Cationic free radical triazine-based polyacetylene and its preparation method and photocatalytic application

Abstract

Disclosed are a cationic radical-type triazine-based polyacetylene, a preparation method thereof, and photocatalytic applications. The chemical structure is shown in Formula 3. The preparation method comprises the following steps: using 2,4,6-tris(4-pyridyl)-1,3,5-triazine shown in Formula 1 and propargyl bromide shown in Formula 2 as raw materials, without a catalyst or initiator, to directly prepare the cationic radical-type triazine-based polyacetylene Tz-IRPA-1 shown in Formula 3 in one step through a quaternization-induced in-situ polymerization reaction. The functional polymer prepared by the present invention has a simple process, requiring only a one-step reaction to in-situ prepare the non-metallic polymer catalyst Tz-IRPA-1. The prepared Tz-IRPA-1 is used in a photocatalytic cycloaddition reaction of an epoxy compound and CO2, exhibiting excellent heterogeneous photocatalytic activity under normal temperature and pressure conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of novel functional porous organic polymers, and in particular to a cationic free radical type triazine-based polyacetylene and a preparation method and photocatalytic application thereof. Background Art

[0002] In recent years, the threat of excessive CO₂ emissions leading to global warming has garnered widespread public attention. In this context, the development of carbon capture, storage, and utilization (CCSU) technologies is crucial. CO₂ is a sustainable, abundant, and renewable C₁ resource, and its conversion into high-value-added products is essential. One promising strategy is the conversion of CO₂ with epoxides into cyclic carbonates via cycloaddition reactions. These reactions offer advantages such as 100% atomic efficiency, low energy consumption, and the fact that they are non-redox reactions. The resulting cyclic carbonates have a wide range of applications. Currently, thermally driven catalytic CO₂ cycloadditions dominate, and numerous homogeneous and heterogeneous catalysts have been developed for this reaction. However, most catalysts primarily utilize nucleophilic halide anions and electrophilic metal sites as active sites, resulting in relatively harsh reaction conditions. Numerous research efforts are underway to address these challenging reaction conditions, such as high temperature and pressure, and to further improve catalytic efficiency, with the goal of developing green, mild, efficient, and energy-efficient heterogeneous catalytic CO₂ conversion systems. As a green, sustainable and renewable resource, visible light is expected to replace thermal energy to drive CO2 cycloaddition reactions.

[0003] In recent years, for the photocatalytic CO2 cycloaddition reaction, research groups at home and abroad have designed and prepared various types of photocatalysts to achieve efficient CO2 conversion under normal pressure and mild conditions. Currently, these photocatalysts mainly include metal-based composite catalysts, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and porous organic polymers (POPs). However, the photocatalysts used in the above-mentioned photocatalytic CO2 cycloaddition reaction systems are basically metal-based catalytic materials, requiring additional halogen-type homogeneous catalysts such as tetrabutylammonium bromide (TBAB) to obtain ideal photocatalytic activity. However, reaction systems without the use of co-catalysts are rare. For example, researchers designed and synthesized a multifunctional photocatalyst composed of metal cobalt porphyrin and imidazolium ionic liquid modified quinoline-based covalent organic framework (COF-PI-2), which exhibited excellent catalytic performance in light-induced photothermal CO2 conversion without the use of co-catalysts. However, this catalyst relies on electrophilic metal species. Ionic porous organic polymers have been used in thermocatalytic CO2 cycloaddition reactions, but there are very few examples of CO2 cycloaddition reactions being used in photocatalysis. For example, researchers have designed a class of polyionic liquids (PILs) containing electron donor-acceptor (DA) structures that exhibit excellent heterogeneous photocatalytic performance as catalysts in photocatalytic CO2 cycloaddition reactions under mild conditions and atmospheric pressure. This work provides new ideas for the design of ionic polymer photocatalysts. Inspired by these works, the development of green and efficient non-metallic ionic porous organic polymer heterogeneous photocatalysts for the catalytic conversion of CO2 under mild conditions has great potential and excellent application prospects. Summary of the Invention

[0004] The purpose of the present invention is to provide a cationic free radical triazine-based polyacetylene and its preparation method and photocatalytic application. The preparation process of the polymer is simple, and only one-step reaction is required to in situ prepare a non-metallic halogen type cationic free radical triazine-based polyacetylene. The prepared polymer is used in a photocatalytic CO2 cycloaddition reaction and exhibits excellent heterogeneous photocatalytic activity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a functionalized ionic porous organic polymer, which is a cationic free radical triazine-based polyacetylene Tz-IRPA-1, and its chemical structure is shown in Formula 3:

[0006]

[0007] The present invention also provides a method for preparing the cationic radical-type triazine-based polyacetylene, comprising the following steps:

[0008] (1) Using 2,4,6-tris(4-pyridyl)-1,3,5-triazine and bromopropyne as raw materials, a cationic radical triazine-based polyacetylene Tz-IRPA-1 as shown in Formula 3 was synthesized in one step through a quaternization-induced in situ polymerization reaction.

[0009] The structural formula of 2,4,6-tris(4-pyridyl)-1,3,5-triazine shown in Formula 1 is The structure of formula 2 is

[0010] Furthermore, the method specifically includes the following steps:

[0011] S1: Add 2,4,6-tris(4-pyridyl)-1,3,5-triazine shown in Formula 1 into a container containing an organic solvent N,N-dimethylformamide (abbreviated as DMF), and stir to completely dissolve it to obtain a uniform solution;

[0012] S2: The uniform solution obtained in step S1 is transferred to a reaction tube, propidium bromide is added, and the mixed solution is placed in the reaction tube, without a catalyst and an initiator, and a quaternization-induced polymerization reaction is carried out at a certain reaction temperature for a period of time.

[0013] S3: After the reaction is completed, the cationic radical type triazine polyacetylene Tz-IRPA-1 (Tz is the English abbreviation of triazine group, IR is the English abbreviation of cationic radical, PA is the English abbreviation of polyacetylene) is obtained by washing, filtering and drying.

[0014] Preferably, in step S2, the molar ratio of 2,4,6-tris(4-pyridyl)-1,3,5-triazine represented by formula 1 to propyne bromide is 1:3.

[0015] Preferably, in step S2, the solvent is DMF, the reaction temperature is 120° C., and the reaction time is 24 h.

[0016] The present invention also provides the use of the cationic free radical type triazine-based polyacetylene Tz-IRPA-1 in the photocatalytic conversion of CO2.

[0017] Furthermore, it specifically includes: using an epoxy compound as a substrate and Tz-IRPA-1 as a heterogeneous photocatalyst, performing a photocatalytic cycloaddition reaction of CO2 and the epoxy compound in a CO2 atmosphere at room temperature and pressure and under the conditions of white light LEDs.

[0018] Preferably, the structural formula of the epoxy compound is Wherein, R is one of methyl, ethyl, chloromethyl, bromomethyl, n-butyl, allylmethoxy and benzyloxy.

[0019] This invention prepares a cationic radical-type triazine-based polyacetylene (Tz-IRPA-1) through a simple one-pot strategy. The entire process uses 2,4,6-tris(4-pyridinyl)-1,3,5-triazine and propargyl bromide as raw materials, without the need for catalysts or initiators. The cationic radical-type triazine-based polyacetylene Tz-IRPA-1 is prepared in one step through a quaternization-induced in situ polymerization reaction. Subsequently, a triazine-free cationic radical-type polyacetylene (TPh-IRPA-2) is prepared as a comparative catalyst using 1,3,5-tris(4-pyridinyl)benzene and propargyl bromide as raw materials. Its chemical structure is shown in Formula 4:

[0020]

[0021] Among them, Tz-IRPA-1 exhibits excellent heterogeneous catalytic activity in the photocatalytic CO2 cycloaddition reaction to produce cyclic carbonates under normal pressure and mild conditions. Therefore, the present invention has developed a triazine-based porous organic polymer rich in cationic free radicals for use as a non-metallic halogen heterogeneous photocatalyst, achieving efficient photocatalytic conversion of CO2 under normal pressure and temperature conditions in the absence of solvents or co-catalysts.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The preparation process of the present invention requires only one step of reaction, mild reaction conditions, does not require the use of any catalyst or initiator, and the equipment used is simple, thus having broad prospects for industrial and large-scale application;

[0024] (2) Through quaternization-induced in situ polymerization, a polymer containing abundant cationic radicals, triazine groups, and polyacetylene as photoactive groups and halogen bromide anions as nucleophilic catalytic sites was obtained. The prepared polymer exhibited excellent photocatalytic activity.

[0025] (3) The functionalized porous organic polymer in the present invention exhibits excellent photocatalytic performance in the photocatalytic cycloaddition reaction of epoxy compounds and CO2 under solvent-free and catalyst-free conditions. The photocatalyst also has the advantages of being metal-free and easy to separate and recycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The infrared (FTIR) spectra of the raw materials 2,4,6-tris(4-pyridyl)-1,3,5-triazine (abbreviated as TPT), propyne bromide and the prepared Tz-IRPA-1 used in this Example 1 are shown;

[0027] Figure 2X-ray photoelectron spectroscopy (XPS) spectrum of Tz-IRPA-1 prepared in Example 1 and electron paramagnetic resonance (EPR) spectra of Tz-IRPA-1 and TPh-IRPA-2, including (A) full spectrum, (B) C 1s, (C) N 1s, (D) Br3d, (E) O 1s, and (F) EPR spectrum;

[0028] Figure 3 X-ray powder diffraction (XRD) spectra of Tz-IRPA-1 and TPh-IRPA-2 prepared in Example 1;

[0029] Figure 4 Scanning electron microscope (SEM) images of Tz-IRPA-1 prepared in Example 1, including (A) a 250 nm SEM spectrum and (B) a 2.5 μm SEM image;

[0030] Figure 5 N2 adsorption-desorption curve and BJH pore size distribution diagram of Tz-IRPA-1 prepared in Example 1 at 77K. In the figure, (A) N2 adsorption-desorption curve and (B) BJH pore size distribution diagram;

[0031] Figure 6 The CO2 adsorption isotherms of Tz-IRPA-1 prepared in Example 1 at 273K and 298K;

[0032] Figure 7 This is the solid-state carbon NMR spectrum of Tz-IRPA-1 prepared in Example 1;

[0033] Figure 8 Ultraviolet-visible absorption (UV-vis) spectra of Tz-IRPA-1 and TPh-IRPA-2 prepared in Example 1 and Tauc plots obtained using the Kubelka-Munk function and optical band gap linear fitting, where (A) UV-vis spectra and (B) Tauc plots;

[0034] Figure 9 The photocurrent density response and impedance spectrum represented by Nyquist plot of Tz-IRPA-1 and TPh-IRPA-2 prepared in Example 1, including (A) photocurrent density response and (B) impedance spectrum;

[0035] Figure 10 This is a study on the substrate applicability of Tz-IRPA-1 prepared in Example 1 in the photocatalytic CO2 cycloaddition reaction;

[0036] Figure 11-17 is the product of each reaction in this embodiment 3 1 H NMR spectrum. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the embodiments.

[0038] Example 1: Preparation of cationic free radical triazine polyacetylene Tz-IRPA-1

[0039] Synthesis route:

[0040]

[0041] 2,4,6-Tris(4-pyridyl)-1,3,5-triazine (0.3 mmol, 0.0937 g) and propargyl bromide (0.9 mmol, 0.1071 g) were weighed and fully dissolved in N,N-dimethylformamide (10 mL). The mixture was then placed in a 25 mL reaction tube and reacted in a 120°C reaction module for 24 h. After the reaction, the mixture was cooled to room temperature, washed with water, trifluoroethanol, and ethanol several times, and then filtered. The filtered solid was placed in a vacuum drying oven at 80°C for 12 h to obtain the cationic free radical triazine-based polyacetylene Tz-IRPA-1. TPh-IRPA-2 was prepared using the same method, replacing 2,4,6-tris(4-pyridyl)-1,3,5-triazine with 1,3,5-tris(pyridin-4-yl)benzene. The synthetic route is as follows:

[0042]

[0043] Structural and compositional characterization:

[0044] Figure 1 The infrared spectra of the raw material 2,4,6-tris(4-pyridyl)-1,3,5-triazine (abbreviated as TPT) and the prepared Tz-IRPA-1 used in this Example 1 are shown in FIG. As can be seen from the figure, the polymer Tz-IRPA-1 has an infrared spectrum at 1630 cm -1 The signal appearing at can be attributed to C=N + Stretching vibration. At 3030cm -1 The characteristic peak at 647cm is attributed to the Ar-H stretching vibration of the benzene ring. -1 The peak at 3410cm is a C=C double bond, indicating that we have successfully synthesized a porous polymer with a polyacetylene structure containing double bonds. -1 The broad peak at is believed to be the hydrogen-bonded water adsorbed by the groups or the water adsorbed in the humid air.

[0045] Figure 2A is the X-ray photoelectron spectroscopy (XPS) spectrum of Tz-IRPA-1. The complete XPS spectrum provides the detailed atomic concentrations of the elements in Tz-IRPA-1: C (76.09 at%), N (15.06 at%), O (5.83 at%), and Br (3.02 at%). Figure 2 In B), the C1s peak is decomposed into the triazine ring, the CN in the aromatic ring and the C=N bond, located at 285.5eV, and the side chain C-Br peak at 286.4eV. Figure 2 C), the main peak at 400.9 eV is attributed to the pyridinium N cation (Py-N + The characteristic peak at 399.1eV is attributed to the pyridine radical (Py · -N) in the N atom, the peak at 398.6eV should be attributed to the neutral N in the triazine ring. Br 3d spectrum ( Figure 2 D) confirm Br - The presence of anions. In addition, in the O1s spectrum with a binding energy of 531.3 eV ( Figure 2 E), water adsorbed in the material is detected. Figure 2 F is the electron paramagnetic resonance (EPR) spectrum of Tz-IRPA-1 and TPh-IRPA-2. It can be seen from the figure that Tz-IRPA-1 and TPh-IRPA-2 respectively show EPR signals of different intensities, indicating that pyridine radicals have been successfully introduced into the synthesized polymer. Among them, the free radical signal of Tz-IRPA-1 is the strongest, with a g value of 2.0063. It is worth noting that the free radical intensity of the polymer TPh-IRPA-2 without a triazine structure is significantly weaker than that of Tz-IRPA-1 containing a triazine structure. This shows that the triazine structure is conducive to the stable existence of free radicals. These results show that this example successfully prepared a cationic free radical type triazine-based polyacetylene Tz-IRPA-1.

[0046] Figure 3 are the XRD spectra of Tz-IRPA-1 and TPh-IRPA-2, indicating that the prepared polymers Tz-IRPA-1 and TPh-IRPA-2 are amorphous structures.

[0047] Figure 4 The scanning electron microscope (SEM) image of Tz-IRPA-1 shows that the polymer has a fluffy morphology of nanoparticle stacking.

[0048] The porous structure of Tz-IRPA-1 was confirmed by nitrogen adsorption-desorption test at 77K. Figure 5As shown in A, the polymer Tz-IRPA-1 exhibits a type II adsorption isotherm with significant N2 absorption at high relative pressures of 0.80 < P / P0 < 0.99, indicating the presence of a large number of mesoporous pores in the polymer. The BET specific surface area of Tz-IRPA-1 is 22.6 m 2 g -1 . In addition, the pore size distribution of Tz-IRPA-1 was calculated using the BJH model. As Figure 5 shown in B, Tz-IRPA-1 has a narrow mesoporous distribution in the range of 4.43 - 11.43 nm, which is consistent with the N2 adsorption-desorption isotherm.

[0049] Figure 6 Figure C shows the CO2 adsorption isotherms of Tz-IRPA-1 at 273 K and 298 K. It can be seen that Tz-IRPA-1 has good CO2 adsorption capacity, and the CO2 adsorption amounts at 273 K and 298 K are 0.67 and 0.42 mmol g -1 respectively.

[0050] Figure 7 Figure D is the solid-state 13C NMR spectrum of Tz-IRPA-1. The broad signal peak at 170.4 ppm is attributed to the carbon atoms on the triazine ring. The two obvious signal peaks at 147.6 ppm and 127.8 ppm are attributed to the carbon atoms in the pyridine ring C-N and C═C linkers, respectively.

[0051] Figure 8 Figure E shows the UV-visible absorption spectra ( Figure 8 A) of Tz-IRPA-1 and TPh-IRPA-2 prepared in Example 1. Tz-IRPA-1 has a broad absorption in the visible light range of 400 - 800 nm, while the visible light absorption ability of TPh-IRPA-2 is lower than that of Tz-IRPA-1, indicating that Tz-IRPA-1 has a stronger visible light absorption ability. As Figure 8 shown in B, according to the linear fitting of the Kubelka-Munk function and the optical band gap, the optical band gaps of Tz-IRPA-1 and TPh-IRPA-2 are 1.27 and 1.39 eV, respectively. It is worth noting that Tz-IRPA-1 shows a broad visible light absorption and a narrow band gap, confirming that Tz-IRPA-1 has a stronger light collection ability.

[0052] Figure 9 Figure F shows the photocurrent density response and the impedance spectrum (EIS) represented by the Nyquist plot of Tz-IRPA-1 and TPh-IRPA-2 prepared in Example 1. First, a photocurrent density response experiment was carried out on the samples to evaluate the separation and mobility of photoinduced charge carriers. As Figure 9As shown in A, when the light is turned on, both samples show a photocurrent density response, among which Tz-IRPA-1 has the strongest photocurrent density response, indicating that it has the best charge separation efficiency. Figure 9 In B), the smaller semicircle indicates that the photocatalytic material has a lower charge transfer resistance and can effectively transport and separate photogenerated carriers. Figure 9 As shown in Figure B, their arc radius is Tz-IRPA-1>TPh-IRPA-2. The interface impedance of Tz-IRPA-1 is smaller and its internal electron transfer ability is stronger, which means that Tz-IRPA-1 can be used as an effective photocatalyst.

[0053] Example 2: Comparison of catalytic performance and reusability of Tz-IRPA-1 in photocatalytic CO2 cycloaddition reaction

[0054] The Tz-IRPA-1 and TPh-IRPA-2 obtained in Example 1 were used in the cycloaddition reaction of CO2 and epichlorohydrin, respectively. The reaction conditions are: epichlorohydrin (1 mmol), the two catalysts (50 mg) prepared in Example 1 were added to a 25 mL Schlenk reaction tube, the air in the reaction tube was first discharged with a vent tube connected to a CO2 gas cylinder, and then a balloon filled with CO2 (0.1 MPa) was inserted into the reaction tube. At room temperature, the reaction was carried out under white light (9 W), blue light (8 W) and dark conditions for 24 hours. After the reaction was completed, a certain amount of ethyl acetate was added to dilute it and stirred at room temperature for 20 minutes. The solution was taken out and centrifuged, and the supernatant was taken out and used 1 The yield was calculated by H NMR analysis, and the results are shown in Table 1. As can be seen from Table 1, under the same conditions, catalyst Tz-IRPA-1 exhibited better catalytic activity under white light atmosphere, and the product yield was 99% at room temperature within 24 h.

[0055] Table 1 Results of the cycloaddition reaction of CO2 and epichlorohydrin catalyzed by catalysts Tz-IRPA-1 and TPh-IRPA-2

[0056]

[0057] Reaction conditions: photocatalyst (50 mg), epichlorohydrin (1 mmol), normal temperature and pressure, no solvent.

[0058] Table 2 Recycling results of the cycloaddition reaction of CO2 and epichlorohydrin catalyzed by Tz-IRPA-1

[0059]

[0060] Reaction conditions: photocatalyst (50 mg), epichlorohydrin (1 mmol), normal temperature and pressure, no solvent, white light (9 W).

[0061] The above experiment was repeated using the catalyst Tz-IRPA-1, with the same reaction temperature and reaction time conditions repeated 1-5 times. The experimental results are shown in Table 2. As can be seen from Table 2, the catalyst Tz-IRPA-1 has good reusability, and the product yield only slightly decreased after the catalyst was reused 5 times.

[0062] Example 3: Comparison of activity and substrate applicability of catalyst Tz-IRPA-1 in the photocatalytic cycloaddition reaction of CO2 with different epoxides.

[0063] In this example, Tz-IRPA-1 prepared in Example 1 was used as a catalyst and various epoxy compounds were used as substrates to compare the activity of the Tz-IRPA-1 catalyst and study the substrate expansion of the CO2 cycloaddition catalytic reaction.

[0064] The following are the specific experimental steps:

[0065] Epichlorohydrin (1mmol) and the Tz-IRPA-1 catalyst (50mg) in Example 1 were added to a 25mL Schlenk reaction tube. The air in the reaction tube was first discharged with a vent tube connected to a CO2 gas cylinder, and then a balloon filled with CO2 (0.1MPa) was inserted into the Schlenk tube and reacted at room temperature for 24 hours. After the reaction was completed, a certain amount of ethyl acetate was added to dilute it and stirred at room temperature for 20 minutes. The solution was taken out and centrifuged, and the supernatant was taken out. The solvent was evaporated using a vacuum rotary evaporator to obtain the crude product 4-(chloromethyl)-1,3-dioxepin-2-one (2c). The yield was calculated by nuclear magnetic hydrogen spectrum. 1 H NMR spectrum Figure 11 As shown, the NMR data are as follows: 1 H NMR (400MHz, CDCl3): δ=5.00~4.94(1H,CH), 4.60~4.37(1H,CH2), 4.41~4.37(1H,CH2) and 3.73~3.66ppm(2H,CH2).

[0066] Under similar reaction conditions, propylene oxide, butylene oxide, epibromopropane, 1,2-epoxyhexane, allyl glycidyl ether and phenyl glycidyl ether were used to replace epichlorohydrin respectively. While other conditions remained unchanged, the reaction time (24-48h) and catalyst dosage (40-80mg) were changed to test the catalytic performance of catalyst Tz-IRPA-1 in the catalytic conversion of CO2 and other epoxy compounds. The experimental results are shown in Figure 2. Figure 10The reaction products are: 4-(methyl)-1,3-dioxo-2-one, 4-(ethyl)-1,3-dioxo-2-one, 4-(bromomethyl)-1,3-dioxo-2-one, 4-butyl-1,3-dioxo-2-one, 4-(allyloxymethyl)-1,3-dioxo-2-one, 4-(phenoxymethyl)-1,3-dioxo-2-one, and the like. 1 The H NMR spectra were Figure 12-17 As shown, the reaction product 1 The HNMR spectrum data are as follows:

[0067] 4-(Methyl)-1,3-dioxetan-2-one (2a) 1 HNMR (400 MHz, CDCl3) Figure 12 ): δ=4.90~4.81(1H,CH), 4.57~4.53(1H,CH2), 4.04~4.01(1H,CH2) and 1.51~1.49ppm(3H,CH3).

[0068] 4-(Ethyl)-1,3-dioxetane-2-one (2b) 1 H NMR (400 MHz, CDCl3) Figure 13 ): δ=4.69~4.63(1H,CH), 4.54~4.50(1H,CH2), 4.10~4.06(1H,CH2), 1.87~1.73(2H,CH2) and 1.05~1.01ppm(3H,CH3).

[0069] 4-(Bromomethyl)-1,3-dioxetan-2-one (2d) 1 H NMR (400 MHz, CDCl3) Figure 14 ): δ=4.98~4.93(1H,CH), 4.61~4.57(1H,CH2), 4.44~4.40(1H,CH2) and 3.76~3.69ppm(2H,CH2).

[0070] 4-Butyl-1,3-dioxepin-2-one (2e) 1 H NMR (400 MHz, CDCl3) Figure 15 ): δ=4.72~4.65(1H,CH2), 4.53~4.49(1H,CH2), 4.07~4.03(1H,CH2), 1.80~1.66(2H,CH2), 1.42~1.3(4H,CH2), and 0.92~0.89ppm(3H,CH3).

[0071] 4-(Allyloxymethyl)-1,3-dioxetan-2-one (2f) 1 H NMR (400 MHz, CDCl3) Figure 16 ): δ=5.88~5.78(1H,CH),5.27~5.16(2H,CH2),4.80-4.79(1H,CH),4.47~4.46(1H,CH2),4.37~4.36(1H,CH2),4.02~4.01(2H,CH2)and 3.68~3.58ppm(2H,CH2).

[0072] 4-(Phenoxymethyl)-1,3-dioxetan-2-one (2g) 1 H NMR (400 MHz, CDCl3) Figure 17 ): δ=7.29~7.26(2H,CH),7.00~6.97(1H,CH),6.90~6.87(2H,CH),4.98(1H,CH),4.59~4.55(1H,CH2),4.51~4.47(1H,CH2),4.21~4.19(1H,CH2)and 4.14-4.06ppm(1H,CH2).

[0073] from Figure 10 The data show that the catalyst Tz-IRPA-1 has excellent catalytic activity and good substrate applicability for different reactants. This may be due to the fact that the catalyst Tz-IRPA-1 is rich in polypropyne and halogen Br - anion.

Claims

1. A cationic radical type triazine-based polyacetylene, characterized in that: The polymer is a functionalized cationic free radical triazine-based polyacetylene Tz-IRPA-1, and its chemical structure is shown in Formula 3:

2. A method for preparing the cationic radical type triazine-based polyacetylene according to claim 1, characterized in that: The following steps are involved: Using 2,4,6-tris(4-pyridyl)-1,3,5-triazine shown in formula 1 and propyne bromide shown in formula 2 as raw materials, a cationic free radical triazine-based polyacetylene Tz-IRPA-1 shown in formula 3 was synthesized in one step through an in-situ polymerization reaction induced by quaternization; The structural formula of 2,4,6-tris(4-pyridyl)-1,3,5-triazine shown in Formula 1 is The structure of formula 2 is 3. The method for preparing a cationic radical type triazine-based polyacetylene according to claim 2, characterized in that: The specific steps include: S1: Add 2,4,6-tris(4-pyridyl)-1,3,5-triazine shown in Formula 1 into a container containing an organic solvent N,N-dimethylformamide, and stir to completely dissolve it to obtain a uniform solution; S2: The uniform solution obtained in step S1 is transferred to a reaction tube, propargyl bromide is added, and the mixed solution is placed in the reaction tube. A quaternization-induced polymerization reaction is carried out at a certain reaction temperature for a period of time without a catalyst and an initiator. After the reaction is completed, a cationic free radical type triazine-based polyacetylene is obtained by washing, filtering, and drying.

4. The method for preparing a cationic radical type triazine-based polyacetylene according to claim 3, characterized in that: In the step S2, the molar ratio of 2,4,6-tris(4-pyridyl)-1,3,5-triazine represented by Formula 1 to propyne bromide is 1:

3.

5. The method for preparing a cationic radical type triazine-based polyacetylene according to claim 3, characterized in that: In step S2, the reaction temperature is 120° C. and the reaction time is 24 h.

6. Use of the cationic free radical triazine-based polyacetylene Tz-IRPA-1 according to claim 1 in photocatalytic CO2 cycloaddition.

7. The use according to claim 6, characterized in that Specifically include: Using an epoxy compound as a substrate and the Tz-IRPA-1 described in claim 1 as a heterogeneous photocatalyst, a photocatalytic cycloaddition reaction of CO2 and the epoxy compound is carried out in a CO2 atmosphere at room temperature and pressure under white light illumination.

8. The use according to claim 7, characterized in that The structural formula of the epoxy compound is Wherein, R is one of methyl, ethyl, chloromethyl, bromomethyl, n-butyl, allylmethoxy and benzyloxy.

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