A method for the synthesis of alpha-alkylidene cyclic carbonates

Abstract

This invention discloses a method for synthesizing α-alkylmethylene cyclic carbonates, which utilizes a porous organic polymer silver-based nanocatalyst to catalyze a carboxylation-cyclization reaction between carbon dioxide and propargyl alcohol compounds to obtain α-alkylmethylene cyclic carbonates; the general structural formula of the porous organic polymer silver-based nanocatalyst is: [Ag-M-(N)4] n M is selected from porphyrin compounds; the structural formula of M is as follows: where R is independently selected from hydrogen atom or nitro group; N is selected from one of N1-N4 compounds: Compared with existing catalysts, the porous organic polymer silver-based nanocatalyst of the present invention is green and pollution-free, has good stability, has a small silver nanoparticle size, and requires a small amount of catalyst for carboxylation and cyclization reactions, and the reaction conditions are relatively mild.

Description

Technical Field

[0001] This invention relates to the field of green chemistry catalysis, and specifically to a method for synthesizing α-alkylmethylene cyclic carbonates. Background Technology

[0002] Carbon dioxide, as an environmentally friendly carbon resource, offers greater economic viability in its resource conversion and utilization, aligning with sustainable development strategies. Among numerous technological routes for carbon dioxide resource utilization, propargyl alcohol, as a type of alkyne derivative, can undergo a carboxylation-cyclization reaction with carbon dioxide. The resulting α-alkylmethylene cyclic carbonate is an important monomer in organic synthesis, used to synthesize hydroxy ketones, oxazolinones, and carbonates. In recent years, catalysts developed for this reaction have primarily included transition metal catalysis (such as Cu / Ag), base catalysis, and ionic liquid catalysis; however, these methods suffer from poor reaction cycle economics. Therefore, exploring a green, inexpensive catalyst that can efficiently catalyze the carboxylation-cyclization reaction of carbon dioxide and propargyl alcohol under relatively mild conditions is of great significance.

[0003] Porous organic polymers, due to their low density, abundant pore structure, and functional groups, exhibit great potential for gas adsorption and conversion. A highly dispersed silver-based catalyst based on porous organic polymers was obtained by in-situ supported reduction of silver nanoparticles. This catalyst demonstrated excellent catalytic activity and good stability in the carboxylation and cyclization reactions of propargyl alcohol and carbon dioxide. However, existing catalysts suffer from problems such as: uneven silver nanoparticle size; demanding reaction conditions, often requiring high temperature and high pressure; and poor catalyst recyclability, making recovery impossible. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a method for synthesizing α-alkylmethylene cyclic carbonates. The porphyrin-based porous organic polymer silver-based nanocatalyst can catalyze the carboxylation and cyclization reaction of carbon dioxide and propyne alcohol under mild conditions to generate α-alkylmethylene cyclic carbonate products.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a method for synthesizing α-alkylmethylene cyclic carbonates, which uses a porous organic polymer silver-based nanocatalyst to catalyze the carboxylation and cyclization reaction of carbon dioxide and propargyl alcohol compounds to obtain α-alkylmethylene cyclic carbonates.

[0007] The general structural formula of the porous organic polymer silver-based nanocatalyst is: [Ag-M-(N)4] n M is selected from porphyrin compounds; the structural formula of M is as follows:

[0008] In the formula, R is independently selected from either a hydrogen atom or a nitro group;

[0009] The N is selected from one of the N1-N4 compounds:

[0010]

[0011] The synthesis strategy of the porous organic polymer silver-based nanocatalyst of this invention is as follows: First, using porphyrin as a building block, suitable monomers are screened to construct porphyrin-based porous organic polymers; second, since the pyrrole hydrogen in the porphyrin ring has a certain reducing property, it can convert Ag... + In-situ restoration to Ag 0 Furthermore, most of the designed porphyrin-based porous organic polymers are nitrogen-rich polymers, and nitrogen-rich groups have a certain attraction effect on the loading of silver nanoparticles, thereby enabling the silver nanoparticles in the porphyrin-based porous organic polymer silver-based nanocatalyst to exist stably in the polymer framework, enhancing the recyclability of the catalyst.

[0012] The reaction formula for synthesizing α-alkylmethylene cyclic carbonates from carbon dioxide and propargyl alcohols according to the present invention is as follows:

[0013]

[0014] When R1 is selected from CH3 and R2 is selected from CH3, the structural formula of the reactants is: The product structure formula is When R1 is selected from CH3 and R2 is selected from C2H5, the structural formula of the reactants is: The product structure formula is When R1 is selected from CH3 and R2 is selected from CH2CH(CH3)2, the structural formula of the reactants is: The product structure formula is When both R1 and R2 are selected from cycloalkyl substituents, the reactant structure is as follows: The product structure formula is When R1 is selected from CH3 and R2 is selected from C6H5, the structural formula of the reactants is: The product structure formula is

[0015] Preferably, the porous organic polymer silver-based nanocatalyst is selected from at least one of the following compounds I-IV;

[0016]

[0017] This invention utilizes porphyrin-based porous organic polymers to design nitrogen-rich structures, and then employs an "in-situ reduction strategy" to in-situ reduce and fix silver into the polymer framework, synthesizing porous organic polymer silver-based nanocatalysts. On one hand, this provides the polymer framework with nano-silver active sites, enabling the activation of substrate alkyne bonds; on the other hand, the interaction between the silver nanoparticles and the nitrogen-rich matrix structure not only ensures uniform silver distribution within the polymer framework but also endows the silver nanoparticles with a certain degree of stability, allowing the catalyst to maintain good activity even after multiple cycles. The strong organic base DBU can simultaneously attract hydrogen atoms from the substrate's hydroxyl groups, further activating the substrate, lowering the reaction energy barrier, and enabling the reaction to proceed efficiently under mild conditions.

[0018] Preferably, the method for synthesizing the α-alkylmethylene cyclic carbonate includes the following steps:

[0019] A porous organic polymer silver-based nanocatalyst, propargyl alcohol compounds, alkaline substances, and solvents are mixed and placed in a reaction vessel. Carbon dioxide gas is introduced to carry out a carboxylation and cyclization reaction. The filtrate is collected by centrifugation to obtain the α-alkylmethylene cyclic carbonate.

[0020] Preferably, the propargyl alcohol compound is selected from... Any one of them.

[0021] Preferably, the alkaline substance is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and / or triethylamine; more preferably, the alkaline substance is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0022] The possible reaction mechanism of the synergistic catalysis of carbon dioxide and propargyl alcohols to synthesize α-alkylmethylene cyclic carbonates by DBU and porous organic polymer silver-based nanocatalysts described in this invention is shown in the following diagram:

[0023]

[0024] Because DBU has the ability to activate the hydroxyl group of propargyl alcohol through acid-base interactions, it attracts hydrogen from the hydroxyl group of the propargyl alcohol substrate. Simultaneously, the silver nanoparticles on the porous organic polymer silver-based nanocatalyst activate the alkyne bond in the propargyl alcohol. Furthermore, since the designed porous organic polymer silver-based nanocatalyst has a complex nitrogen structure and excellent affinity for -CO2, CO2 enriched in the catalyst channels inserts into the activated hydroxyl oxygen of the propargyl alcohol through electrophilic attack, generating an α-alkylmethylene cyclic carbonate intermediate and [DBUH]. +Subsequently, the negatively charged oxygen in the carbonate anion rapidly attacks the carbon-carbon triple bond, resulting in an intramolecular cyclization reaction; finally, with the release of the catalyst, an α-alkylmethylene cyclic carbonate product is formed. The mechanism of action of triethylamine is similar to that of DBU; both are basic substances and attract the hydroxyl hydrogen of propargyl alcohol substrates.

[0025] Preferably, the solvent includes at least one of acetonitrile and N,N-dimethylformamide; more preferably, the solvent is acetonitrile.

[0026] Preferably, the reaction temperature for the carboxylation cyclization is 20-40°C; more preferably, the reaction temperature for the carboxylation cyclization is 20-30°C; and even more preferably, the reaction temperature for the carboxylation cyclization is 25°C.

[0027] Preferably, the reaction pressure of the carboxylation cyclization is 0.1-1.0 MPa; more preferably, the reaction pressure of the carboxylation cyclization is 0.1 MPa.

[0028] Preferably, the molar ratio of propargyl alcohol to the alkaline substance is 2:(1-3); more preferably, the molar ratio of propargyl alcohol to the alkaline substance is 1:1.

[0029] Preferably, the amount of the porous organic polymer silver-based nanocatalyst is 10-30 mg, based on 1 mmol of propargyl alcohol compound.

[0030] Preferably, the reaction time for the carboxylation cyclization is 1-48 h; more preferably, the reaction time for the carboxylation cyclization is 6-12 h.

[0031] Preferably, the porous organic polymer silver-based nanocatalyst has a specific surface area of ​​300-900 m². 2 / g; More preferably, the specific surface area of ​​the porous organic polymer silver-based nanocatalyst is 400-600m². 2 / g.

[0032] Preferably, the porous organic polymer silver-based nanocatalyst has a particle size of 1-10 nm.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] (1) Utilizing the excellent "CO2-loving" properties and ability to attract silver nanoparticles exhibited by nitrogen-rich polymers, porphyrins containing tetrapyrrole macrocycles were used as building blocks. Suitable monomers were screened to construct nitrogen-rich porous organic polymers. Then, through an "in-situ reduction strategy," silver was introduced and in-situ reduced and fixed into the framework structure to obtain porous organic polymer silver-based nanocatalysts. Compared with existing catalysts, the porous organic polymer silver-based nanocatalysts of this invention are green and pollution-free, have good stability, smaller silver nanoparticle size, and require less catalyst for carboxylation and cyclization reactions, while allowing for milder reaction conditions.

[0035] (2) Under the action of solvent acetonitrile and strong organic base DBU, porous organic polymer silver-based nanocatalyst can catalyze propargyl alcohol and carbon dioxide to synthesize α-alkylmethylene cyclic carbonates efficiently under relatively mild conditions, showing good prospects for industrial application.

[0036] (3) The silver nanoparticles in the porous organic polymer silver-based nanocatalyst can effectively activate the alkyne bond of the substrate, thereby activating the substrate; the porous organic polymer framework provides a rich microporous structure and a large specific surface area, and the abundant nitrogen atoms can effectively enrich CO2 molecules, further promoting the reaction; DBU can effectively attract hydrogen atoms on the hydroxyl groups of the substrate molecules, further activating the substrate molecules. Attached Figure Description

[0037] Figure 1 The specific surface area diagram of the porous organic polymer silver-based nanocatalyst in Example 2 is shown.

[0038] Figure 2 The specific surface area diagram of the porous organic polymer silver-based nanocatalyst in Example 4 is shown.

[0039] Figure 3 This is a pore size measurement diagram of the porous organic polymer silver-based nanocatalyst in Example 2;

[0040] Figure 4 This is a pore size measurement diagram of the porous organic polymer silver-based nanocatalyst in Example 4;

[0041] Figure 5 The X-ray photoelectron diffraction energy spectrum narrow-spectrum scan of the porous organic polymer silver-based nanocatalyst in Example 2;

[0042] Figure 6 Here is an HR-TEM image of the porous organic polymer silver-based nanocatalyst from Example 4;

[0043] Figure 7 This is a particle size distribution diagram of the porous organic polymer silver-based nanocatalyst in Example 4;

[0044] Figure 8Unsaturated cyclic carbonate products of 1 H NMR spectrum;

[0045] Figure 9 Unsaturated cyclic carbonate products of 1 H NMR spectrum. Detailed Implementation

[0046] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0048] Example 1

[0049] This embodiment provides a porous organic polymer silver-based nanocatalyst, wherein when M is selected from... N is selected from The porous organic polymer silver-based nanocatalyst is designated Ag / Azo-DAP, and its structural formula is as follows:

[0050]

[0051] It is prepared by a method including the following steps:

[0052] S1. Under an inert atmosphere, add anhydrous KOH to... (CAS No.: 22843-73-8) and The reaction was carried out in a DMF mixture, cooled to room temperature, filtered, washed with acetone, extracted by Soxhlet extraction, and dried to obtain a porous organic polymer.

[0053] The reaction temperature was 180℃, and the reaction time was 24 hours. The molar mass ratio of KOH is 1:1:12.

[0054] S2. Under an inert atmosphere, the porous organic polymer was added to THF containing AgBF4. The mixture was then reacted at 80°C in the dark for 24 hours. After cooling to room temperature, it was filtered, washed with THF and DMF, extracted by Soxhlet extraction, and dried to obtain Ag / Azo-TAPM.

[0055] Example 2

[0056] This embodiment provides a porous organic polymer silver-based nanocatalyst, wherein when M is selected from... N is selected from The porous organic polymer silver-based nanocatalyst is designated Ag / TPP-CTF, and its structural formula is as follows:

[0057]

[0058] It is prepared by a method including the following steps:

[0059] S1. Under an inert atmosphere, anhydrous AlCl3 was added to... (CAS No.: 917-23-7) The reaction was carried out in a mixture of cyanuric chloride and dichloromethane, cooled to room temperature, filtered, washed with acetone, extracted by Soxhlet extraction and dried to obtain a porous organic polymer.

[0060] The reaction temperature was 60℃, and the reaction time was 24 hours. The molar ratio of cyanuric chloride to anhydrous AlCl3 is 3:4:10;

[0061] S2. Under an inert atmosphere, the porous organic polymer was added to THF containing AgBF4. The mixture was then reacted at 80°C in the dark for 24 hours. After cooling to room temperature, it was filtered, washed with THF and DMF, extracted by Soxhlet extraction, and dried to obtain Ag / TPP-CTF.

[0062] Example 3

[0063] This embodiment provides a porous organic polymer silver-based nanocatalyst, wherein when M is selected from... N is selected from The porous organic polymer silver-based nanocatalyst is designated Ag / POP-Scholl, and its structural formula is as follows:

[0064]

[0065] It is prepared by a method including the following steps:

[0066] S1. Under an inert atmosphere, anhydrous AlCl3 was added to... The reaction was carried out in a CHCl3 mixture, cooled to room temperature, filtered, washed with acetone, extracted by Soxhlet extraction, and dried to obtain a porous organic polymer.

[0067] The reaction temperature was 180℃, and the reaction time was 24 hours. The molar mass ratio of anhydrous AlCl3 is 1:1:15;

[0068] S2. Under an inert atmosphere, the porous organic polymer was added to THF containing AgBF4. The mixture was then reacted at 80°C in the dark for 24 hours. After cooling to room temperature, it was filtered, washed with THF and DMF, extracted by Soxhlet extraction, and dried to obtain Ag / POP-Scholl.

[0069] Example 4

[0070] This embodiment provides a porous organic polymer silver-based nanocatalyst, wherein when M is selected from... N is selected from The porous organic polymer silver-based nanocatalyst is designated Ag / Azo-TAPM and has the following structural formula:

[0071]

[0072] It is prepared by a method including the following steps:

[0073] S1. Under an inert atmosphere, add anhydrous KOH to... The reaction was carried out in a DMF mixture (CAS No.: 60532-63-0), cooled to room temperature, filtered, washed with acetone, extracted by Soxhlet extraction and dried to obtain a porous organic polymer.

[0074] The reaction temperature was 180℃, and the reaction time was 24 hours. The molar mass ratio of KOH is 1:1:12;

[0075] S2. Under an inert atmosphere, the porous organic polymer was added to THF containing AgBF4. The mixture was then reacted at 80°C in the dark for 24 hours. After cooling to room temperature, it was filtered, washed with THF and DMF, extracted by Soxhlet extraction, and dried to obtain Ag / Azo-TAPM.

[0076] Example 5

[0077] Weigh out 20 mg of catalyst Ag / TPP-CTF and 84 mg of propargyl alcohol substrate. 1 mmol of DBU (152 mg) and 2 ml of acetonitrile were added to a 10 ml atmospheric pressure reaction tube. The tube was sealed, and carbon dioxide was introduced at 0.1 MPa at room temperature, with the stirring speed controlled at 200 rpm. After 8 hours of reaction, carbon dioxide was slowly released, and the concentration was calculated using gas chromatography. The yield was 67.1%.

[0078] Example 6

[0079] The specific experimental procedure and detection method are the same as in Example 5, except that the catalyst is changed to Ag / Azo-TAPM. 20 mg of the Ag / Azo-TAPM catalyst was weighed. The concentration was calculated using gas chromatography. The yield was 91.4%.

[0080] Example 7

[0081] The specific experimental procedure and detection method are the same as in Example 6, except that the catalyst dosage is changed to 10 mg. 10 mg of the catalyst Ag / Azo-TAPM is weighed. The concentration is calculated using gas chromatography. The yield was 84.2%.

[0082] Example 8

[0083] The specific experimental procedure and detection method are the same as in Example 6, except that the catalyst dosage is changed to 30 mg. 30 mg of the catalyst Ag / Azo-TAPM is weighed. The concentration is calculated using gas chromatography. The yield was 93.9%.

[0084] Example 9

[0085] The specific experimental procedure and detection method are the same as in Example 6, except that the solvent acetonitrile is replaced with DMF. 2 ml of DMF is measured. The concentration is calculated using gas chromatography. The yield was 29.8%.

[0086] Example 10

[0087] The specific experimental procedure and detection method are the same as in Example 6, except that the amount of acetonitrile solvent is changed to 3 ml. Measure 3 ml of acetonitrile. Calculate the concentration using gas chromatography. The yield was 81.4%.

[0088] Example 11

[0089] The specific experimental procedure and detection method are the same as in Example 6, except that the organic base DBU is replaced with NEt3. 101 mg (1 mmol) of NEt3 is weighed. The concentration is calculated using gas chromatography. The yield was 57.2%.

[0090] Example 12

[0091] The specific experimental procedure and detection method are the same as in Example 6, except that the organic base DBU is replaced with Cs2(CO3). 326 mg (1 mmol) of Cs2(CO3) was weighed. The concentration was calculated using gas chromatography. The yield was 2.7%.

[0092] Example 13

[0093] The specific experimental procedure and detection method are the same as in Example 6, except that the amount of organic base DBU is changed to 0.5 mmol. 76 mg (0.5 mmol) of DBU is weighed. The concentration is calculated using gas chromatography. The yield was 57.9%.

[0094] Example 14

[0095] The specific experimental procedure and detection method are the same as in Example 6, except that the amount of organic base DBU is changed to 1.5 mmol. 228 mg (1.5 mmol) of DBU is weighed. The concentration is calculated using gas chromatography. The yield was 98.6%.

[0096] Example 15

[0097] The specific experimental procedure and detection method are the same as in Example 6, except that the reaction time is changed to 10 hours. The results are calculated using gas chromatography. The yield was 99.4%.

[0098] Example 16

[0099] The specific experimental procedure and detection method are the same as in Example 6, except that the reaction time is changed to 6 hours. The results are calculated using gas chromatography. The yield was 72.1%.

[0100] Example 17

[0101] The specific experimental procedure and detection method are the same as in Example 6, except that the reaction time is changed to 4 hours. The results are calculated using gas chromatography. The yield was 36.8%.

[0102] Example 18

[0103] The specific experimental procedure and detection method are the same as in Example 5, except that the reaction temperature is changed to 40℃. The results were calculated using gas chromatography. The yield was 84.1%.

[0104] Example 19

[0105] Weigh out 20 mg of catalyst Ag / TPP-CTF and 84 mg of... 1 mmol of DBU (152 mg) and 2 ml of acetonitrile were added to a 10 ml high-pressure reactor. After sealing, carbon dioxide was introduced at 1.0 MPa at room temperature, with the stirring speed controlled at 200 rpm. After reacting for 1 hour, carbon dioxide was slowly released, and the concentration was calculated using gas chromatography. The yield was 78.7%.

[0106] Example 20

[0107] The specific experimental procedure and detection method are the same as in Example 6, except that the propargyl alcohol substrate is replaced with... Weigh out 98 mg of propargyl alcohol substrate. (1 mmol), reaction time 9 h, and the final product calculated by gas chromatography after the reaction. The yield was 94.6%.

[0108] Example 21

[0109] The specific experimental procedure and detection method are the same as in Example 6, except that the propargyl alcohol substrate is replaced with... Weigh 126 mg of propargyl alcohol substrate. (1 mmol), reaction time 12 h, after which the concentration was calculated by gas chromatography. The yield was 94.1%.

[0110] Example 22

[0111] The specific experimental procedure and detection method are the same as in Example 6, except that the propargyl alcohol substrate is replaced with... Weigh 124 mg of propargyl alcohol substrate. (1 mmol), reaction time 14 h, after which the concentration was calculated by gas chromatography. The yield was 88.2%.

[0112] Example 23

[0113] The specific experimental procedure and detection method are the same as in Example 6, except that the propargyl alcohol substrate is replaced with... Weigh 146 mg of propargyl alcohol substrate. (1 mmol), reaction time 12 h, after which the concentration was calculated by gas chromatography. The yield was 85.6%.

[0114] Example 24

[0115] To investigate the stability and recyclability of porous organic polymer silver-based nanocatalysts, Ag / Azo-TAPM was used as an example. The catalyst after the reaction in Example 6 was recovered by filtration, washing and vacuum drying and then used in the next cycle.

[0116] Example 6: Recovered catalyst Ag / Azo-TAPM, 84 mg propargyl alcohol substrate 1 mmol of DBU (152 mg) and 2 ml of acetonitrile were added to a 10 ml atmospheric pressure reaction tube. The tube was sealed, and carbon dioxide was introduced at 0.1 MPa at room temperature, with the stirring speed controlled at 200 rpm. After 8 hours of reaction, carbon dioxide was slowly released, and the concentration was calculated using gas chromatography. The yield was 91.3%.

[0117] Subsequently, the above operation was repeated three times, and the values ​​were calculated by gas chromatography. The yields were 90.9%, 91.2%, and 90.7%.

[0118] Figure 1 This is a specific surface area diagram of the porous organic polymer silver-based nanocatalyst in Example 2. Figure 2 The figure shows the specific surface area of ​​the porous organic polymer silver-based nanocatalyst in Example 4. As the pressure increases, the adsorption amount gradually increases, and a hysteresis loop appears. This type of isothermal adsorption curve is a typical Type I curve. It can be clearly seen that the specific surface area of ​​the porous organic polymer silver-based nanocatalyst obtained in Example 2 is 420 m². 2 ·g -1 The porous organic polymer silver-based nanocatalyst obtained in Example 4 has a specific surface area of ​​556 m². 2 ·g -1 This confirms that the porous organic polymer silver-based nanocatalyst described in this invention has a large specific surface area.

[0119] The pore size of the porous organic polymer silver-based nanocatalysts from Examples 2 and 4 was measured to investigate the pore structure of the catalysts. The results are as follows: Figure 3-4 As shown in the diagram, the pore size test results indicate that the pore size of this material is mainly distributed in the micropore (below 2nm) region, classifying it as a microporous material.

[0120] The porous organic polymer silver-based nanocatalyst of Example 2 was subjected to X-ray photoelectron diffraction to verify the formation of silver nanoparticles in the catalyst. The results are as follows: Figure 5 As shown, the X-ray photoelectron diffraction energy dispersive spectroscopy (EDS) pattern of Ag3d shows two additional peaks at 373.5 and 367.5 eV, which belong to Ag3d... 3 / 2 and Ag3d 5 / 2 The spin state of the active silver site is consistent with the reported signal of silver, indicating that the active silver site has been successfully incorporated into the catalyst.

[0121] The porous organic polymer silver-based nanocatalyst of Example 4 was subjected to high-resolution TEM (HR-TEM) to study the particle size and distribution of silver nanoparticles on the porous organic polymer. The results are as follows: Figure 6 As shown in the image, HR-TEM images clearly show a uniform distribution of silver nanoparticles on the surface of the porous organic polymer, without aggregation. Particle size analysis revealed that the size ranged from 1 to 9 nm, with an average size of 4.72 nm. Figure 7 As shown.

[0122] Figure 8-9 Unsaturated cyclic carbonate products of 1 HNMR image.

[0123] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for synthesizing an α-alkylmethylene cyclic carbonate, characterized in that, A porous organic polymer silver-based nanocatalyst was used to catalyze the carboxylation and cyclization reaction of carbon dioxide, an alkaline substance, and propargyl alcohol compounds to obtain α-alkylmethylene cyclic carbonates; the alkaline substance was 1,8-diazabicyclo[5.4.0]undec-7-ene and / or triethylamine; The porous organic polymer silver-based nanocatalyst is selected from at least one of the following compounds I-IV; 2. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 1, characterized in that, Includes the following steps: A porous organic polymer silver-based nanocatalyst, propargyl alcohol compounds, alkaline substances, and solvents are mixed and placed in a reaction vessel. Carbon dioxide gas is introduced to carry out a carboxylation and cyclization reaction. The filtrate is collected by centrifugation to obtain the α-alkylmethylene cyclic carbonate.

3. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 2, characterized in that, The propargyl alcohol compounds are selected from... Any one of them.

4. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 2, characterized in that, The solvent includes at least one of acetonitrile and N,N-dimethylformamide.

5. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 2, characterized in that, The reaction temperature for the carboxylation and cyclization is 20-40℃.

6. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 2, characterized in that, The reaction pressure for the carboxylation and cyclization is 0.1-1.0 MPa.

7. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 2, characterized in that, The molar ratio of propargyl alcohol to the alkaline substance is 2:(1-3).

8. The method for synthesizing α-alkylmethylene cyclic carbonate according to claim 2, characterized in that, Based on the amount of 1 mmol of propargyl alcohol compound, the amount of the porous organic polymer silver-based nanocatalyst is 10-30 mg.

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