A process for the preparation of a bifunctional polymeric heterogeneous catalytic material and its use

Abstract

This invention provides a method for preparing bifunctional polymer heterogeneous catalytic materials and their application in catalyzing the cycloaddition reaction of carbon dioxide. First, two vinyl-modified imidazole salt ionic liquids (v-IL and v-BIL) were prepared, and then successfully modified with a porous organic polymer based on metalloporphyrin (POP-TPPMg) via in-situ free radical polymerization. By adjusting the ionic liquid loading, a bifunctional heterogeneous catalyst possessing both Lewis basic and Lewis acidic sites was prepared. Further catalytic tests showed that, under mild, solvent-free, and co-catalyst-free conditions, these catalysts exhibited good catalytic activity in the cycloaddition reaction of CO2 and epoxides. Furthermore, the epoxides were formed into cyclic carbonates, providing a new direction for developing novel and highly efficient CO2 conversion catalysts.

Description

Technical Field

[0001] This invention belongs to the field of catalytic material preparation and application technology, and relates to a method for preparing bifunctional polymer heterogeneous catalytic materials and their application in catalyzing carbon dioxide cycloaddition reactions. Background Technology

[0002] The increase in carbon dioxide concentration has caused many serious global problems. The increasing accumulation of carbon dioxide in the atmosphere is a pressing issue that needs to be addressed, and its capture and conversion have attracted widespread attention. Furthermore, carbon dioxide is an abundant, non-toxic, economical, and renewable C1 resource that can be used to produce useful organic compounds. Therefore, effectively converting carbon dioxide into value-added products and realizing the carbon cycle has significant industrial production and academic research value.

[0003] The preparation of cyclic carbonates via the cycloaddition reaction of epoxides with CO2 is a promising environmentally friendly and atom-economical method, characterized by high yield, no byproducts, and no solvent requirement. Cyclic carbonates formed by the cycloaddition reaction of CO2 and epoxides are widely used in fine chemicals and pharmaceuticals due to their high yield and are considered one of the most important target substances. Currently, a large number of catalytic systems for this conversion have been researched and developed, such as ionic liquids, salon complexes, metal-organic frameworks, covalent organic frameworks, porous organic polymers, and metal oxides. Among them, ionic liquids (ILs) are considered highly efficient catalysts due to their negligible vapor pressure, good thermal stability, tunable structure, and non-flammability. As an advanced porous material, porous organic frameworks (POFs) possess characteristics such as large specific surface area, modular design, tunable pore size, and diverse functions, showing great application potential in various fields.

[0004] In this context, heterogeneous catalysis has attracted widespread attention due to its ease of separation. As a typical linear nonpolar molecule, CO2, due to its inherent thermodynamic barriers and kinetic inertia, requires harsh reaction conditions, co-catalysts, and complex synthetic procedures in some heterogeneous systems. Designing highly efficient catalysts, especially environmentally friendly heterogeneous catalysts, is both urgent and extremely challenging. Heterogeneous bifunctional catalysts composed of metal complexes and ionic liquids are considered effective catalysts under mild conditions, and the combination of ionic liquids with metal-supported polymer backbones is a common approach for CO2 cycloaddition catalysts. Considering the excellent performance of metalloporphyrins and ionic liquids in CO2 capture and conversion, J. Chen's group has reported the synergistic effect of porphyrin-based porous polymers (P-POF-Zn) and thermoresponsive ionic liquids (TR-IL) in CO2 cycloaddition reactions. YJ Chen's group developed bifunctional organic polymers containing ionic liquids and metalloporphyrins via Yamamoto-Ullmann coupling reactions, which have been successfully used as synergistic catalysts for the synthesis of cyclic carbonates.

[0005] In this invention, we rationally designed and synthesized a hierarchical porous organic polymer (POP-TPP) polymerized from a vinyl-modified tetraphenylporphyrin monomer (tetraphenylporphyrin). Following metal coordination, the ionic liquid undergoes in-situ polymerization, with magnesium(II)-based porphyrin as the Lewis acidic center and bromide ions as the nucleophile, forming a novel ionic liquid with a metalloporphyrin framework. The ionic liquid can be integrated into the POP structure, enhancing CO2 adsorption and selectivity through strong electrostatic and van der Waals interactions. By controlling and adjusting the relative ratio of magnesium(II)-based porphyrin and imidazoline bromide monomer, the synergistic behavior of the two different types of active sites can be optimized. In this case, the active moieties on the linear ionic polymer enriched in the pores promote their cooperation with the active sites anchored on the pore walls of the host material, providing excellent performance. This bifunctional catalyst has a very high density of metalloporphyrin and imidazole ionic liquid active sites that are strictly separated from the product. Its catalytic performance in the cycloaddition reaction of epoxides with CO2 under solvent-free conditions was studied in detail, showing activity comparable to that of homogeneous catalysts. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing bifunctional polymer heterogeneous catalytic materials.

[0007] Another object of the present invention is to provide the application of bifunctional polymer heterogeneous catalytic materials in the catalytic cycloaddition reaction of carbon dioxide with epoxides.

[0008] I. Preparation methods of bifunctional polymer heterogeneous catalytic materials

[0009] 1-Vinylimidazolium and either bromoethane or 1,2-dibromoethane are added to methanol and reacted at 65–75 °C for 45–50 hours under a nitrogen atmosphere. After the reaction is complete, the solvent is removed by rotary evaporation. The resulting liquid is dispersed in methanol and added dropwise to vigorously stirred diethyl ether. After washing with diethyl ether, the product is obtained and dried under vacuum to obtain a monovinylimidazolium salt ionic liquid v-IL or a divinylimidazolium salt ionic liquid v-BIL. The molar ratio of 1-vinylimidazolium to 1,2-dibromoethane is 2:1–3:1; the molar ratio of 1-vinylimidazolium to bromoethane is 1:1–1:2.

[0010] (2) Synthesis of vinyl-modified porphyrin monomers:

[0011] Pyrrole and 4-vinylbenzaldehyde were added to propionic acid and reacted in air at 135-145°C for 1-2 hours. The solution was then cooled to room temperature, filtered, washed with methanol and ethyl acetate, and dried to obtain purple crystalline vinyl-modified porphyrin monomer v-TTP. The molar ratio of pyrrole to 4-vinylbenzaldehyde was 1:5 to 1:6.

[0012] (3) Synthesis of magnesium-coordinated vinyl-modified porphyrin monomers:

[0013] v-TPP was added to CH2Cl2, followed by triethylamine and MgBr2·Et2O. After stirring at room temperature for 10–20 minutes, the mixture was washed with water to remove the solvent and dried to obtain the magnesium-coordinated vinyl-modified porphyrin monomer v-TPPMg. The molar ratio of v-TPP to MgBr2·Et2O was 1:18–1:20.

[0014] (4) Synthesis of porous organic tetraphenylporphyrin magnesium polymer:

[0015] v-TPPMg was dissolved in DMF, and azobisisobutyronitrile (AIBN) was added simultaneously. The mixture was then reacted at 95–105 °C for 20–25 hours. After washing the polymer with DMF and Soxhlet extraction with CH2Cl2, a porous organic tetraphenylporphyrin magnesium polymer, POP-TPPMg, was obtained. The mass ratio of v-TPPMg to azobisisobutyronitrile was 10:1.

[0016] (5) Synthesis of bifunctional heterogeneous catalytic materials:

[0017] After completely dispersing POP-TPPMg in methanol and stirring, a monovinylimidazolium salt ionic liquid (v-IL) or a divinylimidazolium salt ionic liquid (v-BIL) and azobisisobutyronitrile (AIBN) were added. The mixture was stirred at room temperature for 20-25 hours, then stirring was stopped, and the reaction system was heated to 95-105°C for 20-25 hours. After filtration, washing, and drying, the bifunctional multiphase catalyst POP-TPPMg-IL or POP-TPPMg-BIL was obtained. The mass ratio of monovinylimidazolium salt ionic liquid (v-IL) or divinylimidazolium salt ionic liquid (v-BIL) to POP-TPPMg was 5:1 to 5:2; the mass ratio of POP-TPPMg to AIBN was 4:1. The synthetic route of POP-TPPMg-BIL is as follows: Figure 12 .

[0018] A magnesium porphyrin-based porous organic polymer, POP-TPPMg, was synthesized via free radical polymerization. A vinylimidazolium salt ionic liquid was then introduced into the pores of POP-TPPMg. Subsequently, the vinylimidazolium salt ionic liquid was polymerized within the pores of POP-TPPMg via in-situ free radical polymerization and anchored therein. This achieved the synthesis of a composite of imidazolium salt ionic liquid and magnesium porphyrin, resulting in corresponding bifunctional heterogeneous catalysts. Using monovinylimidazolium salt ionic liquid (v-IL) and divinylimidazolium salt ionic liquid (v-BIL) as imidazolium salt ionic liquid sources, a series of bifunctional heterogeneous catalysts, POP-TPPMg-IL-x and POP-TPPMg-BIL-x, were synthesized, where x represents the molar ratio of the ionic liquid to the magnesium porphyrin. Furthermore, a POP-TPPZn-IL-x catalyst was synthesized for comparison (by replacing the starting material MgBr2·Et2O with Zn(OAc)2·2H2O during synthesis). These materials are insoluble in any common solvents.

[0019] II. Structural Characterization of Bifunctional Polymer Heterogeneous Catalytic Materials

[0020] Recorded on a Bruker Avance-400 (400MHz) spectrometer 1¹H NMR spectroscopy. Chemical shifts of TMS at δ = 0 ppm are expressed as lower field in ppm. Solid-state cross-polarized magic-angle spin ¹³C (MAS) NMR spectra were recorded on a Varian Infnityplus 400 spectrometer equipped with a magic-angle spin probe in a 4-mm ZrO₂ rotor. Nitrogen adsorption isotherms collected at -196°C were measured using a Micromeritics ASAP 2020M system, with samples pretreated under vacuum at 100°C for 12 hours prior to measurement. Surface area was calculated using the Brunauer-Emmett-Teller (BET) method. Thermogravimetric analysis (TGA) experiments were performed on an SDT Q600 V8.2 Build 100 thermogravimetric analyzer under a N₂ atmosphere. CO₂ adsorption-desorption isotherms were collected at 298 K and 273 K, at 1 atm CO₂ pressure using a Micromeritics ASAP 2010. Samples were pretreated under vacuum at 373 K for 12 hours prior to measurement. X-ray photoelectron spectroscopy (XPS) was performed on a Thermo ESCALAB 250 with Al Kα irradiation at θ = 90°. The binding energy was calibrated using the C 1s peak at 284.8 eV for the X-ray source. Elemental analysis was performed on a Vario microcube organic elemental analyzer (Elementar, Germany). Scanning electron microscopy (SEM) images of the samples were recorded on a Hitachi SU 1510 instrument. Transmission electron microscopy (TEM) experiments were performed on a JEM-2100F field emission electron microscope (JEOL, Japan) with an accelerating voltage of 110 kV.

[0021] POP-TPPMg-BIL-1.57 solid state 13 C NMR spectra as follows Figure 1 As shown. POP-TPPMg-BIL-1.57 13 The CNMR spectrum clearly shows four resonances in the 122–150 ppm range, which can likely be attributed to the carbons of the phenyl and pyrrole rings of the porphyrin macrocycle, as well as the carbons on the imidazole ring of the BIL. More importantly, the NMR spectroscopy reveals novel signals at 49 and 55 ppm corresponding to the methylene (−CH2−) and methyl (−CH3) groups of the BIL moiety, respectively. These results confirm the reliable ordered integration of the vinylimidazolium salt ionic liquid into the pores of POP-TPPMg. Furthermore, the peaks at 28 and 42 ppm can be attributed to the polymerized vinyl groups, indicating successful polymerization.

[0022] The presence of Mg1s, N1s, and Br3d signals in the XPS spectrum confirms the structure of POP-TPPMg-BIL-1.57, indicating the successful incorporation of the polyionic liquid into the polymer. The N1s spectrum of POP-TPPMg-BIL-1.57... Figure 2 B shows characteristic peaks with binding energies of 399.9 eV and 402.5 eV, respectively. The pyrrole nitrogen binding energy of the porphyrin ring is 399.9 eV. The peak at 402.5 eV can be attributed to the N-cation on the imidazole ring. + The peak at 1303.5 eV in the high-resolution spectrum indicates... Figure 2 Mg 1s exists in C. The binding energies of the Br 3d level in all samples are 67.8 eV (3d... 5 / 2 ) and 68.9eV (3d 3 / 2 Table 1 shows the elemental analysis results for POP-TPPMg-BIL-0.37, POP-TPPMg-BIL-1.57, POP-TPPMg-BIL-3.66, and POP-TPPMg-BIL-8.60. Furthermore, the metal content in the heterogeneous catalyst was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) as shown in Table 1. The results indicate that the Mg content in POP-TPPMg-BIL-1.57 is 2.09 wt%.

[0023]

[0024] like Figure 3 As shown in Figure A, the N2 adsorption-desorption isotherm collected at 77 K and the pore size distribution of POP-TPPMg-BIL-1.57 are compared with... Figure 4 Compared to POP-TPPMg-BIL-3.66, the results show that the POP-TPPMg-BIL-3.66 catalyst has a lower nitrogen adsorption capacity, and BJH calculations also indicate that its BET specific surface area is very small. This is mainly because the ionic liquid loading blocks the hierarchical porous structure of the original polymer. The pore size of POP-TPPMg is approximately 4 nm, indicating that the hierarchical porous structure of POP-TPPMg is blocked. Correspondingly, the POP-TPPMg-BIL-1.57 catalyst has a higher nitrogen adsorption capacity, and its N2 adsorption-desorption curves exhibit typical Type I and Type IV curves. The sharp increase in the isotherm when the relative pressure (P / P0) is below 0.2 is due to the filling of micropores, while the slow increase in the isotherm when the relative pressure (P / P0) is above 0.30 is due to the contribution of mesopores. This is consistent with the results of its pore size distribution. Figure 3 As shown in B, the pore size is mainly distributed in the range of 1.86 nm, showing a hierarchical pore structure. Figure 3C and 3D images show SEM and TEM images of POP-TPPMg-IL-1.57, revealing that the bifunctional heterogeneous catalyst is formed by the accumulation of amorphous particles with irregular surface morphology. Figure 5 The SEM images of other catalysts show abundant pore structures. These pore structures are primarily formed by particle packing. The calculated BET surface area of ​​POP-TPPMg-BIL-1.57 is 534 m². 2 g-1, total pore volume is 0.96 cm³. 3 The N2 adsorption isotherms and pore size distributions of POP-TPPMg-BIL-3.66 and POP-TPPMg-IL-2.90 are shown below. Figure 4 and 6 As shown. Figure 7 The DSC-TGA curve of the catalyst is shown. The decomposition temperature of the catalyst is about 300℃, indicating the stability of the catalyst.

[0025] The CO2 adsorption-desorption isotherms of POP-TPPMg-BIL-1.57 at different temperatures were collected at 1 atm CO2, as shown below. Figure 8 As shown, POP-TPPMg-BIL-1.57 exhibits a CO2 adsorption capacity of 1.78 mmol / g at 273 K, decreasing to 1.06 mmol / g at 298 K. POP-TPPMg-BIL-3.66 shows CO2 adsorption capacities of 1.13 mmol / g and 0.73 mmol / g at 273 K and 298 K, respectively. Figure 9 As shown. Correspondingly, at low coverage levels of POP-TPPMg-BIL-1.57 and POP-TPPMg-BIL-3.66, their isothermal heats of adsorption (Qst) calculated from the isotherms using the Virial method are approximately 28.8 and 32.0 kJ / mol, respectively. Figure 8 B, Figure 9 B).

[0026] III. Catalytic Performance Evaluation of Bifunctional Polymer Heterogeneous Catalytic Materials

[0027] The reaction was carried out in a 25 mL Schlenk tube containing 15.0 mmol of epoxide, purged with CO2 after three vacuum injections, and the catalyst was purged in a Schlenk tube equipped with a CO2 balloon at 50 °C for 48 hours. For substrate conversion, the reaction was carried out in a 25 mL Schlenk tube containing 10.0 mmol of epoxide, with the gas in the system replaced by CO2 after three vacuum injections, and the catalyst was purged in a Schlenk tube equipped with a CO2 balloon at the corresponding temperature for 48 hours.

[0028] The conversion of epoxides also occurs through the reaction mixture. 1 The catalyst was analyzed by 1H NMR spectroscopy (Bruker Avance-400 spectrometer, 400 MHz). For the recycling test, the catalyst was separated by centrifugation, washed three times with CH2Cl2, and dried under vacuum. The catalyst was then used for the next run.

[0029] Table 2 shows the catalytic data for the cycloaddition of 1,2-epoxybutane with CO2 to form cyclic carbonates on various catalysts, demonstrating the activity of different bifunctional catalysts using 1,2-epoxybutane as the substrate in the absence of a soluble co-catalyst. For the POP-TPPMg-IL-2.90 and POP-TPPZn-IL-2.95 catalysts, when the catalyst dosage is 0.167 mol% of the substrate 1,2-epoxybutane and the reaction temperature is 30 °C, the conversions are 27% and 24%, respectively, with a selectivity of 99%. When the reaction temperature is increased to 50 °C, the conversions are 52% and 54%, respectively, with a selectivity of 99%. Increasing the catalyst dosage to 0.5 mol% can improve the conversions of POP-TPPMg-IL-2.90 and POP-TPPZn-IL-2.95 to 99% and 84%, respectively, with a selectivity of 99%. For the POP-TPPMg-BIL-x catalyst, the conversion rate of POP-TPPMg-BIL-0.37 was 21%, while that of POP-TPPMg-BIL-1.57 was 60%, with a selectivity of 99%. The results showed that the catalytic activity of POP-TPPMg-BIL-3.66 was similar to that of POP-TPPMg-BIL-1.57, with a conversion rate of 54% and a selectivity of 99%. Furthermore, the catalytic activity decreased with increasing v-BIL content; under the same conditions, the catalytic activity of POP-TPPMg-BIL-8.60 was only 37%. We selected POP-TPPMg-BIL-1.57 as a representative catalyst. When the catalyst dosage increased to 0.333 mol%, the conversion rate reached 93%, and the selectivity was 99%.

[0030]

[0031] a Reaction conditions: 1.0815 g, 15 mmol of 1,2-epoxybutane, catalyst dosage of 0.167 mol% (0.025 mmol) of substrate, reaction time of 48 h, 1 atm CO2; b The catalyst was used at 0.5 mol% (0.075 mmol) of the substrate. c The catalyst was used at a concentration of 0.333 mol% (0.05 mmol) of the substrate.d 18.6 mg POP-TPPMg and 14.8 mg PIL-BIL. e Conversion rate and selectivity are determined by 1 H NMR monitoring.

[0032] To determine the substrate adaptability of the heterogeneous catalyst, we investigated the CO2 cycloaddition performance of POP-TPPMg-1.57 under optimized conditions for five different substrate epoxides. As shown in Table 3, it can be seen that POP-TPPMg-BIL-1.57 can convert all these substrates in moderate to good yields at slightly higher temperatures.

[0033]

[0034] a Reaction conditions: substrate (10 mmol), POP-TPPMg-1.57 catalyst (44.4 mg, 0.333 mol%), 1 atm CO2.

[0035] b1 H NMR monitoring.

[0036] The recovery performance of the POP-TPPMg-BIL-1.57 catalyst was studied. For example... Figure 10 As shown, the POP-TPPMg-BIL-1.57 catalyst maintained its activity essentially after six cycles, with the conversion rate consistently remaining at 99%, although the catalytic activity decreased slightly. Furthermore, XPS analysis of the reused samples showed that the signals of Mg1s, N1s, and Br3d were almost identical to those of the fresh samples. These results confirm the stability of POP-TPPMg-BIL-1.57 during the catalytic process. TEM images ( Figure 11 It is also used to explore chemical structures and has been found that the pores of catalysts are partially blocked, which is the main reason for the reduction in catalyst activity.

[0037] In summary, this invention successfully introduced imidazolium bromide ionic liquid into the porous organic polymer POP-TPPMg via in-situ free radical polymerization, constructing a bifunctional heterogeneous catalyst with Lewis acidic and basic sites. The synthesized catalyst exhibits excellent activity and selectivity for the cycloaddition reaction of CO2 and epoxides without any soluble co-catalyst. During the reaction, the microporous structure of the catalyst effectively adsorbs CO2, achieving CO2 enrichment and conversion. Further cycling experiments demonstrate that this bifunctional heterogeneous catalyst is easy to separate and recover, exhibiting good recovery performance and stability. Attached Figure Description

[0038] Figure 1For POP-TPPMg-BIL-1.57 13 C60 solid carbon spectrum;

[0039] Figure 2 The full XPS spectrum of AD for POP-TPPMg-BIL-1.57 includes Mg 1s, N 1s, and Br 3d spectra.

[0040] Figure 3 The images show (A) N2 adsorption isotherm, (B) pore size distribution curve, (C) SEM image, and (D) TEM image of POP-TPPMg-BIL-1.57.

[0041] Figure 4 (A) N2 adsorption isotherm and (B) pore size distribution curve for POP-TPPMg-BIL-3.66.

[0042] Figure 5 SEM images of (A) POP-TPPMg-IL-2.60, (B) POP-TPPMg-BIL-0.37, (C) POP-TPPMg-BIL-3.66, and (D) POP-TPPMg-BIL-8.60;

[0043] Figure 6 (A) N2 adsorption isotherm and (B) pore size distribution curve for POP-TPPMg-BIL-3.66.

[0044] Figure 7 Thermogravimetric curves for POP-TPPZn-IL-2.95, POP-TPPMg-IL-2.90, and POP-TPPMg-BIL-x;

[0045] Figure 8 (A) CO2 adsorption isotherm of POP-TPPMg-BIL-1.57; (B) Equivalent heat of adsorption;

[0046] Figure 9 (A) CO2 adsorption isotherm of POP-TPPMg-BIL-3.66; (B) Equivalent heat of adsorption;

[0047] Figure 10 The conversion and selectivity of the cycloaddition reaction of 1,2-epoxybutane with CO2 in POP-TPPMg-BIL-1.57 were determined by cyclic testing.

[0048] Figure 11 TEM image of POP-TPPMg-BIL-1.57 after five cycles;

[0049] Figure 12The synthetic route for POP-TPPMg-BIL is as follows. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] Experimental materials:

[0052] Pyrrole and 4-bromostyrene were obtained from Aladdin and Meryer Chemical Technology (Shanghai), respectively, and were distilled before use. Tetrahydrofuran (THF) was distilled on LiAlH4, and N,N-dimethylformamide (DMF), dichloromethane, and triethylamine were distilled on CaH2. Other commercially available reagents, including azobisisobutyronitrile (AIBN), MgBr2·Et2O, 1,2-epoxybutane, 1,3-epoxyhexane, styrene oxide, allyl glycidyl ether, butyl glycidyl ether, phenyl ether, 1-vinylimidazolium, 1,2-dibromoethane, and methanol, were purchased in high purity and used without further purification.

[0053] Example 1: Synthesis of POP-TPPMg-BIL-1.57

[0054] (1) Synthesis of 3,3'-(ethane-1,2-diyl)bis(1-vinyl-1H-imidazol-3-onium) bromide (v-BIL):

[0055] v-BIL was synthesized under N2 protection. 5 mL of methanol, 1-vinylimidazole (2 g, 21.3 mmol), and 1,2-dibromoethane (1.6 g, 8.5 mmol) were added to a 25 mL Schlenk tube under N2 atmosphere at 70 °C and reacted for 48 hours. After the reaction was complete, the solvent was removed by rotary evaporation. The resulting liquid was dispersed with a small amount of methanol and added dropwise to 400 mL of vigorously stirred diethyl ether. After washing with diethyl ether, the product was obtained and dried under vacuum overnight to give v-BIL (3.01 g, yield 74.9%).

[0056] The synthetic route is as follows:

[0057]

[0058] (2) Synthesis of 4-vinylbenzaldehyde:

[0059] 4-Bromostyrene (18 g, 98.4 mmol) was added dropwise to a THF solution containing activated magnesium at 0°C and N2, followed by the addition of 9.12 mL of DMF. The mixture was stirred overnight at room temperature and quenched with 50 mL of saturated NH4Cl solution. Extraction was performed with ethyl acetate, followed by washing with brine, drying over anhydrous MgSO4, filtration, and purification by column chromatography (11.83 g, 91.3% yield).

[0060] (3) Synthesis of vinyl-modified porphyrin monomers (v-TTP):

[0061] The v-TTP monomer was synthesized in a typical one-pot reaction. Pyrrole (3.45 g, 10 mmol) and 4-vinylbenzaldehyde (6.80 g, 51.5 mmol) were added to a flask containing propionic acid (250 mL) and heated to 140 °C in air. After reacting for 1 hour, the solution was cooled to room temperature. After filtration and washing with methanol and ethyl acetate, and drying the compound, a purple crystalline porphyrin monomer (2.05 g, 22.1% yield) was obtained.

[0062] (4) Synthesis of magnesium-coordinated vinyl-modified porphyrin monomers (v-TPPMg):

[0063] v-TPP (1.0 g, 1.4 mmol) was added to a three-necked round-bottom flask containing 150 mL of CH2Cl2, followed by 22.6 mL of triethylamine and MgBr2·Et2O (7.16 g, 27.7 mmol). After stirring at room temperature for 15 minutes, the mixture was washed with water to remove the solvent and the product was dried (0.95 g, 92.0% yield).

[0064] (5) Synthesis of porous organic tetraphenylporphyrin magnesium polymer:

[0065] POP-TPPMg was prepared by solvothermal polymerization. v-TPPMg (1 g, 1.3 mmol) was dissolved in 10 ml DMF, and 100 mg AIBN was added simultaneously. The mixture was then placed in an autoclave at 100°C for 24 hours. After washing the polymer with DMF and Soxhlet extraction (CH2Cl2, 72 hours), the POP-TPPMg catalyst (0.96 g, 96.0% yield) was obtained.

[0066] (6) Synthesis of POP-TPPMg-BIL-1.57:

[0067] 0.2 g of POP-TPPMg was completely dispersed in 10 mL of methanol in a 50 mL Schlenk tube. After stirring for 10 minutes, v-BIL (0.5 g, 1.3 mmol) and 50 mg AIBN were added. The mixture was stirred at room temperature for 24 hours, and then stirring was stopped. The reaction system was heated to 100 °C for 24 hours. After filtration, washing, and drying, the corresponding bifunctional heterogeneous catalyst POP-TPPMg-BIL-1.57 was obtained. The catalytic performance is shown in Tables 2 and 3.

[0068] Example 2: Synthesis of POP-TPPMg-BIL-3.66

[0069] Steps (1)-(5) are the same as in Example 1;

[0070] 0.2 g of POP-TPPMg was completely dispersed in 10 mL of methanol in a 50 mL Schlenk tube. After stirring for 10 minutes, v-BIL (1 g, 2.66 mmol) and 50 mg of AIBN were added. The mixture was stirred at room temperature for 24 hours, and then stirring was stopped. The reaction system was heated to 100 °C for 24 hours. After filtration, washing, and drying, the corresponding bifunctional heterogeneous catalyst POP-TPPMg-BIL-3.66 was obtained.

[0071] Example 3 Synthesis of POP-TPPMg-IL-2.90

[0072] Synthesis of monovinylimidazolium salt ionic liquids (v-ILs):

[0073] 5 mL of methanol, 1-vinylimidazole (2 g, 21.3 mmol), and bromoethane (3.48 g, 31.9 mmol) were added to a 25 mL Schlenk tube at 70 °C under a nitrogen atmosphere for 48 hours. After the reaction was complete, the solvent was removed using a rotary evaporator, and the resulting liquid was dispersed with a small amount of methanol and added dropwise to 400 mL of vigorously stirred ether. The product was washed with diethyl ether and dried under vacuum overnight (3.82 g, 87.8% yield).

[0074] The synthetic route is as follows:

[0075]

[0076] The synthesis of POP-TPPMg is the same as in Example 1;

[0077] Synthesis of POP-TPPMg-IL-2.90: 0.2 g of POP-TPPMg was completely dispersed in 10 mL of methanol in a 50 mL Schlenk tube. After stirring for 10 minutes, v-IL (0.5 g, 2.5 mmol) and 50 mg AIBN were added. The mixture was stirred at room temperature for 24 hours, and then stirring was stopped. The reaction system was heated to 100 °C for 24 hours. After filtration, washing, and drying, the corresponding bifunctional heterogeneous catalyst POP-TPPMg-IL-2.90 was obtained. The catalytic performance is shown in Table 2.

Claims

1. A method for preparing bifunctional polymer heterogeneous catalytic materials, comprising the following steps: (1) Synthesis of vinyl-modified imidazole salt ionic liquids: 1-Vinylimidazolium and bromoethane or 1,2-dibromoethane were added to methanol and reacted at 65-75°C for 45-50 hours under N2 atmosphere. After the reaction was completed, the solvent was removed by rotary evaporation. The resulting liquid was dispersed in methanol and added dropwise to diethyl ether under vigorous stirring. After washing with diethyl ether, the product was obtained and dried under vacuum to obtain monovinylimidazolium salt ionic liquid v-IL or divinylimidazolium salt ionic liquid v-BIL. (2) Synthesis of vinyl-modified porphyrin monomers: Pyrrole and 4-vinylbenzaldehyde were added to propionic acid and heated in air to 135-145°C for 1-2 hours. The solution was then cooled to room temperature, filtered, washed with methanol and ethyl acetate, and dried to obtain a purple crystalline vinyl-modified porphyrin monomer v-TTP. (3) Synthesis of magnesium-coordinated vinyl-modified porphyrin monomers: v-TPP was added to CH2Cl2, followed by triethylamine and MgBr2·Et2O. After stirring at room temperature for 10-20 minutes, the mixture was washed with water to remove the solvent and dried to obtain the magnesium-coordinated vinyl-modified porphyrin monomer v-TPPMg. (4) Synthesis of porous organic tetraphenylporphyrin magnesium polymer: v-TPPMg was dissolved in DMF, and azobisisobutyronitrile was added. The mixture was then reacted at 95-105℃ for 20-25 hours. The polymer was washed with DMF and extracted with CH2Cl2 using a Soxhlet extracter to obtain the porous organic tetraphenylporphyrin magnesium polymer POP-TPPMg. (5) Synthesis of bifunctional heterogeneous catalytic materials: After completely dispersing POP-TPPMg in methanol and stirring, add monovinylimidazolium salt ionic liquid v-IL or divinylimidazolium salt ionic liquid v-BIL and azobisisobutyronitrile. Stir the mixture at room temperature for 20-25 hours, then stop stirring and heat the reaction system to 95-105℃ for 20-25 hours. After filtration, washing and drying, obtain bifunctional multiphase catalyst materials POP-TPPMg-IL or POP-TPPMg-BIL.

2. The process for the preparation of a bifunctional polymeric heterogeneous catalytic material according to claim 1, characterized in that: In step (1), the molar ratio of 1-vinylimidazole to 1,2-dibromoethane is 2:1 to 3:1; the molar ratio of 1-vinylimidazole to bromoethane is 1:1 to 1:

2.

3. The method of making a bifunctional polymeric heterogeneous catalytic material according to claim 1, wherein: In step (2), the molar ratio of pyrrole to 4-vinylbenzaldehyde is 1:5 to 1:

6.

4. The method of making a bifunctional polymeric heterogeneous catalytic material according to claim 1, wherein: In step (3), the molar ratio of v-TPP to MgBr2·Et2O is 1:18~1:

20.

5. The method of making a bifunctional polymeric heterogeneous catalytic material according to claim 1, wherein: In step (4), the mass ratio of v-TPPMg to azobisisobutyronitrile is 10:

1.

6. The method for preparing bifunctional polymer heterogeneous catalytic materials according to claim 1, characterized in that: In step (5), the mass ratio of monovinylimidazolium salt ionic liquid v-IL or divinylimidazolium salt ionic liquid v-BIL to POP-TPPMg is 5:1 to 5:

2.

7. The method for preparing bifunctional polymer heterogeneous catalytic materials according to claim 1, characterized in that: In step (5), the mass ratio of POP-TPPMg to azobisisobutyronitrile is 4:

1.

8. The application of the bifunctional polymer heterogeneous catalytic material prepared by the method according to claim 1 in the catalytic cycloaddition reaction of CO2 with epoxides to prepare cyclic carbonates.

9. The application of the bifunctional polymer heterogeneous catalytic material according to claim 8 in the catalytic cycloaddition reaction of CO2 with epoxides to prepare cyclic carbonates, characterized in that: Using bifunctional polymer heterogeneous catalysts as catalysts, cycloaddition reactions were carried out with epoxides and carbon dioxide as substrates to obtain cyclic carbonates; epoxides were used as catalysts. The molar amount of the bifunctional polymer multiphase catalyst is 0.1~0.4% of the molar amount of the epoxide; the reaction temperature is 50~100℃; and the carbon dioxide pressure is 1 atm.

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