Crosslinked Teleg base polymers, the resulting Teleg base gas separation membranes and their applications

Abstract

This invention provides a crosslinked telage base polymer, the resulting telage base gas separation membrane, and its applications, belonging to the field of gas separation membrane technology. The crosslinked telage base polymer is prepared by reacting a homopolymer or copolymer formed by polymerizing at least one diamine monomer and its derivative, or at least one polyamine monomer and its derivative, or at least one diamine monomer and its derivative with at least one polyamine monomer and its derivative, with dimethoxymethane and trifluoroacetic acid. This polymer allows for one-step in-situ crosslinking to form a membrane during polymerization, and the resulting membrane exhibits excellent gas separation performance, with high permeability for O2 and H2, and low permeability for N2 and CH4. It can be used for air enrichment, in-situ nitrogen production, hydrogen enrichment, and hydrogen-methane separation.

Description

Technical Field

[0001] This invention belongs to the field of gas separation membrane technology, and particularly relates to a cross-linked Teleg base polymer, the resulting Teleg base gas separation membrane and its applications. Background Technology

[0002] Gas separation technology is an essential technology in many industrial processes, such as flue gas treatment, hydrogen purification, natural gas decarbonization, air oxygen enrichment, and in-situ nitrogen production. Membrane separation technology, in particular, has seen rapid development in recent years due to its advantages such as high efficiency, convenience, and small footprint.

[0003] Membrane-based oxygen enrichment / nitrogen production is currently an important application scenario for membrane gas separation, accounting for more than 50% of all gas membrane separations. Its core component is the membrane material, which is required to have high oxygen flux, high oxygen / nitrogen selectivity, and a certain mechanical strength.

[0004] Base (TB) is a novel, highly permeable, selective, self-porous polymer (Science, 2013, 339, 303), and is a polymer with development potential. CN117247515A will... Base introduces polyimide to improve gas separation performance. CN112275146A uses TB polymer treated with phosphoric acid to solve the technical problems of low selectivity and low separation efficiency of existing separation membranes for light gases such as hydrogen and carbon dioxide.

[0005] The presence of twisted aromatic ring structures and base units in the main molecular chain inhibits the effective stacking of polymer chains, resulting in a relatively large free volume that facilitates gas permeation. Simultaneously, crosslinking inhibits pore collapse, giving it excellent heat resistance, solvent resistance, mechanical strength, chemical stability, and solvent resistance. This makes crosslinked TB a potential candidate material for oxygen / nitrogen separation gas separation membranes. CN108291026A proposes that the functional groups of the TB polymer side chains can react with corresponding covalently crosslinked polymers to form covalent crosslinks or activate unsubstituted aryl groups to undergo nucleophilic aromatic substitution to form covalent crosslinks. Similarly, US9018270 describes an interfacial polymerization technique for preparing thin-film composite membranes including TB layers, but it does not obtain the membrane material through in-situ crosslinking. Therefore, providing a method to prepare crosslinked membranes with excellent gas separation performance without relying on covalent or ionic crosslinking bonds generated by post-membrane treatment would represent a significant advancement in this field. Summary of the Invention

[0006] This invention provides a crosslinked Teleg base polymer, the resulting Teleg base gas separation membrane, and its applications. The polymer can be crosslinked in situ in one step during polymerization to form a membrane, and the resulting membrane has excellent gas separation performance, with high O2 permeability and low N2 permeability. It can be used for CO2 removal from natural gas / biogas, hydrogen recovery, and air separation.

[0007] To achieve the above objectives, the present invention provides a crosslinked telage base polymer, which is prepared by reacting at least one diamine monomer and its derivative, or at least one polyamine monomer and its derivative, or at least one polyamine monomer and its derivative with at least one diamine monomer and its derivative, with dimethoxymethane and trifluoroacetic acid, wherein the molar amount of dimethoxymethane is 2-4 times that of the amino functional group, and the molar amount of trifluoroacetic acid is 30-200 times that of the amino monomer.

[0008] Preferably, the structural formula of the homopolymer or copolymer formed by polymerizing at least one diamine monomer and its derivative with at least one polyamine monomer and its derivative is shown in formula (1) or formula (2) below:

[0009]

[0010] Wherein, A represents the polyamine moiety, B represents the diamine moiety, and the molar ratio of A to B is 0.0001:1 to 1:0.

[0011] Preferably, the gelation rate of the homopolymer or copolymer is in the range of 0-100.

[0012] Preferably, the diamine moiety is selected from any one of the following groups:

[0013]

[0014] Preferably, the polyamine moiety is selected from any one of the following groups:

[0015]

[0016] The present invention also provides a Teleg base gas separation membrane, which is prepared by using the cross-linked Teleg base polymer described in any of the above technical solutions.

[0017] As a preferred option, the following steps are included:

[0018] A homopolymer or copolymer formed by polymerizing at least one diamine monomer and its derivative, or at least one polyamine monomer and its derivative, or at least one diamine monomer and its derivative with at least one polyamine monomer and its derivative is dissolved in dimethoxymethane in a certain proportion. The system is cooled to an ice bath and stirred thoroughly. Then, the solvent is added dropwise to the system. After the solvent is added, the ice bath is removed, and the reaction is stirred at a low temperature of -20 to 80°C for 0.01 to 48 hours to obtain a low viscosity mixed solution with a viscosity of 1 to 100,000 cp.

[0019] The resulting mixed solution was transferred to a petri dish or glass plate or scraped with a doctor blade to prepare a homogeneous polymer membrane by the sol-gel method.

[0020] After homogenizing the obtained polymer membrane, the unreacted acids and salts are neutralized, or, based on neutralization, Soxhlet extraction is performed to remove residues in the polymer, followed by drying to obtain the corresponding cross-linked Teleg base polymer membrane.

[0021] Preferably, the solvent added is trifluoroacetic acid;

[0022] The swelling solvent used for swelling is selected from at least one of water, methanol, ethanol, glycerol, n-hexane, n-pentane, dichloromethane, acetone, and toluene;

[0023] Neutralization is carried out using at least one of ammonia water, sodium bicarbonate, and potassium carbonate aqueous solution;

[0024] The solvent used for Soxhlet extraction is selected from at least one of anhydrous methanol, anhydrous ethanol, dichloromethane, chloroform, and acetone;

[0025] The drying temperature is 40-200℃, and the time is 30min-72h.

[0026] Preferably, when preparing a polymer homogenized membrane using the sol-gel method, the polymer mass percentage in the casting solution is 5-40 wt.%.

[0027] The film-forming temperature is 0-40℃, and the evaporation time is 2-72h;

[0028] The film thickness is controlled between 10μm and 200μm.

[0029] The present invention also provides an application of the Telger base gas separation membrane according to any of the above technical solutions in at least one of the following: air oxygen enrichment, in-situ nitrogen production, hydrogen enrichment, hydrogen-methane separation, and air separation.

[0030] Preferably, the oxygen permeability is 3.0-2000 Barrer and the oxygen-nitrogen selectivity is 3.6-8.9 when applied.

[0031] Hydrogen permeability is 323-15000 Barrer, and hydrogen-nitrogen selectivity is 16-181.

[0032] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0033] 1. This invention provides a crosslinked Teleg base polymer prepared based on diamine monomers and polyamine monomers and their derivatives. Through this polymer, polyamine monomers can be used as crosslinking sites to form a film in one step during polymerization, thereby obtaining a Teleg base gas separation membrane with a crosslinking degree of up to 100%.

[0034] 2. The Teleg base gas separation membrane provided by the present invention has excellent gas separation performance. Specifically, it has a high permeability to O2 and a low permeability to N2. Therefore, it can be used for air oxygen enrichment, in-situ nitrogen production, hydrogen enrichment, hydrogen-methane separation, and air separation. In particular, it has great potential for separately treating N2 and O2 in air. Attached Figure Description

[0035] Figure 1 The cross-linked Teleg base homogeneous membrane prepared in Example 8 of the present invention;

[0036] Figure 2 The image shown is a scanning electron microscope (SEM) image of the membrane cross-section prepared in Example 9 of the present invention.

[0037] Figure 3 This is a magnified scanning electron microscope (SEM) image of the membrane cross-section prepared in Example 9 of the present invention;

[0038] Figure 4 (a) is the Teleg base polymer prepared in Example 6 of this invention. 1 H NMR and (b) 13 C NMR spectrum;

[0039] Figure 5 Infrared images of the Teleg base polymers prepared in Examples 6-10 of this invention;

[0040] Figure 6 These are BET diagrams from embodiments 6-10 of the present invention;

[0041] Figure 7 The infrared image is of the Teleg base polymer prepared in Example 21 of this invention. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Examples 1-5

[0044] The homogeneous membrane (Telelag base gas separation membrane) prepared using cross-linked Telelag base polymer has the following molecular structure:

[0045]

[0046] Preparation and characterization of Teleg base gas separation membranes:

[0047] Example 1

[0048] 2,6-Diamino-trimethomorph (0.35 mmol) and dimethoxymethane (1.75 mmol) were added to a 20.0 mL reaction flask, cooled to 0 °C in an ice bath, and stirred for 10 min. Trifluoroacetic acid (0.9 mL) was then added dropwise, and the ice bath was removed. The reaction mixture was stirred for another 1 h at room temperature, then poured into a petri dish and placed in a fume hood. Finally, after controlling solvent evaporation for 72 h, a red dry film was obtained (air humidity should be below 30%). The film was immersed in an aqueous ammonia solution for 12 h and then further dried in a vacuum oven at 40 °C for 72 h. Yield: 98.0%.

[0049] Example 2

[0050] 2,6-Diamino-trimethomorph (0.24 mmol), 2,6,13(14)-triamino-trimethomorph (0.08 mmol), and dimethoxymethane (1.95 mmol) were added to a 20.0 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 2.0 mL of trifluoroacetic acid was added dropwise. After the addition, the ice bath was removed, and the reaction was stirred at room temperature for 30 min. The mixture was then transferred to a flat petri dish in a fume hood. Finally, a red dry film was obtained after controlling solvent evaporation for 72 h (air humidity should be below 30%). The film was soaked in an ammonia solution for 24 h and then further dried in a tube furnace at 200 °C for 30 min. The film thickness was approximately 80 μm (±20 μm), and the yield was 97.8%. Solid-state NMR was performed using powder samples. 13 CP-MAS (101MHz, solid state, ppm): δ145.9,137.65,124.26,112.07,67.77,59.00,54.52.

[0051] Example 3

[0052] 2,6-Diamino-trimethomorph (0.17 mmol), 2,6,13(14)-triamino-trimethomorph (0.17 mmol), and dimethoxymethane (2.23 mmol) were added to a 20.0 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 3.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 5–30 min. The reaction was then stirred at room temperature for another 30–60 min, and then transferred to a flat petri dish in a fume hood. Finally, a red dry film was obtained after controlling solvent evaporation for 48 h (air humidity should be below 30%). The film was soaked in an ammonia solution for 24 h and then further dried in a vacuum oven at 80 °C for 48 h. The film thickness was approximately 80 μm (±20 μm), and the yield was 95.5%. Solid-state NMR was performed using powder samples. 13 CP-MAS (101MHz, solidstate, ppm): δ145.9,136.94,123.94,111.22,68.24,59.62,54.86.

[0053] Example 4

[0054] 2,6-Diamino-trimethomorph (0.08 mmol), 2,6,13(14)-triamino-trimethomorph (0.24 mmol), and dimethoxymethane (2.31 mmol) were added to a 20.0 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 4.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 30 min. The mixture was then transferred to a flat petri dish in a fume hood. Finally, a red dry film was obtained after controlling solvent evaporation for 48 h (air humidity should be below 30%). The film was soaked in an ammonia solution for 48 h and then further dried in a vacuum oven at 120 °C for 10 h. The film thickness was approximately 80 μm (±20 μm), and the yield was 98.5%. Solid-state NMR was performed using powder samples. 13 CP-MAS (101MHz, solid state, ppm): δ145.96,136.76,123.39,110.96,69.0,59.33,55.04.

[0055] Example 5

[0056] 2,6,13(14)-triamino-trimethoxymethane (0.33 mmol) and dimethoxymethane (2.48 mmol) were added to a 20.0 mL reaction flask, cooled to 0 °C, and stirred for 10 min. Trifluoroacetic acid (5.0 mL) was then added dropwise. The reaction was stirred in an ice bath for 1 h. The mixture was then transferred to a petri dish cooled to 0 °C in a fume hood. Finally, a red dry film was obtained after controlling solvent evaporation for 72 h (air humidity should be below 30%). The film was soaked in an ammonia solution for 72 h and then further dried in a vacuum oven at 150 °C for 10 h. The film thickness was approximately 200 μm (±20 μm), and the yield was 93.0%. Solid-state NMR was performed using powder samples. 13 CP-MAS (101MHz, solid state, ppm): δ145.8,137.65,123.1,111.1,67.7,59.25,54.22.

[0057] Table 1 Monomer ratios of Examples 1-5

[0058]

[0059] Examples 6-10

[0060] The Teleg base polymer membranes obtained in Examples 1-5 were extracted with anhydrous MeOH using Soxhlet extraction for 8 hours, and then dried in a vacuum oven at 120°C for 4 hours to obtain Examples 6-10. Among them, the membrane thickness of Examples 6-9 was 80 μm (±20 μm), and the membrane thickness of Example 10 was 200 μm (±20 μm).

[0061] Digital photograph of the membrane in Example 8 is shown below. Figure 1 The cross-linked membrane exhibits good film-forming properties.

[0062] Furthermore, as shown in the cross-sectional scanning electron microscope image of Example 9, the film exhibits a smooth and defect-free structure, such as... Figure 2-3 .

[0063] The structure of Example 6 was characterized by proton and carbon NMR spectra, such as... Figure 4 . 1 HNMR (400MHz, CDCl3, ppm): δ7.18(s,2H),6.96(s,2H),6.84(s,2H),6.76(s,2H),5.05(s,2H),4.43(s,2H),3.90(s,4H). 13 C NMR (100MHz, CDCl3): δ144.6,144.0,140.6,140.2,125.2,124.0,123.3,121.6,120.2,66.7,58.2,53.0.

[0064] Fourier transform infrared spectroscopy was performed on the films obtained in Examples 6-10, as follows: Figure 5 As shown, all membranes are at 1628 cm⁻¹. -1 The CN characteristic peak appears at ~2950 cm⁻¹. -1 The appearance of the CH stretching vibration peak of -CH2 indicates that the TB polymer was successfully synthesized.

[0065] BET tests were performed on Examples 6-10, such as... Figure 6 As shown, it can be concluded that its pore distribution is mainly located in Specific surface area is 503-900 m² 2 / g -1 This conforms to the characteristics of microporous polymers.

[0066] Examples 11-12:

[0067] The molecular structure of the homogenizing membrane (Telelag base gas separation membrane) prepared using cross-linked Telelag base polymer is as follows:

[0068]

[0069] Preparation and characterization of Teleg base gas separation membranes:

[0070] Example 11

[0071] 4,4'-(hexafluoroisopropylidene)diphenylamine (6FA, 0.9 mmol), 1,3,5-tris(4-aminophenyl)benzene (TPB, 0.1 mmol), and dimethoxymethane (5.2 mmol) were added to a 50 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 15.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into petri dishes and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry membrane was obtained (air humidity should be below 30%). The membrane was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The membrane thickness was 80 μm (±20 μm).

[0072] Example 12

[0073] 6FA (0.7 mmol), 1,3,5-tris(4-aminophenyl)benzene (TPB, 0.3 mmol), and dimethoxymethane (5.6 mmol) were added to a 50 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 15.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into petri dishes and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 80 μm (±20 μm).

[0074] Table 2 Monomer ratios for Examples 11-12

[0075]

[0076] Examples 13-15

[0077] The molecular structure of the homogenizing membrane (Telelag base gas separation membrane) prepared using cross-linked Telelag base polymer is as follows:

[0078]

[0079] Preparation and characterization of Teleg base gas separation membranes:

[0080] Example 13

[0081] 2,6-Diamino-Triterpenes (TDA, 0.9 mmol), TPB (0.1 mmol), and dimethoxymethane (5.2 mmol) were added to a 50 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 15.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into petri dishes and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 80 μm (±20 μm).

[0082] Example 14

[0083] 2,6-Diamino-Triterpenes (TDA, 0.5 mmol), TPB (0.5 mmol), and dimethoxymethane (6.0 mmol) were added to a 50 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 15.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into petri dishes and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 80 μm (±20 μm).

[0084] Example 15

[0085] 2,6-Diamino-trimethomorphene (TDA, 0.25 mmol), TPB (0.75 mmol), and dimethoxymethane (6.5 mmol) were added to a 50 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Trifluoroacetic acid was then added dropwise. After addition, the ice bath was removed, and the reaction mixture was stirred at room temperature for 1 h. The reaction mixture was poured into petri dishes and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 80 μm (±20 μm).

[0086] Table 3 Monomer ratios for Examples 13-15

[0087]

[0088] Examples 16-20

[0089] The molecular structure of the homogenizing membrane (Telelag base gas separation membrane) prepared using cross-linked Telelag base polymer is as follows:

[0090]

[0091] Preparation and characterization of Teleg base gas separation membranes:

[0092] Example 16

[0093] 3,3'-Dimethylbenzidine (DMA, 0.35 mmol) and dimethoxymethane (1.75 mmol) were added to a 20 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Trifluoroacetic acid (5.0 mL) was then added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into a petri dish and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 40 μm (±10 μm).

[0094] Example 17

[0095] 3,3'-Dimethylbenzidine (DMA, 0.24 mmol), TPB (0.08 mmol), and dimethoxymethane (1.95 mmol) were added to a 20 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Then, 5.0 mL of trifluoroacetic acid was added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into a petri dish and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 140 μm (±20 μm).

[0096] Example 18

[0097] DMA (0.17 mmol), TPB (0.17 mmol), and dimethoxymethane (2.23 mmol) were added to a 20 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Trifluoroacetic acid (5.0 mL) was then added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into a petri dish and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 140 μm (±20 μm).

[0098] Example 19

[0099] DMA (0.08 mmol), TPB (0.24 mmol), and dimethoxymethane (2.31 mmol) were added to a 20 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Trifluoroacetic acid (5.0 mL) was then added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into a petri dish and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 140 μm (±20 μm).

[0100] Example 20

[0101] TPB (0.33 mmol) and dimethoxymethane (2.48 mmol) were added to a 20 mL reaction flask, cooled to an ice bath, and stirred for 10 min. Trifluoroacetic acid (5.0 mL) was then added dropwise. After addition, the ice bath was removed, and the reaction was stirred at room temperature for 1 h. The reaction mixture was poured into a petri dish and placed in a fume hood. Finally, after controlling solvent evaporation for 48 h, a red dry film was obtained (air humidity should be below 30%). The film was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The thickness was 140 μm (±20 μm).

[0102] Table 4 Monomer ratios for Examples 16-20

[0103]

[0104] Example 21

[0105] The homogeneous membrane (Telelag base gas separation membrane) prepared using cross-linked Telelag base polymer has the following molecular structure:

[0106]

[0107] Example 21

[0108] 100 mg of 4',5'-bis(4-aminophenyl)-[1,1':2',1”-terphenyl]-4,4”-diamine (Mn = 442, 0.443 mmol) was added to a 20 mL reaction flask. 0.2 mL of dimethoxymethane (0.265 g, 3.5 mmol, 8 eq) was added dropwise, and the mixture was stirred in an ice-water bath for 30 min. Then, 5.0 mL of trifluoroacetic acid was slowly added dropwise, and the solution turned black. After stirring for 30 min, the reaction mixture was poured into a petri dish and placed in a fume hood overnight to form a tetraamine crosslinked TB membrane. The membrane was soaked in an aqueous ammonia solution for 24 h. Soxhlet extraction with anhydrous MeOH was performed for 8 h, followed by drying in a vacuum oven at 120 °C for 4 h. The membrane thickness was 80 μm (±20 μm). Fourier transform infrared spectroscopy was performed on the membrane obtained in Example 21. Figure 7 As shown, at 1608cm -1 The CN characteristic peak appears at ~2950 cm⁻¹. -1 The appearance of the CH stretching vibration peak of -CH2 indicates the successful synthesis of Example 21.

[0109] Example 22

[0110] The Teleg base polymer membrane obtained in Example 9 was extracted with dichloromethane using a soxo-dichloromethane method for 8 hours, and then dried in a vacuum oven at 120°C for 4 hours.

[0111] Example 23

[0112] Example 23 is the Tereg base polymer film obtained in Example 9 after aging for one month under vacuum sealing conditions.

[0113] Determination of pure gas permeability and selectivity:

[0114] The encapsulated membrane was placed in the constant volume pressure change test device. After the instrument was evacuated, the gas to be tested was introduced upstream at 0.2 MPa. The change in downstream pressure of the test membrane over time was used to obtain the amount of gas permeation per unit time, thereby obtaining its gas flux. The test data are shown in Table 5.

[0115] Table 5 Pure Gas Separation Performance Test

[0116]

[0117] Note: The unit for gas permeability of the dense membrane is Barrer. The permeation flux and selectivity were measured at 35°C and 2 bar pressure. 1 bar = 0.1 MPa.

[0118] The O2 permeability of Example 1 without Soxhlet extraction was 407 Barrer. The O2 / N2 selectivity was 4.7, and the membrane permeability was also affected by the post-treatment method. For example, methanol Soxhlet extraction helps remove impurities from the membrane material and enhances the membrane's permeability selectivity. After Soxhlet extraction, the O2 permeability of Example 6 increased from 407 Barrer to 693 Barrer, and the O2 / N2 selectivity increased from 4.7 to 5.7. When TTA-75 was treated with dichloromethane using Soxhlet extraction, although the O2 permeability decreased to 390 Barrer, the O2 / N2 selectivity reached 8.9, the H2 permeability was 8000 Barrer, and the H2 / CH4 selectivity was 208, which is the highest reported for a PIM material to date.

[0119] As the triamine content in Examples 6-10 increased from 0 to 100%, their permeability selectivity simultaneously improved. For example, O2 permeability increased from 693 Barrer in Example 6 to 1654 Barrer in Example 10, and the O2 / N2 selectivity also gradually increased from 5.7 to 6.6. The trends for H2 / CH4 and CO2 / CH4 were similar. This resistance to trade-offs is due to several factors: (i) First, the three-dimensional network PIM membrane has greater microporosity and specific surface area ( Figure 6 (ii) Secondly, it also has a high microporosity, which enhances the size screening capability of the resulting membrane.

[0120] Determination of mixed gas flux and selectivity:

[0121] The membrane packaged in Example 23 was placed in the cross-flow constant volume pressure change test device. After the instrument was evacuated, compressed air of 0.2-1.5 MPa was introduced upstream. The change of downstream pressure of the membrane over time was tested to obtain the permeation amount of gas per unit time. The permeate side components were analyzed by gas chromatography to obtain the permeability of each gas pair. The test results are shown in Table 6.

[0122] Table 6. Gas Separation Performance Test

[0123]

[0124] Note: The unit for gas permeability of the dense membrane is Barrer. The permeation flux and selectivity were measured at 35°C and a pressure of 2-15 bar. 1 bar = 0.1 MPa.

[0125] Due to the excellent gas separation performance of Example 23, the O2 / N2 mixed gas separation performance of Example 23 was studied. In the mixed gas test, the O2 / N2 permeability decreased due to competitive adsorption. For example, as the pressure increased from 2 bar to 15 bar, the O2 permeability continuously decreased from 740 barrer to 654 barrer, but the O2 / N2 mixed gas selectivity remained at ~7.2 at different pressures. The overall pressure-dependent performance of the O2 / N2 mixed gas separation is still higher than the latest 2015 upper limit for pure O2 / N2 gas and significantly better than the state-of-the-art membranes reported, demonstrating the great potential for O2 enrichment and N2 generation industries.

Claims

1. A Teleg base gas separation membrane, characterized in that, Includes the following steps: A polyamine monomer and a diamine monomer, or a polyamine monomer, are dissolved in dimethoxymethane. The system is cooled to an ice bath and stirred thoroughly. Trifluoroacetic acid is then added dropwise to the system. After addition, the ice bath is removed, and the reaction is stirred at a low temperature of -20 to 80°C for 0.01 to 48 h to obtain a low-viscosity mixed solution with a viscosity of 1 to 100,000 cp. The resulting mixed solution was transferred to a petri dish or glass plate or scraped with a doctor blade to prepare a homogeneous polymer membrane by the sol-gel method. After the obtained polymer is homogenized and the membrane is swollen, the unreacted acid and salt are neutralized, or after neutralization, Soxhlet extraction is performed to remove the residue in the polymer, and then the membrane is dried to obtain the corresponding cross-linked Teleg base polymer membrane. The solvent used for Soxhlet extraction is selected from at least one of anhydrous methanol, anhydrous ethanol, dichloromethane, chloroform, and acetone; The molar amount of dimethoxymethane is 2-4 times that of the amino functional group, and the molar amount of trifluoroacetic acid is 30-200 times that of the amino monomer. The polymer has the following structural formula: The polymer's gelation rate ranges from 0 to 100%.

2. The Teleg base gas separation membrane according to claim 1, characterized in that, The swelling solvent used for swelling is selected from at least one of water, methanol, ethanol, glycerol, n-hexane, n-pentane, dichloromethane, acetone, and toluene; Neutralization is carried out using at least one of ammonia water, sodium bicarbonate, and potassium carbonate aqueous solution; The drying temperature is 40-200℃, and the time is 30 min-72 h; When preparing homogeneous polymer films using the sol-gel method, the polymer mass percentage in the casting solution is 5-40 wt.%. The film-forming temperature is 0-40℃, and the evaporation time is 2-72 h; The film thickness is controlled between 10μm and 200μm.

3. The application of the Teleg base gas separation membrane according to any one of claims 1-2 in at least one of the following: air enrichment, in-situ nitrogen production, hydrogen enrichment, hydrogen-methane separation, and air separation.

4. The application according to claim 3, characterized in that, When applied, the oxygen permeability is 3.0-2000 Barrer, and the oxygen-nitrogen selectivity is 3.6-8.

9. Hydrogen permeability is 323-15000 Barrer, and hydrogen-nitrogen selectivity is 16-181.

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