Zirconium oxide / poly-ionic liquid composite catalytic material and preparation method and application thereof

Abstract

The application discloses a zirconium oxide / polyionic liquid composite catalytic material and a preparation method and application thereof, and belongs to the technical field of catalyst preparation. The zirconium oxide aerogel is used as a carrier, and 3-iodine-2-(iodomethyl) propionic acid is used as a precursor monomer of the polyionic liquid to prepare the composite catalytic material. The molecular structure of the monomer simultaneously has double iodine active sites and terminal carboxyl functional groups, so that quaternary ammonium of the double iodine sites can be realized, and the strong hydrogen bond effect between the carboxyl and the surface hydroxyl of the zirconium oxide can be utilized to realize the covalent bond loading of the polyionic liquid on the surface of the carrier, so that the loss problem of the active components caused by the physical loading can be greatly improved. In addition, the composite catalytic material retains the nucleophilic sites, the carboxyl weak acid sites in the PILs and the Lewis acid sites in the zirconium oxide, and high-efficiency multifunctional catalysis can be realized through the synergistic effect of the three.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and in particular relates to a zirconium oxide / polyionic liquid composite catalytic material, its preparation method and application. Background Technology

[0002] In recent years, the excessive use of fossil fuels has led to a sharp rise in atmospheric CO2 concentration, causing environmental problems such as global warming and ocean acidification that seriously threaten the ecological balance. How to effectively reduce atmospheric CO2 concentration and realize its resource utilization has become a major challenge in the environmental and energy fields.

[0003] Although CO2 is one of the major greenhouse gases, it is also an abundant, inexpensive, non-toxic, and non-flammable renewable C1 resource. Capturing it and converting it into high-value-added products through chemical conversion technology is of great practical significance and ecological value.

[0004] CO2, as a C1 resource, can be converted into various high-value-added chemical products, such as methanol, urea, formic acid, carbonates, oxazolidinones, and quinazolinones, through the development of advanced catalytic technologies. Among these, the cycloaddition reaction of CO2 with epoxides to synthesize cyclic carbonates has attracted widespread attention. On the one hand, this reaction is 100% atom-economical and can replace the traditional phosgene process to produce high-value-added cyclic carbonates; on the other hand, cyclic carbonates are a very important class of chemical products, widely used in lithium-ion battery solvents, polymer monomers, pharmaceutical intermediates, and other fields.

[0005] Developing efficient catalytic systems is crucial for the efficient synthesis of cyclic carbonates through the cycloaddition reaction of CO2 with epoxides. Polyionic liquids, as heterogeneous catalysts, have shown promising applications in cycloaddition reactions due to their abundant nucleophilic (halogen anion) active sites. However, their application is limited by issues such as the single active site, low specific surface area, complex preparation steps, and relatively low catalytic activity. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a zirconia / polyionic liquid composite catalytic material, its preparation method, and its applications. Based on the high specific surface area and abundant Lewis acidic sites of zirconia aerogel, this invention uses zirconia aerogel as a carrier and employs an in-situ quaternization reaction between imidazole monomers and dihalogenated compounds to prepare a zirconia / polyionic liquid composite catalytic material. The composite catalytic material prepared by this strategy retains the nucleophilic sites and weakly acidic carboxyl sites of PILs, as well as the Lewis acidic sites of zirconia, achieving highly efficient and multifunctional catalysis through the synergistic effect of these three elements.

[0007] In a first aspect, the present invention provides a method for preparing a zirconia / polyionic liquid composite catalytic material, comprising the following steps: adding zirconia aerogel to an organic solvent of an imidazole monomer, mixing evenly, adding a dihalogenated compound, mixing evenly again, purging with nitrogen gas, heating to react, centrifuging, washing, and drying after the reaction is completed to obtain the zirconia / polyionic liquid composite catalytic material.

[0008] Further, the imidazole monomer is selected from tris-(4-imidazolylphenyl)amine or 1,3,5-tris((1H-imidazol-1-yl)methyl)benzene; and / or, The dihalogenated product is selected from 3-iodo-2-(iodomethyl)propionic acid or 3-bromo-2-(bromomethyl)propionic acid.

[0009] Furthermore, the organic solvent is selected from ethanol, N,N-dimethylformamide, methanol, or acetonitrile.

[0010] Further, the molar ratio of the imidazole monomer to the dihalogenated product is 2:1; the ratio of the sum of the masses of the imidazole monomer and the dihalogenated product to the mass of the zirconia aerogel is 1:(1-3); and the mass-to-volume ratio of the zirconia aerogel to the organic solvent is 0.38-0.4 g:10 mL.

[0011] Furthermore, the heating reaction is carried out at a temperature of 100 °C for 24 h.

[0012] Further, the preparation method of the zirconia aerogel includes the following steps: adding an inorganic zirconium source to a methanol-water mixed solvent, mixing well, adding N,N-dimethylformamide, mixing again, adding propylene oxide, performing gelation aging, modifying the surface of the obtained gel to be hydrophobic, then immersing the modified gel in anhydrous ethanol for solvent replacement, then centrifuging and drying to obtain a zirconia aerogel precursor, and calcining the zirconia aerogel precursor to prepare zirconia aerogel.

[0013] Furthermore, the ratio of the inorganic zirconium source, propylene oxide, N,N-dimethylformamide, and methanol-water mixed solvent is 0.02 mol: 0.2 mol: 0.02 mol: 100 mL; the gelation reaction temperature is 60 °C. The specific operation of the surface hydrophobic modification is as follows: the gel is placed in a mixed solution of n-hexane and silane coupling agent and reacted at 50 °C for 24 h; The solvent replacement temperature is 50 °C and the time is 24 h; The calcination temperature was 600 °C and the time was 2 h.

[0014] Furthermore, the inorganic zirconium source is selected from zirconium oxynitrate, zirconium oxychloride, or zirconium nitrate; Furthermore, the silane coupling agent is selected from hexamethyldisilazane, trimethylchlorosilane, methyltrimethoxysilane, or trimethylethoxysilane; preferably trimethylchlorosilane.

[0015] Secondly, the present invention provides a zirconium oxide / polyionic liquid composite catalytic material prepared by the above preparation method.

[0016] Thirdly, the present invention provides an application of the zirconium oxide / polyionic liquid composite catalytic material in the catalytic cycloaddition reaction of epoxide and CO2 to synthesize cyclic carbonates, comprising the following steps: adding epoxide and the zirconium oxide / polyionic liquid composite catalytic material to a high-pressure reactor, sealing the reactor, replacing the air in the reactor with CO2, and heating the reactor to synthesize cyclic carbonates.

[0017] Furthermore, the epoxide is selected from propylene oxide, cyclohexene oxide, or styrene oxide.

[0018] Furthermore, after CO2 replaces the air in the reactor, the pressure in the high-pressure reactor is 0.2-3 MPa; the temperature of the heating reaction is 80-120 ℃.

[0019] This invention synthesizes zirconia aerogel under mild conditions using inexpensive inorganic zirconium salts as precursors, water and methanol as solvents, propylene oxide as a coagulant, DMF (N,N-dimethylformamide) as a desiccant, and a silane coupling agent as a surface modifier. In the presence of the zirconia aerogel, an in-situ quaternization reaction is carried out using imidazole monomers and dihalogenated derivatives as monomers to obtain a zirconia / polyionic liquid (PIL@ZrO2) composite catalytic material. The prepared PIL@ZrO2 composite catalytic material simultaneously possesses abundant nucleophilic sites, carboxyl weakly acidic sites, and Lewis acidic sites, which can achieve highly efficient and multifunctional catalysis through synergistic effects. As a catalyst, this composite material exhibits excellent catalytic performance and cycle stability in the cycloaddition reaction of CO2 with epoxides, and shows promise for practical industrial production.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects: This invention uses zirconia aerogel as a carrier and 3-iodo-2-(iodomethyl)propionic acid as a precursor monomer for polyionic liquids to prepare composite catalytic materials. The monomer's molecular structure possesses both diiodine active sites and terminal carboxyl functional groups, enabling quaternization of the diiodine sites and, simultaneously, utilizing the strong hydrogen bonding between the carboxyl groups and the hydroxyl groups on the zirconia surface to achieve covalent loading of the polyionic liquid on the carrier surface. This significantly mitigates the problem of active component loss caused by physical loading.

[0021] The zirconia / polyionic liquid composite catalytic material prepared by this invention retains the nucleophilic sites of PILs, the weakly acidic sites of carboxyl groups, and the Lewis acidic sites of zirconia. The synergistic catalytic effect of these three can significantly reduce the energy barrier for ring opening of epoxides and significantly improve the reaction rate and catalytic efficiency.

[0022] This composite catalytic material, as a catalyst, exhibits excellent catalytic performance and recyclability in the cycloaddition reaction of CO2 with epoxides, and is expected to be used in actual industrial production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 Nitrogen adsorption-desorption isotherm curve of the zirconia aerogel prepared in this invention; Figure 2 The XRD pattern of PIL@ZrO2-1 prepared in Example 1; Figure 3 TEM image of PIL@ZrO2-1 prepared in Example 1; Figure 4 SEM image of PIL@ZrO2-1 prepared in Example 1; Figure 5 The image shows the FT-IR spectrum of PIL@ZrO2-1 prepared in Example 1. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] The room temperature in this invention refers to 25±2℃.

[0031] The method for preparing zirconia aerogel used in this embodiment of the invention is as follows: 4.62 g (0.02 mol) zirconium oxynitrate (ZrO(NO3)2·2H2O) was dissolved in 100 mL of a mixed solution of distilled water and methanol (volume ratio 1:3). After stirring until completely dissolved, 1.46 g (0.02 mol) of DMF was added and stirred until homogeneous. Then, 11.62 g (0.2 mol) of propylene oxide was added and stirred for 10 min. The molar ratio of Zr / DMF / propylene oxide was 1:1:10. The sample was then sealed and gelled in a 60 °C oven (approximately 5 min) and aged for 24 h. The aged gel was then placed in a mixed solution of hexane and trimethylchlorosilane at a solid-liquid volume ratio of 1:3 for surface hydrophobic modification (50 °C, 24 h). After modification, the gel was centrifuged and then immersed in anhydrous ethanol at 50 °C for 24 h for solvent replacement. After replacement, the gel was centrifuged again to obtain the modified gel. The modified gel was then dried in a 100 °C oven for 24 h to obtain ZrO2 aerogel precursor powder. The ZrO2 aerogel precursor powder was then placed in a muffle furnace and calcined at 600 °C for 2 h to obtain zirconia aerogel.

[0032] This invention performs nitrogen adsorption-desorption isotherm analysis on the prepared zirconia aerogel. Figure 1 The nitrogen adsorption-desorption isotherm curve of the zirconia aerogel prepared in this invention is shown. The measurement results indicate that the specific surface area of ​​the zirconia aerogel is 466 m².2 / g, the material is rich in micropores, mesopores and macropores, with an average pore size of 5.8 nm.

[0033] Example 1: A method for preparing a zirconium oxide / polyionic liquid composite catalytic material (PIL@ZrO2-1) 20 mL of DMF and 0.27 g (0.6 mmol) of tri-(4-imidazolylphenyl)amine were added to a 35 mL pressure-resistant bottle and stirred thoroughly until the tri-(4-imidazolylphenyl)amine was completely dissolved. Then, 0.76 g of zirconia aerogel was added to the mixture, and after stirring until homogeneous, the mixture was sonicated for 1 h. Next, 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid was added to the pressure-resistant bottle, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant bottle for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was complete, the mixture was centrifuged, and the product was washed five times with DMF. It was then dried in a vacuum drying oven at 60 °C for 12 h to obtain the zirconia / polyionic liquid composite catalyst, denoted as PIL@ZrO2-1.

[0034] Elemental analysis of PIL@ZrO2-1 was performed using oxygen bomb combustion-ion chromatography. The results showed that the iodine content in PIL@ZrO2-1 was 6.97 wt%. Figure 2 The image shows the XRD pattern of PIL@ZrO2-1 prepared in Example 1. Figure 3 This is a TEM image of PIL@ZrO2-1 prepared in Example 1. Figure 4 This is a SEM image of PIL@ZrO2-1 prepared in Example 1. Figure 5 The image shows the FT-IR spectrum of PIL@ZrO2-1 prepared in Example 1. TEM and SEM analyses indicate that the prepared PIL@ZrO2-1 exhibits an irregular shape with a rough surface. XRD results show characteristic diffraction peaks at 2θ of 28.05º and 50.82°, which can be attributed to tetragonal zirconia, indicating that the crystal structure of the zirconia aerogel did not change significantly during the composite process with PILs. The FT-IR spectrum shows that the polyionic liquid has been successfully loaded onto the zirconia aerogel.

[0035] Example 2: A method for preparing a zirconium oxide / polyionic liquid composite catalyst (PIL@ZrO2-2) 10 mL of DMF and 0.27 g (0.6 mmol) of tri-(4-imidazolylphenyl)amine were added to a 15 mL pressure-resistant bottle and stirred thoroughly until the tri-(4-imidazolylphenyl)amine was completely dissolved. Then, 0.38 g of zirconia aerogel was added to the mixture, and after stirring until homogeneous, the mixture was sonicated for 1 h. Next, 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid was added to the pressure-resistant bottle, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant bottle for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was complete, the mixture was centrifuged, and the product was washed five times with DMF. It was then dried in a vacuum drying oven at 60 °C for 12 h to obtain the zirconia / polyionic liquid composite catalyst, denoted as PIL@ZrO2-2.

[0036] Elemental analysis showed that the iodine content in PIL@ZrO2-2 was 10.12 wt%. TEM and SEM analyses showed that the prepared PIL@ZrO2-2 exhibited an irregular shape with a rough surface. XRD results showed characteristic diffraction peaks at 2θ of 28.05º and 50.82°, which can be attributed to tetragonal zirconia, indicating that the crystal structure of zirconia aerogel did not change significantly during the composite process with PILs. FT-IR spectra showed that polyionic liquids were successfully loaded onto zirconia aerogel.

[0037] Example 3: A method for preparing a zirconium oxide / polyionic liquid composite catalyst (PIL@ZrO2-3) 30 mL of DMF and 0.27 g (0.6 mmol) of tri-(4-imidazolylphenyl)amine were added to a 50 mL pressure-resistant bottle and stirred thoroughly until the tri-(4-imidazolylphenyl)amine was completely dissolved. Then, 1.14 g of zirconia aerogel was added to the mixture, and after stirring until homogeneous, the mixture was sonicated for 1 h. Next, 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid was added to the pressure-resistant bottle, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant bottle for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was complete, the mixture was centrifuged, and the product was washed five times with DMF. It was then dried in a vacuum drying oven at 60 °C for 12 h to obtain the zirconia / polyionic liquid composite catalyst, denoted as PIL@ZrO2-3.

[0038] Elemental analysis showed that the iodine content in PIL@ZrO2-3 was 5.26 wt%. TEM and SEM analyses showed that the prepared PIL@ZrO2-3 exhibited an irregular shape with a rough surface. XRD results showed characteristic diffraction peaks at 2θ of 28.05º and 50.82°, which can be attributed to tetragonal zirconia, indicating that the crystal structure of zirconia aerogel did not change significantly during the composite process with PILs. FT-IR spectra showed that the polyionic liquid was successfully loaded onto zirconia aerogel.

[0039] Example 4: A method for preparing a zirconium oxide / polyionic liquid composite catalyst (PIL@ZrO2-4) 15 mL of DMF and 0.19 g (0.6 mmol) of 1,3,5-tris((1H-imidazol-1-yl)methyl)benzene were added to a 35 mL pressure-resistant flask and stirred thoroughly until the 1,3,5-tris((1H-imidazol-1-yl)methyl)benzene was completely dissolved. Then, 0.6 g of zirconia aerogel was added to the mixture, and after thorough stirring, the mixture was sonicated for 1 h. Next, 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid was added to the pressure-resistant flask, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant flask for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was complete, the mixture was centrifuged, and the product was washed five times with DMF. It was then dried in a vacuum drying oven at 60 °C for 12 h to obtain the zirconia / polyionic liquid composite catalyst, denoted as PIL@ZrO2-4.

[0040] Elemental analysis showed that the iodine content in PIL@ZrO2-4 was 8.91 wt%. TEM and SEM analyses showed that the prepared PIL@ZrO2-4 exhibited an irregular shape with a rough surface. XRD results showed characteristic diffraction peaks at 2θ of 28.05º and 50.82°, which can be attributed to tetragonal zirconia, indicating that the crystal structure of zirconia aerogel did not change significantly during the composite process with PILs. FT-IR spectra showed that polyionic liquids were successfully loaded onto zirconia aerogel.

[0041] Example 5: A method for preparing a zirconium oxide / polyionic liquid composite catalyst (PIL@ZrO2-5) 18 mL of DMF and 0.27 g (0.6 mmol) of tri-(4-imidazolylphenyl)amine were added to a 35 mL pressure-resistant bottle and stirred thoroughly until the tri-(4-imidazolylphenyl)amine was completely dissolved. Then, 0.69 g of zirconia aerogel was added to the mixture, and after thorough stirring, the mixture was sonicated for 1 h. Next, 0.074 g (0.3 mmol) of 3-bromo-2-(bromomethyl)propionic acid was added to the pressure-resistant bottle, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant bottle for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was complete, the mixture was centrifuged, and the product was washed five times with DMF. It was then dried in a vacuum drying oven at 60 °C for 12 h to obtain the zirconia / polyionic liquid composite catalyst, denoted as PIL@ZrO2-5.

[0042] Elemental analysis showed that the bromine content in PIL@ZrO2-5 ​​was 4.53 wt%. TEM and SEM analyses showed that the prepared PIL@ZrO2-5 ​​exhibited an irregular shape with a rough surface. XRD results showed characteristic diffraction peaks at 2θ of 28.05º and 50.82°, which can be attributed to tetragonal zirconia, indicating that the crystal structure of zirconia aerogel did not change significantly during the composite process with PILs. FT-IR spectra showed that polyionic liquids were successfully loaded onto zirconia aerogel.

[0043] Example 6: A method for preparing a zirconium oxide / polyionic liquid composite catalytic material (PIL@ZrO2-6) 20 mL of methanol and 0.27 g (0.6 mmol) of tri-(4-imidazolylphenyl)amine were added to a 35 mL pressure-resistant bottle and stirred thoroughly until the tri-(4-imidazolylphenyl)amine was completely dissolved. Then, 0.76 g of zirconia aerogel was added to the mixture, and after stirring until homogeneous, the mixture was sonicated for 1 h. Next, 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid was added to the pressure-resistant bottle, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant bottle for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was complete, the mixture was centrifuged, and the product was washed five times with DMF. It was then dried in a vacuum drying oven at 60 °C for 12 h to obtain the zirconia / polyionic liquid composite catalyst, denoted as PIL@ZrO2-6.

[0044] Elemental analysis showed that the iodine content in PIL@ZrO2-6 was 6.94 wt%. TEM and SEM analyses showed that the prepared PIL@ZrO2-6 exhibited an irregular shape with a rough surface. XRD results showed characteristic diffraction peaks at 2θ of 28.05º and 50.82°, which can be attributed to tetragonal zirconia, indicating that the crystal structure of zirconia aerogel did not change significantly during the composite process with PILs. FT-IR spectra showed that the polyionic liquid was successfully loaded onto zirconia aerogel.

[0045] Application Example 1 PIL@ZrO2-1 catalyzes the cycloaddition reaction of propylene oxide with CO2. 29.04 g (0.5 mol) of propylene oxide and 27.33 mg of PIL@ZrO2-1 catalyst (n(I)) were added to a high-pressure reactor. - The reaction vessel was sealed with CO2 (0.015 mmol), and the air inside was replaced with CO2. This process was repeated three times, followed by priming with 0.2 MPa of CO2. The vessel was then heated to 100 °C and reacted for 1 h. After the reaction was complete, the product was qualitatively and quantitatively analyzed by gas chromatography. The yield of propylene carbonate was 95%, the selectivity was 99.6%, and the TOF frequency was 31667 (mol / L). PC mol I -1 h -1 ).

[0046] Application Example 2 Similar to Application Example 1, except that the reaction temperature is changed from 100 ℃ to 80 ℃.

[0047] In this application example, the yield of propylene carbonate was 72%, the selectivity was 99.6%, and the time-to-flight (TOF) frequency was 24000 (mol). PC mol I -1 h -1 ).

[0048] Application Example 3 Similar to Application Example 1, the only difference is that the reaction temperature is changed from 100 ℃ to 120 ℃ and the reaction time is changed from 1 h to 0.5 h.

[0049] In this application example, the yield of propylene carbonate was 79%, the selectivity was 99.5%, and the time-to-flight frequency (TOF) was 52667 (mol). PC mol I -1 h -1 ).

[0050] Application Example 4 Similar to Application Example 1, except that the reaction pressure is changed from 0.2 MPa to 3 MPa.

[0051] In this application example, the yield of propylene carbonate was 96%, the selectivity was 99.6%, and the time-to-flight frequency (TOF) was 32000 (mol). PC mol I -1 h -1 ).

[0052] Application Example 5 In this application example, PIL@ZrO2-1 in Application Example 1 is replaced with PIL@ZrO2-2, PIL@ZrO2-3, PIL@ZrO2-4, PIL@ZrO2-5, and PIL@ZrO2-6, respectively. The specific application and experimental results are as follows: The 27.33 mg PIL@ZrO2-1 catalyst in Application Example 1 was replaced with 27.33 mg PIL@ZrO2-2 catalyst (n(I - With a concentration of 0.02 mmol, and all other conditions and parameters remaining unchanged, the yield of propylene carbonate was 70%, the selectivity was 99.7%, and the time-to-flight (TOF) frequency was 17500 mmol / L. PC mol I -1 h -1 ).

[0053] The 27.33 mg PIL@ZrO2-1 catalyst in Application Example 1 was replaced with 27.33 mg PIL@ZrO2-3 catalyst (n(I - With a concentration of 0.01 mmol, and all other conditions and parameters remaining unchanged, the yield of propylene carbonate was 81%, the selectivity was 99.4%, and the time-to-flight (TOF) frequency was 40,500 mmol / L. PC mol I -1 h -1 ).

[0054] The 27.33 mg PIL@ZrO2-1 catalyst in Application Example 1 was replaced with 21.38 mg PIL@ZrO2-4 catalyst (n(I - With a concentration of 0.015 mmol, and all other conditions and parameters remaining unchanged, the yield of propylene carbonate was 87%, the selectivity was 99.5%, and the time-to-flight (TOF) frequency was 29000 mol / L. PC mol I -1 h -1 ).

[0055] The 27.33 mg PIL@ZrO2-1 catalyst in Application Example 1 was replaced with 26.49 mg PIL@ZrO2-5 ​​catalyst (n(I - With a concentration of 0.015 mmol, and all other conditions and parameters remaining unchanged, the yield of propylene carbonate was 84%, the selectivity was 99.8%, and the time-to-flight (TOF) frequency was 28000 mol / L. PC mol I -1 h -1 ).

[0056] The 27.33 mg PIL@ZrO2-1 catalyst in Application Example 1 was replaced with 27.45 mg PIL@ZrO2-6 catalyst (n(I - With a concentration of 0.015 mmol, and all other conditions and parameters remaining unchanged, the yield of propylene carbonate was 94%, the selectivity was 99.7%, and the time-to-flight (TOF) frequency was 31333 mol / L. PC mol I -1 h -1 ).

[0057] Application Example 6 In this application example, propylene oxide in Application Example 1 is replaced with cyclohexene oxide. The specific application and experimental results are as follows: Referring to Application Example 1, 29.04 g of propylene oxide was replaced with 49.07 g (0.5 mol) of cyclohexene oxide, the reaction time was changed from 1 h to 12 h, and the reaction temperature was changed from 100 ℃ to 120 ℃, while all other conditions and parameters remained unchanged.

[0058] In this application example, the yield of cyclohexene carbonate was 74%, the selectivity was 92%, and the TOF was 2061 (mol). PCHC mol I -1 h -1 ).

[0059] Application Example 7 In this application example, propylene oxide in Application Example 1 is replaced with styrene oxide. The specific applications and experimental results are as follows: Referring to Application Example 1, 29.04 g of propylene oxide was replaced with 60.1 g (0.5 mol) of styrene oxide, the reaction time was changed from 1 h to 4 h, and all other conditions and parameters remained unchanged.

[0060] In this application example, the yield of styrene carbonate was 83%, the selectivity was 94%, and the TOF was 6916 (mol). PSC mol I -1 h-1 ).

[0061] Comparative Application Example 1 Similar to Application Example 1, except that the reaction temperature is changed from 100 °C to room temperature.

[0062] In this application example, the yield of propylene carbonate was 0.2%, the selectivity was 99.9%, and the time-to-flight (TOF) frequency was 67 (mol / L). PC mol I -1 h -1 ).

[0063] Comparative Application Example 2 PILs catalyze the cycloaddition reaction of propylene oxide with CO2. 29.04 g (0.5 mol) of propylene oxide and 8.84 mg of PILs catalyst (n(I)) were added to a high-pressure reactor. - The reaction vessel was sealed with CO2 (0.015 mmol), and the air inside was replaced with CO2. This process was repeated three times, followed by priming with 0.2 MPa of CO2. The vessel was then heated to 100 °C and reacted for 1 h. After the reaction, the product was qualitatively and quantitatively analyzed by gas chromatography. The yield of propylene carbonate was 22%, the selectivity was 99.8%, and the TOF (time-to-frequency) was 7333 mol / L. PC mol I -1 h -1 ).

[0064] The preparation method of the PILs catalyst described in this comparative application example includes the following steps: 20 mL of DMF and 0.27 g (0.6 mmol) of tri-(4-imidazolylphenyl)amine were added to a 35 mL pressure-resistant flask and stirred thoroughly until the tri-(4-imidazolylphenyl)amine was completely dissolved. Then, 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid was added to the pressure-resistant flask, and the mixture was stirred at room temperature for 5 min. Nitrogen gas was then introduced into the pressure-resistant flask for protection, and the mixture was stirred at 100 °C for 24 h. After the reaction was completed, the mixture was centrifuged, and the product was washed five times with DMF. Then, it was dried in a vacuum drying oven at 60 °C for 12 h to obtain the polyionic liquid catalyst material, denoted as PILs.

[0065] Comparative Application Example 3 PILs-1 catalyzes the cycloaddition reaction of propylene oxide with CO2. Compared to the PILs-catalyzed cycloaddition reaction of propylene oxide and CO2 in Comparative Application Example 2, the only difference is that 8.84 mg of PILs catalyst (n(I -()=0.015 mmol) was changed to 9.02 mg PILs-1 catalyst (n(I) - The yield of propylene carbonate was 15%, the selectivity was 99.5%, and the time-to-flight (TOF) was 5000 mmol / L (0.015 mmol / L). PC mol I -1 h -1 ).

[0066] The preparation method of the PILs-1 catalyst described in this comparative application example includes the following steps: The only difference between the preparation method of the PILs catalyst and that in Comparative Application Example 2 is that 0.11 g (0.3 mmol) of 3-iodo-2-(iodomethyl)propionic acid is replaced with 0.089 g (0.3 mmol) of 1,3-diiodopropane.

[0067] Comparative Application Example 4 Similar to Application Example 1, except that the 27.33 mg PIL@ZrO2-1 catalyst was replaced with 18.22 mg zirconia aerogel.

[0068] In this application example, the yield of propylene carbonate was 0.3% and the selectivity was 99.1%.

[0069] Performance testing and recycling of zirconia / polyionic liquid composite catalysts 29.04 g of propylene oxide and 27.33 mg of PIL@ZrO2-1 catalyst were added to a high-pressure reactor. The reactor was sealed, and the air inside was replaced with CO2. This process was repeated three times, followed by charging with 0.2 MPa of CO2. The reactor was then heated to 100 °C and reacted for 1 h. After the reaction, the product was qualitatively and quantitatively analyzed by gas chromatography. The yield of propylene carbonate was 95%, and the selectivity was 99.6%. After the reaction, the centrifuged catalyst was washed 3-5 times, dried under vacuum at 60 °C for 12 h, and the catalytic reaction was repeated 20 times to examine the catalyst's recyclability. The catalytic activity results are shown in Table 1 below.

[0070] Table 1 As can be seen from Table 1, the zirconium oxide / polyionic liquid composite catalytic material prepared by this invention can still have high catalytic performance after being recycled multiple times.

[0071] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a zirconium oxide / polyionic liquid composite catalytic material, characterized in that, The process includes the following steps: adding zirconia aerogel to an organic solvent containing imidazole monomers, mixing thoroughly, adding a dihalogenated compound, mixing thoroughly again, purging with nitrogen, heating to react, and centrifuging, washing, and drying after the reaction to obtain the zirconia / polyionic liquid composite catalytic material.

2. The preparation method according to claim 1, characterized in that, The imidazole monomer is selected from tris-(4-imidazolylphenyl)amine or 1,3,5-tris((1H-imidazol-1-yl)methyl)benzene; and / or, The dihalogenated product is selected from 3-iodo-2-(iodomethyl)propionic acid or 3-bromo-2-(bromomethyl)propionic acid.

3. The preparation method according to claim 1, characterized in that, The organic solvent is selected from ethanol, N,N-dimethylformamide, methanol, or acetonitrile.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the imidazole monomer to the dihalogenated product is 2:1; the ratio of the sum of the masses of the imidazole monomer and the dihalogenated product to the mass of the zirconia aerogel is 1:(1-3); and the mass-volume ratio of the zirconia aerogel to the organic solvent is 0.38-0.4 g:10 mL.

5. The preparation method according to claim 1, characterized in that, The heating reaction was carried out at a temperature of 100 °C for 24 h.

6. The preparation method according to claim 1, characterized in that, The preparation method of the zirconia aerogel includes the following steps: adding an inorganic zirconium source to a methanol-water mixed solvent, mixing well, adding N,N-dimethylformamide, mixing again, adding propylene oxide, gelling and aging, modifying the surface of the resulting gel to be hydrophobic, then immersing the modified gel in anhydrous ethanol for solvent replacement, centrifuging and drying to obtain a zirconia aerogel precursor, and calcining the zirconia aerogel precursor to prepare zirconia aerogel.

7. The preparation method according to claim 6, characterized in that, The ratio of the inorganic zirconium source, propylene oxide, N,N-dimethylformamide, and methanol-water mixed solvent is 0.02 mol: 0.2 mol: 0.02 mol: 100 mL; the gelation reaction temperature is 60 °C. The specific operation of the surface hydrophobic modification is as follows: the gel is placed in a mixed solution of n-hexane and silane coupling agent and reacted at 50°C for 24 h; The solvent replacement temperature is 50 °C and the time is 24 h; The calcination temperature was 600 °C and the time was 2 h.

8. A zirconium oxide / polyionic liquid composite catalytic material prepared by the preparation method according to any one of claims 1-7.

9. The application of the zirconium oxide / polyionic liquid composite catalytic material according to claim 8 in the catalytic cycloaddition reaction of epoxides with CO2 to synthesize cyclic carbonates, characterized in that, Includes the following steps: An epoxide and the zirconium oxide / polyionic liquid composite catalyst are added to a high-pressure reactor. The reactor is then sealed, and the air inside is replaced with CO2. The reactor is then heated to synthesize cyclic carbonates.

10. The application according to claim 9, characterized in that, The epoxide is selected from propylene oxide, cyclohexene oxide, or styrene oxide; and / or, After CO2 replaces the air in the reactor, the pressure in the high-pressure reactor is 0.2-3 MPa; the temperature of the heating reaction is 80-120℃.

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