A single-crystal covalent organic framework material, a preparation method and application of purifying c3h6 from ternary c3 hydrocarbons in one step

Abstract

The application discloses a kind of single crystal covalent organic framework materials, the structural formula of single crystal covalent organic framework material is:;Single crystal covalent organic framework material of the application has the advantages such as high adsorption capacity, stable selectivity, low regeneration energy consumption and excellent cycle performance, provides a new adsorption separation material system for propylene low-energy consumption purification;The adsorption capacity of C3H4 and C3H8 is significantly higher than C3H6 under normal temperature and pressure, so as to realize the one-step separation and purification of propylene in C3H4 / C3H6 / C3H8 ternary mixed gas, and polymerization grade propylene can be directly obtained.

Description

Technical Field

[0001] This invention belongs to the field of porous organic materials and hydrocarbon gas separation technology, specifically relating to a single-crystal covalent organic framework material, its preparation method, and its application in purifying C3H6 from ternary C3 hydrocarbons in one step. Background Technology

[0002] Propylene (C3H6) is one of the world's most important bulk chemical raw materials, widely used in the production of polypropylene, acrylonitrile, propylene oxide, and other products. With the rapid development of the high-end materials industry, global demand for propylene continues to grow. However, in industrial production processes such as naphtha cracking or propane dehydrogenation, byproducts such as propyne (C3H4) and propane (C3H8) are inevitably generated, forming a ternary mixture system of C3H4 / C3H6 / C3H8. Due to the high similarity of these three molecules in terms of kinetic diameter, polarizability, and physicochemical properties, efficient purification of propylene remains one of the most energy-intensive and technically challenging separation processes in the petrochemical industry. Currently, industrial methods mainly employ cryogenic distillation and selective hydrogen processing to remove propyne and propane. These methods suffer from high energy consumption, complex processes, and significant carbon emissions, making it difficult to meet the demands of green and low-carbon development. Therefore, developing an energy-efficient separation material capable of one-step propylene purification under ambient temperature and pressure conditions has significant industrial and scientific importance.

[0003] Covalent organic frameworks (COFs) are a class of porous crystalline materials formed by organic building blocks linked by covalent bonds. They possess advantages such as strong structural designability, tunable pore size, large specific surface area, and excellent chemical stability. In particular, three-dimensional covalent organic frameworks (3D COFs), compared to two-dimensional COFs, have a fully extended three-dimensional network structure and uniform open channels, which are more conducive to the selective adsorption and transport of gas molecules. However, most current COF materials suffer from low crystallinity, difficulty in structural analysis, and insufficient phase purity, limiting their application in fine gas separation. Especially in achieving one-step purification of propylene in the C3H4 / C3H6 / C3H8 ternary system, there is still a lack of effective solutions based on single COF materials. Summary of the Invention

[0004] The present invention addresses the problems of high energy consumption and complex process in existing propylene purification processes by providing a single-crystal covalent organic framework material with a highly crystalline three-dimensional structure, and applying it to the one-step separation and purification of propylene in the C3H4 / C3H6 / C3H8 ternary system under normal temperature and pressure conditions.

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

[0006] A single-crystal covalent organic framework material, the structural formula of which is: .

[0007] Furthermore, the preparation method of single-crystal covalent organic framework materials includes the following steps:

[0008] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl, aniline and anhydrous 1,4-dioxane to the reaction flask in sequence, and sonicate until the solid is completely dissolved.

[0009] Step 2: Add glacial acetic acid to the reaction flask;

[0010] Step 3: Add 4,4',4'',4'''-methanetetraphenylamine dissolved in anhydrous 1,4-dioxane to the reaction flask;

[0011] Step 4: The reaction mixture is allowed to stand at room temperature to react and generate TAM-TFTB-COF single crystal particles;

[0012] Step 5: The single crystal particles are exchanged with solvent, filtered, and activated to obtain an activated sample, which is a single crystal covalent organic framework material.

[0013] Furthermore, the static reaction time in step four is 10 ± 2 days.

[0014] Furthermore, the solvent in step five is 1,4-dioxane, methanol, and acetone.

[0015] Furthermore, the single crystal particles are exchanged in 1,4-dioxane for 24 hours, with fresh 1,4-dioxane being replaced every 8 hours during the exchange.

[0016] Furthermore, the single crystal particles are exchanged in methanol for 24 hours, with fresh methanol being replaced every 8 hours during the exchange period.

[0017] Furthermore, the single crystal particles are exchanged in acetone for 24 hours, with fresh acetone being replaced every 8 hours during the exchange.

[0018] Furthermore, the activation in step five is performed under dynamic vacuum conditions at 100°C for 12 hours.

[0019] An application of a single-crystal covalent organic framework material in the purification of C3H6 in ternary C3 hydrocarbons, wherein the single-crystal covalent organic framework material according to any one of claims 1-8 is used for the separation and purification of C3H6 in the C3H4 / C3H6 / C3H8 ternary system under normal temperature and pressure conditions.

[0020] Furthermore, a single-crystal covalent organic framework material enables one-step purification of C3H6 in a ternary system.

[0021] The technological advancements achieved by this invention compared to existing technologies are as follows:

[0022] (1) The single-crystal covalent organic framework material of the present invention has the advantages of high adsorption capacity, stable selectivity, low regeneration energy consumption and excellent cycle performance. When applied to the one-step separation and purification of propylene in the C3H4 / C3H6 / C3H8 ternary system under normal temperature and pressure conditions, it significantly reduces energy consumption and solves the problems of high energy consumption and complex process of existing propylene purification process.

[0023] (2) The application of this invention has pioneered a new technical path for one-step propylene purification in a ternary system using a single single-crystal covalent organic framework material.

[0024] (3) The adsorption heat of the single-crystal covalent organic framework material of the present invention for C3H4, C3H6, and C3H8 is less than 35 kJ / mol. -1 It is easily regenerated. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0026] In the attached diagram:

[0027] Figure 1 The infrared spectrum of TAM-TFTB-COF;

[0028] Figure 2 The solid-state carbon NMR spectrum of TAM-TFTB-COF;

[0029] Figure 3 The powder X-ray diffraction pattern of TAM-TFTB-COF;

[0030] Figure 4 A scanning electron microscope image of TAM-TFTB-COF;

[0031] Figure 5 Thermogravimetric curve of TAM-TFTB-COF;

[0032] Figure 6 This is a diagram of the stacking structure of TAM-TFTB-COF;

[0033] Figure 7 The nitrogen adsorption-desorption isotherm of TAM-TFTB-COF at 77 K;

[0034] Figure 8 The adsorption isotherms of TAM-TFTB-COF at 298 K for C3H4, C3H6, and C3H8 are shown.

[0035] Figure 9 The breakthrough curve of TAM-TFTB-COF for a ternary gas mixture of C3H4 / C3H8 / C3H6 is shown. Detailed Implementation

[0036] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0037] Example: A single-crystal covalent organic framework material, its preparation method, and its application in purifying C3H6 from ternary C3 hydrocarbons in one step.

[0038] Laboratory supplies: 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl (TFTB), 4,4',4'',4'''-methanetetraphenylamine (TAM), aniline, anhydrous 1,4-dioxane, 1,4-dioxane, methanol, acetone, etc., can all be purchased on the market.

[0039] This embodiment 1 discloses a method for preparing a single-crystal covalent organic framework material, including the following steps:

[0040] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl, aniline and anhydrous 1,4-dioxane to the reaction flask in sequence, and sonicate until the solid is completely dissolved.

[0041] Step 2: Add glacial acetic acid to the reaction flask;

[0042] Step 3: Add 4,4',4'',4'''-methanetetraphenylamine dissolved in anhydrous 1,4-dioxane to the reaction flask;

[0043] Step 4: The reaction mixture is allowed to stand at room temperature to react and generate TAM-TFTB-COF single crystal particles;

[0044] Step 5: The single crystal particles are exchanged with solvent, filtered, and activated to obtain an activated sample, which is a single crystal covalent organic framework material.

[0045] This embodiment 2 discloses a method for preparing single-crystal covalent organic framework materials, including the following steps:

[0046] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl, aniline and anhydrous 1,4-dioxane to the reaction flask in sequence, and sonicate until the solid is completely dissolved.

[0047] Step 2: Add glacial acetic acid to the reaction flask;

[0048] Step 3: Add 4,4',4'',4'''-methanetetraphenylamine dissolved in anhydrous 1,4-dioxane to the reaction flask;

[0049] Step 4: The reaction mixture is allowed to stand at room temperature for 10±2 days to generate TAM-TFTB-COF single crystal particles;

[0050] Step 5: Place the single crystal particles in solvents 1,4-dioxane, methanol, and acetone for 24 hours each (replace with fresh solvent of the same type every 8 hours during the exchange), filter, and activate under dynamic vacuum conditions at 100℃ for 12 hours to finally obtain activated samples, which are single crystal covalent organic framework materials.

[0051] This embodiment 3 discloses a method for preparing a single-crystal covalent organic framework material, including the following steps:

[0052] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl (179.6 mg, 0.26 mmol), aniline (1.0 mL, 42 equivalents), and 5.0 mL of anhydrous 1,4-dioxane to a 20 mL reaction flask in sequence, and sonicate the mixture until the solid is completely dissolved;

[0053] Step 2: Add 2.0 mL of glacial acetic acid to the reaction flask;

[0054] Step 3: Add 99.0 mg, 0.26 mmol of 4,4',4'',4'''-methanetetraphenylamine (99.0 mg, 0.26 mmol) dissolved in 5.0 mL of anhydrous 1,4-dioxane to the solution in the reaction flask;

[0055] Step 4: The reaction mixture was allowed to stand at room temperature for 10 days to generate a large number of TAM-TFTB-COF single crystal particles with regular octahedral morphology.

[0056] Step 5: Place the single crystal particles in 1,4-dioxane for 24 hours for exchange, replacing them with fresh 1,4-dioxane every 8 hours during the exchange period;

[0057] Step 6: Place the single crystal particles in methanol for 24 hours to exchange, replacing the methanol with fresh methanol every 8 hours during the exchange period;

[0058] Step 7: The single crystal particles were then placed in acetone for 24 hours for exchange, with fresh acetone replaced every 8 hours during the exchange. Afterwards, the mixture was filtered and activated under dynamic vacuum at 100°C for 12 hours, ultimately yielding 137.7 mg of activated sample, with a yield of 53%. The structural formula of the activated sample is: .

[0059] This embodiment 4 discloses a method for preparing a single-crystal covalent organic framework material, including the following steps:

[0060] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl (179.6 mg, 0.26 mmol), aniline (1.0 mL, 42 equivalents), and 5.0 mL of anhydrous 1,4-dioxane to a 20 mL reaction flask in sequence, and sonicate the mixture until the solid is completely dissolved;

[0061] Step 2: Add 2.0 mL of glacial acetic acid to the reaction flask;

[0062] Step 3: Add 99.0 mg, 0.26 mmol of 4,4',4'',4'''-methanetetraphenylamine (99.0 mg, 0.26 mmol) dissolved in 5.0 mL of anhydrous 1,4-dioxane to the solution in the reaction flask;

[0063] Step 4: The reaction mixture was allowed to stand at room temperature for 8 days to generate a large number of TAM-TFTB-COF single crystal particles with regular octahedral morphology.

[0064] Step 5: Place the single crystal particles in 1,4-dioxane for 24 hours for exchange, replacing them with fresh 1,4-dioxane every 8 hours during the exchange period;

[0065] Step 6: Place the single crystal particles in methanol for 24 hours to exchange, replacing the methanol with fresh methanol every 8 hours during the exchange period;

[0066] Step 7: The single crystal particles were then placed in acetone for 24 hours for exchange, with fresh acetone replaced every 8 hours during the exchange. Afterwards, the mixture was filtered and activated under dynamic vacuum at 100°C for 12 hours, ultimately yielding 121.5 mg of activated sample, with a yield of 46.7%. The structural formula of the activated sample is as follows: .

[0067] Example 5 discloses a method for preparing a single-crystal covalent organic framework material, including the following steps:

[0068] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl (179.6 mg, 0.26 mmol), aniline (1.0 mL, 42 equivalents), and 5.0 mL of anhydrous 1,4-dioxane to a 20 mL reaction flask in sequence, and sonicate the mixture until the solid is completely dissolved;

[0069] Step 2: Add 2.0 mL of glacial acetic acid to the reaction flask;

[0070] Step 3: Add 99.0 mg, 0.26 mmol of 4,4',4'',4'''-methanetetraphenylamine (99.0 mg, 0.26 mmol) dissolved in 5.0 mL of anhydrous 1,4-dioxane to the solution in the reaction flask;

[0071] Step 4: The reaction mixture was allowed to stand at room temperature for 12 days to generate a large number of TAM-TFTB-COF single crystal particles with regular octahedral morphology.

[0072] Step 5: Place the single crystal particles in 1,4-dioxane for 24 hours for exchange, replacing them with fresh 1,4-dioxane every 8 hours during the exchange period;

[0073] Step 6: Place the single crystal particles in methanol for 24 hours to exchange, replacing the methanol with fresh methanol every 8 hours during the exchange period;

[0074] Step 7: The single crystal particles were then placed in acetone for exchange for 24 hours, with fresh acetone replaced every 8 hours during the exchange. Afterwards, the mixture was filtered and activated under dynamic vacuum at 100°C for 12 hours, ultimately yielding 143.9 mg of activated sample, with a yield of 55.3%. The structural formula of the activated sample is as follows: .

[0075] This embodiment 6 discloses a method for preparing a single-crystal covalent organic framework material, including the following steps:

[0076] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl (179.6 mg, 0.26 mmol), aniline (1.0 mL, 42 equivalents), and 5.0 mL of anhydrous 1,4-dioxane to a 20 mL reaction flask in sequence, and sonicate the mixture until the solid is completely dissolved;

[0077] Step 2: Add 2.0 mL of glacial acetic acid to the reaction flask;

[0078] Step 3: Add 99.0 mg, 0.26 mmol of 4,4',4'',4'''-methanetetraphenylamine (99.0 mg, 0.26 mmol) dissolved in 5.0 mL of anhydrous 1,4-dioxane to the solution in the reaction flask;

[0079] Step 4: The reaction mixture was allowed to stand at room temperature for 2 days to generate a small number of TAM-TFTB-COF single crystal particles with regular octahedral morphology.

[0080] Step 5: Place the single crystal particles in 1,4-dioxane for 24 hours for exchange, replacing them with fresh 1,4-dioxane every 8 hours during the exchange period;

[0081] Step 6: Place the single crystal particles in methanol for 24 hours to exchange, replacing the methanol with fresh methanol every 8 hours during the exchange period;

[0082] Step 7: Place the single crystal particles in acetone for 24 hours for exchange, replacing the acetone with fresh acetone every 8 hours during the exchange. Then filter and activate under dynamic vacuum at 100°C for 12 hours to obtain the activated sample. The structural formula of the activated sample is: .

[0083] This embodiment 7 discloses a method for preparing a single-crystal covalent organic framework material, including the following steps:

[0084] Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl (179.6 mg, 0.26 mmol), aniline (1.0 mL, 42 equivalents), and 5.0 mL of anhydrous 1,4-dioxane to a 20 mL reaction flask in sequence, and sonicate the mixture until the solid is completely dissolved;

[0085] Step 2: Add 2.0 mL of glacial acetic acid to the reaction flask;

[0086] Step 3: Add 99.0 mg, 0.26 mmol of 4,4',4'',4'''-methanetetraphenylamine (99.0 mg, 0.26 mmol) dissolved in 5.0 mL of anhydrous 1,4-dioxane to the solution in the reaction flask;

[0087] Step 4: The reaction mixture was allowed to stand at room temperature for 24 days to generate a large number of TAM-TFTB-COF single crystal particles with regular octahedral morphology.

[0088] Step 5: Place the single crystal particles in 1,4-dioxane for 24 hours for exchange, replacing them with fresh 1,4-dioxane every 8 hours during the exchange period;

[0089] Step 6: Place the single crystal particles in methanol for 24 hours to exchange, replacing the methanol with fresh methanol every 8 hours during the exchange period;

[0090] Step 7: The single crystal particles were then placed in acetone for 24 hours for exchange, with fresh acetone replaced every 8 hours during the exchange. Afterwards, the mixture was filtered and activated under dynamic vacuum at 100°C for 12 hours, ultimately yielding 179.5 mg of activated sample, with a yield of 69.0%. The structural formula of the activated sample is as follows: .

[0091] Single-crystal covalent organic framework materials are constructed by a Schiff base condensation reaction of 4,4',4'',4'''-methanetetraphenylamine and 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl, as shown in the following reaction formula: The obtained material has a pure-phase single-crystal structure and the molecular formula is: C 69 H 50N4O4 exhibits a regular octahedral morphology, with the amount of material produced gradually increasing with reaction time. Its crystal belongs to the tetragonal crystal system, with space group P4̅n2. In its crystal structure, the building units can be simplified to four-connected tetrahedral nodes, linked by imine bonds to form a triple interpenetrating dia-b topological three-dimensional network structure, constructing regular three-dimensional open channels. The pore size is mainly distributed in the range of approximately 0.88-1.50 nm, and the specific surface area can reach up to 2899 m². 2 g -1 It possesses permanent microporous features and excellent structural stability.

[0092] The examples provided characterize the activated single-crystal covalent organic framework material:

[0093] (a) Fourier transform infrared spectroscopy (FT-IR)

[0094] The infrared spectra of the samples were determined using a Bruker ALPHA II infrared spectrometer. The results showed that the NH stretching vibration peaks in the original monomer (approximately 3410 and 3338 cm⁻¹) were present. -1 The peak of the original aldehyde group C=O stretching vibration (approximately 1698 cm⁻¹) disappeared; -1 ) disappeared; at 1625-1629 cm -1 A new C=N stretching vibration peak appears at this point; the above structure indicates that the imine condensation reaction occurred successfully and the target covalent organic framework was successfully constructed. Figure 1 .

[0095] (b) Solid-state nuclear magnetic resonance (NMR) 13 C CP / MAS NMR)

[0096] The measurements were performed using a Bruker Avance II 400 MHz solid-state NMR spectrometer. A distinct C=N bond resonance peak was observed at approximately 157 ppm, further confirming the successful formation of the imine bond. Figure 2 .

[0097] (c) Powder X-ray diffraction (PXRD)

[0098] The diffraction pattern of the sample was determined using a PANalytical Empyrean X-ray diffractometer (Cu Ka radiation, 45 kV, 40 mA). The TAM-TFTB-COF sample showed multiple strong and sharp diffraction peaks, indicating that the material has high crystallinity. Figure 3 The resulting material has a pure phase single crystal structure.

[0099] (d) Scanning electron microscope (SEM)

[0100] SEM tests showed that the material exhibits a regular octahedral morphology with a size of 3-5 µm. Figure 4 .

[0101] (e) Thermogravimetric analysis (TGA)

[0102] The thermogravimetric analysis (TGA) was performed using a PerkinElmer TG-DTA6300 thermogravimetric analyzer under a nitrogen atmosphere at a heating rate of 10 °C / min. The results show that the material exhibits structural stability up to 400 °C, and no significant skeletal decomposition was observed, indicating that the material possesses good thermal stability. Figure 5 .

[0103] The structure determination and analysis of the activated single-crystal covalent organic framework material obtained in the examples are as follows:

[0104] Three-dimensional electron diffraction (3D ED) data of TAM-TFTB-COF were acquired at an accelerating voltage of 200 kV. The sample was dispersed on a copper mesh and measured at low temperature (100 K). During data acquisition, the electron microscope goniometer stage rotated continuously, with an exposure time of 1.0 s. Data processing was performed using XDS and REDp software. Structural analysis was based on merged and scaled electron diffraction data. The crystal belongs to the tetragonal crystal system with space group P4̅n2. In the crystal structure, the building blocks can be simplified to four-connected tetrahedral nodes, with cell parameters: a = b ≈ 23.0 Å, c ≈ 36.1 Å, α = β = γ = 90°. The 3D ED data, combined with powder diffraction and theoretical simulations, ultimately determined that the material has a triple interpenetrating dia-b topological three-dimensional network structure. Figure 6 The material has regular three-dimensional open channels with pore sizes mainly distributed in the range of approximately 0.88-1.50 nm.

[0105] Gas adsorption performance tests of activated single-crystal covalent organic framework materials obtained in the examples:

[0106] (a) Nitrogen adsorption test

[0107] The nitrogen adsorption-desorption isotherm at 77 K was tested using a Micromeritics ASAP 2020 PLUS HD88. Figure 7 The activated TAM-TFTB-COF exhibits typical type I adsorption behavior, with a BET specific surface area of ​​2899 m². 2 g -1 The volume of the experimental well is 1.15 cm³. 3 g -1 It possesses permanent microporous features and excellent structural stability.

[0108] (b) Adsorption of C3 hydrocarbon gases

[0109] The single-component adsorption isotherm was measured at 298 K and 1 bar, and the results are as follows: C3H4: 294.8 cm⁻¹ 3 g-1 C3H8: 205.2 cm 3 g -1 C3H6: 173.4 cm 3 g -1 The material exhibits an adsorption order of C3H4 > C3H8 > C3H6. Figure 8 Based on this differentiated adsorption behavior, the material can simultaneously and preferentially adsorb C3H4 and C3H8 under normal temperature and pressure conditions, realizing one-step purification of propylene in a ternary mixed gas of C3H4 / C3H6 / C3H8, and directly obtaining polymer-grade propylene products.

[0110] Penetration experiments were conducted on activated single-crystal covalent organic framework materials obtained in the examples.

[0111] Dynamic separation experiments were conducted using a self-built fixed-bed breakthrough apparatus. Approximately 1.0 g of activated TAM-TFTB-COF was packed into a 5.0 mm × 200 mm stainless steel column, and the test was performed at 298 K and 1 atm. The ternary gas mixing ratio was (V / V / V = 1 / 1 / 98, C3H4 / C3H8 / C3H6), and the total flow rate was 1.0 mL / min. -1 , Figure 9 .

[0112] The results showed that C3H6 broke through first, followed by C3H8, and finally C3H6, achieving one-step purification of propylene and directly obtaining polymer-grade C3H6. The adsorbent could be recycled at least five times after He purging regeneration, with no significant decrease in separation performance. This material possesses advantages such as high adsorption capacity, stable selectivity, low regeneration energy consumption, and excellent recyclability.

[0113] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A single-crystal covalent organic framework material, characterized in that: The structural formula of the single-crystal covalent organic framework material is: .

2. The single-crystal covalent organic framework material according to claim 1, characterized in that: The preparation method of single-crystal covalent organic framework materials includes the following steps: Step 1: Add 3,3′,5,5′-tetra(4-formylphenyl)-2,2′,6,6′-tetramethoxybiphenyl, aniline and anhydrous 1,4-dioxane to the reaction flask in sequence, and sonicate until the solid is completely dissolved. Step 2: Add glacial acetic acid to the reaction flask; Step 3: Add 4,4',4'',4'''-methanetetraphenylamine dissolved in anhydrous 1,4-dioxane to the reaction flask; Step 4: The reaction mixture is allowed to stand at room temperature to react and generate TAM-TFTB-COF single crystal particles; Step 5: The single crystal particles are exchanged with solvent, filtered, and activated to obtain an activated sample, which is a single crystal covalent organic framework material.

3. The single-crystal covalent organic framework material according to claim 2, characterized in that: The static reaction time in step four is 10 ± 2 days.

4. The single-crystal covalent organic framework material according to claim 2, characterized in that: The solvents used in step five are 1,4-dioxane, methanol, and acetone.

5. The single-crystal covalent organic framework material according to claim 4, characterized in that: The single crystal particles are exchanged in 1,4-dioxane for 24 hours, with fresh 1,4-dioxane replaced every 8 hours during the exchange.

6. The single-crystal covalent organic framework material according to claim 5, characterized in that: The single crystal particles are exchanged in methanol for 24 hours, with fresh methanol being replaced every 8 hours during the exchange period.

7. The single-crystal covalent organic framework material according to claim 6, characterized in that: The single crystal particles are exchanged in acetone for 24 hours, with fresh acetone being replaced every 8 hours during the exchange period.

8. The single-crystal covalent organic framework material according to claim 2, characterized in that: The activation in step five is performed under dynamic vacuum conditions at 100°C for 12 hours.

9. An application of a single-crystal covalent organic framework material in the purification of C3H6 from ternary C3 hydrocarbons, characterized in that: According to any one of claims 1-8, the single-crystal covalent organic framework material is used for the separation and purification of C3H6 in the C3H4 / C3H6 / C3H8 ternary system under normal temperature and pressure conditions.

10. The application of the single-crystal covalent organic framework material according to claim 9 in the purification of C3H6 from ternary C3 hydrocarbons, characterized in that: A one-step purification method for ternary C3H6 was achieved using a single monocrystalline covalent organic framework material.

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