Preparation method and application of high-activity-site polyion liquid catalyst

Abstract

The invention discloses a preparation method and application of a high-activity-site polyion liquid catalyst, and belongs to the field of green catalytic synthesis. The preparation method comprises the following steps: introducing imidazole on an amine-functionalized ionic liquid through an aldehyde-amine condensation method, introducing dipyridine through free radical polymerization, and finally introducing metal zinc through a method of metallization after synthesis to synthesize the polyionic liquid catalyst with Lewis acid-base sites, nucleophilic reagent sites, hydrogen bond donors and carbon dioxide adsorption sites. Compared with the prior art, the catalyst has multiple active sites, the synthesis method is simple, the product is easy to separate, and the catalyst has excellent performance in catalysis of cycloaddition reaction of carbon dioxide and epoxypropane.

Description

Technical Field

[0001] The invention belongs to the field of green catalytic synthesis, and specifically relates to a preparation method and application of a high-activity site polyionic liquid catalyst. Background Art

[0002] In recent years, the frequent use of fossil fuels in energy production has led to a surge in CO2 concentrations, which in turn has caused a series of environmental problems such as global warming. Therefore, research aimed at capturing CO2 and converting it into value-added products is booming, such as methanol, formic acid, cyclic carbonates, polycarbonates, polyurethanes, etc. Among them, cyclic carbonates synthesized from CO2 and epoxides have an atomic utilization rate of 100% and a wide range of product applications, making them one of the most promising strategies for CO2 resource utilization. Although CO2 is an abundant, non-toxic and easily available C1 resource, its inherent kinetic inertness and thermodynamic stability require the development of efficient catalysts that can promote cycloaddition reactions under mild conditions to be put on the agenda.

[0003] Generally, the catalysts used for CO2 cycloaddition reaction can be divided into homogeneous catalysts and heterogeneous catalysts according to their phase. The former include metal halides, metal complexes, porphyrins and ionic liquids, but homogeneous catalysts have the disadvantages of difficult separation, high viscosity and high cost; the latter include polyionic liquids (PILs), highly cross-linked ionic polymers (HIPs), covalent organic frameworks (COFs), metal organic frameworks (MOFs), etc. For example, Jose Tharun et al. published a catalyst synthesized by grafting iodinated aminopyridinium ionic liquid onto n-ZIF-90 structure through aldehyde amine condensation in the article "Ionic Liquid Tethered PostFunctionalized ZIF-90 Framework for the Cycloaddition of Propylene Oxide and CO2" (Green Chemistry, 2016, 18, 2479-2487). The catalyst catalyzed propylene oxide at 1 MPa, 120 ° C, and 3 h with a conversion rate of 97% and a selectivity of 98%. However, the weight of the catalyst after compounding with ionic liquid continues to decrease from 180°C, and the thermodynamic stability is poor. The Chinese invention patent document with publication number CN115888824A discloses a method for preparing an amide functionalized polymerized ionic liquid catalyst, using imidazolium ionic liquid as a monomer, and a cross-linking agent with an amide group and a cross-linking agent with a benzene ring through free radical copolymerization to obtain a cross-linked polymerized ionic liquid, which catalyzes propylene oxide at a yield of 98% under the conditions of 1Mpa, 100°C, and 3h. However, there are fewer active sites and a large amount of catalyst is used. Yawen Fu et al. published in the article "Mesoporous Poly (Ionic Liquids) with Dual Active Sites for Highly Efficient CO2 Conversion" (Green Energy & Environment, 2023, 8, 478-486) ​​a method of synthesizing a quaternary ammonium-based monomer, copolymerizing it with bipyridine, and then metallizing and supercritical CO2 drying to obtain a new mesoporous polyionic liquid with dual active sites. Under the conditions of 0.1Mpa, 50°C, and 24h, it catalyzed epichlorohydrin with a conversion rate of 98.9% and a selectivity of 96.9%. However, the synthesis process is cumbersome and requires multiple steps. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a high-activity site polyionic liquid catalyst. The prepared catalyst has Lewis acid-base sites, nucleophilic reagent sites, hydrogen bond donors and carbon dioxide adsorption sites, and performs excellently in catalyzing the cycloaddition reaction of carbon dioxide and propylene oxide.

[0005] To achieve the purpose of the invention, the present invention provides a technical solution for a method for preparing a high-activity site polyionic liquid catalyst, comprising the following steps: (1) Add 1-vinyl imidazole or 1-allylimidazole and halogenated alkane to an organic solvent, and react at 70-90°C for 12-24 hours under a nitrogen atmosphere; after the reaction, remove the solvent under reduced pressure, wash with ethyl acetate, and dry to obtain an ionic liquid with a halogen terminal; (2) adding the halogen-terminated ionic liquid obtained in step (1) to the amino compound, reacting at 100 to 120° C. for 12 to 24 hours under a nitrogen atmosphere, cooling to room temperature, separating the solvent, washing with ethyl acetate, and drying to obtain an amine-functionalized ionic liquid; (3) The amine-functionalized ionic liquid and imidazole-2-carboxaldehyde obtained in step (2) are added to dimethyl sulfoxide, and the mixture is reacted at 40 to 80° C. for 24 to 48 hours. A crosslinking agent 5,5'-divinyl-2,2'-bipyridine and an initiator are added, and the mixture is reacted at 90 to 110° C. for 24 to 48 hours under a nitrogen atmosphere. The mixture is cooled to room temperature and centrifuged. The product is washed with ethanol and extracted with ethanol by reflux Soxhlet for 1 to 3 hours. The product is immersed in ethanol, zinc halide is added, and the mixture is stirred at room temperature for 24 to 48 hours. The mixture is centrifuged, washed with ethanol, and dried to obtain a high-activity site polyionic liquid catalyst.

[0006] Furthermore, in step (1), the molar ratio of 1-vinylimidazole or 1-allylimidazole to halogenated alkane is 0.25 to 1: 1; the halogenated alkane is one of 1,2-dibromoethane, 1,2-dichloroethane, 1,3-dibromopropane, 1,3-dichloropropane, 1,4-dibromobutane and 1,4-dichlorobutane; the molar concentration of the halogenated alkane in the organic solvent is 0.8 to 1.6 mol / L; and the organic solvent is toluene or acetonitrile.

[0007] Furthermore, in step (2), the molar concentration of the halogen-terminated ionic liquid in the amino compound is 0.5 to 1.2 mol / L; and the amino compound is triethylenetetramine or tetraethylenepentamine.

[0008] Furthermore, in step (3), the molar ratio of the amine-functionalized ionic liquid to imidazole-2-carboxaldehyde is 1:1 to 1.2; the molar concentration of the amine-functionalized ionic liquid in dimethyl sulfoxide is 0.1 to 0.2 mol / L; the molar ratio of the amine-functionalized ionic liquid to the crosslinking agent 5,5'-divinyl-2,2'-bipyridine is 0.5 to 2:1; the initiator is one of azobisisobutyronitrile or azobisisopropionitrile; the initiator is 5% to 8% of the sum of the mass of the amine-functionalized ionic liquid and the crosslinking agent; the molar ratio of the zinc halide to the amine-functionalized ionic liquid is 2 to 5:1; and the zinc halide is one of zinc bromide or zinc chloride.

[0009] The present invention also provides an application of the high-activity site polyionic liquid catalyst, wherein the catalyst is used to catalyze the cycloaddition reaction of carbon dioxide and propylene oxide.

[0010] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a method for preparing a high-activity site polyionic liquid catalyst. First, imidazole is introduced into the amine-functionalized ionic liquid through a condensation reaction between an aldehyde group and a primary amine. Then, bipyridine is introduced through a free radical polymerization reaction. Finally, metallic zinc is introduced through a post-synthesis metallization method. The synthesis method is simple, the ionic liquid is not easily lost, and the synthesis of propylene carbonate from carbon dioxide and propylene oxide can be efficiently promoted.

[0011] (2) The present invention provides a method for preparing a high-activity site polyionic liquid catalyst. In addition to the imidazole ring and halogen ion as sites for promoting the effective ring-opening of propylene oxide, the amine-functionalized ionic liquid also has a large number of secondary amines. On the one hand, the secondary amines on the bipyridine and the imidazole on the imidazole-2-carboxaldehyde are coordinated with the metal zinc to introduce a large number of Lewis acid sites to promote the ring-opening. At the same time, the incompletely coordinated secondary amines on the ionic liquid can serve as multi-adjacent hydrogen bond donors to form hydrogen bonds with propylene oxide to promote the ring-opening. The catalyst has an imine group that can adsorb carbon dioxide. The multiple effects synergistically promote the ring-opening reaction of propylene oxide, solving the problem of few catalyst active sites and high catalyst usage.

[0012] (3) The high-activity site polyionic liquid catalyst provided by the present invention has good thermodynamic stability. The material is stable and does not decompose before 200°C.

[0013] (4) The present invention provides an application of a prepared high-activity site polyionic liquid catalyst for catalyzing the cycloaddition reaction of carbon dioxide and propylene oxide, which has the advantages of simple product separation and a catalytic carbon dioxide and propylene oxide yield of more than 93%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a thermogravimetric curve of the high-activity site polyionic liquid catalyst (Cat1) in Example 1 under a nitrogen atmosphere; Figure 2 is a graph showing the carbon dioxide adsorption of the high-activity site polyionic liquid catalyst (Cat3) in Example 3 at 273.15K and 1atm; Figure 3 FT-IR spectra of the amine-functionalized ionic liquid (N5-IL-5) and the high-activity site polyionic liquid catalyst (Cat5) in Example 5. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to specific embodiments and drawings, but is not limited thereto.

[0016] Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available products unless otherwise specified. Example 1

[0017] (1) 0.01 mol 1-vinylimidazole and 0.04 mol 1,2-dibromoethane were added to 50 mL acetonitrile and reacted at 75°C for 24 h under a nitrogen atmosphere. After the reaction, the solvent was removed under reduced pressure, and the oily liquid was washed three times with ethyl acetate to remove unreacted 1,2-dibromoethane, and then dried under vacuum at 40°C for 12 h to obtain an ionic liquid with a halogen terminal, namely IL-1.

[0018] (2) Add 0.01 mol of IL-1 obtained in step (1) to 10 mL of triethylenetetramine, and react at 110° C. for 12 h under a nitrogen atmosphere; cool to room temperature, separate the solvent, wash the oily liquid three times with ethyl acetate to remove unreacted triethylenetetramine, and dry under vacuum at 40° C. for 12 h to obtain an amine-functionalized ionic liquid, namely N4-IL-1.

[0019] (3) 0.001 mol N4-IL-1 and 0.0012 mol imidazole-2-carboxaldehyde obtained in step (2) were added to 5 mL dimethyl sulfoxide, stirred at 50°C for 24 h, 0.001 mol cross-linker 5,5'-divinyl-2,2'-bipyridine and 5% of the mass of the initiator azobisisopropionitrile were added, reacted at 90°C for 24 h under nitrogen atmosphere, cooled to room temperature, centrifuged, the product was washed three times with ethanol and extracted with ethanol reflux Soxhlet for 1 h to remove unreacted imidazole-2-carboxaldehyde, cross-linker and initiator, the product was immersed in ethanol, 0.002 mol zinc chloride was added, stirred at room temperature for 24 h, centrifuged, washed three times with ethanol to remove excess zinc chloride, and dried in vacuo at 70°C for 12 h to obtain a high active site polyionic liquid catalyst, namely Cat1.

[0020] 100 mg of catalyst Cat1 and 10 mmol of propylene oxide were added to a 15 mL stainless steel autoclave equipped with a magnet, and 1 MPa of carbon dioxide was charged, and the reaction was stirred at 90°C for 6 hours. After the reaction was completed, the temperature was cooled in an ice water bath, and the excess carbon dioxide was slowly released. Ethanol and an appropriate amount of biphenyl (internal standard for chromatographic analysis) were added to the liquid after the reaction, and the solid catalyst was separated by centrifugation. The liquid sample was analyzed by gas chromatography (GC-2030) equipped with a PEG column (30m*0.32mm*0.5um), and the yield of propylene carbonate was 79%. Example 2

[0021] (1) 0.02 mol 1-allylimidazole and 0.04 mol 1,2-dichloroethane were added to 30 mL toluene and reacted at 90°C for 24 h under a nitrogen atmosphere. After the reaction, the solvent was removed under reduced pressure, and the oily liquid was washed three times with ethyl acetate to remove unreacted 1,2-dichloroethane, and then dried under vacuum at 40°C for 12 h to obtain an ionic liquid with a halogen terminal, namely IL-2.

[0022] (2) Add 0.01 mol of IL-2 obtained in step (1) to 12.5 mL of tetraethylenepentamine, and react at 100° C. for 24 h under a nitrogen atmosphere; cool to room temperature, separate the solvent, wash the oily liquid three times with ethyl acetate to remove unreacted tetraethylenepentamine, and dry under vacuum at 40° C. for 12 h to obtain an amine-functionalized ionic liquid, namely N5-IL-2.

[0023] (3) 0.001 mol N5-IL-2 and 0.0011 mol imidazole-2-carboxaldehyde obtained in step (2) were added to 10 mL dimethyl sulfoxide, stirred at 40° C. for 48 h, 0.0005 mol cross-linker 5,5'-divinyl-2,2'-bipyridine and 5% of the mass of the initiator azobisisopropionitrile as the sum of the mass of the amine-functionalized ionic liquid and the cross-linker were added, and the mixture was reacted at 100° C. for 24 h under a nitrogen atmosphere. The mixture was cooled to room temperature and centrifuged. The product was washed three times with ethanol and extracted with ethanol reflux for 2 h to remove unreacted imidazole-2-carboxaldehyde, cross-linker and initiator. The product was immersed in ethanol, 0.003 mol zinc bromide was added, stirred at room temperature for 48 h, centrifuged, washed three times with ethanol to remove excess zinc bromide, and dried under vacuum at 70° C. for 12 h to obtain a high-activity site polyionic liquid catalyst, namely Cat2.

[0024] The only difference from the application in Example 1 is that the catalyst used is Cat2, and the yield of propylene carbonate is 83%. Example 3

[0025] (1) 0.03 mol 1-vinylimidazole and 0.04 mol 1,3-dibromopropane were added to 25 mL toluene and reacted at 80°C for 18 h under a nitrogen atmosphere. After the reaction, the solvent was removed under reduced pressure, and the oily liquid was washed three times with ethyl acetate to remove unreacted 1,3-dibromopropane, and then dried under vacuum at 40°C for 12 h to obtain an ionic liquid with a halogen terminal, namely IL-3.

[0026] (2) Add 0.01 mol IL-3 obtained in step (1) to 8.3 mL tetraethylenepentamine, and react at 110° C. for 18 h under a nitrogen atmosphere; cool to room temperature, separate the solvent, wash the oily liquid three times with ethyl acetate to remove unreacted tetraethylenepentamine, and dry under vacuum at 40° C. for 12 h to obtain an amine-functionalized ionic liquid, namely N5-IL-3.

[0027] (3) 0.001 mol N5-IL-3 and 0.001 mol imidazole-2-carboxaldehyde obtained in step (2) were added to 7 mL dimethyl sulfoxide, stirred at 60° C. for 36 h, 0.002 mol cross-linker 5,5'-divinyl-2,2'-bipyridine and 7% of the mass of the initiator azobisisopropionitrile as the sum of the mass of the amine-functionalized ionic liquid and the cross-linker were added, and the mixture was reacted at 110° C. for 36 h under a nitrogen atmosphere. The mixture was cooled to room temperature and centrifuged. The product was washed three times with ethanol and extracted with ethanol reflux for 3 h to remove unreacted imidazole-2-carboxaldehyde, cross-linker and initiator. The product was immersed in ethanol, 0.004 mol zinc bromide was added, stirred at room temperature for 36 h, centrifuged, washed three times with ethanol to remove excess zinc bromide, and dried under vacuum at 70° C. for 12 h to obtain a high-activity site polyionic liquid catalyst, namely Cat3.

[0028] The only difference from the application in Example 1 is that the catalyst used is Cat3, and the yield of propylene carbonate is 89%. Example 4

[0029] (1) 0.04 mol 1-allylimidazole and 0.04 mol 1,3-dichloropropane were added to 50 mL acetonitrile and reacted at 70°C for 12 h under a nitrogen atmosphere. After the reaction, the solvent was removed under reduced pressure, and the oily liquid was washed three times with ethyl acetate to remove unreacted 1,3-dichloropropane, and then dried under vacuum at 40°C for 12 h to obtain an ionic liquid with a halogen terminal, namely IL-4.

[0030] (2) Add 0.01 mol of IL-4 obtained in step (1) to 15 mL of triethylenetetramine, and react at 120° C. for 18 h under a nitrogen atmosphere; cool to room temperature, separate the solvent, wash the oily liquid three times with ethyl acetate to remove unreacted triethylenetetramine, and dry under vacuum at 40° C. for 12 h to obtain an amine-functionalized ionic liquid, namely N4-IL-4.

[0031] (3) 0.001 mol N4-IL-4 and 0.0011 mol imidazole-2-carboxaldehyde obtained in step (2) were added to 5 mL dimethyl sulfoxide, stirred at 70° C. for 24 h, 0.0005 mol cross-linker 5,5'-divinyl-2,2'-bipyridine and 8% of the mass of the initiator azobisisopropionitrile were added, reacted at 90° C. for 48 h under nitrogen atmosphere, cooled to room temperature, centrifuged, the product was washed three times with ethanol and extracted with ethanol reflux Soxhlet for 1 h to remove unreacted imidazole-2-carboxaldehyde, cross-linker and initiator, the product was immersed in ethanol, 0.005 mol zinc chloride was added, stirred at room temperature for 24 h, centrifuged, washed three times with ethanol to remove excess zinc chloride, and dried in vacuo at 70° C. for 12 h to obtain a high-activity site polyionic liquid catalyst, namely Cat4.

[0032] The only difference from the application in Example 1 is that the catalyst used is Cat4, and the yield of propylene carbonate is 78%. Example 5

[0033] (1) 0.01 mol 1-vinylimidazole and 0.04 mol 1,4-dibromobutane were added to 40 mL acetonitrile and reacted at 75°C for 24 h under a nitrogen atmosphere. After the reaction, the solvent was removed under reduced pressure, and the oily liquid was washed three times with ethyl acetate to remove unreacted 1,2-dibromoethane, and then dried under vacuum at 40°C for 12 h to obtain an ionic liquid with a halogen terminal, namely IL-5.

[0034] (2) Add 0.01 mol of IL-5 obtained in step (1) to 10 mL of tetraethylenepentamine, and react at 120° C. for 24 h under a nitrogen atmosphere; cool to room temperature, separate the solvent, wash the oily liquid three times with ethyl acetate to remove unreacted tetraethylenepentamine, and dry under vacuum at 40° C. for 12 h to obtain an amine-functionalized ionic liquid, namely N5-IL-5.

[0035] (3) 0.001 mol N5-IL-5 and 0.0012 mol imidazole-2-carboxaldehyde obtained in step (2) were added to 10 mL dimethyl sulfoxide, stirred at 60° C. for 48 h, 0.001 mol cross-linker 5,5'-divinyl-2,2'-bipyridine and 6% of the mass of the initiator azobisisobutyronitrile were added, reacted at 100° C. for 48 h under nitrogen atmosphere, cooled to room temperature, centrifuged, the product was washed three times with ethanol and extracted with ethanol reflux Soxhlet for 2 h to remove unreacted imidazole-2-carboxaldehyde, cross-linker and initiator, the product was immersed in ethanol, 0.004 mol zinc bromide was added, stirred at room temperature for 36 h, centrifuged, washed three times with ethanol to remove excess zinc bromide, and dried under vacuum at 70° C. for 12 h to obtain a high-activity site polyionic liquid catalyst, namely Cat5.

[0036] The only difference from the application in Example 1 is that the catalyst used is Cat5, and the yield of propylene carbonate is 93%. Example 6

[0037] (1) 0.02 mol 1-allylimidazole and 0.04 mol 1,4-dichlorobutane were added to 30 mL toluene and reacted at 85°C for 24 h under a nitrogen atmosphere. After the reaction, the solvent was removed under reduced pressure, and the oily liquid was washed three times with ethyl acetate to remove unreacted 1,4-dichlorobutane, and then dried under vacuum at 40°C for 12 h to obtain an ionic liquid with a halogen terminal, namely IL-6.

[0038] (2) Add 0.01 mol of IL-6 obtained in step (1) to 20 mL of triethylenetetramine, and react at 100° C. for 12 h under a nitrogen atmosphere; cool to room temperature, separate the solvent, wash the oily liquid three times with ethyl acetate to remove unreacted triethylenetetramine, and dry under vacuum at 40° C. for 12 h to obtain an amine-functionalized ionic liquid, namely N4-IL-6.

[0039] (3) 0.001 mol N4-IL-6 and 0.001 mol imidazole-2-carboxaldehyde obtained in step (2) were added to 7 mL dimethyl sulfoxide, stirred at 80° C. for 24 h, 0.0007 mol cross-linker 5,5'-divinyl-2,2'-bipyridine and 7% of the mass of the initiator azobisisopropionitrile as the sum of the mass of the amine-functionalized ionic liquid and the cross-linker were added, and the reaction was carried out at 110° C. for 36 h under a nitrogen atmosphere. The product was cooled to room temperature and centrifuged. The product was washed three times with ethanol and extracted with ethanol reflux Soxhlet for 3 h to remove unreacted imidazole-2-carboxaldehyde, cross-linker and initiator. The product was immersed in ethanol, 0.003 mol zinc chloride was added, stirred at room temperature for 48 h, centrifuged, washed three times with ethanol, excess zinc chloride was removed, and vacuum dried at 70° C. for 12 h to obtain a high-activity site polyionic liquid catalyst, namely Cat6.

[0040] The only difference from the application in Example 1 is that the catalyst used is Cat6, and the yield of propylene carbonate is 81%.

[0041]

[0042] Thermogravimetric characterization of Cat1 in Example 1 was performed under nitrogen atmosphere (see Appendix Figure 1 ), the results showed that the weight loss of the catalyst before 100 °C was due to the evaporation of water and solvent. After 200 °C, the catalyst began to decompose, indicating that the material has good thermodynamic stability.

[0043] Cat3 in Example 3 was subjected to a carbon dioxide adsorption test at 273.15K and 1atm (see Appendix). Figure 2 ), the carbon dioxide adsorption amount is 0.57mmol / g, which indicates that the imine groups in the catalyst can adsorb carbon dioxide and further promote the cycloaddition reaction.

[0044] The N5-IL-5 and Cat5 in Example 5 were characterized by infrared spectroscopy (see Appendix). Figure 3 ), the results show that 1604cm -1 The peak at 474 cm-1 can be attributed to the imine bond formed by the aldehyde-amine condensation reaction, indicating the successful introduction of imidazole-2-carboxaldehyde. -1 The peak at can be attributed to the Zn-N bond, indicating that metallic zinc has been successfully introduced into the polyionic liquid, the catalyst has many active sites, and can efficiently catalyze the cycloaddition reaction of carbon dioxide and propylene oxide.

[0045] For those skilled in the art, any technical solution formed by equivalent transformation or equivalent replacement according to the above description and conception should fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a high-activity site polyionic liquid catalyst, characterized in that: The following steps are involved: (1) Add 1-vinyl imidazole or 1-allylimidazole and halogenated alkane to an organic solvent, react at 70-90°C for 12-24 hours under a nitrogen atmosphere, remove the solvent under reduced pressure, wash with ethyl acetate, and dry to obtain an ionic liquid with a halogen terminal; (2) adding the halogen-terminated ionic liquid obtained in step (1) to the amino compound, reacting at 100 to 120° C. for 12 to 24 hours under a nitrogen atmosphere, cooling to room temperature, separating the solvent, washing with ethyl acetate, and drying to obtain an amine-functionalized ionic liquid; (3) The amine-functionalized ionic liquid and imidazole-2-carboxaldehyde obtained in step (2) are added to dimethyl sulfoxide, and the mixture is reacted at 40 to 80° C. for 24 to 48 hours. A crosslinking agent 5,5'-divinyl-2,2'-bipyridine and an initiator are added, and the mixture is reacted at 90 to 110° C. for 24 to 48 hours under a nitrogen atmosphere. The mixture is cooled to room temperature and centrifuged. The product is washed with ethanol and extracted with ethanol by reflux Soxhlet for 1 to 3 hours. The product is immersed in ethanol, zinc halide is added, and the mixture is stirred at room temperature for 24 to 48 hours. The mixture is centrifuged, washed with ethanol, and dried to obtain a high-activity site polyionic liquid catalyst.

2. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (1), the molar ratio of 1-vinylimidazole or 1-allylimidazole to halogenated alkane is 0.25 to 1:1; the halogenated alkane is one of 1,2-dibromoethane, 1,2-dichloroethane, 1,3-dibromopropane, 1,3-dichloropropane, 1,4-dibromobutane and 1,4-dichlorobutane.

3. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (1), the molar concentration of the halogenated alkane in the organic solvent is 0.8 to 1.6 mol / L; the organic solvent is toluene or acetonitrile.

4. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (2), the molar concentration of the halogen-terminated ionic liquid in the amino compound is 0.5 to 1.2 mol / L; the amino compound is triethylenetetramine or tetraethylenepentamine.

5. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (3), the molar ratio of the amine-functionalized ionic liquid to imidazole-2-carboxaldehyde is 1:1-1.2; and the molar concentration of the amine-functionalized ionic liquid in dimethyl sulfoxide is 0.1-0.2 mol / L.

6. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (3), the molar ratio of the amine-functionalized ionic liquid to the cross-linking agent 5,5'-divinyl-2,2'-bipyridine is 0.5 to 2:

1.

7. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (3), the initiator is one of azobisisobutyronitrile and azobisisopropionitrile; the initiator is 5% to 8% of the sum of the mass of the amine-functionalized ionic liquid and the cross-linking agent.

8. The method for preparing a high-activity site polyionic liquid catalyst according to claim 1, characterized in that: In the step (3), the molar ratio of zinc halide to amine-functionalized ionic liquid is 2 to 5:1; the zinc halide is one of zinc bromide and zinc chloride.

9. An application of a high-activity site polyionic liquid catalyst prepared by the preparation method according to any one of claims 1 to 8, characterized in that: Highly active site polyionic liquid catalysts were used to catalyze the cycloaddition reaction of carbon dioxide and propylene oxide.

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