Biomass-based porous liquid type catalyst, application and method for preparing cyclic carbonate substances by using biomass-based porous liquid type catalyst

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a biomass-based porous liquid catalyst, a preparation method and a method for applying the biomass-based porous liquid catalyst to catalysis of cyclization reaction of an epoxy compound and CO2 to prepare cyclic carbonate substances. The method for preparing the cyclic carbonate substances by using the catalyst comprises the following steps: catalyzing an epoxy compound and CO2 to generate a cyclization reaction by using a porous liquid formed by a metal organic framework and a biomass-based ionic liquid as the catalyst, cooling to room temperature after the reaction is finished, filtering, adding silica gel into a product, and carrying out vacuum spin-drying, thereby obtaining the cyclic carbonate substances. And further purifying by silica gel column chromatography, and pumping by a vacuum pump to obtain the cyclic carbonate substance. Compared with other synthesis methods, the method for preparing the cyclic carbonate substances by adopting the catalyst provided by the invention has the advantages of high efficiency, mild reaction conditions and simple catalytic system, so that the highest yield of the cyclic carbonate can reach about 97%.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and in particular relates to a biomass-based porous liquid catalyst and the application of the catalyst, and also relates to a method for preparing cyclic carbonates by catalyzing the cyclization reaction of epoxy compounds with CO2. Background Art

[0002] With the rapid growth of the global economy, fossil fuels are consumed in large quantities, and carbon dioxide (CO2) emissions are increasing day by day, causing the greenhouse effect, leading to global warming, and continuously threatening human survival and development. In order to reduce the concentration of CO2 in the atmosphere, my country has proposed a dual carbon target. CO2 is a rich, non-toxic and renewable carbon C1 resource. Converting it into high-value-added chemical products can meet the requirements of sustainable development and is of great strategic significance to the realization of CO2 conversion.

[0003] In order to help China achieve the "dual carbon goals" as soon as possible and implement important measures for green, low-carbon and sustainable development in the chemical industry, catalytic CO2 conversion is expected to become a green transformative technology to reduce the concentration of CO2 in the atmosphere. The key is the development of high-performance catalysts. As a type of liquid material with permanent pores, porous liquids have the advantages of easy pipeline transportation and good mass and heat transfer of liquid absorbents and the advantages of high specific surface area and high porosity of solid adsorbents. They are expected to become a new generation of green transformative media for catalytic CO2 conversion.

[0004] Biomass-based ionic liquids are a type of ionic liquid prepared from renewable biomass resources. They have significant advantages in terms of environmental friendliness, renewability, physical and chemical properties, and economic benefits. Biomass-based ionic liquids can be used as green catalysts to catalyze the conversion of CO2, but the reaction conditions require a high pressure and are not easy to industrialize. Biomass-based porous liquids are expected to combine the advantages of porous liquids and biomass-based ionic liquids to achieve efficient catalytic conversion of CO2 under low-pressure and mild conditions. Summary of the invention

[0005] In order to solve the problems of complex catalytic system and low catalytic efficiency in the process of preparing cyclic carbonate substances from CO2 and epoxides, the present invention provides a method for synthesizing a series of cyclic carbonates with a simple catalytic system, mild reaction conditions, high catalytic efficiency, wide application range and environmental friendliness. The key to this method is the use of a specific biomass-based porous liquid catalyst.

[0006] The above-mentioned biomass-based porous liquid catalyst is prepared using ZIF-8 nanoparticles and biomass-based ionic liquid as raw materials.

[0007] The specific method is: by mass fraction, 4.0%-10.0% ZIF-8 nanoparticles and 90.0%-96.0% biomass-based ionic liquid are added into a reaction tube, and stirred to react at 110°C to 130°C to obtain a biomass-based porous liquid catalyst.

[0008] More specifically, the preparation method of the above-mentioned ZIF-8 nanoparticles is as follows (taking a laboratory test as an example):

[0009] According to the percentage by mass fraction, 2.0%-3.0% zinc nitrate hexahydrate and 2.0%-3.0% 2-methylimidazole are dissolved in 45%-48% methanol solvent, and then ultrasonicated at 30℃-50℃ for 10-30min, and then the methanol solution of zinc nitrate hexahydrate is quickly poured into the methanol solution of 2-methylimidazole, and allowed to stand at room temperature for 12-15h to obtain a white solid precipitate, and the white precipitate is centrifuged at a speed of 8000-12000rpm for 5-15min, repeatedly centrifuged, and the precipitate is washed with methanol having a molar concentration of 99.5%, and the lower layer of white precipitate is removed, and it is vacuum dried at 60℃-80℃ for 12-48h to obtain white ZIF-8 nanoparticles. The structural schematic diagram of the ZIF-8 nanoparticles obtained and used in the present invention is shown in the attached figure. Figure 2 shown.

[0010] The schematic diagram of the structure of the above biomass-based ionic liquid is as follows:

[0011]

[0012] Among them, X － CF3SO3 － , T S O － 、CH3 SO 3－ 、HSO4 － ,I － Br － and Cl － Any of .

[0013] The preparation method of the above-mentioned biomass-based ionic liquid is as follows (taking a laboratory test as an example to prepare 1-iodooctane biomass ionic liquid):

[0014] Add 20 mL of methanol, 0.5 mol of 5-hydroxymethylfurfural and 0.6 mol of ethylenediamine to a 100 mL flask, and react with magnetic stirring at room temperature for 30-60 min. Then, add a reducing agent NaBH4 in an equal molar ratio to 5-hydroxymethylfurfural in an ice-water bath. Stop stirring after 4 h, remove the solvent methanol in a vacuum at 40 ° C, add 15 mL of saturated sodium chloride solution, extract with dichloromethane several times, and then separate and purify by silica gel column chromatography to obtain an ionic liquid intermediate. Add the corresponding ionic liquid intermediate and 1-iodooctane in a molar ratio of 1:1 to a 100 mL flask, add 20 mL of acetonitrile, heat and stir under reflux at 80 ° C for 12 h, wash the product with 15 mL of ethyl acetate after the reaction, and vacuum dry at 100 ° C for 24 h to obtain the final biomass-based ionic liquid.

[0015] The above-mentioned 1-iodooctane can also be 1-bromooctane, or 1-iodoheptane, or 1-bromoheptane. Such changes also fall within the protection scope of the present invention.

[0016] In industrial production, the above ratio can be enlarged accordingly, and the above parameters are only the data used in the experimental process. If it fluctuates around the parameter, it is also considered as the scope of protection of the present invention.

[0017] The method for preparing the above-mentioned biomass-based porous liquid catalyst comprises the following steps:

[0018] (1) preparing white ZIF-8 nanoparticles, see the above steps for ZIF-8 nanoparticles;

[0019] (2) Preparation of biomass-based ionic liquids, taking 1-iodooctane biomass ionic liquid as an example, refer to the above preparation steps of biomass-based ionic liquids;

[0020] (3) Take 90.0%-96.0% of the 1-iodooctane biomass ionic liquid in (2) and 4.0%-10.0% of the ZIF-8 nanoparticles in (1) in terms of mass percentage, add them into a 10 mL reaction tube, add a magnet and stir at 110° C.-130° C. for 1-6 h to obtain a biomass-based porous liquid catalyst.

[0021] The schematic diagram of the preparation method of the above-mentioned biomass-based porous liquid catalyst is shown in the attached Figure 1 The Fourier transform infrared spectra comparison of the 1-iodooctane biomass ionic liquid and the 1-iodooctane biomass-based porous liquid in the present invention are shown in FIG. Figure 3 The TGA comparison of ZIF-8, 1-iodooctane biomass-based ionic liquid and 1-iodooctane biomass-based porous liquid in the present invention is shown in FIG. Figure 4 The actual picture of 1-iodooctane biomass-based porous liquid catalyst is shown in Figure 5 shown.

[0022] The application of the biomass-based porous liquid catalyst obtained by the above method in the preparation of cyclic carbonate substances is also the key content to be protected by the present invention.

[0023] The above catalyst is applied to the method for preparing cyclic carbonate substances, the steps of which are: in a reaction solvent or in the absence of a reaction solvent, a biomass-based porous liquid is used as a catalyst to catalyze the cyclization reaction of an epoxy compound with CO2, and then the target product cyclic carbonate substances are obtained through purification.

[0024] During the reaction, the specific parameters are: CO2 is 0.1-5MPa; the porous liquid catalyst formed by the biomass-based ionic liquid and ZIF-8 accounts for 1-10% of the molar percentage of the epoxy compound; the reaction temperature is 40°C-160°C, and the reaction time is 1-24h.

[0025] The above purification steps are specifically as follows: after the reaction is completed, the product is cooled to room temperature, transferred to an eggplant-shaped bottle, silica gel is added, vacuum dried, further purified by silica gel column chromatography, and then the solvent is removed by a vacuum pump and vacuum dried to obtain the product cyclic carbonate substance.

[0026] The above-mentioned cyclic carbonate substances have the following structural formula:

[0027]

[0028] Where R 1 , R 2 are all selected from any one of propargyloxymethyl, allyloxymethyl, alkyl, alkoxymethyl, chloromethyl, phenyl, phenoxymethyl or hydrogen; R 1 , R 2 Same or different.

[0029] The above-mentioned epoxy compound has the following structural formula:

[0030]

[0031] The reaction equation of the cyclization reaction is as follows:

[0032]

[0033] Where R 1 , R 2 are all selected from any one of propargyloxymethyl, allyloxymethyl, alkyl, alkoxymethyl, chloromethyl, phenyl, phenoxymethyl or hydrogen; R 1 , R 2 Same or different.

[0034] The preparation reaction of the present invention uses a porous liquid formed by a biomass-based ionic liquid and a metal organic framework as a catalyst, realizes the cyclization reaction of CO2 and epoxides to prepare cyclic carbonate substances, and provides a new way for the utilization of CO2 and the preparation of cyclic carbonate substances. In addition, the developed biomass-based porous liquid catalytic system has the advantages of being green and efficient, mild reaction conditions, and a simple catalytic system.

[0035] Compared with other catalyst-catalyzed preparation methods, the present invention has the following advantages:

[0036] (1) The catalyst system is a green, low-pressure catalyst system with good economic efficiency and high catalytic performance;

[0037] (2) The reaction can produce cyclic carbonate substances with a relatively high yield; in the embodiment with the highest yield, it can reach 97% (Example 4);

[0038] (3) The substrate has a wide range and good functional group tolerance. Under optimized reaction conditions, substrates with various substituents can react smoothly to obtain the target product; for example, the substituent can be any of propargyloxymethyl, allyloxymethyl, alkyl, alkoxymethyl, chloromethyl, phenyl, phenoxymethyl or hydrogen;

[0039] (4) It provides a new approach for the utilization of CO2 and the preparation of cyclic carbonates;

[0040] (5) Biomass is used as raw material, which is renewable and sustainable, thereby reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flow chart of the method for preparing biomass-based porous liquid in the present invention;

[0042] Figure 2 Schematic diagram of the structure of ZIF-8 nanoparticles used in the present invention;

[0043] Figure 3 It is a Fourier transform infrared spectrum comparison diagram of 1-iodooctane biomass ionic liquid and 1-iodooctane biomass-based porous liquid;

[0044] Figure 4 It is a TGA comparison diagram of ZIF-8, 1-iodooctane biomass-based ionic liquid and 1-iodooctane biomass-based porous liquid;

[0045] Figure 5 This is a physical picture of 1-iodooctane biomass-based porous liquid;

[0046] Figure 6 and 7 is the NMR spectrum of Example 1; wherein, Figure 6is the hydrogen spectrum, 1 HNMR, 400 MHz, CDCl3; Figure 7 is the carbon spectrum, 13 C NMR, 101 MHz, CDCl3;

[0047] Figure 8 and 9 is the NMR spectrum of Example 2; wherein, Figure 8 is the hydrogen spectrum, 1 HNMR, 400 MHz, CDCl3; Fig. 9 is the carbon spectrum, 13 C NMR, 101 MHz, CDCl3;

[0048] Fig.10 and 11 is the NMR spectrum of Example 3; wherein, Fig.10 is the hydrogen spectrum, 1 HNMR, 400 MHz, CDCl3; Fig.11 is the carbon spectrum, 13 C NMR, 101 MHz, CDCl3;

[0049] Fig.12 and 13 is the NMR spectrum of Example 4; wherein, Fig.12 is the hydrogen spectrum, 1 HNMR, 400 MHz, CDCl3; Fig.13 is the carbon spectrum, 13 C NMR, 101 MHz, CDCl3;

[0050] Fig.14 and 15 is the NMR spectrum of Example 5; wherein, Fig.14 is the hydrogen spectrum, 1 HNMR, 400 MHz, CDCl3; Fig.15 is the carbon spectrum, 13 C NMR, 101 MHz, CDCl3. DETAILED DESCRIPTION

[0051] The essential features and remarkable effects of the present invention can be reflected in the following embodiments, but they do not limit the present invention in any way. Those skilled in the art may make some non-essential improvements and adjustments based on the content of the present invention, which all belong to the protection scope of the present invention. The present invention is further described below through specific embodiments.

[0052] The drugs involved in the present invention: 5-hydroxymethylfurfural (98%), diethylamine (98%), iodomethane (98%), 1-bromooctane (99%), 1-iodooctane (99%), 1-iodopropane (99%), 1-iodododecane (99%), propylene oxide (98%), epichlorohydrin (98%), styrene oxide (98%), butyl glycidyl ether (99%), allyl glycidyl ether (98%), sodium borohydride (98%), 2-methylimidazole (98%), sodium chloride (99%) and other drugs were purchased from Shanghai MacLean Biochemical Technology Co., Ltd., ethyl acetate (99.5%), dichloromethane (99.5%), petroleum ether (AR), acetonitrile (99.9%), zinc nitrate hexahydrate (99%) and other drugs were purchased from Tianjin Kaitong Chemical Reagent Co., Ltd.; methanol (99.9%).

[0053] Yield calculation method: Yield = actual yield / theoretical yield × 100%;

[0054] Yield calculation refers to GB / T 27417-2017.

[0055] Example 1

[0056] S1: Preparation of catalyst, taking 1-iodooctane biomass-based porous liquid as an example:

[0057] (1) According to the percentage by mass fraction, 2.3% zinc nitrate hexahydrate and 2.7% 2-methylimidazole were dissolved in 47.5% methanol solvent, and then ultrasonicated at 35°C for 10 minutes. Then, the methanol solution of zinc nitrate hexahydrate was quickly poured into the methanol solution of 2-methylimidazole, and the mixture was allowed to stand at room temperature for 12 hours to obtain a white solid precipitate. The white precipitate was centrifuged at 8000 rpm for 15 minutes, and the centrifugation was repeated. After washing with methanol, the lower layer of white precipitate was taken and vacuum dried at 80°C for 12 hours to obtain white ZIF-8 nanoparticles;

[0058] (2) Add 20 mL of methanol, 0.5 mol of 5-hydroxymethylfurfural, and 0.6 mol of ethylenediamine to a 100 mL flask, and react under magnetic stirring at room temperature for 30 minutes. Then, add a reducing agent NaBH4 in an equal molar ratio to 5-hydroxymethylfurfural in an ice-water bath. Stop stirring after 4 hours, remove the solvent methanol under vacuum at 40°C, add 15 mL of saturated sodium chloride solution, extract with dichloromethane several times, and then separate and purify by silica gel column chromatography to obtain an ionic liquid intermediate. Add the corresponding ionic liquid intermediate and 1-iodooctane in a molar ratio of 1:1 to a 100 mL flask, then add 20 mL of acetonitrile, heat and stir under reflux at 80°C for 12 hours, wash the product with 15 mL of ethyl acetate after the reaction, and vacuum dry at 100°C for 24 hours to obtain the final 1-iodooctane biomass ionic liquid;

[0059] (3) According to the percentage by mass fraction, 95.2% of the 1-iodooctane biomass ionic liquid in (2) and 4.8% of the ZIF-8 nanoparticles in (1) were added to a 10 mL reaction tube, a magnetic particle was added, and then stirred at 120° C. for 5 h to obtain a biomass-based porous liquid catalyst - 1-iodooctane biomass-based porous liquid;

[0060] S2: 1 mmol of epichlorohydrin and 0.0212 g of 1-iodooctane biomass-based porous liquid (prepared in S1) were added to the reaction tube in sequence, and then a strong magnet was added to the reaction tube. The reaction tube was then placed in a high-pressure reactor, and 2.5 MPa of CO2 was flushed into the high-pressure reactor. The high-pressure reactor was then placed at 90°C and heated with stirring for 6 h.

[0061] S3: After the reaction is completed, the product is transferred to a 100 mL eggplant-shaped bottle, silica gel (100-200 mesh) is added, and the mixture is vacuum-dried and further purified by silica gel column chromatography (petroleum ether: ethyl acetate). The obtained product is pumped dry by a vacuum pump and an oil pump to obtain a colorless liquid product.

[0062] Yield 90%(122.86mg); 1 H NMR (400MHz, Chloroform-d) δ5.03 (dtd, J=8.7, 5.3, 3.5Hz, 1H), 4.62 (t, J=8.6Hz, 1H), 4.43 (dd, J=8.9, 5.7Hz, 1H), 3.90-3.68 (m, 2H). 13 C NMR (101MHz, Chloroform-d) δ154.49,74.45,67.00,44.06.

[0063] Example 2

[0064] The preparation steps of the catalyst in S1 are the same as those in Example 1;

[0065] S2: 1 mmol of allyl glycidyl ether and 0.0163 g of 1-iodooctane biomass-based porous liquid (prepared in S1) were added to the reaction tube in sequence, and then a strong magnet was added to the reaction tube. The reaction tube was then placed in a high-pressure reactor, and 2.5 MPa of CO2 was injected into the high-pressure reactor. The high-pressure reactor was then heated and stirred at 90°C for 6 h.

[0066] S3: After the reaction is completed, the product is transferred to a 100 mL eggplant-shaped bottle, silica gel (100-200 mesh) is added, and the mixture is vacuum-dried and further purified by silica gel column chromatography (petroleum ether: ethyl acetate). The obtained product is pumped dry by a vacuum pump and an oil pump to obtain a colorless liquid product.

[0067] Yield 93%(145.59mg); 1 H NMR (400MHz, Chloroform-d) δ5.88 (ddt, J=16.4, 10.9, 5.6Hz, 1H), 5.26 (dd, J=25.8, 13.8Hz, 2H), 4.85 (tdd, J=9. 2,4.2,2.3Hz,1H),4.52(td,J=8.4,1.4Hz,1H),4.42(dd,J=8.3,6.3Hz,1H),4.15-3.99(m,2H),3.79-3.55(m,2H). 13 C NMR (101MHz, Chloroform-d) δ155.06,133.67,117.94,117.92,75.12,72.55,68.81,66.28.

[0068] Example 3

[0069] S1 Preparation of catalyst see Example 1;

[0070] S2: 1 mmol of butyl glycidyl ether and 0.0177 g of 1-iodopropane biomass-based porous liquid (prepared in S1) were added to the reaction tube in sequence, and then a strong magnet was added to the reaction tube. The reaction tube was then placed in a high-pressure reactor, and 2.5 MPa of CO2 was flushed into the high-pressure reactor. The high-pressure reactor was then heated and stirred at 90°C for 6 hours.

[0071] S3: After the reaction is completed, the product is transferred to a 100 mL eggplant-shaped bottle, silica gel (100-200 mesh) is added, and the mixture is vacuum-dried and further purified by silica gel column chromatography (petroleum ether: ethyl acetate). The obtained product is pumped dry by a vacuum pump and an oil pump to obtain a colorless liquid product.

[0072] Yield 92%(155.91mg); 1 H NMR(400MHz,Chloroform-d)δ4.82(dtd,J=9.2,4.9,4.3,2.4Hz,1H),4.51(td,J=8.3,1.3Hz,1H),4.40(ddd,J=8.1,6 .1,1.3Hz,1H),3.77-3.56(m,2H),3.51(t,J=6.5Hz,2H),1.61-1.48(m,2H),1.36(h,J=7.4Hz,2H),0.98-0.83(m,3H). 13 C NMR (101MHz, Chloroform-d) δ75.14,71.86,69.59,66.31,31.50,19.15,13.87.

[0073] Example 4

[0074] S1: preparing catalyst, see Example 1;

[0075] S2: 1 mmol of styrene oxide and 0.0228 g of 1-iodododecane biomass-based porous liquid (prepared in S1) were added to the reaction tube in sequence, and then a strong magnet was added to the reaction tube. The reaction tube was then placed in a high-pressure reactor, and 2.5 MPa of CO2 was flushed into the high-pressure reactor. The high-pressure reactor was then placed at 90°C and heated with stirring for 6 h.

[0076] S3: After the reaction is completed, the product is transferred to a 100 mL eggplant-shaped bottle, silica gel (100-200 mesh) is added, and the mixture is vacuum-dried and further purified by silica gel column chromatography (petroleum ether: ethyl acetate). The obtained product is pumped dry by a vacuum pump and an oil pump to obtain a colorless liquid product.

[0077] Yield 85%(139.16mg); 1 H NMR (400MHz, Chloroform-d) δ7.51-7.29(m,5H),5.67(t,J=8.0Hz,1H),4.79(t,J=8.4Hz,1H),4.32(t,J=8.2Hz,1H). 13 C NMR (101MHz, Chloroform-d) δ155.03,135.87,129.75,129.25,126.01,78.10,71.26.

[0078] Example 5

[0079] S1 Preparation of catalyst, taking 1-bromooctane biomass-based porous liquid as an example:

[0080] (1) Preparation of white ZIF-8 nanoparticles, as in Example 1;

[0081] (2) Add 20 mL of methanol with a molar concentration of 99.5%, 0.5 mol of 5-hydroxymethylfurfural, and 0.6 mol of ethylenediamine to a 100 mL flask, and react under magnetic stirring at room temperature for 30 minutes. Then, add a reducing agent NaBH4 with a molar ratio equivalent to 5-hydroxymethylfurfural in an ice-water bath. Stop stirring after 4 hours, remove the solvent methanol in a vacuum at 40°C, add 15 mL of saturated sodium chloride solution, extract with dichloromethane several times, and then separate and purify by silica gel column chromatography to obtain an ionic liquid intermediate. Add the corresponding ionic liquid intermediate and 1-bromooctane in a molar ratio of 1:1 to a 100 mL flask, then add 20 mL of acetonitrile, heat and stir under reflux at 80°C for 12 hours, wash the product with 15 mL of ethyl acetate after the reaction, and vacuum dry at 100°C for 24 hours to obtain the final 1-bromooctane biomass ionic liquid;

[0082] (3) 95.2% of the 1-bromooctane biomass ionic liquid in (2) and 4.8% of the ZIF-8 nanoparticles in (1) were added to a 10 mL reaction tube, and a magnetic particle was added and stirred at 120° C. for 5 h to obtain a biomass-based porous liquid catalyst, 1-bromooctane biomass-based porous liquid;

[0083] S2: 1 mmol of propylene oxide and 0.0188 g of 1-bromooctane biomass-based porous liquid (prepared in S1) were added to the reaction tube in sequence, and then a strong magnet was added to the reaction tube. The reaction tube was then placed in a high-pressure reactor, and 2.5 MPa of CO2 was flushed into the high-pressure reactor. The high-pressure reactor was then placed at 90°C and heated with stirring for 6 h.

[0084] S3: After the reaction is completed, the product is transferred to a 100 mL eggplant-shaped bottle, silica gel (100-200 mesh) is added, and the mixture is vacuum-dried and further purified by silica gel column chromatography (petroleum ether: ethyl acetate). The obtained product is pumped dry by a vacuum pump and an oil pump to obtain a colorless liquid product.

[0085] Yield 80%(46.46 mg); 1 H NMR(400 MHz,Chloroform-d)δ4.90(tt,J=

[0086] 13.4, 4.7 Hz, 1H), 4.59 (t, J = 8.1 Hz, 1H), 4.06 (dd, J = 8.5, 7.2 Hz, 1H), 1.50 (d, J = 6.4 Hz, 3H). 13 C NMR (101 MHz, Chloroform-d) δ 155.22, 73.76, 70.74, 19.28.

Claims

1. A biomass-based porous liquid catalyst, characterized in that: The catalyst is prepared by using ZIF-8 nanoparticles and biomass-based ionic liquid as raw materials.

2. The biomass-based porous liquid catalyst according to claim 1, characterized in that: In terms of mass fraction, 4.0%-10.0% of ZIF-8 nanoparticles and 90.0%-96.0% of biomass-based ionic liquid are added into a reaction tube, and stirred for reaction at 110° C. to 130° C. to obtain a biomass-based porous liquid catalyst.

3. The biomass-based porous liquid catalyst according to claim 1, characterized in that: The preparation method of the ZIF-8 nanoparticles is as follows: Zinc nitrate hexahydrate and 2-methylimidazole were dissolved in methanol solvent respectively, and then ultrasonically treated. The methanol solution of zinc nitrate hexahydrate was poured into the methanol solution of 2-methylimidazole, and the mixture was allowed to stand at room temperature to obtain a white solid precipitate. The mixture was centrifuged, and the precipitate was washed with methanol. The lower layer of white precipitate was taken and vacuum dried to obtain ZIF-8 nanoparticles.

4. The biomass-based porous liquid catalyst according to claim 1, characterized in that: The preparation method of the biomass-based ionic liquid is as follows: Methanol, 5-hydroxymethylfurfural and ethylenediamine are mixed and stirred for reaction. Then, a reducing agent NaBH4 is added in an ice-water bath and stirred. The solvent methanol is removed by vacuum rotation. A saturated sodium chloride solution is added and extracted with dichloromethane. Then, an ionic liquid intermediate is separated and purified by silica gel column chromatography to obtain the ionic liquid intermediate. The ionic liquid intermediate and alkyl halide are added to a flask, and acetonitrile is added. The mixture is heated and stirred to reflux. After the reaction is completed, the product is washed with ethyl acetate and dried in vacuo to obtain the final biomass-based ionic liquid.

5. The method for preparing the biomass-based porous liquid catalyst according to claim 1, comprising the following steps: (1) According to the percentage by mass, 2.0%-3.0% zinc nitrate hexahydrate and 2.0%-3.0% 2-methylimidazole are respectively dissolved in 45%-48% methanol solvent, and then ultrasonicated at 35°C-50°C for 10-30 minutes, and then the methanol solution of zinc nitrate hexahydrate is quickly poured into the methanol solution of 2-methylimidazole, and the mixture is allowed to stand at room temperature for 12-15 hours to obtain a white solid precipitate, and the white precipitate is centrifuged at a speed of 8000-12000 rpm for 5-15 minutes, and the centrifugation is repeated. After washing with methanol, the lower layer of white precipitate is taken out and vacuum dried at 60°C-80°C for 12-48 hours to obtain white ZIF-8 nanoparticles; (2) Add 20 mL of methanol, 0.5 mol of 5-hydroxymethylfurfural, and 0.6 mol of ethylenediamine to a 100 mL flask, and react under magnetic stirring at room temperature for 30-60 min. Then, add a reducing agent NaBH4 in an equal molar ratio to 5-hydroxymethylfurfural in an ice-water bath. Stop stirring after 4 h, remove the solvent methanol under vacuum at 40 ° C, add 15 mL of saturated sodium chloride solution, extract with dichloromethane for multiple times, and then separate and purify by silica gel column chromatography to obtain an ionic liquid intermediate. Add the corresponding ionic liquid intermediate and alkyl halide in a molar ratio of 1:1 to a 100 mL flask, add 20 mL of acetonitrile, heat and stir under reflux at 80 ° C for 12 h, wash the product with 15 mL of ethyl acetate after the reaction, and vacuum dry at 100 ° C for 24 h to obtain the final biomass ionic liquid; (3) Take 90.0%-96.0% of the biomass ionic liquid in (2) and 4.0%-10.0% of the ZIF-8 nanoparticles in (1) in terms of mass percentage, add them into a 10 mL reaction tube, add a magnet and stir at 110° C.-130° C. for 1-6 h to obtain a biomass-based porous liquid catalyst.

6. Use of the biomass-based porous liquid catalyst as claimed in claim 1 in the preparation of cyclic carbonate substances.

7. A method for preparing cyclic carbonate substances by applying the catalyst according to claim 1, characterized in that: In a reaction solvent or in the absence of a reaction solvent, a biomass-based porous liquid is used as a catalyst to catalyze a cyclization reaction between an epoxy compound and CO2, and then the target product, a cyclic carbonate substance, is obtained through purification.

8. The method according to claim 7, characterized in that The cyclic carbonate substance has the following structural formula: Where R 1 , R 2 are all selected from any one of propargyloxymethyl, allyloxymethyl, alkyl, alkoxymethyl, chloromethyl, phenyl, phenoxymethyl or hydrogen; R 1 , R 2 Same or different.

9. The method according to claim 7, characterized in that The epoxy compound has the following structural formula: The reaction equation of the cyclization reaction is as follows: Where R 1 , R 2 are all selected from any one of propargyloxymethyl, allyloxymethyl, alkyl, alkoxymethyl, chloromethyl, phenyl, phenoxymethyl or hydrogen; R 1 , R 2 Same or different.

10. The method according to claim 7, characterized in that CO2 is 0.1-5MPa; the porous liquid catalyst formed by the biomass-based ionic liquid and ZIF-8 accounts for 1%-10% of the molar percentage of the epoxy compound; the reaction temperature is 40°C-160°C, and the reaction time is 1-24h.

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