Germany

[0029] Table 2: Experimental reagents used in this application

[0030]

[0031]

[0032] Example 1

[0033] The present application provides a urea-functionalized imidazole polyionic liquid, the preparation process of which is as follows:

[0034] Step 1: Polyvinyl imidazole (PAVImNH 2 )

[0035] Freshly distilled N-vinylimidazole (AVIm, 2.4 g, 25.50 mmol, 5 eq) was added to a 250 mL double-necked round-bottom flask, anhydrous ethanol (50 ml) and BHT (0.05 g) were added, and the mixture was evacuated and nitrogen was passed through. 2 2-Bromoethylamine hydrobromide (C 2 H 4 BnB 2 ·HBr, 5.9 g, 28.79 mmol, 6 eq) in ethanol solution (50 mL), reflux for 12 h and cool to room temperature, then filter and recover the crude product, wash three times with ethanol to remove unreacted monomers, and dry in a vacuum oven overnight to obtain a white solid amino-modified imidazolium ionic liquid (AVImNH 2 HBr, 6.8 g, yield: 89.1%).

[0036] The synthesized AVImNH 2HBr (6.8 g, 22.7 mmol) was dissolved in an appropriate amount of methanol solution, AIBN (0.05 g) was added and the mixture was transferred to a 150 mL round-bottom flask, refluxed at 70 °C for 24 h and then cooled to room temperature. The solid polymer was separated by filtration, washed with methanol, and the solid was collected and dried in a vacuum oven overnight to obtain a white solid PAVImNH 2 ·HBr. Then the obtained PAVImNH 2 ·HBr selects triethylamine (EtN 3 ) was deprotonated and dried to obtain amino-modified polyvinyl imidazole (PAVImNH 2 , 6.4 g, yield: 94.1%).

[0037] The reaction equation of the above process is as follows:

[0038]

[0039] Step 2: Preparation of 2,4,6-tris(4-isocyanatophenyl)-1,3,5-triazine (TITZ)

[0040] The three-necked flask was fixed in an ice-water bath, a magnetic rod was added, vacuum was drawn, nitrogen was filled, and chloroform (CHCl 3 , 20 ml) and TfOH (15 ml). 4-Aminobenzonitrile (3.0 g, 25.3 mmol) was dissolved in CHCl 3 (20ml) to obtain 4-aminobenzonitrile solution. Keep 0℃, slowly add 4-aminobenzonitrile solution to the three-necked flask, after the addition is complete, react for 2h; then react at room temperature for 45h, a total of about 48h. After the reaction is completed, add 100ml of distilled water to dilute, and neutralize with 2M NaOH solution to pH = 7 (the solution changes from off-white to yellow and then to light yellow). Filter the solution, CHCl 3 (10 ml) and dried in a vacuum oven at 55°C for 24 h to obtain a light yellow product, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TATZ, 2.3 g, yield: 77.3%).

[0041] TATZ (2g, 6.4mmol, 2eq) was dissolved in anhydrous THF (20ml) to obtain a TATZ solution, and triphosgene (BTC, 2.5g, 8.4mmol, 2.5eq) was dissolved in anhydrous THF (20ml) to obtain a triphosgene solution. A three-necked flask was fixed in an ice-water bath and the dissolved triphosgene solution was added, vacuumed, and nitrogen was passed. The TATZ solution was slowly added dropwise. After the addition was completed, the reaction was allowed to proceed for 2h (the solution was opaque milky white). The mixture was transferred to an oil pan and refluxed for 4h (the solution was transparent yellow), for a total of about 7-8h. THF was removed by rotary evaporation. Anhydrous CH 2 Cl 2(30 ml), ultrasonicated for 30 min, filtered, and dried under vacuum at 30°C to obtain dark yellow solid TITZ (1.8 g, yield: 73.7%).

[0042] The reaction equation of the above process is as follows:

[0043]

[0044] Step 3: Preparation of triazine / urea functionalized polyionic liquid (CTF-IU-PIL-x)

[0045] TITZ (1.5 g, 3.46 mmol, 1 eq), PAVImNH 2 (5.1 g, 17.3 mmol, 5 eq) was dissolved in anhydrous DMF. A three-necked flask was placed in an oil bath, evacuated, filled with nitrogen, and TITZ, PAVImNH 2 DMF solution, 100°C, 24h. Stop the reaction, cool and filter, wash the filter cake with anhydrous DMF, and dry in vacuo at 60°C to obtain a yellow solid triazine / urea functionalized polyionic liquid catalyst (CTF-IU-PIL-5, 5.3g, yield: 80.3%).

[0046] The reaction equation of the above process is as follows:

[0047]

[0048] TITZ and PAVImNH 2 The molar ratios of were replaced with 1:3 and 1:7, respectively, and TITZ and PAVImNH were prepared by a similar method as above. 2 The cross-linked polymers with different molar ratios were named CTF-IU-PIL-3 and CTF-IU-PIL-7, respectively.

[0049] In order to explore the effect of triazine ring on the catalytic reaction, TITZ was replaced by TIBZ (1,3,5-tri(4-isocyanato)benzene) and the reaction with PAVImNH 2 The molar ratio of was 1:3, and a phenyl / urea functionalized polyionic liquid (Ben-IU-PIL-3) was synthesized using a similar method as described above.

[0050] The obtained product was subjected to performance testing.

[0051] 1) Solid-state carbon NMR ( 13 C SSNMR)

[0052] pass 13 C SSNMR was used to further analyze the polymer backbone of CTF-IU-PIL-5 obtained in Example 1. Figure 1As shown (due to space limitations, only part of the structure is listed in the figure, but it does not affect the carbon number labeling), 13 In the C SSNMR spectrum, 40-50 ppm is attributed to the characteristic vibration signal peaks of the polymerized double bond carbon and methylene bridge. The obvious signal peaks at 108, 119 and 139 ppm are attributed to the characteristic peaks of unsaturated carbon and -C=C- and -C=N+. The peak on the benzene ring appears in the range of 119-130 ppm. The signal around 153 ppm is attributed to the carbonyl carbon of the urea group. The characteristic peak of -C=N- belonging to the triazine ring can be observed at 168 ppm. The successful preparation of the cross-linked structure is further confirmed by solid-state carbon nuclear magnetic resonance spectroscopy.

[0053] 2) Fourier transform infrared spectroscopy (FT-IR)

[0054] Fourier transform infrared spectroscopy analysis was performed on the samples corresponding to each reaction stage in the above preparation to analyze the structure of the modified functional groups. Figure 2 (a) shows that the C=O absorption peak of triphosgene appears at 1818 cm -1 In TITZ, 2249 and 1702 cm -1 The characteristic absorption peaks at 1496, 1428, and 1361 cm in TATZ are attributed to isocyanate. -1 The three stretching vibration peaks are attributed to -NH 2 , by NH 2 The disappearance of and the generation of isocyanate groups indicated the successful synthesis of the TITZ intermediate. Figure 2 (b) As shown: at 3381, 2915, 1654 and 1163 cm -1 The characteristic absorption bands on the left and right correspond to the NH stretching vibration in the urea group, the CH stretching vibration of the benzene ring, the characteristic peak of the carbonyl group in the urea group, and the characteristic vibration peak of the CN on the imidazole ring. The disappearance of the characteristic peak of isocyanate in CTF-UI-PIL-5, the appearance of the carbonyl peak in the urea group and the imidazole ring prove the successful preparation of the urea-functionalized imidazole polyionic liquid. The characteristic peak of the CH of the para-substituted benzene ring appears at 800 cm -1 Around 1498, 1407, 1364cm -1 The absorption band at is attributed to the characteristic stretching vibration of the triazine ring, indicating that the triazine ring is successfully introduced into the polymer. The changes in the infrared spectra of the above samples prove the successful preparation of urea-functionalized imidazole polyionic liquids.

[0055] 3) Thermogravimetric analysis (TGA)

[0056] Thermogravimetric analysis of TITZ, PAVIm NH 2 The thermal stability of CTF-UI-PIL-5 was studied. Figure 3 As shown in the figure, in the range of room temperature to 100°C, due to the evaporation of absorbed water, the weight loss is about <10%. When the temperature is further increased to about 260°C, TITZ, PAVIm NH 2 and the CTF-UI-PIL-5 framework began to decompose, indicating that the urea-functionalized imidazole polyionic liquid CTF-UI-PIL-5 was stable as a catalyst under the cycloaddition reaction conditions selected in the present application.

[0057] 4) Low temperature N 2 Adsorption and desorption

[0058] In order to investigate the structural parameters of urea-functionalized imidazole polyionic liquids, such as specific surface area and pore size distribution, nitrogen adsorption and desorption experiments (77K, i.e. -196°C) were carried out on CTF-UI-PIL-5. Figure 4 As shown in Figure 2, the nitrogen adsorption-desorption curve of CTF-UI-PIL-5 is a typical type IV curve, indicating that there is a mesoporous structure in CTF-UI-PIL-5. The specific surface area of ​​CTF-UI-PIL-5 is 19.6 m 2 / g; the pore size distribution of CTF-UI-PIL-5 is mainly between 1 and 5 nm, which further illustrates that CTF-UI-PIL-5 belongs to a micro-mesoporous structure.

[0059] 5) Catalytic performance

[0060] As shown in Table 3: 40.0 mg of catalyst was added to a 25 ml Schlenk tube equipped with a magnet, and 10 mmol of epichlorohydrin (ECH) was weighed as an epoxy substrate and added to the Schlenk tube. Under solvent-free conditions, 0.1 MPa CO 2 , 80℃ reaction conditions catalyze the reaction of epoxy substrate with CO 2 The cycloaddition reaction was continued for 12 h. After the reaction was completed, 1 H NMR was used to determine the reaction selectivity and conversion rate of the substrate. Finally, the catalyst was separated by filtration, washed three times with dichloromethane, and dried at 60°C in a vacuum before continuing to the next catalytic cycle.

[0061] Among them, when no catalyst was added (No. 1 in Table 3) or TITZ (No. 2 in Table 3) and TATZ (No. 3 in Table 3) were added, the conversion rate was almost zero. Under the same conditions, the conversion rate of ECH to the homopolymer of 2-bromoethylamine hydrobromide was 64.62% (No. 4 in Table 3). 2The coupling reaction has high reactivity and selectivity, which is consistent with literature reports. After deprotonation with triethylamine solution, the conversion rate of ECH reached 97.45% (No. 5 in Table 3). This may be because after deprotonation, the amino group is exposed as a hydrogen bond donor, providing more sites to activate the epoxide and promote ring opening. After the triazine ring in the catalyst (CTF-UI-PIL-3) was replaced with a benzene ring, the catalytic effect was significantly reduced (No. 6 in Table 3), which shows that triazine has a promoting effect on the cycloaddition reaction. The increase of PIL in the urea-functionalized imidazole polyionic liquid shows that the content of PIL is proportional to the conversion rate of the catalyst, which may be because the increase of bromide ions in the catalyst promotes the ring-opening reaction of ECH (No. 7, 8, 9 in Table 3).

[0062] Table 3: Effect of the catalyst of the control group on CO 2 Effect of cycloaddition reaction with ECH

[0063]

[0064]

[0065] In summary, among the products of the above process, TATZ, PAVImNH 2 ·HBr、PAVIm NH 2 When Ben-UI-PIL-3, CTF-UI-PIL-3, CTF-UI-PIL-5 and CTF-UI-PIL-7 are used as catalysts, their selectivity for chloropropane cyclic carbonate is above 99%. The above catalytic reactions show that under normal pressure, in the absence of metals, solvents and co-catalysts, the reaction product of this case can be used as a catalyst to effectively convert carbon dioxide and ECH to obtain cyclic carbonate.

[0066] 6) Substrate suitability

[0067] Based on the above screening of the catalytic performance of the process products, CTF-UI-PIL-5 was used as a representative to study its performance as a catalyst in different epoxide and CO 2 Catalytic performance in cycloaddition reaction, reaction conditions: CTF-UI-PIL-54 0.0 mg, epoxy substrate 5 mmol, no solvent, 0.1 MPa CO 2 The reaction was carried out at 80°C for 36 hours. The catalytic results are shown in Table 4.

[0068] Table 4: Synthesis of cyclic carbonates catalyzed by CTF-UI-PIL-5 from different epoxy substrates

[0069]

[0070]

[0071] It can be observed from Table 4 that, whether it is an aromatic epoxy substrate or an alicyclic epoxy substrate, the corresponding epoxy substrate has a relatively high conversion rate under the catalytic system of the urea-functionalized imidazole polyionic liquid catalyst provided in the present application. Among them, when there are highly electronegative heteroatoms (such as phenyl glycidyl ether, methacrylate glycidyl ester, butyl glycidyl ether and allyl glycidyl ether) on the side chain of the epoxide, the conversion rate can reach more than 90% (see sequence numbers 3 to 6 in Table 4); while the epoxide catalyst activity of long-chain alkyl and styrene oxide is relatively low, which is because the steric hindrance hinders the nucleophilic attack of the halogen ion on the epoxide, and the ring opening rate is reduced, affecting the catalytic activity. In each catalytic reaction, without adding any co-catalyst or solvent, the urea-functionalized imidazole polyionic liquid converts each epoxide into the corresponding cyclic carbonate, indicating that the urea-functionalized imidazole polyionic liquid provided in the present application has good universality as a catalyst for various epoxy substrates.

[0072] In summary, an imidazolyl ionic polymer containing urea groups was synthesized by condensing amino groups with triazine-containing isocyanates to form urea groups, which can be used as a heterogeneous catalyst for the chemical fixation of carbon dioxide. Urea-functionalized imidazolyl polyionic liquids, especially CTF-UI-PIL-5, have good performance in CO2 fixation. 2 The excellent catalytic performance in the cycloaddition reaction is due to the interaction of CTF-UI-PIL-5 with CO 2 The unique structure and specific active sites give it a catalytic activity far higher than that of catalysts without triazine. 13 The target polymer was characterized by C NMR, FTIR, TGA, etc., which proved to be consistent with the designed target. In the presence of hydrogen bond donors and halogen bromide anions, under the synergistic effect of the bifunctional active centers in its structure, it showed excellent CO catalysis under normal pressure, without solvent and co-catalyst. 2 It has excellent catalytic conversion performance and is generally applicable and highly selective to a variety of epoxy substrates.

[0073] The above-mentioned embodiments only express several feasible implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention, and the embodiments are not used to limit the scope of protection in the claims of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and all equivalent implementations or changes that do not depart from the present invention should be included in the technology of the present invention.

Claims

1. Urea-functionalized imidazole polyionic liquid, characterized in that: The urea-functionalized imidazole polyionic liquid satisfies the following structural formula: Among them, a is 1 to 100, and b is 1 to 600.

2. The urea-functionalized imidazole polyionic liquid according to claim 1, characterized in that: The urea-functionalized imidazole polyionic liquid satisfies the following structural formula:

3. A method for preparing a urea-functionalized imidazole polyionic liquid, characterized in that: The amino-modified polyvinylimidazole is obtained by condensation reaction with triazine-containing isocyanate, and the structural formula of the amino-modified polyvinylimidazole is: The structural formula of triazine-containing isocyanate is The added molar ratio of the triazine-containing isocyanate to the amino-modified polyvinyl imidazole is 1:3 to 1:

7.

4. The method for preparing a urea-functionalized imidazole polyionic liquid according to claim 3, characterized in that: The temperature of the condensation reaction is 90-110°C.

5. The method for preparing a urea-functionalized imidazole polyionic liquid according to claim 3, characterized in that: The molar ratio of the triazine-containing isocyanate to the amino-modified polyvinylimidazole is 1:3 to 1:

7.

6. The method for preparing a urea-functionalized imidazole polyionic liquid according to claim 3, characterized in that: In the condensation reaction, amino-modified polyvinyl imidazole and triazine-containing isocyanate are dissolved in anhydrous DMF to form an amino-modified polyvinyl imidazole solution and a triazine-containing isocyanate solution, which are added in the form of solutions and reacted.

7. The method for preparing a urea-functionalized imidazole polyionic liquid according to any one of claims 3 to 6, characterized in that: The preparation method of the amino-modified polyvinyl imidazole is as follows: adding anhydrous ethanol and BHT to N-vinyl imidazole, evacuating and passing nitrogen, adding an ethanol solution of 2-bromoethylamine hydrobromide under a N2 gas flow, cooling to room temperature, filtering and recovering a crude product after reflux reaction, washing with ethanol to remove unreacted monomers, and vacuum drying overnight to obtain an amino-modified imidazolium ionic liquid; dissolving the amino-modified imidazolium ionic liquid in an appropriate amount of methanol solution, adding AIBN, refluxing the mixture, cooling to room temperature, filtering and separating a solid polymer, eluting with methanol, collecting the solid, vacuum drying overnight, deprotonating, and drying to obtain the amino-modified polyvinyl imidazole.

8. The method for preparing a urea-functionalized imidazole polyionic liquid according to any one of claims 3 to 6, characterized in that: The preparation method of the isocyanate containing triazine is as follows: 4-aminobenzonitrile is dissolved in CHCl3, and then added dropwise to a mixed solution of chloroform and TfOH at 0-20°C. After the reaction is completed, distilled water is added to dilute and neutralize to neutrality. The solution is filtered, washed with CHCl3, and vacuum dried. The obtained product and triphosgene are dissolved in anhydrous THF to obtain a TATZ solution and a triphosgene solution, respectively. The TATZ solution is added dropwise to the triphosgene solution in an ice-water bath. After the reaction is completed, the reaction is refluxed, THF is removed by rotary evaporation, anhydrous CH2Cl2 is added for ultrasonic dispersion, filtration, and vacuum drying to obtain the isocyanate containing triazine.

9. An application of the urea-functionalized imidazole polyionic liquid according to claim 1, wherein the urea-functionalized imidazole polyionic liquid is used for the cycloaddition reaction of an epoxy substrate with CO2, and the cycloaddition reaction is carried out under normal pressure, in the absence of solvent and a co-catalyst.

10. The use of the urea-functionalized imidazole polyionic liquid according to claim 9, characterized in that: The epoxy substrate is any one of the following structures: epichlorohydrin,

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