A carbazole / IPr·HCl dual-functionalized hypercrosslinked porous organic polymer and its preparation and application

Abstract

The invention discloses a carbazole / IPr·HCl bifunctionalized super-crosslinked porous organic polymer and a preparation and application thereof. The invention first designs and synthesizes a carbazole-functionalized IPr·HCl monomer (BiCz‑IPr), then uses dimethylformal as a crosslinking agent, and under the action of ferric chloride, a Friedel‑Crafts alkylation reaction is performed to prepare a carbazole and IPr·HCl bifunctionalized super-crosslinked porous organic polymer (HCP‑BiCz‑IPr); under the action of an appropriate amount of base NaHMDS, the HCP‑BiCz‑IPr generates active NHC online, and shows an excellent catalytic effect in the reaction of catalyzing CO2 conversion into cyclic carbonate; in addition, the HCP‑BiCz‑IPr has good stability, can be continuously recycled for more than 6 times after separation and recovery, and still maintains considerable catalytic activity;

Description

Technical Field

[0001] The invention relates to the technical field of preparation of heterogeneous catalysts in organic chemical industry, and in particular to a bifunctionalized hyper-crosslinked porous organic polymer (HCP-BiCz-IPr) of carbazole and N-heterocyclic carbene precursor 3-bis(2,6-diisopropylphenyl)imidazolium chloride (IPr·HCl) and a preparation method thereof, as well as application of the polymer in catalyzing the conversion of CO2 and ethylene oxide compounds into cyclic carbonates by cycloaddition. Background Art

[0002] CO2 is one of the components of the atmosphere and a basic component of the carbon cycle in nature. Since the Industrial Revolution, the amount of CO2 gas emitted into the atmosphere by humans has increased year by year, far exceeding the self-circulation and purification capacity of the earth itself, thus bringing about a series of environmental and social problems, such as abnormal climate, rising sea levels, land desertification, species extinction, etc. Excessive CO2 emissions have attracted widespread attention from governments around the world. In 2021, my country took the initiative to propose the "dual carbon" goal, which has become a major strategic goal for my country to achieve green and sustainable development. The absorption and resource utilization (CCUS) of CO2, converting it into useful chemical products, can not only turn waste into treasure, but also promote the realization of the "dual carbon" goal. The cycloaddition reaction of CO2 with ethylene oxide compounds to generate five-membered cyclic carbonates is an important chemical transformation, which has received widespread attention from the business community and academia in recent years. First of all, the cyclic carbonates obtained by this reaction have a wide range of practical application value, such as polar aprotic solvents, electrolytes for lithium-ion batteries, and organic synthesis intermediates. Secondly, the reaction has high atom economy and can achieve 100% utilization of CO2. Due to the stability and chemical inertness of CO2, the reaction requires the action of a catalyst, and a large number of homogeneous and heterogeneous catalysts have been reported in the literature. Heterogeneous catalysts are easy to separate, recycle and reuse, and have been the focus of research in recent years.

[0003] As a special organic base catalyst, N-heterocyclic carbene (NHC) has a good ability to activate CO2 and is widely used in the chemical conversion of CO2. So far, the literature has reported the preparation of some heterogeneous NHC catalysts and their catalytic cycloaddition reactions of carbon dioxide and oxirane compounds. As document 1 (Green Chem. 2011, 13, 644-650), IPr-CO2 is loaded on the surface of mesoporous molecular sieve MCM-41 by silane coupling method, and MCM-41-IPr-CO2 is prepared for catalysis of the cyclization reaction. In CH2Cl2 medium, when the dosage of MCM-41-IPr-CO2 is 0.5 mol%, the pressure of CO2 is 2.0 MPa, and the reaction is carried out at 120°C for 48 hours. The yield of 5 organic cyclic carbonates is between 87-100%, and the catalyst can be recycled more than 4 times. Generally speaking, basic functional groups can adsorb and activate CO2. Therefore, in the heterogeneous catalyst for the catalytic conversion of CO2, the introduction of additional basic functional groups will be beneficial to the enrichment and conversion of CO2. Based on this concept, Literature 2 (ChemSusChem2020, 13, 5996-6004) reported a new type of triazine / NHC bifunctional heterogeneous catalyst. They first designed and prepared a cyano-functionalized IPr·HCl monomer. Then, in a trifluoromethanesulfonic acid medium, while the cyano group was trimerized into triazine, an IPr·HCl functionalized porous organic polymer was constructed. The latter was then added with carbon dioxide under the action of sodium bis(trimethylsilyl)amide (KHMDS) to obtain an IPr-CO2 addition polymer (NHC-CO2-Triazine@Polymer). In this material, triazine is not only a link connecting IPr-CO2, but also can adsorb and activate CO2. When the dosage of NHC-CO2-Triazine@Polymer is 0.5 mol%, there is no solvent, the CO2 pressure is 0.5 MPa, and the reaction is carried out at 100-120 ° C for 6 hours, the yield of 5 organic cyclic carbonates is between 89-98%, and NHC-CO2-Triazine@Polymer can be recycled more than 8 times. Not long ago, Literature 3 reported another base-assisted NHC-CO2 heterogeneous catalyst PEMCx (CN 111138591A, Chem. Eng. J. 2021, 403, 126460). They first free radical polymerized N-vinylimidazole and ethylene glycol dimethacrylate to obtain an imidazole-functionalized porous organic polymer, and then the polymer was solvent-thermally treated with dimethyl carbonate. Part of the imidazole was converted into NHC-CO2, and the unconverted imidazole acted as a base to assist in catalysis. When the dosage of PEMC1 is 1.1 mol%, without solvent, CO2 pressure is 10 bar, and the reaction is carried out at 120°C for 4-16 hours, the yield of 10 organic cyclic carbonates is between 94-99%, and PEMC1 can be recycled for more than 5 times.

[0004] In summary, it can be found that heterogeneous NHC catalysts have shown important development potential in catalyzing the cycloaddition of CO2 and organic oxirane compounds into cyclic carbonates. In particular, the recent development of base-assisted NHC bifunctional catalysts can significantly improve the catalytic activity of the catalyst and improve production efficiency. However, the existing heterogeneous NHC catalysts still have disadvantages such as large catalyst usage and complex catalyst preparation process. In particular, the NHC catalyst needs to be converted into a CO2 adduct (NHC-CO2), which increases the preparation steps of the catalyst. Therefore, it is still necessary to develop a heterogeneous catalyst with low production cost, simple synthesis method, high catalyst activity and can be used for catalytic conversion of CO2 into cyclic carbonates. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a bifunctionalized hyper-crosslinked porous organic polymer (HCP-BiCz-IPr) of carbazole and N-heterocyclic carbene precursor IPr·HCl and a preparation method thereof, as well as an application of the HCP-BiCz-IPr in catalyzing the conversion of CO2 into cyclic carbonates.

[0006] The present invention first designs and synthesizes carbazole-functionalized IPr·HCl monomer (BiCz-IPr), and then uses dimethylformal (FDA) as a crosslinking agent, and in the presence of ferric chloride, a series of carbazole and IPr·HCl dual-functionalized hyper-crosslinked porous organic polymers (HCP-BiCz-IPr) are prepared through Friedel-Crafts alkylation reaction. Under the action of an appropriate amount of base KHMDS, HCP-BiCz-IPr generates active NHC online, and shows an excellent catalytic effect in the reaction of catalyzing CO2 to convert into cyclic carbonate. The reaction can be smoothly carried out under the reaction conditions of relatively low pressure (3.0Mpa), very small amount of catalyst (0.1mol%) and 120°C. In addition, HCP-BiCz-IPr has good stability, and can be continuously recycled for more than 6 times after separation and recovery, and still maintains considerable catalytic activity.

[0007] The technical solution of the present invention is as follows:

[0008] A carbazole-functionalized IPr·HCl monomer, denoted as BiCz-IPr, is shown in Formula 4:

[0009]

[0010] A method for preparing a carbazole-functionalized IPr·HCl monomer as shown in formula 4 comprises the following steps:

[0011] (1) 2,6-diisopropylaniline, saturated sodium bicarbonate solution and organic solvent A are mixed, and a solution of elemental iodine in organic solvent B is added dropwise at room temperature within 1.0-3.0 hours (preferably 2.0 hours). After the addition is completed, the reaction is continued with stirring for 3.0-8.0 hours (preferably 5.0 hours), and then post-treated to obtain the intermediate shown in Formula 1;

[0012]

[0013] In step (1), the molar ratio of 2,6-diisopropylaniline to elemental iodine is 1:0-1.3, preferably 1:1.1;

[0014] A saturated sodium bicarbonate solution provides a reaction environment, and preferably the volume mass ratio of the saturated sodium bicarbonate solution to 2,6-diisopropylaniline is 16.7:1, mL / g;

[0015] Preferably, both organic solvent A and organic solvent B are methyl tert-butyl ether; preferably, the volume mass ratio of organic solvent A to 2,6-diisopropylaniline is 2.0:1, mL / g; preferably, the volume mass ratio of organic solvent B to elemental iodine is 5.0-7.0:1, mL / g, preferably 6.0:1, mL / g;

[0016] The specific post-treatment method is: after the reaction is completed, sodium thiosulfate is added to the reaction solution to remove excess iodine, the organic phase is separated, the aqueous phase is extracted with methyl tert-butyl ether, the organic phases are combined, dried over anhydrous sodium sulfate, filtered, and the organic solvent is recovered by vacuum rotary evaporation to obtain the intermediate shown in Formula 1; preferably, the molar ratio of sodium thiosulfate to 2,6-diisopropylaniline is 1.0:5.6;

[0017] The organic solvent A and organic solvent B mentioned above have no special meanings, and are marked as "A" and "B" only to distinguish the organic solvents used in different operation steps, and the same applies to the following;

[0018] (2) mixing the intermediate 1, carbazole, cuprous chloride, o-phenanthroline, potassium hydroxide and an organic solvent C, stirring and reacting at 140° C. for 20-48 h (preferably 36 h), and then post-treating to obtain the intermediate shown in formula 2;

[0019]

[0020] In step (2), the molar ratio of intermediate 1, carbazole, cuprous chloride, o-phenanthroline and potassium hydroxide is 1.0:0.5-2.0:0.1-0.5:0.1-0.5:3.0-6.0, preferably 1.0:1.0:0.3:0.3:4.0;

[0021] Preferably, the organic solvent C is toluene, and the volume mass ratio of the organic solvent C to the intermediate 1 is preferably 10.6:1, mL / g;

[0022] The specific post-treatment method is as follows: after the reaction is completed, ammonia water is added and stirred for 6 hours, the toluene layer is separated, washed with water until neutral, dried over anhydrous sodium sulfate, filtered, and the solvent is recovered by vacuum rotary evaporation, the residue is slurried with methanol, filtered, and dried under vacuum for 1 hour to obtain the intermediate shown in Formula 2;

[0023] (3) Intermediate 2, glyoxal, formic acid and organic solvent D are mixed and reacted at room temperature for 12-36 hours (preferably 24 hours), then heated to 40° C. and continued to react for 12 hours, followed by post-treatment to obtain the intermediate shown in Formula 3;

[0024]

[0025] In step (3), the molar ratio of intermediate 2, glyoxal and formic acid is 1.0:0.5-1.0:0.4-0.8, preferably 1.0:0.5:0.4;

[0026] Preferably, glyoxal is fed in the form of an aqueous solution with a mass concentration of 40%;

[0027] The preferred organic solvent D is DMF, and the preferred volume mass ratio of the organic solvent D to the intermediate 2 is 10.6:1, mL / g;

[0028] The specific post-treatment method is as follows: after the reaction is completed, the reaction solution is filtered, the filter cake is slurried and washed with DMF and methyl tert-butyl ether, and the obtained solid is dried under vacuum at 60°C for 1h;

[0029] (4) The intermediate 3, polyformaldehyde and organic solvent E are mixed, stirred at 70° C. for 45 min, trimethylsilyl chloride is added, and the reaction is continued at 70° C. for 10-36 h (preferably 24 h), followed by post-treatment to obtain the BiCz-IPr monomer shown in formula 4;

[0030]

[0031] In step (4), the molar ratio of intermediate 3, paraformaldehyde and trimethylsilyl chloride is 1.0:1.0-2.0:1.0-2.0, preferably 1.0:1.1:1.1;

[0032] Preferably, the organic solvent E is ethyl acetate, and the volume mass ratio of the organic solvent E to the intermediate 3 is preferably 6.0-20.0:1, mL / g, particularly preferably 10.8:1, mL / g;

[0033] The specific post-treatment method is as follows: after the reaction is completed, the reaction solution is filtered, the filter cake is slurried and washed with ethyl acetate, and the obtained solid is dried under vacuum at 60° C. for 1 h.

[0034] A bifunctionalized hypercrosslinked porous organic polymer of carbazole and N-heterocyclic carbene precursor (IPr·HCl), denoted as HCP-BiCz-IPr, was prepared as follows:

[0035] Under a protective atmosphere (preferably a nitrogen atmosphere), the BiCz-IPr monomer shown in formula 4, dimethylformal (FDA), ferric chloride and an organic solvent F are mixed, and stirred and polymerized at 50-120° C. (preferably 80° C.) for 24-72 h (preferably 48 h), and then post-treated to obtain HCP-BiCz-IPr;

[0036] Wherein, the molar ratio of BiCz-IPr monomer to dimethylformal is 1.0:10.0-30.0, preferably 1.0:20.0;

[0037] The molar ratio of BiCz-IPr monomer to ferric chloride is 1.0:1.0-30.0, preferably 1.0:20.0;

[0038] Preferably, the organic solvent F is 1,2-dichloroethane, and the volume mass ratio of the organic solvent F to the BiCz-IPr monomer is preferably 15.0-40.0:1, mL / g, particularly preferably 20.0:1, mL / g;

[0039] The specific post-treatment method is as follows: after the polymerization reaction is completed, the mixture is cooled to room temperature, the obtained solid is washed with methanol, transferred to a Soxhlet extractor, and washed continuously for 24 hours using methanol as a washing agent, and the obtained solid is vacuum dried at 80°C for 12 hours;

[0040] The structural formula of the obtained carbazole and N-heterocyclic carbene precursor (IPr·HCl) dual-functionalized hyper-crosslinked porous organic polymer is shown in Formula 5:

[0041]

[0042] The wavy lines indicate the connection sites.

[0043] The synthetic route involved in the present invention is as follows:

[0044]

[0045] Furthermore, the N content of HCP-BiCz-IPr was measured to be 4.74% by elemental analysis, and the IPr·HCl loading in HCP-BiCz-IPr was calculated to be 0.85 mmoL / g. The specific surface area of ​​HCP-BiCz-IPr was measured to be 498.36 m 2 / g, pore diameter is 4.56nm, pore volume is 0.22cm 3 / g; the carbon dioxide adsorption experiment measured the carbon dioxide adsorption capacity of HCP-BiCz-IPr to be 2.22mmoL / g; the characteristic peaks of carbazole and IPr·HCl could be seen through infrared characterization; solid-state nuclear magnetic resonance could prove that HCP-BiCz-IPr contained aromatic and isopropyl functional groups; SEM and TEM could show that HCP-BiCz-IPr had abundant mesopores and micropores, indicating that HCP-BiCz-IPr was a hyper-cross-linked polymer with a porous structure.

[0046] The hyper-crosslinked porous organic polymer HCP-BiCz-IPr provided by the present invention can be used as a heterogeneous catalyst in the reaction of catalyzing the cycloaddition of CO2 and ethylene oxide compounds into cyclic carbonates;

[0047] The ethylene oxide compound is an ethylene oxide substituted with an alkyl or aryl group, or an ethylene oxide substituted with a cyclohexyl group.

[0048] Compared with the prior art, the beneficial effects of the present invention are specifically embodied in:

[0049] Carbazole-substituted 3-bis(2,6-diisopropylphenyl)imidazolium chloride (IPr·HCl) was designed and synthesized, and the corresponding hyper-crosslinked porous organic polymer (HCP-BiCz-IPr) was prepared using cheap and readily available FDA as a crosslinker. The polymer showed good catalytic activity in the cycloaddition reaction of CO2 and ethylene oxide compounds, and can be recycled and reused many times, which has broad practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 :Polymerization of BiCz-IPr monomer 1 H NMR spectrum (400 MHz).

[0051] Figure 2 :Polymerization of BiCz-IPr monomer 13 C NMR spectrum (100 MHz).

[0052] Figure 3 : IR spectra of monomer BiCz-IPr and catalyst HCP-BiCz-IPr.

[0053] Figure 4 :Solid-state catalyst HCP-BiCz-IPr 13 C NMR spectrum (100 MHz, rotation speed 8000 Hz).

[0054] Figure 5 : TGA diagram of catalyst HCP-BiCz-IPr.

[0055] Figure 6: Nitrogen adsorption-desorption isotherm of catalyst HCP-BiCz-IPr.

[0056] Figure 7 : Pore size distribution diagram of catalyst HCP-BiCz-IPr.

[0057] Figure 8 : SEM image of catalyst HCP-BiCz-IPr.

[0058] Fig. 9 : TEM image of catalyst HCP-BiCz-IPr.

[0059] Fig.10 : Physical sample photo of catalyst HCP-BiCz-IPr.

[0060] Fig.11 : CO2 adsorption isotherm of catalyst HCP-BiCz-IPr.

[0061] Fig.12 : Catalytic effect diagram of 6 consecutive cycle experiments. DETAILED DESCRIPTION

[0062] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0063] Example 1 Preparation of Catalyst HCP-BiCz-IPr

[0064] Preparation of intermediate 1 (2,6-diisopropyl-4-iodoaniline): In a 1L four-necked bottle, add 2,6-diisopropylaniline (15.0g, 85mmoL), 30mL methyl tert-butyl ether and 250mL saturated sodium bicarbonate solution in sequence. Under room temperature and stirring, add 140mL methyl tert-butyl ether solution containing iodine (23.6g, 93mmoL) dropwise within 2h. After the dropwise addition, continue stirring at room temperature for 5h. After the reaction is completed, add sodium thiosulfate (2.4g, 15mmoL) to remove excess iodine in the reaction solution. The reaction solution is extracted with 60mL×3 methyl tert-butyl ether, the extracts are combined, dried over anhydrous sodium sulfate, filtered, and the organic solvent is recovered by vacuum rotary evaporation to obtain 24.9g of yellow oily liquid with a yield of 97.1%. The product is characterized as follows: 1 H NMR (500MHz, CDCl3) δ7.30 (s, 2H), 3.75 (s, 2H), 1.26 (d, J = 6.9Hz, 12H) ppm; 13 CNMR (125MHz, CDCl3) δ140.1,135.1,131.8,81.1,77.3,77.1,76.9,27.9,22.3ppm.

[0065] Preparation of intermediate 2 (2,6-diisopropyl-4-carbazolylaniline): In a 50mL single-mouth bottle, add intermediate 1 (3.0g, 10mmoL), carbazole (1.7g, 10mmoL), CuCl (0.3g, 3mmoL), o-phenanthroline (0.6g, 3mmoL), KOH (2.2g, 40mmoL) and 20mL of toluene in sequence. The mixture was stirred at 140°C for 36h. After the reaction was completed, 20mL of 25% ammonia water was added, stirred for 6h, the toluene layer was separated, washed with water until neutral, dried over anhydrous sodium sulfate, and the solvent was recovered by vacuum rotary evaporation. The residue was added with 50mL of methanol for pulping, filtered, and dried at room temperature to obtain 3.3g of gray solid with a yield of 96.4%. Melting point: 300.3°C. The product is characterized as follows: 1 H NMR (400MHz, CDCl3) δ8.23 (d, J = 7.72Hz, 2H), 7.50-7.42 (m, 4H), 7.36-7.30 (m ,2H),7.26(s,2H),4.06(s,2H),3.13-3.07(m,2H),1.38(d,J=3.4Hz,12H)ppm; 13 C NMR (100MHz, CDCl3) δ141.5,139.4,133.9,128.5,125.7,122.9,121.9,120.2,119.3,109.9,28.2,22.5ppm.

[0066] Preparation of intermediate 3 (N,N'-bis(2,6-diisopropylphenyl-4-carbazolyl)-1,4-diazabutadiene): In a 150mL single-mouth bottle, intermediate 2 (9.9g, 29mmoL), glyoxal aqueous solution (2.7mL, 15mmoL), formic acid (0.4mL) and DMF (30mL) were added in sequence. The mixture was stirred at room temperature (25°C) for 24h, and then heated to 40°C for 12h. After the reaction was completed, it was filtered, and the filter cake was washed with 50mL DMF and 50mL methyl tert-butyl ether in sequence, and then dried under vacuum at 60°C for 1h to obtain 8.2g of yellow solid with a yield of 80.0%. Melting point: greater than 400°C. The product is characterized as follows: 1 H NMR (400MHz, CDCl3) δ8.23(s,2H),8.09(d,J=8.0Hz,2H),7.39-7.32(m,12H),7.24-7.14(m,6H),3.06-2.99(m,4H),1.21(d,J=8.0Hz,24H)ppm; 13C NMR (100MHz, CDCl3) δ163.5,146.9,141.0,138.8,134.8,126.0,123.3,122.0,120.4,119.9,109.9,28.4,23.5ppm.

[0067] Preparation of BiCz-IPr monomer 4 (N,N'-bis(2,6-diisopropylphenyl-4-carbazolyl)-imidazole chloride): In a 250mL single-mouth round-bottom flask, add the above intermediate 3 (8.5g, 12mmoL), paraformaldehyde (0.4g, 13mmoL) and 240mL ethyl acetate in sequence. The mixture was stirred at 70°C for 1h, and then trimethylsilyl chloride (1.8mL, 13mmoL) was added in three batches within 1h. After the addition, the reaction was continued to stir at this temperature for 12h. After the reaction was completed, it was cooled to room temperature, filtered, and the filter cake was slurried with 50mL ethyl acetate, and then vacuum dried at 60°C for 1h to obtain 6.3g of white solid with a yield of 70.5%. Melting point: greater than 400°C. The product is characterized as follows: 1 H NMR(400MHz, CDCl3)δ11.20(s,1H),8.16-8.14(m,6H),7.59(s,4H),7.52-7.50 (m,4H),7.46-7.43(m,4H),7.33-7.30(m,4H),2.62-2.59(m,4H),1.37-1.33(m 24H) ppm; 13 C NMR (100MHz, CDCl3) δ147.4,141.4,140.7,140.2,128.3,126.4,123.8,122.9,120.7,120.5,109.8,29.6,24.7,23.8ppm.

[0068] Preparation of catalyst 5 (HCP-BiCz-IPr): Under nitrogen protection, BiCz-IPr monomer (0.8g, 1mmoL), FDA (1.5g, 20mmoL) and 20mL dichloroethane were added to a 50mL single-necked flask in sequence. After stirring evenly, FeCl3 (3.2g, 20mmoL) was added, and the mixture was stirred at 45°C for 5h, and then heated to 80°C for 48h. After the reaction was completed, the mixture was cooled to room temperature, and the obtained polymer was washed with 20mL water and 20mL methanol in sequence, and then transferred to a Soxhlet extractor, and washed continuously for 24h with methanol as the washing liquid. Finally, it was vacuum dried at 80°C for 12h to obtain 1.0g of black solid. The polymer was ground into powder and used directly in the catalytic reaction.

[0069] Example 2 Cycloaddition reaction of CO2 and ethylene oxide compounds catalyzed by HCP-BiCz-IPr

[0070] Take the cycloaddition reaction of CO2 and styrene oxide catalyzed by HCP-BiCz-IPr as an example: HCP-BiCz-IPr (7mg, 0.1moL%), styrene oxide (570μL, 5mmoL) and NaHMDS (5μL, 0.2moL%) were added to a 50mL pressure reactor in sequence. The air in the reactor was replaced with CO2 gas 3 times, and then the pressure was increased to 3.0MPa, and the temperature was raised to 120℃ for reaction for 12h. After the reaction, 5mL of dichloromethane was added to the system, and the mixture was transferred to a centrifuge tube, centrifuged, and the upper liquid was separated. The residual catalyst in the centrifuge tube was washed with 3.0mL×2 dichloromethane, and the dichloromethane washings were combined. The solvent was recovered by vacuum rotary evaporation, and the residue was purified by column chromatography (200-300 mesh silica gel, ethyl acetate / petroleum ether as eluent) to obtain 0.82g of 4-phenyl-1,3-dioxolane-2-one with a yield of 98.2%. White solid, melting point: 56.2℃, 1 H NMR (400MHz, CDCl3) δ7.44-7.42(m,3H),7.37-7.35(m,2H),5.68(t,J=8.0Hz,1H),4.80(t,J=8.0Hz,1H),4.34(t,J=8.0Hz,1H)ppm.

[0071] The reaction equation is as follows:

[0072]

[0073]

[0074] Characterization data of products prepared by reactions 2 to 9:

[0075] 2:4-(Chloromethyl)-1,3-dioxolane-2-one

[0076] Colorless liquid, 1 H NMR (400MHz, CDCl3) δ: 4.95-4.91 (m, 1H), 4.54 (t, J = 8.0Hz, 1H), 4.37-4.33 (m, 1H), 3.77-3.63 (m, 2H) ppm.

[0077] 3: 4-(Bromomethyl)-1,3-dioxolane-2-one

[0078] Colorless liquid, 1 H NMR (400MHz, CDCl3) δ: 4.98-4.92 (m, 1H), 4.60 (t, J = 8.0Hz, 1H), 4.37-4.33 (m, 1H), 3.58-3.57 (m, 2H) ppm.

[0079] 4: 4-methyl-1,3-dioxolane-2-one

[0080] Colorless liquid, 1 H NMR (400MHz, CDCl3) δ: 4.84-4.75 (m, 1H), 4.49 (t, J = 8.0Hz, 1H), 3.97 (t, J = 8.0Hz, 1H) 1.43 (d, J = 8.0Hz, 3H) ppm.

[0081] 5: 4-phenoxymethyl-1,3-dioxolane-2-one

[0082] White solid, melting point: 96.2℃, 1 H NMR (400MHz, CDCl3) δ: 7.25-7.21(m,2H),6.94(t,J=8.0Hz,1H),6.83(d,J=8.0Hz,2H),4.97-4.93(m,1H),4.55-4.44(m,2H),4.18-4.04(m,2H)ppm.

[0083] 6: 4-(Butoxymethyl)-1,3-dioxolane-2-one

[0084] Colorless liquid, 1 H NMR(400MHz, CDCl3)δ:4.82-4.77(m,1H),4.50-4.46(m,1H),4.40-4.36(m,1H),3 .71-3.57(m,2H),3.52-3.43(m,2H),1.59-1.50(m,4H),0.90(t,J=8.0Hz,3H)ppm.

[0085] 7:4-Butyl-1,3-dioxolane-2-one

[0086] Colorless liquid, 1 H NMR (400MHz, CDCl3) δ: 4.68-4.61 (m, 1H), 4.49-4.43 (m, 1H), 4.02-3.99 (m, 1H), 1.80-1.56 (m, 2H), 1.48-1.29 (m, 4H), 0.85 (t, J = 8.0Hz, 3H) ppm.

[0087] 8:4-(o-Tolyloxymethyl)-1,3-dioxolane-2-one

[0088] White solid, melting point: 95.4℃, 1H NMR(400MHz, CDCl3)δ:7.17-7.14(m,2H),6.92(t,J=8.0Hz,1H),6.78-6.76(m, 1H),5.06-5.03(m,1H),4.64-4.55(m,2H),4.27-4.10(m,2H),2.21(s,3H)ppm.

[0089] 9: Hexahydrobenzo[D][1,3]-dioxolane-2-one

[0090] Colorless liquid, 1 H NMR (400MHz, CDCl3) δ: 4.63-4.61(m,2H), 1.91-1.73(m,4H), 1.58-1.14(m,4H)ppm.

[0091] Example 3 Recovery and Recycling of Catalyst HCP-BiCz-IPr

[0092] The above-mentioned catalyst HCP-BiCz-IPr separated by centrifugation can be recycled for multiple times after being washed with 3.0mL×2THF and vacuum dried at 80°C for 2h. The recovered catalyst HCP-BiCz-IPr and styrene oxide (570μL, 5mmoL) were added to a 50mL pressure reactor in sequence. The air in the reactor was replaced with CO2 gas 3 times, and then the pressure was increased to 3.0MPa, and the temperature was raised to 120°C for reaction for 12h. After the same post-treatment, the separation yield of 4-phenyl-1,3-dioxolane-2-one was 97%. After the catalyst HCP-BiCz-IPr was washed with THF and vacuum dried, it was continuously recycled for 6 times and still maintained a high catalytic activity. The results are as follows Fig.12 shown.

[0093] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0094] (1) The heterogeneous catalyst does not need to be converted into CO2 adduct (NHC-CO2). Under the action of NaHMDS, carbene is generated online to catalyze the cycloaddition reaction of CO2 and organic oxirane compounds.

[0095] (2) The multiphase catalyst has high catalytic activity, requires little catalyst, and the highest TON can reach 996.

[0096] (3) After the reaction, the catalyst can be used continuously for more than 6 times through simple post-treatment and still maintain excellent catalytic activity.

Claims

1. A carbazole-functionalized IPr·HCl monomer, denoted as BiCz-IPr, as shown in Formula 4:

2. A method for preparing a carbazole-functionalized IPr·HCl monomer as shown in formula 4, characterized in that: The steps include: (1) 2,6-diisopropylaniline, saturated sodium bicarbonate solution and organic solvent A are mixed, and a solution of elemental iodine in organic solvent B is added dropwise at room temperature within 1.0-3.0 hours. After the addition is completed, the reaction is continued with stirring for 3.0-8.0 hours, and then post-treated to obtain an intermediate shown in Formula 1; The molar ratio of 2,6-diisopropylaniline to elemental iodine is 1:0-1.3; (2) mixing the intermediate 1, carbazole, cuprous chloride, o-phenanthroline, potassium hydroxide and an organic solvent C, stirring and reacting at 140° C. for 20-48 hours, and then post-treating to obtain the intermediate shown in formula 2; The molar ratio of intermediate 1, carbazole, cuprous chloride, o-phenanthroline and potassium hydroxide is 1.0:0.5-2.0:0.1-0.5:0.1-0.5:3.0-6.0; (3) Intermediate 2, glyoxal, formic acid and organic solvent D are mixed and reacted at room temperature for 12-36 hours, then heated to 40° C. and continued to react for 12 hours, followed by post-treatment to obtain the intermediate shown in Formula 3; The molar ratio of intermediate 2, glyoxal and formic acid is 1.0:0.5-1.0:0.4-0.8; (4) The intermediate 3, polyformaldehyde and organic solvent E are mixed, stirred at 70° C. for 45 min, trimethylsilyl chloride is added, and the reaction is continued at 70° C. for 10-36 h, followed by post-treatment to obtain the BiCz-IPr monomer shown in Formula 4; The molar ratio of intermediate 3, paraformaldehyde and trimethylsilyl chloride is 1.0:1.0-2.0:1.0-2.

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3. The method for preparing the carbazole-functionalized IPr·HCl monomer of formula 4 as claimed in claim 2, characterized in that: In step (1), organic solvent A and organic solvent B are both methyl tert-butyl ether.

4. The method for preparing the carbazole-functionalized IPr·HCl monomer of formula 4 as claimed in claim 2, characterized in that: In step (2), the organic solvent C is toluene.

5. The method for preparing the carbazole-functionalized IPr·HCl monomer of formula 4 as claimed in claim 2, characterized in that: In step (3), the organic solvent D is DMF.

6. The method for preparing the carbazole-functionalized IPr·HCl monomer of formula 4 as claimed in claim 2, characterized in that: In step (4), the organic solvent E is ethyl acetate.

7. A carbazole and N-heterocyclic carbene precursor bifunctionalized hyper-crosslinked porous organic polymer, referred to as HCP-BiCz-IPr, characterized in that: Prepared as follows: Under a protective atmosphere, the BiCz-IPr monomer shown in formula 4, dimethylformal, ferric chloride and an organic solvent F are mixed, and stirred and polymerized at 50-120° C. for 24-72 hours, and then post-treated to obtain HCP-BiCz-IPr; Wherein, the molar ratio of BiCz-IPr monomer to dimethylformal is 1.0:10.0-30.0; The molar ratio of BiCz-IPr monomer to ferric chloride is 1.0:1.0-30.0; The organic solvent F is 1,2-dichloroethane.

8. Use of the bifunctionalized hyper-crosslinked porous organic polymer of carbazole and N-heterocyclic carbene precursor as claimed in claim 7 as a heterogeneous catalyst in catalyzing the cycloaddition reaction of CO2 and ethylene oxide compounds to convert them into cyclic carbonates.

9. The use according to claim 8, characterized in that The ethylene oxide compound is an ethylene oxide substituted with an alkyl or aryl group, or an ethylene oxide substituted with a cyclohexyl group.

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