Ion pair porous polymer material and application thereof

Abstract

The invention discloses an ion pair porous polymer material. The general formula of the ion pair porous polymer material is POPn-[COO-] [XH +]. The material not only has a high specific surface area and abundant alkaline sites, can efficiently enrich and activate CO2 molecules, but also can be used as a heterogeneous catalyst to regulate and control a reaction path, so that a required high-value target product is obtained. Experiments show that CO2 can be efficiently converted into a target product in a catalytic system taking POP7-[COO-] [XH +] as the catalyst, and the catalyst has good cycle stability. The invention discloses dual functions of the ion pair porous catalyst in directional conversion of diluted CO2, namely capture enrichment and catalytic regulation. Due to the fact that a differentiated interaction mechanism exists between CO2 and different catalytic materials, a new material basis is provided for development of a capture-catalysis integrated platform, and the product range of CO2 resource utilization is expanded.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer materials and green catalysis technology, specifically relating to a novel ion-pair porous polymer material and its application in capturing and catalytically converting diluted carbon dioxide into high-value-added chemicals. Background Technology

[0002] Climate change poses a serious threat to global sustainable development, and using carbon dioxide as a C1 resource to synthesize high-value-added chemicals is an important way to achieve carbon neutrality.

[0003] In the field of CO2 capture and conversion, most existing catalytic technologies rely on high-purity CO2 (≥99.99%), which requires additional purification steps in practical applications, resulting in high costs, high energy consumption, and difficulties in storage and transportation. In contrast, CO2 in actual emission sources (such as industrial flue gas) is usually in a diluted state (volume fraction of about 10%-15%), requiring expensive and energy-intensive purification and concentration steps before direct utilization.

[0004] Porous organic polymers (POPs) have shown potential as efficient CO2 reactors due to their high specific surface area, excellent chemical stability, abundant pores, and structural diversity. However, traditional POP catalysts have significant limitations: their low density of nucleophilic active sites and insufficient basic sites make it difficult to simultaneously and efficiently activate CO2 and reaction substrates.

[0005] On the other hand, superbase-derived ionic liquids (SILs) are proton-type ionic liquids formed by the reaction of organic superbases such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) with proton acids. In recent years, they have shown great promise in the field of CO2 catalytic conversion. Strongly basic anions can efficiently activate CO2 molecules, driving them to participate in various reactions, making them a highly promising catalytic platform in metal-free reaction systems. SILs possess advantages such as high catalytic activity, good selectivity, tunable structure, strong recyclability, and low volatility, conforming to the principles of green chemistry. However, their high viscosity, strong hygroscopicity, difficulty in separating from products, and high recovery costs limit their practical application.

[0006] Therefore, developing a novel porous catalytic material that integrates efficient CO2 capture and catalytic conversion, is suitable for diluting CO2 sources, and is easy to recycle and reuse, has significant scientific importance and promising prospects for industrial applications. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an ion-pair porous polymer material that combines high CO2 enrichment capacity and excellent catalytic activity, as well as its ability to directly convert diluted CO2 into high-value-added material under mild conditions. SThe application of formylated products enables the direct capture and conversion of diluted CO2, overcoming the limitations of existing technologies.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides an ion-pair porous polymer material, comprising a polymer backbone formed by copolymerization of a nitrogen-heterocyclic carbene monomer S1, divinylbenzene, and acrylic acid, and an organic base loaded via ionic bonds to form an ion-pair polymer with a porous structure, the general formula of which is: POP n -[COO - [XH] + ]; Wherein, POP represents a porous organic polymer framework, and n is an integer from 1 to 13, representing different monomer molar ratios; COO - Derived from the carboxyl group on the polymer backbone; XH + X is a protonated organic base cation, wherein X is preferably selected from 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tetramethylguanidine (TMG) or 1,3-diphenylguanidine (DPG), and more preferably TBD.

[0009] Preferably, the nitrogen-containing heterocyclic carbene monomer S1 is prepared by a quaternization reaction of 1-vinylimidazolium with 1,2-dibromomethylbenzene; The molar ratio of the nitrogen-containing heterocyclic carbene monomer S1 to divinylbenzene and acrylic acid in the polymer is 1:(1-8):(1-6), preferably 1:7:4, in which case the material is POP7-[COO] - [XH] + ].

[0010] Preferably, the CO2 adsorption capacity of the material at 273 K and 298 K is 4.49 to 12.93 cm⁻¹, respectively. 3 / g and 1.64 to 7.56 cm 3 / g, the material has a high specific surface area, ranging from 13.57 m². 2 / g up to 139.90 m 2 / g.

[0011] Secondly, the present invention provides the application of the above-mentioned ion-paired porous polymer material in the S-formylation reaction of carbon dioxide and thiol compounds in catalytic conversion.

[0012] Preferably, the application is carried out under a diluted carbon dioxide atmosphere, catalyzing the reaction of thiols with carbon dioxide and phenylsilane. S -Formylation reaction, to generate the corresponding thiocarbamate; The diluted carbon dioxide can be derived from industrial flue gas or ambient air, and its volume concentration range is wide, from 0.04% to 30%, all of which can be effectively converted. The reaction can be carried out at room temperature and pressure without the addition of any co-catalyst.

[0013] Suitable thiol substrates include, but are not limited to: benzyl mercaptan, p-chlorobenzyl mercaptan, p-tert-butylbenzyl mercaptan, p-methoxybenzyl mercaptan, p-toluenemethanethiol, o-toluenemethanethiol, thiophene-2-methylthiol, 2-phenylethylthiol, etc.

[0014] Thirdly, the present invention provides a reaction system for carbon dioxide capture and conversion, the system comprising a gas circulation device and a reactor, and using the aforementioned ion-pair porous polymer material as a catalyst, which can significantly reduce gas consumption and improve CO2 capture and conversion efficiency.

[0015] Compared with the prior art, the present invention has the following significant advantages: Integrated design: The material of this invention combines the high specific surface area and abundant pores of porous polymers with the highly catalytically active sites of ionic liquids through ionic bonds, creating a "reactor" that has both efficient CO2 capture and catalytic conversion functions.

[0016] Suitable for CO2 dilution: The nitrogen heterocyclic carbene sites in the material can strongly adsorb CO2, forming a local high concentration around the active site, which allows it to directly utilize low concentrations of CO2 in industrial flue gas or even ambient air, eliminating the need for expensive pre-concentration steps.

[0017] Synergistic catalytic mechanism: nitrogen heterocyclic carbene and COO in the material - and TBDH + A synergistic catalytic microenvironment of "nucleophilic-electrostatic-stabilization" was constructed, realizing a highly efficient integrated process for CO2 molecule enrichment, activation and conversion, with high catalytic efficiency.

[0018] The reaction conditions are mild: the reaction can be carried out efficiently at room temperature and normal pressure, and no co-catalyst is required, which is in line with the principles of green chemistry.

[0019] Good stability and easy recycling: The material is a heterogeneous catalyst with excellent thermal and chemical stability. It can be recovered by simple filtration and reused at least 5 times without significant decrease in activity, showing good prospects for industrial application.

[0020] Strong environmental tolerance: The catalytic system has good tolerance to common impurity gases such as SO2 and NO2 in actual flue gas and is not affected by them.

[0021] The prospects for industrialization are clear: it is applicable to actual gas sources such as flue gas and air, and has the potential for large-scale application. Attached Figure Description

[0022] Figure 1 The present invention relates to the ion-pair porous polymer material POP. n -[COO - [XH] + A schematic diagram of the synthesis route.

[0023] Figure 2 For the present invention S - General formula for formylation reaction and the substrates and products involved in the examples.

[0024] Figure 3 The diagram shows the results of the optimized reaction conditions in the examples, including the effects of (a) catalyst dosage, (b) reaction temperature, (c) reducing agent dosage, (d) solvent type selection, (e) solvent volume, and (f) reaction time.

[0025] Figure 4 The effect of the proportion of DVB (a) and the proportion of acrylic acid (b) in the copolymer on the catalytic performance is shown in the examples.

[0026] Figure 5 The DFT calculations in the examples show the interaction between different organic bases (TBD(a), TMG(b), DBU(c), and DPG(d)) and CO2, and the corresponding Sign(I2)r-colored IRI scatter plots of TBD(e), TMG(f), DBU(g), and DPG(h).

[0027] Figure 6 This is a comparison chart of the catalytic performance of different organic base supported catalysts in the examples.

[0028] Figure 7 In the examples, POP7-COOH and POP7-[COO] - ][TBDH + FT-IR spectrum comparison diagram.

[0029] Figure 8 In the example, POP7-[COO] - ][TBDH + The solid-state NMR spectrum, thermogravimetric analysis and XPS analysis results are shown in the figure. In the figure, (a) POP7-[COO - ][TBDH + Solid-state ¹³C NMR spectrum; (b)POP7-[COO - ][TBDH + Thermogravimetric analysis; (c) POP7-[COO - ][TBDH +The full spectrum of XPS; (d) N 1s spectrum; (e) O 1s spectrum; (f) Br 3d spectrum.

[0030] Figure 9 In the example, POP7-[COO] - ][TBDH + SEM images before (a) and after (b) use.

[0031] Figure 10 In the example, POP7-[COO] - ][TBDH + Adsorption isotherms of CO2 and N2 at 273 K (a) and 298 K (b).

[0032] Figure 11 In the example, POP7-[COO] - ][TBDH + CO2 / N2 adsorption selectivity (a) and in-situ Raman spectra in CO2 and N2 atmospheres (b).

[0033] Figure 12 The diagram shows the frontier molecular orbitals and electrostatic potentials of each catalyst in the examples; In the figure, (a) POP7-COOH, (b) TBD, and (c) POP7-[COO] - ][TBDH + (d) POP7-COOH, (e) TBD and (f) POP7-[COO] frontier molecular orbitals (HOMO and LUMO); - ][TBDH + The electrostatic potential of ].

[0034] Figure 13 The figures show the optimized adsorption configurations and differential charge density diagrams of CO2 on each catalyst in the examples. In the figure, CO2 is present in (a) POP7-COOH, (b) TBD, and (c) POP7-[COO] - ][TBDH + Optimized adsorption configuration on ]; CO2 in (d) POP7-COOH, (e) TBD and (f) POP7-[COO - ][TBDH + The corresponding differential charge density diagram of adsorption on the surface.

[0035] Figure 14 The TBD loading equivalent and the catalytic performance of different catalyst components were screened in the examples.

[0036] Figure 15The example in which POP7-[COO] is presumed to be the basis for this. - ][TBDH + Catalyst S - Schematic diagram of the formylation reaction mechanism.

[0037] Figure 16 For different thiol substrates in the examples S - Yield in the formylation reaction (using diluted CO2 or actual cement kiln exhaust gas).

[0038] Figure 17 The effect of different coexisting flue gas components on the catalytic reaction is illustrated in the examples.

[0039] Figure 18 The examples show the effect of CO2 concentration on catalytic yield (a) and the catalyst recycling performance (b).

[0040] Figure 19 This is a schematic diagram of the carbon dioxide capture and conversion reaction system of the present invention. Detailed Implementation

[0041] The technical solution of the present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the following embodiments.

[0042] The materials and reagents used in the examples are as follows: Cement kiln flue gas (composition: N2: 70%, CO2: 25%, O2: 4%, CO: 0.1%, NO2: 4%) x (0.08% SO2, 115ppm) was collected from the flue gas emission section of a cement kiln factory in Guilin City, Guangxi Province.

[0043] The following chemicals were purchased from commercial suppliers and, unless otherwise stated, were used directly without further purification: petroleum ether (PE), ethyl acetate (EA), methanol (MeOH), toluene, 1,4-dioxane, tetrahydrofuran (THF), acetonitrile (MeCN), N,N-dimethylformamide (DMF), dichloromethane (DCM), 2,2'-azobisisobutyronitrile (AIBN), divinylbenzene (DVB, 80%, containing 1000 ppm TBC stabilizer), phenylsilane (PhSiH3), 1,2-dibromomethylbenzene, 1-vinylimidazolium, allyl propionic acid, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tetramethylguanidine (TMG), 1,3-diphenylguanidine (DPG), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). Compounds 2a-2h were synthesized. Figure 16 All the starting materials required are commercially available. All of these chemicals are readily available commercially and require no additional purification.

[0044] Example 1: Synthesis of nitrogen-containing heterocyclic carbene monomer S1; like Figure 1 As shown, monomers are synthesized by quaternization reaction of N-vinylimidazolium with haloaromatic hydrocarbons;

[0045] The specific steps are as follows: Weigh 1,2-dibromomethylbenzene (10.0 mmol, 2.7 g) into a flask, add 20 mL of toluene and stir to dissolve, then slowly add 1-vinylimidazole (21.0 mmol, 1.8 mL), stir and react in an oil bath at 90 °C for 24 hours, cool the mixture to room temperature and filter, wash several times with ethyl acetate, and dry under vacuum to obtain the nitrogen heterocyclic carbene monomer S1.

[0046] Example 2: Synthesis of polymer precursor POPn-COOH; like Figure 1 As shown, specific amounts of Si, acrylic acid, DVB, and AIBN were dissolved in 1 mL of DMSO in a polytetrafluoroethylene (PTFE) high-pressure reaction tube at 100 °C. o The reaction was carried out at C for 24 h. The resulting solid was collected, filtered, thoroughly washed with ethyl acetate and methanol, and dried under vacuum to obtain polymer POP. n -COOH (where n=1,2,3……13).

[0047] Reference Figure 4 By changing the ratio of DVB to acrylic acid, the synthesized polymers were named as follows: POP1-COOH (S1:DVB:acrylic acid = 1:1:4), POP2-COOH (S1:DVB:acrylic acid = 1:2:4), POP3-COOH (S1:DVB:acrylic acid = 1:3:4), POP4-COOH (S1:DVB:acrylic acid = 1:4:4), POP5-COOH (S1:DVB:acrylic acid = 1:5:4), POP6-COOH (S1:DVB:acrylic acid = 1:6:4), POP7-COOH (S1:DVB:acrylic acid = 1:7:4), POP8-COOH (S1:DVB:acrylic acid = 1:8:4), POP9-COOH (S1:DVB:acrylic acid = 1:7:1), POP 10 -COOH(S1:DVB:acrylic acid = 1:7:2), POP 11 -COOH(S1:DVB:acrylic acid = 1:7:3), POP 12 -COOH(S1:DVB:acrylic acid = 1:7:5), POP 13 -COOH(S1:DVB:acrylic acid=1:7:6), where all proportions are molar ratios.

[0048] Taking POP7-COOH as an example, in a polytetrafluoroethylene high-pressure reaction tube, with a molar ratio of S1 : DVB : acrylic acid = 1 : 7 : 4, the corresponding mass of monomer was added, and an appropriate amount of AIBN was added as an initiator. The mixture was dissolved in 1 mL of DMSO and reacted at 100℃ for 24 hours. The resulting solid was collected, filtered, and thoroughly washed with ethyl acetate and methanol in sequence. After vacuum drying, the polymer POP7-COOH was obtained.

[0049] Example 3: Ion-pair porous polymer POP n -[COO - [XH] + The synthesis of ]; Each POP n -COOH and an organic base (X), such as DBU, TMG, DPG, or TBD, are mixed in a DCM solution and stirred for 24 hours. The resulting solid product is filtered, washed with ethyl acetate, and dried under vacuum to give the final product, POP. n -[COO - [XH] + ].

[0050] The POP7-COOH obtained in Example 2 was mixed with 1 equivalent of TBD in DCM, stirred at room temperature for 12 hours, the resulting solid was filtered, washed with ethyl acetate, and dried under vacuum to obtain the final product POP7-[COO] - ][TBDH + Similarly, using other organic bases such as DBU, TMG, and DPG, POP can be obtained. n -[COO - ][DBUH + ], POP n -[COO - ][TMGH + ] and POP n -[COO - ][ DPGH + Materials such as […].

[0051] Example 4: Material Characterization; For the synthesized POP7-[COO - ][TBDH +Systematic characterization was performed. ¹H / ¹³C nuclear magnetic resonance (NMR) spectra were recorded using a Bruker AVANCE-III 400 / 500 spectrometer; solid-state ¹³C NMR spectra were obtained using a Bruker AVANCE NEO 400WB spectrometer; functional group analysis was performed using a Thermo Scientific iN10 Fourier transform infrared (FT-IR) spectrometer; material composition and morphology were observed using a Tesken MIRA scanning electron microscope (SEM); specific surface area (BET) and pore size distribution were measured at 77 K using a KUBO-X1000 instrument via nitrogen adsorption-desorption; surface elemental composition was analyzed using X-ray photoelectron spectroscopy (XPS, Thermo Scientific Nexsa); thermal stability and decomposition temperature were assessed using a thermogravimetric analyzer (TGA, DTA8112); the C, N, and H content in the material was detected using an elemental analyzer; and the CO₂ activation process was observed using a Horiba HR Evolution Raman spectrometer.

[0052] The synthesized polymers were systematically characterized to elucidate POP7-[COO] - ][TBDH + The structural characteristics of the sample confirmed its successful preparation. Figure 7 As shown, in the range of 3100-2850 cm -1 The significant absorption peak in this region corresponds to the stretching vibration of the aliphatic -CH2- bond. 1640 cm⁻¹ -1 1610 cm -1 and 1445 cm -1 The peak is caused by the vibration of C=N and CN bonds, confirming the integrity of the aryl imidazole skeleton. 712 cm⁻¹ -1 The peak reflects the planar bending vibration of the -CH- bond, indicating that the monomer and DVB have successfully crosslinked. Furthermore, at 1720 cm⁻¹... -1 The position represents the OH bond in COOH; when the TBD unit is introduced, the value is 1720 cm⁻¹. -1 The vibration peak at 1564 cm disappeared, and instead appeared at 1564 cm. -1 With 1390 cm -1 New peaks appeared at the specified locations, corresponding to the symmetric stretching vibrations of the NH bond and -COO- in TBD, respectively. The FT-IR spectroscopy results directly confirmed the neutralization reaction between TBD and the carboxyl groups in the polymer, demonstrating the successful ionic loading of TBD.

[0053] POP7-[COO - ][TBDH + The spectrum and XPS analysis results, such as Figure 8As shown, POP7-[COO] - ][TBDH + Solid-state nuclear magnetic resonance (NMR) spectrum ( Figure 8 a) The results show that the vibrational peaks appearing at 120-150 ppm are related to the aromatic ring, imidazole ring, and C atoms of TBD. Characteristic peaks of polyethylene appear at 20-60 ppm, indicating that vinyl groups participated in the reaction and completed polymerization. Furthermore, thermogravimetric analysis revealed that POP7-[COO] - ][TBDH + It has good thermal stability. Figure 8 b). XPS analysis was used to study POP7-[COO] - ][TBDH + ] Surface element types, full spectrum ( Figure 8 c) shows that the polymer contains C, N, O, and Br elements. Figure 8 In the N1s spectrum of d, the fitted peaks at 399.70 eV and 400.50 eV confirm the presence of the imidazole ring, while the peak at 401.60 eV is due to the introduction of TBD. Figure 8 In the O1s spectrum shown in Figure e, the two peaks fitted at 530.75 eV and 532.50 eV correspond to CO and C=O on the carboxyl group, respectively. Figure 8 The two characteristic peaks at 68.50 eV and 67.50 eV in f are characteristic peaks of the Br element.

[0054] Scanning electron microscope (SEM) images, such as Figure 9 As shown, POP7-[COO] is displayed. - ][TBDH + It has a significant porous structure, and these pores are interconnected to form a three-dimensional network structure. It is observed that there is no obvious structural difference before and after use.

[0055] Further on POP n -[COO - ][TBDH + The polymer underwent nitrogen adsorption-desorption experiments and specific surface area measurements. With increasing DVB polymer content, POP... n -[COO - ][TBDH + The specific surface area of ​​[POP7-[COO]] increased from 13.57 m² / g to 139.90 m² / g. The CO2 adsorption capacity at 273 K increased from 4.49 cm³ / g to 12.93 cm³ / g, while its CO2 adsorption capacity at 298 K also increased from 1.64 cm³ / g to 7.56 cm³ / g. Among them, POP7-[COO] exhibited the best catalytic performance. -][TBDH + The specific surface area is 134.16 m² / g, and the CO2 adsorption capacities at 273 K and 298 K are 11.61 cm³ / g and 7.23 cm³ / g, respectively. Figure 10 As shown.

[0056] In addition, the isothermal adsorption method was also used to test POP7-[COO] - ][TBDH + The adsorption capacity for CO2 and N2 was calculated, and the selective adsorption coefficient was determined. Figure 11 As shown in a, POP7-[COO] - ][TBDH + It exhibits significant CO2 adsorption selectivity. In-situ Raman spectroscopy, such as... Figure 11 b shows that when the atmosphere is switched from N2 to CO2, the temperature at 2231 cm⁻¹... -1 A characteristic signal appears at the point, corresponding to the antisymmetric stretching vibration signal of the CO2 molecule at the nitrogen site. These results indicate that POP7-[COO - ][TBDH + It possesses both highly selective CO2 adsorption capacity and efficient catalytic activation performance.

[0057] Example 5: Catalytic performance evaluation — S -Formylation reaction; like Figure 2 As shown, where, The compounds are benzyl mercaptan, (4-chlorophenyl)methanethiol, (4-(tert-butyl)phenyl)methanethiol, (4-methoxyphenyl)methanethiol, p-toluenemethanethiol, o-toluenemethanethiol, thiophene-2-ylmethanethiol, and 2-phenylethane-1-thiol. It includes S-benzyl thiocarbamate, S-(4-chlorobenzyl) thiocarbamate, S-(4-(tert-butyl)benzyl) thiocarbamate, S-(4-methoxybenzyl) thiocarbamate, S-(4-methylbenzyl) thiocarbamate, S-(2-methylbenzyl) thiocarbamate, S-(thiophene-2-ylmethyl) thiocarbamate, and S-phenethyl thiocarbamate.

[0058] Evaluation was conducted under typical reaction conditions: POP7-[COO] was added to the reaction flask. - ][TBDH +The catalyst (50 mg), benzyl mercaptan (0.5 mmol), phenylsilane (1.5 mmol), and 1,4-dioxane (1.5 mL) were reacted at 25 °C under a certain CO2 concentration (0.04%-30% or actual cement kiln exhaust gas) for 24 hours. After the reaction, the catalyst was recovered by filtration, and the reaction solution was post-processed and purified to obtain S-benzyl thiocarbamate. The product structure was determined and the yield was calculated by means of nuclear magnetic resonance and other methods.

[0059] Example 6: Optimization of reaction conditions, substrate expansion and application testing; Condition optimization: Use POP7-[COO] - ][TBDH + [Using a catalyst, investigate the optimal reaction conditions as follows] Figure 3 As shown, catalyst dosage Figure 3 (a) Reaction temperature Figure 3 (b) Dosage of reducing agent Figure 3 (c) Solvent type screening Figure 3 (d) Solvent volume Figure 3 (e) and reaction time Figure 3 Figure 3 (f) The optimal reaction conditions were determined: phenylsilane (1.5 mmol), 1,4-dioxane (1.5 mL), 25 o Reacting at C for 24 hours, POP7-[COO] - ][TBDH + Catalyst 50 mg.

[0060] Catalyst structure determined: Refer to Figure 4 The method for determining the molar ratio of monomer S1 to divinylbenzene and acrylic acid is as follows: first, fix the amounts of S1 and acrylic acid, then change the amount of divinylbenzene. The molar ratio of the three is S1:divinylbenzene:acrylic acid = 1:1:4 to 1:8:4. Figure 4 As shown in (a).

[0061] After determining the amount of divinylbenzene, change the amount of acrylic acid. The molar ratio of the three is S1:divinylbenzene:acrylic acid = 1:7:1 to 1:7:6. Figure 4 As shown in (b).

[0062] The optimal structural ratio of the catalyst was determined to be POP7-COOH (S1:DVB:acrylic acid = 1:7:4) under optimal reaction conditions.

[0063] Performance evaluation of catalysts supported on different organic bases, such as Figure 6 As shown, the results indicate that TBD is the optimal base catalyst for POP7-[COO]. - ][TBDH +[Optimal performance]

[0064] Substrate expansion: Under optimal reaction conditions, diluted CO2 (30 vol% CO2 / 70 vol% N2, v / v) or actual cement kiln exhaust gas (composition: N2: 70%, CO2: 25%, O2: 4%, CO: 0.1%, NO) was used. x (0.08%, SO2: 115 ppm), for a series of S The formylation reaction was evaluated, and compounds 2a-2h were synthesized, such as... Figure 16 As shown in the figure. Experimental results indicate that various substituted thiols react smoothly to give the corresponding thiocarbamates in moderate to excellent yields, demonstrating good substrate applicability.

[0065] Tolerance testing: such as Figure 17 As shown, in simulated flue gas containing impurity gases such as SO2 and NO2, the catalyst... The activity was not significantly affected, demonstrating excellent environmental tolerance.

[0066] Sample 1 in the figure: CO2 (30%), CO (0.103%), O2 (2.0%), SO2 (15.0 ppm), N2 (equilibrium); Sample 2: CO2 (30%), CO (0.103%), O2 (2.0%), SO2 (50.3 ppm), NO2 (50.8 ppm), N2 (equilibrium); Sample 3: CO2 (30%), CO (0.103%), O2 (2.0%), SO2 (93.6 ppm), NO2 (104.6 ppm), N2 (equilibrium); Sample 4: CO2 (30%), CO (0.103%), O2 (2.0%), SO2 (206.0 ppm), NO2 (219.1 ppm), N2 (equilibrium).

[0067] CO2 dilution and circulation test: such as Figure 18 As shown, the reaction remained feasible as the CO2 concentration gradually decreased to 15 vol% and 10 vol%, with yields of approximately 57% and 42%, respectively. Even at CO2 concentrations as low as 0.04% (ambient air), product formation was still detectable, although the yield decreased to approximately 1%. Figure 18 As shown in a.

[0068] Catalyst cycling experiments, such as Figure 18As shown in b, the results indicate that the catalytic efficiency did not decrease significantly after five reaction cycles. Furthermore, even with continuous CO2 (30 vol%) flow, scale-up of the reaction still achieved a 95% yield of CO2 to the target product, demonstrating good stability and promising prospects for industrial application.

[0069] Closed-loop system testing: such as Figure 19 The carbon dioxide capture and conversion reaction system shown includes a gas circulation device and a reactor. The reactor uses an ion-pair porous polymer material as a catalyst. After 24 hours of cyclic reaction, the CO2 concentration decreased from 30% to 12.9%, and the average yield of product 2a reached 67%, demonstrating the potential of this material in practical application systems.

[0070] Example 7: Catalytic mechanism study; like Figure 5 As shown in Figures 12 and 13, through DFT calculations and comparative experiments... Figure 14 As shown in Figure 15, the catalytic mechanism was studied in depth.

[0071] Density functional theory (DFT) calculations were performed using ORCA 6.0.0 software, such as... Figure 5 a-5h illustrate the interactions between various bases (TBD, TMG, DBU, DPG) and CO2: blue areas represent strong electrostatic interactions, green areas represent van der Waals interactions, and red areas show strong steric hindrance. In reactions involving CO2, catalysts typically induce CO2 to change from a linear structure to a bent configuration, leading to alterations in molecular orbital shape and energy levels. Each base activates CO2, decreasing the O=C=O bond angle from 180° to 172.9°, 176.1°, 177.2°, and 177.2°, respectively. Furthermore, through experiments ( Figure 6 The mutual verification between the calculation and the base selection results shows that POP7-[COO] - ][TBDH + [Performance is better.]

[0072] To investigate POP7-[COO - ][TBDH + The catalytic mechanisms of each component in the catalyst are comprehensively and deeply revealed from different scales and dimensions through the organic combination of periodic and molecular calculations. Frontier orbital calculations based on the B3LYP / def2-TZVP theoretical level show that, as... Figure 12 As shown, TBD, POP7-COOH and POP7-[COO - ][TBDH +The electronic structures of POP7-COOH and POP7-[COO2] exhibit significant differences, which are closely related to their catalytic activity. TBD, in particular, displays a very large band gap (7.119 eV) and an extremely low HOMO level (-6.31 eV). Its electrostatic potential distribution is generally neutral and positively charged, lacking a distinct negative potential region (blue area), indicating high chemical inertness and poor electron-donating ability, making it difficult to initiate the initial steps of CO2 activation. Conversely, POP7-COOH and POP7-[COO2]... - ][TBDH + [POP7-[COO]] possesses a small band gap (1.608 eV and 1.655 eV) and a high HOMO level (-3.51 eV and -3.52 eV), indicating high chemical reactivity and excellent electron-donating ability. It can effectively transfer electrons to the LUMO orbitals of CO2, thereby weakening the C=O bond and achieving efficient activation. More importantly, POP7-[COO] - ][TBDH + The electrostatic potential diagram shows significant negative potential regions around both the carboxyl group and the TBDH⁺ site, indicating multiple active sites provided by their synergistic effect. This combines the dual functions of nitrogen heterocyclic carbene and protonated TBD, achieving a synergistic catalytic effect.

[0073] To further verify the catalytic trend revealed by the above electronic structure from a thermodynamic perspective, the adsorption energy (E) of each catalyst for CO2 was calculated. ads ) and binding energy (E) bind ),like Figure 13 As shown. The results indicate that ( Figure 13 a-13c), POP7-[COO] - ][TBDH + It exhibits the strongest CO2 adsorption capacity (Eads = -1.20 eV) and the most stable complex structure (E... bind = -5.30 eV), and its binding energy is significantly higher than that of POP7-COOH (-4.01 eV) and TBD (-2.74 eV), indicating that the complex has the best CO2 activation ability thermodynamically.

[0074] Of particular importance is the differential charge density map ( Figure 13 d-13f) intuitively reveals the nature of their interaction: in POP7-[COO - ][TBDH +In the POP7-CO2 complex, significant electron density rearrangement was observed. Electrons (yellow region) mainly accumulated in the C=O antibonding orbital region of the CO2 molecule, while electron consumption (blue region) occurred near the active site of the catalyst. This directly confirms that electrons were effectively transferred from the catalyst site to the LUMO orbital of CO2, thereby substantially weakening the C=O bond and driving its efficient activation. This result is highly consistent with frontier orbital and electrostatic potential analyses, jointly confirming the POP7-[COO2] complex. - ][TBDH + The synergistic effect of nitrogen-containing heterocyclic carbene and protonated TBD constructs a highly efficient catalytic microenvironment, which not only enhances the electron supply capacity of the material but also strengthens its interaction with CO2, providing a key theoretical basis for its excellent catalytic performance.

[0075] The examples further investigated the catalytic performance of POP7-COOH alone, TBD alone, and a physical mixture of POP7-COOH and TBD in the reaction system, thus corroborating the above calculation results. The results are as follows: Figure 14 As shown, their yields were significantly low, at 0%, 2%, and 2%, respectively. In stark contrast, the yields of POP7-[COO] prepared via the loading process were much higher. - ][TBDH + A yield of nearly 90% was achieved, which fully demonstrates the necessity of the TBD loading process.

[0076] To further investigate the effect of TBD loading on catalytic performance, experimental studies were conducted. The results showed that when the TBD loading was below 1 equivalent, the catalytic efficiency was limited due to insufficient number of active sites; while when the loading exceeded 1 equivalent, the active sites reached saturation, thus achieving optimal catalytic performance.

[0077] POP7-[COO - ][TBDH + The mechanism of CO2 adsorption and activation, such as Figure 15 As shown, the core of this mechanism lies in the nitrogen heterocyclic carbene and -COO. - and TBDH + Together, they constructed a highly efficient "nucleophilic-electrostatic-stabilized" synergistic catalytic microenvironment. First, the nitrogen heterocyclic carbene site, acting as a strong nucleophile, covalently captures CO2 molecules through an irreversible nucleophilic addition reaction, forming a stable NHC-CO2 adduct, thus completing the initial fixation of the reactants; subsequently, the -COO... - As a highly efficient electron donor, it transfers electrons to the π antibonding orbitals of CO2, significantly weakening the C=O bond and achieving deep activation at the electronic level; simultaneously, the adjacent TBDH +The cations stabilize CO2 molecules and reaction intermediates through electrostatic interactions, significantly enhancing the stability of the catalyst-substrate complex. These three components—covalent trapping of the carbene, electron donation from the carboxyl group, and electrostatic stabilization of the cation—together construct a unique synergistic catalytic microenvironment, enabling it to exhibit excellent CO2 adsorption capacity and extremely strong binding stability, thereby achieving highly efficient activation of CO2 molecules.

[0078] This invention successfully synthesized a novel ion-pair porous CO2 reactor, exhibiting excellent catalytic activity and outstanding stability. The polymer incorporates imidazole groups, enabling CO2 adsorption. Furthermore, the imidazole structural units can be integrated into the main chain, allowing for the adjustment and control of catalytic active sites, thus providing the possibility of obtaining catalysts with high active site density. In addition, the introduction of TBD into the polymer via ionic bonding to act as a hydrogen bond donor enhances its catalytic performance for CO2. Based on this, POP7-[COO - ][TBDH + It can directly catalyze the generation of CO2 in cement kiln exhaust gas under normal temperature and pressure conditions without the need for a co-catalyst. S -Formylation reaction.

Claims

1. An ion-pairing porous polymeric material, characterized in that, The material is formed by copolymerization of aza carbene monomer S1, divinyl benzene and acrylic acid to form a polymer skeleton, and is loaded with an organic base through an ionic bond to form an ion pair polymer with a porous structure, and its general formula is: POP n -[COO - ][XH + ] Wherein, POP represents a porous organic polymer skeleton, n is an integer from 1 to 13, representing different monomer feeding molar ratios; XH + is a protonated organic base selected from one of TBDH + , DBUH + , TMGH + , DPGH + .

2. The material of claim 1, wherein The organic base is 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

3. The material of claim 1, wherein The azolide monomer S1 is prepared by quaternization reaction of 1-vinylimidazole and 1,2-dibromomethylbenzene; The molar ratio of the azolide monomer S1 to divinylbenzene and acrylic acid in the polymer is 1:(1-8):(1-6).

4. The material of claim 3, wherein, The molar ratio of the nitrogen heterocyclic carbene monomer S1, divinylbenzene and acrylic acid in the polymer is 1 :7:4, at which point the material is POP7-[COO - ][XH + ].

5. The material according to any one of claims 1 to 4, characterized in that, The CO2adsorption capacity of the material at 273 K and 298 K is 4.49 to 12.93 cm 3 / g and 1.64 to 7.56 cm 3 / g, respectively, and the specific surface area is 13.57 to 139.90 m 2 / g.

6. An ion-paired porous polymer material as described in any one of claims 1-5 for the catalytic conversion of CO2 and thiol compounds. S Applications in formylation reactions.

7. Use according to claim 6, characterized in that, The application catalyzes S-formylation reaction of mercaptans with carbon dioxide and phenylsilane to generate thiocarbamate under a diluted carbon dioxide atmosphere. The diluted carbon dioxide is from industrial flue gas or environmental air, and the volume concentration ranges from 0.04% to 30%.

8. Use according to claim 6, characterized in that, The reaction is carried out at normal temperature and pressure without additional addition of a cocatalyst.

9. Use according to claim 6, characterized in that, The mercaptans include at least one of benzyl mercaptan, p-chlorobenzyl mercaptan, p-tert-butylbenzyl mercaptan, p-methoxybenzyl mercaptan, o-tolyl mercaptan, thiophene-2-yl methyl mercaptan or 2-phenylethan-1-thiol.

10. A reaction system for carbon dioxide capture and conversion, characterized in that, The system comprises a gas circulating device and a reactor, and the ion pair porous polymer material as claimed in any one of claims 1-4 is used as a catalyst in the reactor.

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