Porous carbon materials coupled with multiple active sites and their preparation and application in catalytic coupling of CO2 with epoxides to prepare cyclic carbonates

Abstract

The present invention belongs to the field of functional material preparation and catalysis technology, and proposes a porous carbon material coupled with multiple active sites and its application in preparing and catalyzing the coupling of CO2 and epoxide to prepare cyclic carbonates. The present invention regulates the composition of multiple precursors and adopts the "in situ polymerization-pyrolysis" one-pot method to construct a series of novel porous carbon materials rich in multiple active sites of metal Lewis acids and Lewis bases. The porous carbon materials are used as catalysts to synthesize corresponding cyclic carbonates using carbon dioxide and epoxides with different substituents as raw materials, thereby achieving the synthesis of cyclic carbonates with high selectivity under normal pressure and solvent-free conditions. The porous carbon material is easy to separate, and its catalytic activity does not decrease significantly after being recycled 5 times. It has a stable structure and excellent adsorption and catalytic conversion dual functionality for carbon dioxide, which solves the problem of poor comprehensive performance of the current catalytic system in terms of catalytic activity, stability, and separation and reuse, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional material preparation and catalysis, and relates to a porous carbon material coupled with multiple active sites and its application in preparing and catalyzing the coupling of CO2 and epoxide to prepare cyclic carbonate. Background Art

[0002] Due to the widespread use of fossil fuels, CO2 emissions have surged annually, leading to a series of environmental problems such as the greenhouse effect, global warming, and sea level rise. Therefore, reducing CO2 emissions is imperative. While CO2 poses threats and damage to human society and the ecological environment, it is also an important non-toxic, low-cost, and renewable C1 resource for industry. With the rapid advancement of catalytic technology, the chemical resource utilization of CO2 has demonstrated increasing scientific and economic significance, aligning with the country's strategic need to effectively control carbon emissions and possessing significant significance from the perspectives of environmental protection and sustainable development. Due to the thermodynamic stability and kinetic inertness of CO2, its resource utilization requires the development of effective catalytic technologies. Currently, the resource utilization rate of CO2 from industrial production is reportedly only 0.36% of total global emissions. Therefore, there is still significant room for development in the chemical resource utilization of CO2.

[0003] The coupling of CO₂ with epoxides to prepare cyclic carbonates is a promising industrial pathway for large-scale resource utilization of CO₂ and has attracted widespread attention. This reaction route is atom-economical, offering a potential alternative to the traditional toxic phosgene process and meeting the requirements of green chemistry. Furthermore, the resulting cyclic carbonates possess excellent physical and chemical properties, such as high boiling point, high polarity, low volatility, and good biodegradability and solubility. They are widely used in green aprotic solvents, lithium-ion battery electrolytes, additives, plastics, pharmaceuticals, and fine chemical intermediates.

[0004] A variety of catalysts have been reported for the cycloaddition reaction of CO₂ with epoxides. Homogeneous catalysts include alkali metal salts, organic bases, metal-salen complexes, and ionic liquids, but they suffer from issues such as cumbersome product separation procedures and partial catalyst loss. Heterogeneous catalysts include polyionic liquids, porous organic polymers, MOFs, metal oxides, and mesoporous organosilicon. While these overcome the drawback of homogeneous catalysts and product separation, they still present drawbacks such as difficulty in catalyst preparation, high raw material costs, demanding catalytic reaction conditions (high temperature and high pressure), and the tendency for active components to be lost. Therefore, the development of highly efficient catalysts with stable structures, easy separation and recovery, and the ability to catalyze the cycloaddition reaction of CO₂ with epoxides under mild conditions is an inevitable trend.

[0005] Porous carbon materials have high specific surface area, excellent porous structure, controllable chemical composition and synthetic diversity, which makes them more competitive in optimizing CO2 adsorption capacity and improving CO2 conversion efficiency. In 2021, Liu et al. (Reaction Chemistry & Engineering, 2021, 6 (10): 1911-1919.) used ammonium hydroxide as a nitrogen source and base catalyst to synthesize N-doped mesoporous carbon spheres (N-MCSs) by dissolution-reassembly method, studied the adsorption activation and conversion performance of CO2, and avoided the use of co-catalysts when catalyzing the cycloaddition reaction of CO2 and epoxides. Under the conditions of 140 ° C and 1.6 MPa for 12 h, the conversion rate of ECH reached 59.1% and the selectivity was 98%. The reaction conditions are relatively harsh and the catalytic activity still needs to be further improved. In 2018, Samikannu A et al. (Applied Catalysis B: Environmental, 2019, 241: 41-51.) prepared porous carbon materials using cheap biomass as precursors. Under the conditions of solvent-free, temperature (100-150 ° C), CO2 pressure (5-50 Bar) and time (5-15h), the coupling reaction of epoxides and CO2 was catalyzed to prepare cyclic carbonates with a yield of 99%. Due to the small number of exposed active sites, the coupling of multiple active sites cannot be achieved, resulting in harsh reaction conditions. Therefore, there is an urgent need for porous carbon material catalysts with designable structures and easy coupling of multiple active sites, so as to realize the catalytic cycloaddition reaction of CO2 and epoxides under normal pressure and solvent-free conditions. Based on this, we proposed this invention research. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects in the prior art, provide a highly active, easily recyclable and reusable porous carbon material with multiple active site coupling, and provide a simple, cost-effective and environmentally friendly construction method for its preparation, and provide its use as a catalyst for the cycloaddition reaction of carbon dioxide and epoxides and a method for catalyzing the coupling of CO2 and epoxides to prepare cyclic carbonates.

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

[0008] In one aspect, the present invention provides a method for preparing a porous carbon material having multiple active sites coupled thereto, comprising the following steps:

[0009] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate are mixed at room temperature in a molar ratio of 3:2:13.4-27:0.28-4 to obtain a precursor; (2) the above precursor is heated to 500-900°C under inert gas protection conditions and kept warm for 1-3 hours to obtain a porous carbon material with multiple active sites coupled.

[0010] As some preferred embodiments of the present invention, after the reaction of step (2) is completed, washing, filtering and drying are further included.

[0011] As some preferred embodiments of the present invention, after the reaction in step (2) is completed, the temperature is naturally lowered to room temperature, and the mixture is washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively, and then filtered. The solid product is vacuum dried to obtain a porous carbon material coupled with multiple active sites.

[0012] As some preferred embodiments of the present invention, the molar ratio of 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate in step (1) is 3:2:27:0.57-3.42.

[0013] As some preferred embodiments of the present invention, in step (2), the temperature is heated to 700° C. at a heating rate of 3-10° C. / min and kept at this temperature for 2 h.

[0014] As some preferred embodiments of the present invention, in step (2), the temperature is heated to 700° C. at a heating rate of 5° C. / min and kept at this temperature for 2 h.

[0015] Another aspect of the present invention provides the use of the porous carbon material coupled with multiple active sites prepared by the above method as a catalyst for the cycloaddition reaction of carbon dioxide and epoxide.

[0016] In another aspect, the present invention provides a method for preparing cyclic carbonates by catalyzing the coupling reaction of carbon dioxide with an epoxide using a porous carbon material coupled with multiple active sites prepared by the aforementioned method. The method is characterized in that the cyclic carbonates are synthesized by a cycloaddition reaction of epoxide and carbon dioxide using the porous carbon material coupled with multiple active sites as a catalyst. The reaction equation is as follows:

[0017]

[0018] As some preferred embodiments of the present invention, the structural formula of the epoxide is as follows:

[0019]

[0020] As some preferred embodiments of the present invention, the amount of the porous carbon material catalyst coupled with multiple active sites is 5%-5.5% of the mass of the epoxide.

[0021] As some preferred embodiments of the present invention, the cycloaddition reaction temperature is 30-80° C., the reaction pressure is 0.1-2 MPa, and the reaction time is 6-25 h.

[0022] As some preferred embodiments of the present invention, the cycloaddition reaction temperature is 40° C., the reaction pressure is 0.1 MPa, and the reaction time is 24 h.

[0023] The working principle and beneficial effects of the present invention are:

[0024] The porous carbon material provided by the present invention has a high specific surface area (up to 564m 2 / g), high nitrogen content (7.56%), and possesses synthetic versatility, high chemical and thermal stability, and high carbon dioxide capture performance.

[0025] The catalyst of the present invention contains Lewis acid (Zn) and Lewis base (pyridine N) active groups that can efficiently activate epoxy compounds and inert carbon dioxide molecules. The method of using the porous carbon material coupled with multiple active sites as a cycloaddition reaction catalyst in the catalytic conversion of carbon dioxide to synthesize cyclic carbonates allows the catalytic process to be carried out under normal pressure and solvent-free conditions. The catalyst is easily recyclable and has excellent catalytic recycling performance, demonstrating good universality. This overcomes the drawbacks of currently reported catalytic systems, such as low activity, poor stability, and difficulty in recycling, and has good potential for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 It is the reaction scheme of the present invention.

[0028] Figure 2 These are infrared spectra of TFPT, DAP, TDPOP, and 4% Zn@CTDPOP-IL-X of the present invention. In (a), TDPOP is obtained by washing the precursor obtained in Example 2 with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt removed, DAP is 2,6-diaminopyridine, and TFPT is 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine. (b) is 4% Zn@CTDPOP-IL-X, where X represents different calcination temperatures.

[0029] Figure 3This is the X-ray photoelectron spectrum of Zn 2p in the porous carbon material 4%Zn@CTDPOP-IL-700 coupled with multiple active sites of the present invention;

[0030] Figure 4 This is the ICP test of the porous carbon material 4%Zn@CTDPOP-IL-700 coupled with multiple active sites of the present invention;

[0031] Figure 5 This is a scanning electron microscope image of the porous carbon material 4% Zn@CTDPOP-IL-700 coupled with multiple active sites of the present invention;

[0032] Figure 6 This is the adsorption isotherm of the porous carbon material 4%Zn@CTDPOP-IL-X coupled with multiple active sites of the present invention, where (a) is at 273K and (b) is at 303K;

[0033] Among them, 4% Zn@CTDPOP-IL-500, 4% Zn@CTDPOP-IL-600, 4% Zn@CTDPOP-IL-700, 4% Zn@CTDPOP-IL-800 and 4% Zn@CTDPOP-IL-900 represent the porous carbon materials coupled with multiple active sites of Example 3, Example 4, Example 2, Example 5 and Example 6, respectively. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0035] Example 1

[0036] Preparation of 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine (TFPT)

[0037] Weigh p-hydroxybenzaldehyde (0.5495 g, 4.5 mmol) and sodium hydroxide (0.18 g, 4.5 mmol) into a 50 ml beaker, add 16 ml of a mixed solvent (water:acetone = 1:1 (volume ratio), and stir at room temperature for 0.5 h to obtain an orange-red sodium p-methylcarbonylphenolate solution;

[0038] Weigh cyanuric chloride (1.5 mmol, 0.2796 g) into a three-necked flask, add 18 ml of acetone solution, control the reaction temperature to 5 ° C, and stir under N2 gas protection for 0.5 h to obtain a clear and transparent solution; slowly add the orange-red sodium p-methylcarbonylphenolate solution dropwise to the three-necked flask, control the reaction temperature to 5 ° C under N2 protection, stir for 1 h, then stir at room temperature for 1 h, then heat to the reaction temperature of 80 ° C and reflux with stirring for 4 h. As the temperature drops to room temperature, some precipitate precipitates in the three-necked flask. Add 50 ml of ice water to produce a large amount of precipitate. Stir for 2 h, repeat 3 times, and dry the product in vacuum at 80 ° C for 12 h to obtain 0.598 g of a white solid (yield: 90%), namely TFPT.

[0039] Example 2

[0040] Preparation of porous carbon materials (4% Zn@CTDPOP-IL-700) coupled with multiple active sites

[0041] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:27:2.28 to obtain a precursor; Figure 1 TFPT is located at 1697 cm -1 The characteristic peaks of -CHO and DAP are located at 3384 cm -1 The -NH2 characteristic peak disappears, which indicates that the Schiff base polymerization reaction between the aldehyde monomer and the amino monomer is relatively complete;

[0042] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0043] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 4% Zn@CTDPOP-IL-700 with multiple active sites coupled, and the specific surface area was 468 m 2 / g. Figure 2 , demonstrating that the zinc sites were successfully integrated into the porous carbon material and successfully retained in the pores of the carbon material after calcination; Figure 3 , proving that the Zn loading in 4%Zn@CTDPOP-IL-700 is 6.9%; Figure 4 , the sample exhibits a bulk porous carbon structure.

[0044] Reaction route such as Figure 1 .

[0045] Example 3

[0046] Preparation of porous carbon materials (4% Zn@CTDPOP-IL-500) coupled with multiple active sites

[0047] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at a molar ratio of 3:2:27:2.28 at room temperature to obtain a precursor;

[0048] (2) Place the above precursor in a tube furnace, heat to 500°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0049] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material with multiple active sites coupled. 4% Zn@CTDPOP-IL-500, with a specific surface area of ​​564m 2 / g.

[0050] Example 4

[0051] Preparation of porous carbon materials (4% Zn@CTDPOP-IL-600) coupled with multiple active sites

[0052] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at a molar ratio of 3:2:27:2.28 at room temperature to obtain a precursor;

[0053] (2) Place the above precursor in a tube furnace, heat to 600°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0054] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material with multiple active sites coupled. 4% Zn@CTDPOP-IL-600, with a specific surface area of ​​527m 2 / g.

[0055] Example 5

[0056] Preparation of porous carbon materials (4% Zn@CTDPOP-IL-800) coupled with multiple active sites

[0057] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at a molar ratio of 3:2:27:2.28 at room temperature to obtain a precursor;

[0058] (2) Place the above precursor in a tube furnace, heat to 800°C at a heating rate of 5°C / min under N2 atmosphere, and keep the reaction at this temperature for 2 hours;

[0059] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 4% Zn@CTDPOP-IL-800 with multiple active sites coupled, and the specific surface area was 360 m 2 / g.

[0060] Example 6

[0061] Preparation of porous carbon materials (4% Zn@CTDPOP-IL-900) coupled with multiple active sites

[0062] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at a molar ratio of 3:2:27:2.28 at room temperature to obtain a precursor;

[0063] (2) Place the above precursor in a tube furnace, heat to 900°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0064] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 4% Zn@CTDPOP-IL-900 with multiple active sites coupled, and the specific surface area was 181 m 2 / g.

[0065] like Figure 1 , 4% Zn@CTDPOP-IL-X at 1570-1209 cm -1 The intensity of the characteristic peak in the region is significantly weakened, indicating that the sample is carbonized at high temperature; Figure 5 , the amount of CO2 adsorbed decreases with the increase of adsorption temperature and the decrease of CO2 pressure.

[0066] Example 7

[0067] Preparation of porous carbon materials (1% Zn@CTDPOP-IL-700) coupled with multiple active sites

[0068] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:27:0.57 to obtain a precursor;

[0069] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0070] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol, and acetone, respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 1% Zn@CTDPOP-IL-700 coupled with multiple active sites.

[0071] Example 8

[0072] Preparation of porous carbon materials (2% Zn@CTDPOP-IL-700) coupled with multiple active sites

[0073] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:27:1.14 to obtain a precursor;

[0074] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0075] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol, and acetone, respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 2% Zn@CTDPOP-IL-700 coupled with multiple active sites.

[0076] Example 9

[0077] Preparation of porous carbon materials (6% Zn@CTDPOP-IL-700) coupled with multiple active sites

[0078] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:27:3.42 to obtain a precursor;

[0079] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0080] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol, and acetone, respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 6% Zn@CTDPOP-IL-700 coupled with multiple active sites.

[0081] Comparative Example 1

[0082] Preparation of porous carbon material (CTDPOP-700) coupled with multiple active sites

[0083] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt were mixed uniformly at room temperature in a molar ratio of 3:2:27, and then 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was washed away with anhydrous ethanol to obtain a precursor;

[0084] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0085] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material CTDPOP-700 with multiple active sites coupled, with a specific surface area of ​​349 m 2 / g.

[0086] Comparative Example 2

[0087] Preparation of porous carbon material (CTDPOP-IL-700) coupled with multiple active sites

[0088] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt were mixed uniformly at room temperature in a molar ratio of 3:2:27 to obtain a precursor;

[0089] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0090] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol and acetone respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material CTDPOP-IL-700 coupled with multiple active sites with a specific surface area of ​​396 m 2 / g.

[0091] Comparative Example 3

[0092] Preparation of porous carbon materials (0.5% Zn@CTDPOP-IL-700) coupled with multiple active sites

[0093] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:27:0.28 to obtain a precursor;

[0094] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0095] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol, and acetone, respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 0.5% Zn@CTDPOP-IL-700 coupled with multiple active sites.

[0096] Comparative Example 4

[0097] Preparation of porous carbon materials (7% Zn@CTDPOP-IL-700) coupled with multiple active sites

[0098] (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:27:4 to obtain a precursor;

[0099] (2) Place the above precursor in a tube furnace, heat to 700°C at a heating rate of 5°C / min under N2 atmosphere, and keep the temperature for 2 hours;

[0100] (3) After the reaction, the product was cooled naturally and washed with N,N-dimethylformamide, anhydrous ethanol, and acetone, respectively. The solid product was filtered and vacuum dried to obtain a porous carbon material 7% Zn@CTDPOP-IL-700 coupled with multiple active sites.

[0101] Application Example 1

[0102] The reactant propylene oxide, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-700 prepared in Example 2 were added in sequence to a 50 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner, wherein 34.5 mmol of propylene oxide, 1.72 mmol of TBAI, accounting for 5% of the molar amount of the reactant PO, and 0.1 g of 4% Zn@CTDPOP-IL-700, accounting for 5% of the mass content of the reactants; CO2 gas was slowly introduced into the reactor to remove the residual air inside; then, the reactor was heated to 30°C in an oil bath, CO2 gas was introduced to maintain a constant pressure of 1.5 MPa, and the reaction was continued for 25 hours; after the reaction was completed, the reactor was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a propylene carbonate yield of 93% and a selectivity of ≥99%.

[0103] Application Example 2

[0104] The reactant propylene oxide, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-700 prepared in Example 2 were added in sequence to a 50 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner, wherein 34.5 mmol of propylene oxide, 1.72 mmol of TBAI, accounting for 5% of the molar amount of the reactant PO, and 0.1 g of 4% Zn@CTDPOP-IL-700, accounting for 5% of the mass content of the reactants; CO2 gas was slowly introduced into the reactor to remove the residual air inside; then, the reactor was heated to 70°C in an oil bath, CO2 gas was introduced to maintain a constant pressure of 2 MPa, and the reaction was continued for 7 hours; after the reaction was completed, the reactor was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a propylene carbonate yield of 97% and a selectivity of ≥99%.

[0105] Application Example 3

[0106] The reactant propylene oxide, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-700 prepared in Example 2 were added in sequence to a 50 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner, wherein 34.5 mmol of propylene oxide, 1.72 mmol of TBAI, accounting for 5% of the molar amount of the reactant PO, and 0.1 g of 4% Zn@CTDPOP-IL-700, accounting for 5% of the mass content of the reactants; CO2 gas was slowly introduced into the reactor to remove the residual air inside; then, the reactor was heated to 80°C in an oil bath, CO2 gas was introduced to maintain a constant pressure of 1.0 MPa, and the reaction was continued for 6 hours; after the reaction was completed, the reactor was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a propylene carbonate yield of 95% and a selectivity of ≥99%.

[0107] Application Example 4

[0108] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-700 prepared in Example 2 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 4% Zn@CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under 0.1 MPa CO2 pressure for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 94% and a selectivity of ≥99%.

[0109] Application Example 5

[0110] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 1% Zn@CTDPOP-IL-700 prepared in Example 7 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 1% Zn@CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under 0.1 MPa CO2 pressure for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 70% and a selectivity of ≥99%.

[0111] Application Example 6

[0112] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 2% Zn@CTDPOP-IL-700 prepared in Example 8 were added sequentially to a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 2% Zn@CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under 0.1 MPa CO2 pressure for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 89% and a selectivity of ≥99%.

[0113] Application Example 7

[0114] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 6% Zn@CTDPOP-IL-700 prepared in Example 9 were added sequentially to a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 6% Zn@CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under a CO2 pressure of 0.1 MPa for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 87% and a selectivity of ≥99%.

[0115] Application Example 8

[0116] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-500 prepared in Example 3 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 4% Zn@CTDPOP-IL-500, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under a CO2 pressure of 0.1 MPa for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 75% and a selectivity of ≥99%.

[0117] Application Example 9

[0118] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-600 prepared in Example 4 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 4% Zn@CTDPOP-IL-600, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under 0.1 MPa CO2 pressure for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 81% and a selectivity of ≥99%.

[0119] Application Example 10

[0120] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-800 prepared in Example 5 were added sequentially to a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 4% Zn@CTDPOP-IL-800, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under 0.1 MPa CO2 pressure for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 87% and a selectivity of ≥99%.

[0121] Application Example 11

[0122] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 4% Zn@CTDPOP-IL-900 prepared in Example 6 were added sequentially to a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 4% Zn@CTDPOP-IL-900, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; then, the reaction flask was heated to 40°C in an oil bath and the reaction was continued under 0.1 MPa CO2 pressure for 24 hours; after the reaction was completed, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 82% and a selectivity of ≥99%.

[0123] Application Example 12

[0124] The specific experimental process and detection method are the same as those in Application Example 4, except that epichlorohydrin is replaced by other epoxides with different substituents, and the cycloaddition reactions are carried out with carbon dioxide respectively. The obtained results are shown in Table 1.

[0125] Table 1 Cycloaddition reaction results of different epoxides with carbon dioxide catalyzed by 4% Zn@CTDPOP-IL-700

[0126]

[0127] Application Examples 13-17

[0128] The specific experimental conditions and steps were the same as those in Application Example 4. The residual product was washed with ethyl acetate and the catalyst 4% Zn@CTDPOP-IL-700 was recovered by centrifugation. Five cycle experiments were carried out using the recovered catalyst under the same conditions. The results are shown in Table 2.

[0129] Table 2 Experimental results of catalyst recycling in Examples 8-12

[0130]

[0131] Application Example 18

[0132] Table 3 below compares the novel multi-active site coupled porous carbon material 4% Zn@CTDPOP-IL-700 proposed in the present invention with other catalysts reported in the literature. Under the catalytic reaction conditions reported in each literature (only epoxide, temperature, pressure, and time are listed in the table), the yields are shown below:

[0133] Table 3 Catalytic reaction conditions and activity comparison

[0134] Catalyst type Epoxides Temperature / ℃ Pressure / MPa Time / h Product yield / % ZnO@NPC-Ox-700 / TBAB Epichlorohydrin 60 0.1 24 94 NSC-773 / TBAI Epichlorohydrin 70 0.1 24 95 <![CDATA[ox-bc hw / Drugs]]> Epichlorohydrin 110 1.0 6 97 Co@CNFs-700 / DMF Epichlorohydrin 140 0.7 20 91.7 NSAC-(1:1)550(1) / TBAB Epichlorohydrin 120 1 8 90 AP-GO / TBAI Epichlorohydrin 100 0.1 27 75 N-GQD-BPA Propylene oxide 140 1.0 8 98 4%Zn@CTDPOP-IL-700 Propylene oxide 70 2 7 97 4%Zn@CTDPOP-IL-700 Epichlorohydrin 40 0.1 24 94

[0135] Comparative Application Example 1

[0136] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst CTDPOP-700 prepared in Comparative Example 1 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of CTDPOP-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; thereafter, the reaction flask was heated to 40°C in an oil bath, and the reaction was continued for 24 hours under a CO2 pressure of 0.1 MPa; after the reaction, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 50% and a selectivity of ≥99%.

[0137] Application Comparative Example 2

[0138] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst CTDPOP-IL-700 prepared in Comparative Example 2 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; thereafter, the reaction flask was heated to 40°C in an oil bath, and the reaction was continued for 24 hours under a CO2 pressure of 0.1 MPa; after the reaction, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a product yield of 54% and a selectivity of ≥99%.

[0139] Application Comparative Example 3

[0140] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 0.5% Zn@CTDPOP-IL-700 prepared in Comparative Example 3 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar amount of the reactant epichlorohydrin, and 0.05 g of 0.5% Zn@CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; thereafter, the reaction flask was heated to 40°C in an oil bath and the reaction was continued for 24 hours under a CO2 pressure of 0.1 MPa; after the reaction, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a yield of 58% of propylene carbonate and a selectivity of ≥99%.

[0141] Comparative Application Example 4

[0142] The reactant epichlorohydrin, the co-catalyst tetrabutylammonium iodide (TBAI), and the catalyst 7% Zn@CTDPOP-IL-700 prepared in Comparative Example 4 were added sequentially into a 100 mL Schlenk reaction flask connected to a CO2 balloon, wherein 10 mmol of epichlorohydrin, 0.5 mmol of TBAI, accounting for 5% of the molar weight of the reactant epichlorohydrin, and 0.05 g of 7% Zn@CTDPOP-IL-700, accounting for 5.5% of the mass content of the reactants; the residual air inside was removed by decompression; thereafter, the reaction flask was heated to 40°C in an oil bath and the reaction was continued for 24 hours under a CO2 pressure of 0.1 MPa; after the reaction, the reaction flask was cooled to room temperature in an ice-water bath, and the product was quantitatively analyzed by gas chromatography, with a yield of 62% of propylene carbonate and a selectivity of ≥99%.

[0143] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a porous carbon material with multiple active sites coupled, characterized in that: The steps include: (1) 2,6-diaminopyridine, 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and zinc acetate dihydrate were mixed at room temperature in a molar ratio of 3:2:13.4-27:0.57-3.42 to obtain a precursor; (2) The precursor is heated to 500-900 °C under inert gas protection and kept warm for 1-3 h to obtain a porous carbon material with multiple active sites coupled.

2. The method for preparing a porous carbon material with multiple active sites coupled according to claim 1, characterized in that: After the reaction of step (2) is completed, the steps further include washing, filtering and drying.

3. The method for preparing a porous carbon material with multiple active sites coupled according to claim 1, characterized in that: In the step (2), the temperature is heated to 700°C at a heating rate of 3-10°C / min and kept at this temperature for 2 h.

4. Use of the porous carbon material coupled with multiple active sites prepared according to the method of claim 1 as a catalyst for the cycloaddition reaction of carbon dioxide and epoxide.

5. A method for preparing cyclic carbonate by catalyzing the coupling of carbon dioxide and epoxide using a porous carbon material coupled with multiple active sites prepared according to the method of claim 1, characterized in that: Using porous carbon materials coupled with multiple active sites as catalysts, cyclic carbonates are synthesized by cycloaddition reaction of epoxides and carbon dioxide.

6. The method for preparing cyclic carbonate by coupling carbon dioxide and epoxide catalyzed by a porous carbon material coupled with multiple active sites according to claim 5, characterized in that: The structural formula of the epoxide is as follows: 。 7. The method for preparing cyclic carbonate by coupling carbon dioxide and epoxide catalyzed by a porous carbon material coupled with multiple active sites according to claim 5, characterized in that: The amount of the porous carbon material catalyst coupled with multiple active sites is 5%-5.5% of the mass of the epoxide.

8. The method for preparing cyclic carbonate by coupling carbon dioxide and epoxide catalyzed by a porous carbon material coupled with multiple active sites according to claim 5, characterized in that: The cycloaddition reaction temperature is 30-80°C, the reaction pressure is 0.1-2 MPa, and the reaction time is 6-25 h.

9. The method for preparing cyclic carbonate by coupling carbon dioxide and epoxide catalyzed by a porous carbon material coupled with multiple active sites according to claim 5, characterized in that: The cycloaddition reaction temperature is 40°C, the reaction pressure is 0.1 MPa, and the reaction time is 24 h.

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