A furanyl aromatic polyamide gas separation membrane, its preparation method and application

Abstract

This invention discloses a furanyl aromatic polyamide gas separation membrane, its preparation method, and its applications. The gas separation membrane is made of a polymer copolymerized from an aromatic diacyl chloride, a furanyl diacyl chloride, and an aromatic diamine monomer. This gas separation membrane exhibits high water vapor permeability and H2O / N2 selectivity, as well as excellent mechanical strength, thermal stability, and hydrolytic stability. Furthermore, the furanyl diacyl chloride monomer of this furanyl aromatic polyamide is prepared through the conversion of biomass raw materials, greatly improving the conversion rate and utilization rate of biomass raw materials. Moreover, this furanyl aromatic polyamide is biodegradable, environmentally friendly, and in line with sustainable development goals.

Description

Technical Field

[0001] This invention relates to a furanyl aromatic polyamide gas separation membrane, its preparation method, and its application, belonging to the fields of polymer materials and gas separation membranes. Background Technology

[0002] Excessive humidity in the air promotes mold growth, which is harmful to human health, damages the precision of electronic equipment, and harms buildings. Air dehumidification is the process of removing moisture from humid air to achieve optimal indoor humidity levels. To date, dehumidification technology is mainly based on two solutions: condensation and absorption dehumidification. However, these traditional dehumidification technologies suffer from drawbacks such as high energy consumption, low dehumidification efficiency, high maintenance costs, and space limitations. Compared to traditional dehumidification technologies, membrane-based dehumidification (MAD) technology has proven to be a potential alternative due to its advantages such as high dehumidification efficiency, low energy consumption, low cost, and environmental friendliness. Membrane materials, as the core component of MAD, are crucial for improving dehumidification performance. Developing low-cost membrane materials with high water vapor permeability and high stability is a key issue for MAD technology.

[0003] Aromatic polyamides (PAs) are high-performance materials with high thermal and mechanical stability, as well as excellent film-forming ability. PAs are linked by amide bonds, which, compared to other chemical bonds, exhibit superior hydrolytic stability, making them a promising candidate for dehumidification applications. Currently, the monomers for polyamide polymerization are generally derived from fossil fuels, consuming vast amounts of petroleum resources. While the growth rate of proven petroleum reserves has slowed significantly, remaining production capacity is limited. However, the demand for petroleum resources continues to grow, and the extraction, refining, storage, transportation, and use of petroleum can easily damage the ecological environment. With the growing awareness of sustainable development, the conversion and utilization of biomass raw materials has become a new research hotspot. Among these, bio-based polymers, especially bio-based polyamides, have received increasing attention from academia and industry in recent years.

[0004] Furan dicarboxylic acid (FDCA), a five-membered heterocyclic diacid, is a bio-based chemical produced from biomass through chemical or biological methods, exhibiting excellent biodegradability. FDCA has been recognized by the U.S. Department of Energy as one of the 12 most valuable bio-based platform compounds, and furan diacyl chloride monomers are further synthesized using FDCA. The synthesis of bio-based furan polyamides using furan-based diacyl chlorides and aromatic diamines via low-temperature solution polycondensation has attracted widespread attention as a high-performance alternative to traditional polyamides. Existing literature reports semi-aromatic polyamides based on the renewable monomer 2,5-furan dicarboxylic acid (FDCA), and TGA testing shows that the thermal decomposition temperature of this semi-aromatic polyamide is close to 400℃, comparable to that of petroleum-based corresponding polyamides (European Polymer Journal 178(2022)111496). Further research has shown that furanyl polyamides possess similar thermal stability to traditional high-performance aromatic polyamides, with significantly improved solubility (JPolym Sci. 2020; 58:2140–2150). CN113429569A discloses a method for preparing high molecular weight furanyl polyamides; the synthesis process is green and harmless, yielding furanyl polyamide resins with high molecular weight, high thermal transition, and good mechanical properties. CN115160561A discloses a furanyl aromatic polyamide and its polyamide film; these films possess good mechanical and optical properties and are mainly used in the optical field. However, these studies are limited to investigating the properties of the furanyl aromatic polyamide polymer itself and have not expanded its applications, especially in the dehumidification field; there are no published reports or patents on this topic. Therefore, overall, compared with traditional aromatic polyamides, furanyl aromatic polyamides, due to the inherent conjugation and aromaticity of the furan heterocycles (similar to benzene rings), can achieve better mechanical properties and thermal stability. Simultaneously, furan heterocycles also exhibit good solubility and stability. In dehumidification applications, the furan five-membered heterocycle, with its slightly hydrophilic oxygen atoms, can interact with water vapor molecules, thereby increasing the affinity and solubility of water vapor with the membrane, achieving high water vapor permeability and H2O / N2 selectivity. Furthermore, the furan-based aromatic polyamide backbone is linked by amide bonds, and the high water resistance of these amide bonds endows the dehumidification membrane with excellent hydrolytic stability.

[0005] Currently, commercially available dehumidification membranes include: the polyethylene dehumidification membrane material used by AIR PRODUCTS in the United States, which suffers from low water vapor permeability due to the lack of hydrophilic functional groups; the CA flat sheet membrane used by SeParex for natural gas dehumidification, which can lower the dew point of natural gas to -48°C under conditions of pressure > 0.7 MPa and temperature of 38°C; and the polyimide (PI) membrane used by UBE in Japan, which can lower the dew point of air to -10 to -50°C. However, PI polymers are prone to hydrolysis and ring-opening, exhibiting poor hydrolytic stability, which severely affects the stability of dehumidification performance during use. In summary, no commercially available dehumidification membrane material has yet been developed that combines high water vapor permeability with high hydrolytic stability.

[0006] To address the above problems, this invention provides a gas separation and dehumidification membrane prepared by copolymerizing at least two or more different aromatic and furanyl monomers to form furanyl aromatic polyamide (PA). This produces a gas separation and dehumidification membrane with high water vapor permeability and high H2O / N2 selectivity, while also possessing practical-grade mechanical strength, thermal stability, and excellent hydrolytic stability. Summary of the Invention

[0007] The purpose of this invention is to use an aromatic diacyl chloride and a furanyl diacyl chloride, with these two diacyl chlorides having different structures, to copolymerize with different aromatic diamine monomers via a low-temperature solution condensation reaction to obtain furanyl aromatic polyamides. These polyamides are then applied to air dehumidification or natural gas dehumidification applications to improve the dehumidification performance of gas separation membranes.

[0008] This invention provides a furanyl aromatic polyamide gas separation membrane, its preparation method, and its applications. The gas separation membrane of this invention is a dense, ultrathin, symmetrical planar membrane structure. The furanyl aromatic polyamide backbone of this invention contains amide bonds. These amide bonds not only enhance the affinity between water vapor molecules and the membrane, enabling rapid adsorption and permeation of water vapor, but also provide excellent hydrolytic stability due to their higher water resistance compared to chemical bonds. The furanyl aromatic polyamide backbone contains a furan five-membered heterocycle with a slightly hydrophilic functional group oxygen atom. The presence of this slightly hydrophilic functional group oxygen atom further enhances the water vapor permeability of the dehumidification membrane. Furthermore, the close packing of the furan and benzene rings in the furanyl aromatic polyamide leads to a reduction in molecular chain spacing and free volume, effectively reducing the permeability of nitrogen in the air and methane in natural gas, thereby achieving highly efficient separation of water vapor from air and natural gas, exhibiting extremely high H2O / N2 and H2O / CH4 selectivity. In addition, the rigid benzene ring backbone and the hydrogen bonding of the amide bonds also endow this furanyl aromatic polyamide with excellent mechanical properties and thermal stability.

[0009] To achieve the above objective, the technical solution adopted by the present invention is:

[0010] The furan-based aromatic polyamide gas separation membrane of the present invention is made of furan-based aromatic polyamide, and the general structural formula of the furan-based aromatic polyamide is as follows:

[0011]

[0012] Ar1 is an aromatic unit structure forming aromatic diamine, and Ar2 is an aromatic unit structure forming aromatic diacyl chloride; wherein, x and y are molar percentages of Ar2 and furan-based diacyl chloride moieties in the polymer respectively, x+y=100, 0<x<100, 0<y<100; n represents the degree of polymerization, n is a positive integer of 10-200, and the weight average molecular weight of the furan-based aromatic polyamide is between 5000-800000.

[0013] Further, wherein x and y are molar percentages of Ar2 and furan-based diacyl chloride moieties in the polymer respectively, 0<x<100, preferably x is 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 99. 0<y<100, preferably y is 99, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15 or 1.

[0014] Further, n is 10, 15, 20, 25, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190 or 200.

[0015] Further, the weight average molecular weight of the furan-based aromatic polyamide is 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000, 100000, 200000, 300000, 400000, 500000, 600000, 700000 or 800000.

[0016] Ar1 represents one or more of the following structures:

[0017]

[0018] The Ar1 structure is characterized by having a diamine monomer with an aromatic structure. This structure, which includes a rigid benzene ring, can enhance the mechanical properties and thermal stability of the polymer. At the same time, by changing the structure of the functional groups on the benzene ring, the free volume and hydrophilicity / hydrophobicity of the polymer can be further regulated, thereby optimizing the dehumidification performance.

[0019] Ar2 represents one or more of the following structures:

[0020]

[0021] The preparation method of the furanyl aromatic polyamide gas separation and dehumidification membrane as described above includes the following steps:

[0022] (1) Under nitrogen atmosphere and ice bath conditions, N,N-dimethylacetamide (DMAc) is added to the aromatic diamine monomer. After complete dissolution, Ar2-structured aromatic dichloride and furanyl dichloride are added in batches. After complete dissolution, propylene oxide (PO) is added, and the reaction is carried out for 12-24 hours to obtain a reaction solution. Preferably, the aromatic diamine monomer is 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) or 3,5-diaminobenzoic acid (DABA). Preferably, the Ar2-structured aromatic dichloride is terephthaloyl chloride (TPC). Preferably, the furanyl dichloride is 2,5-furandicarboxylic acid (FDCC).

[0023] (2) The reaction solution is precipitated in methanol solution to obtain fibrous polymer. After washing, the obtained polymer is vacuum dried to remove excess solvent, and dried fibrous polymer is obtained. Preferably, the vacuum drying temperature is 120-180℃. For example, the vacuum drying temperature is 120℃, 130℃, 140℃, 150℃, 160℃, 170℃ or 180℃.

[0024] (3) The dried fibrous polymer is dissolved in N,N-dimethylacetamide (DMAc) solvent to obtain a polyamide solution; preferably, the concentration of the polyamide solution is 5-15 wt%. For example, the concentration of the polyamide solution is 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, 12 wt%, 12.5 wt%, 13 wt%, 13.5 wt%, 14 wt%, 14.5 wt%, or 15 wt%.

[0025] (4) The polyamide solution was poured onto a clean glass substrate and allowed to flow naturally. It was then dried overnight in an oven at 80-90°C to completely evaporate the solvent, yielding a transparent membrane with a thickness of 20-50 μm. The prepared membrane was then immersed in anhydrous methanol for 12-20 h, and subsequently dried in a vacuum oven at 120-130°C for 6-12 h and 180-190°C for 6-12 h to obtain the aforementioned furanyl aromatic polyamide gas separation membrane.

[0026] Further, in step (1), the total molar amounts of the aromatic diamine monomer and the Ar2-structured aromatic dichloride and furanyl dichloride are the same, and the molar amount of propylene oxide is 5 times that of the aromatic diamine monomer.

[0027] Further, in step (1), the molar ratio of furanyl dichloride to Ar2 aromatic dichloride is 2.1-0.5:0-2.1. For example, the molar ratio of furanyl dichloride to Ar2 aromatic dichloride is 2.1-0.5:0.1, 2-0.6:0.2, 2-0.6:0.3, 2-0.6:0.4, 2-0.6:0.5, 2-0.6:0.6, 2-0.6:0.7, 2-0.6:0.8, 2-0.6:0.9, 2-0.6:1, 2-0.6:1.2, 2-0.6:1.4, 2-0.6:1.6, 2-0.6:1.8, 2-0.6:2, 12:0, 14:6, 1:1, 8:12, or 6:14.

[0028] Furthermore, in step (1), the reaction time is 12 hours.

[0029] Furthermore, in step (2), the vacuum drying temperature is 120°C and the vacuum drying time is 12 hours.

[0030] Furthermore, in step (3), the concentration of the polyamide solution is 5 wt%.

[0031] Further, in step (4), the gas separation membrane has a thickness of 20–50 μm; preferably, about 25 μm. The gas separation membrane has a thickness of 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm.

[0032] The application of the furanyl aromatic polyamide gas separation membrane as described above or the gas separation and dehumidification prepared by the method described above, wherein the separation membrane is used for dehumidification; preferably, the separation membrane is used for gas dehumidification; more preferably, the separation membrane is used for air dehumidification.

[0033] The production and performance of the furanyl aromatic polyamide gas separation membrane of the present invention will be described in detail below. However, it should be understood that the present invention is by no means limited to these embodiments.

[0034] Preparation of a polyamide solution with a polymer concentration of 5 wt%.

[0035] (1) Under nitrogen atmosphere and ice bath conditions, N,N-dimethylacetamide (DMAc) solvent was added to a three-necked round-bottom flask containing aromatic diamine monomer. After complete dissolution, aromatic dichloride with Ar2 structure and furanyl dichloride were added in batches. After complete dissolution, propylene oxide (PO) was added and the reaction was carried out for 12 hours to obtain a viscous reaction solution.

[0036] (2) The viscous reaction solution was precipitated in methanol solution to obtain fibrous polymer. After washing with methanol three times, the obtained polymer was vacuum dried at 120°C for 12 hours to remove excess solvent and obtain dry fibrous polymer.

[0037] (3) The dried fibrous polymer was dissolved in N,N-dimethylacetamide (DMAc) solvent to obtain a 5 wt% polyamide solution. The concentrations of the aromatic diamine monomer, Ar2-structured aromatic dichloride, and furanyl dichloride in the N,N-dimethylacetamide (DMAc) solvent were 15 wt%. 23 The total molar amounts of the dichloride and furanyl dichloride are the same, and the molar amount of propylene oxide is 5 times that of the monomer.

[0038] Production of furanyl aromatic polyamide gas separation and dehumidification membrane

[0039] The polyamide solution was poured onto a clean glass substrate and allowed to flow naturally. It was then dried overnight in an oven at 80°C to completely evaporate the solvent, yielding a transparent membrane with a thickness of 20–50 μm. The prepared membrane was then immersed in anhydrous methanol for 12 h, followed by drying in a vacuum oven at 120°C for 12 h and then at 180°C for 6 h to obtain the aforementioned furanyl aromatic polyamide gas separation membrane.

[0040] The beneficial results of this invention are:

[0041] (1) Furan-based aromatic polyamide polymers were polymerized by low-temperature solution polycondensation reaction;

[0042] (2) The obtained furanyl aromatic polyamide polymer is well soluble in polar solvents, and the gas separation dehumidification membrane exhibits excellent mechanical properties and hydrolytic stability. After being treated with hot water at 80°C for seven days, the elongation at break of the gas separation dehumidification membrane remains at 90% or greater than that before hot water treatment. Specifically, the tensile strength of the dehumidification membrane is 180 MPa or greater, and the elongation at break is 17% or greater.

[0043] (3) The water vapor permeability (P^H2O) of the furanyl aromatic polyamide gas separation membrane is about 13850 Barrer and the H2O / N2 selectivity (P^H2O / P^N2) is about 18000. It has excellent water vapor permeability and H2O / N2 selectivity, which can meet the practical application of dehumidification. Attached Figure Description

[0044] Figure 1 The above are the 1H NMR spectra of the furanyl aromatic polyamide structures prepared in Examples 1, 3, and 5.

[0045] Figure 2 The molecular weight analysis diagram of the furanyl aromatic polyamide gas separation membrane prepared in Example 1;

[0046] Figure 3 Gas permeability diagram of the furanyl aromatic polyamide gas separation membrane prepared in Example 5;

[0047] Figure 4 The tensile strength and elongation at break of the furanyl aromatic polyamide gas separation membranes prepared in Examples 1, 3, and 5 are shown in the figure.

[0048] Figure 5 Thermogravimetric analysis curve of the furanyl aromatic polyamide gas separation membrane prepared in Example 5. Detailed Implementation

[0049] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are further illustrations of the present invention, but not limitations on its scope. The scope of protection of the present invention should include all the contents of the claims, and those skilled in the art can fully implement all the contents of the claims of the present invention through the following description of the embodiments.

[0050] The performance testing methods for the furanyl aromatic polyamide gas separation membrane in the following embodiments of the present invention are as follows:

[0051] Determination of water vapor permeation performance of furanyl aromatic polyamide gas separation membrane

[0052] The water vapor permeability of the gas separation membrane was measured using a constant pressure / variable volume method with a water vapor permeability testing device. The water vapor permeability of the studied gas separation dehumidification membrane could be measured at different humidity levels. Different humidity levels of the feed air were adjusted by a controllable mixture of dry and wet air streams (water vapor saturated stream). The wet stream was saturated with ultrapure water, and excess water droplets were removed by a demister. The permeate stream was collected by a nitrogen purge stream with an adjustable flow rate. The water vapor content of the feed and permeate streams was monitored using a dew point analyzer. The membrane cell diameter was approximately 12 cm, and the actual effective membrane area tested was 78.5 cm². 2 The conditions for testing water vapor permeability in this device are as follows: operating temperature 35℃, inlet pressure 3.0 bar, and nitrogen purging gas pressure 1.0 bar.

[0053] Determination of the conventional gas separation performance of furanyl aromatic polyamide gas separation membranes

[0054] Permeation tests for pure gases N2, CH4, O2, H2, He, and CO2 were conducted using the constant-volume pressure swing method. The membrane was placed in the membrane tank and firmly adhered to the aluminum foil strip with epoxy resin to prevent gas leakage. Before each test and at least one hour after each test, the upstream and downstream pipelines of the membrane unit and the gas separation membrane were evacuated using a vacuum pump. To ensure the reliability of the gas permeation data, at least three measurements were performed on each membrane. Multiple measurements are necessary to minimize errors in the gas separation tests.

[0055] Determination of tensile strength and elongation at break of furanyl aromatic polyamide gas separation and dehumidification membrane

[0056] The mechanical properties of the dehumidifying membrane were measured using a microcomputer-controlled electronic universal testing machine. The test was conducted at room temperature with a pressure of 0.50 N / min. -1 The tensile rate was measured on a membrane strip with dimensions of 1cm × 4cm.

[0057] Determination of the thermal stability of furanyl aromatic polyamide gas separation and dehumidification membrane

[0058] Thermogravimetric analysis (TGA) was used to evaluate the thermal stability of the gas separation membrane. The test was conducted at 10 °C for [time missing] minutes under a N2 atmosphere. -1 The heating rate and temperature range of 80°C to 800°C are measured.

[0059] Measurement of rotational viscosity

[0060] The rotational viscosity of the polyamide solution was measured at 35°C using a rotational viscometer (rotor shear rate: 1.75 / s).

[0061] Hydrolytic stability determination of furanyl aromatic polyamide gas separation dehumidification membrane

[0062] The prepared dehumidifying membrane samples were immersed in individual beakers containing 500 mL of ultrapure water at a controlled temperature of 80 °C. At a predetermined time, the dehumidifying membrane samples were selected and dried in a vacuum oven at 120 °C for 12 hours. The mechanical properties of these dehumidifying membrane samples were then measured, with the elongation at break retention rate used to reflect the hydrolytic stability of the dehumidifying membrane.

[0063] Example 1

[0064] (1) Under a nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, 3.8597 g of FDCC (FDCC) (3.8597 g, 0.020 mol) was added, followed by the remaining 43 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, 7 ml of propylene oxide (0.100 mol) was added, and the reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation washings, the polymer was filtered, and the obtained fibrous solid polymer was filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 98%. The molar ratio of TFDB to FDCC in the reaction system was 1:1.

[0065] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1410 poise, and the weight-average molecular weight of the polyamide was 218933 g mol. -1 The molecular weight distribution index (PDI) of this polyamide solution is 2.24. The specific production method for producing a gas separation dehumidification membrane using this polyamide solution is as follows: the polyamide solution is poured onto a clean glass substrate and naturally cast, then dried overnight in an oven at 80°C to completely evaporate the solvent, yielding a transparent membrane with a thickness of approximately 25 μm. The prepared membrane is then immersed in anhydrous methanol for 12 h, followed by drying in a vacuum oven at 120°C for 12 h and then at 180°C for 6 h to obtain the aforementioned furanyl aromatic polyamide gas separation membrane. The water vapor and conventional gas separation performance and mechanical properties of this gas separation dehumidification membrane were measured using the aforementioned method. The results are shown in Table 1. The 1H NMR spectrum of this polymer structure is shown below. Figure 1 As shown. Figure 2 As shown, the membrane has a molecular weight of 218933 g / mol. -1 The high weight-average molecular weight endows this membrane with excellent mechanical properties and thermal stability. This furanyl aromatic polyamide gas separation membrane exhibits excellent mechanical properties, such as... Figure 4 As shown, the membrane has a tensile strength of 133 MPa (the mechanical properties of the dehumidification membrane were measured using a microcomputer-controlled electronic universal testing machine at room temperature with a tensile strength of 0.50 N / min). -1 The tensile rate was measured on a 1cm × 4cm membrane strip. The elongation at break was 7%.

[0066] Example 2

[0067] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (2.7018 g, 0.014 mol) was added. After 20 min, terephthaloyl chloride (TPC) (1.2181 g, 0.006 mol) was added, followed by the remaining 63 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 96%. The molar ratio of FDCC to TPC in the reaction system was 7:3.

[0068] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1565 poise, and the weight-average molecular weight of the polyamide was 253869 g mol. -1 Its molecular weight distribution index (PDI) is 2.24. The remaining experimental and application steps are the same as in Example 1.

[0069] Example 3

[0070] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (1.9298 g, 0.010 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.0302 g, 0.010 mol) was added, followed by the remaining 63 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 97%. The molar ratio of FDCC to TPC in the reaction system was 5:5.

[0071] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1895 poise, and the weight-average molecular weight of the polyamide was 284,669 g mol. -1 Its molecular weight distribution index (PDI) is 2.40. The remaining experimental and application procedures are the same as in Example 1. The 1H NMR spectrum of this polymer structure is shown below. Figure 1 As shown. Figure 4 As shown, the membrane has a tensile strength of 180 MPa and an elongation at break of 17%, exhibiting excellent mechanical properties.

[0072] Example 4

[0073] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (1.5439 g, 0.008 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.4362 g, 0.012 mol) was added, followed by the remaining 64 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 98%. The molar ratio of FDCC to TPC in the reaction system was 4:6.

[0074] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1995 poise, and the weight-average molecular weight of the polyamide was 323,837 g mol. -1 Its molecular weight distribution index (PDI) is 2.35. The remaining experimental and application steps are the same as in Example 1.

[0075] Example 5

[0076] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (1.1579 g, 0.006 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.8423 g, 0.014 mol) was added, followed by the remaining 99 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 96%. The molar ratio of FDCC to TPC in the reaction system was 3:7.

[0077] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 2820 poise, and the weight-average molecular weight of the polyamide was 356830 g mol. -1 Its molecular weight distribution index (PDI) is 2.43. The remaining experimental and application procedures are the same as in Example 1. The 1H NMR spectrum of this polymer structure is shown below. Figure 1 As shown. Figure 3 As shown, the gas permeability of this membrane decreases sequentially with increasing kinetic diameter of various gases. In particular, its permeability to N2 and CH4, which have larger kinetic diameters, is significantly lower than the water vapor permeability of the membrane shown in Table 1, exhibiting extremely high H2O / N2 selectivity. This enables highly efficient air dehumidification and natural gas dehumidification applications. Simultaneously, this furanyl aromatic polyamide gas separation membrane possesses excellent mechanical properties and thermal stability, such as… Figure 4 As shown, the membrane has a tensile strength of 211 MPa and an elongation at break of 11%. Figure 5 As shown, the thermal decomposition temperature of this membrane is 385℃, which allows it to be used in high-temperature environments.

[0078] Comparative Example 1

[0079] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, isophthaloyl chloride (IPC) (2.0302 g, 0.010 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.0302 g, 0.010 mol) was added, followed by the remaining 65 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 96%. The molar ratio of IPC to TPC in the reaction system was 5:5.

[0080] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1950 poise, and the weight-average molecular weight of the polyamide was 224783 g mol.-1 Its molecular weight distribution index (PDI) is 2.41. The gas separation dehumidification membrane was produced using this polyamide solution. The specific production method was as follows: the polyamide solution was poured onto a clean glass substrate and allowed to flow naturally. It was then dried overnight in an oven at 80°C to completely evaporate the solvent, yielding a transparent membrane with a thickness of 20–50 μm. The prepared membrane was immersed in anhydrous methanol for 12 h, and then dried in a vacuum oven at 120°C for 12 h and 180°C for 6 h to obtain the aforementioned furanyl aromatic polyamide gas separation membrane. The water vapor and conventional gas separation performance and mechanical properties of this gas separation dehumidification membrane were measured using the aforementioned method. The results are shown in Table 1.

[0081] Comparative Example 2

[0082] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) (6.4046 g, 0.020 mol). After complete dissolution, isophthaloyl chloride (IPC) (2.2181 g, 0.006 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.8423 g, 0.014 mol) was added, followed by the remaining 65 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed, with a yield of 95%. The molar ratio of IPC to TPC in the reaction system was 3:7.

[0083] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 3510 poise, and the weight-average molecular weight of the polyamide was 276523 g mol. -1 Its molecular weight distribution index (PDI) is 2.50. The remaining experimental and application procedures are the same as those in Comparative Example 1.

[0084] Example 6

[0085] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (3.8597 g, 0.020 mol) was added, followed by the remaining 19 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added, and the reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation washings, the polymer was filtered, and the obtained fibrous solid polymer was filtered. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and weighed. The yield was 95%. The molar ratio of DADB to FDCC in the reaction system was 1:1.

[0086] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1546 poise, and the weight-average molecular weight of the polyamide was 231649 g mol. -1 Its molecular weight distribution index (PDI) is 2.21. The remaining experimental and application steps are the same as in Example 1.

[0087] Example 7

[0088] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (2.7018 g, 0.014 mol) was added. After 20 min, terephthaloyl chloride (TPC) (1.2181 g, 0.006 mol) was added, followed by the remaining 20 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 96%. The molar ratio of FDCC to TPC in the reaction system was 7:3.

[0089] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1665 poise, and the weight-average molecular weight of the polyamide was 268675 g mol. -1 Its molecular weight distribution index (PDI) is 2.28. The remaining experimental and application steps are the same as in Example 1.

[0090] Example 8

[0091] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (1.9298 g, 0.010 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.0302 g, 0.010 mol) was added, followed by the remaining 20 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 97%. The molar ratio of FDCC to TPC in the reaction system was 5:5.

[0092] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 1795 poise, and the weight-average molecular weight of the polyamide was 337341 g mol. -1 Its molecular weight distribution index (PDI) is 2.52. The remaining experimental and application steps are the same as in Example 1.

[0093] Example 9

[0094] Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (1.5439 g, 0.008 mol) was added. After a 20-minute interval, terephthaloyl chloride (TPC) (2.4362 g, 0.012 mol) was added, followed by the remaining 20 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added, and the reaction was allowed to proceed for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 98%. The molar ratio of FDCC to TPC in the reaction system was 4:6.

[0095] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 2195 poise, and the weight-average molecular weight of the polyamide was 372163 g mol. -1 Its molecular weight distribution index (PDI) is 2.80. The remaining experimental and application steps are the same as in Example 1.

[0096] Example 10

[0097] Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, 2,5-furandicarboxylic acid chloride (FDCC) (1.1579 g, 0.006 mol) was added. After a 20-minute interval, terephthaloyl chloride (TPC) (2.8423 g, 0.014 mol) was added, followed by the remaining 51 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added, and the reaction was allowed to proceed for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 96%. The molar ratio of FDCC to TPC in the reaction system was 3:7.

[0098] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 3820 poise, and the weight-average molecular weight of the polyamide was 289561 g mol. -1 Its molecular weight distribution index (PDI) is 2.35. The remaining experimental and application steps are the same as in Example 1.

[0099] Comparative Example 3

[0100] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, isophthaloyl chloride (IPC) (2.0302 g, 0.010 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.0302 g, 0.010 mol) was added, followed by the remaining 21 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed. The yield was 96%. The molar ratio of IPC to TPC in the reaction system was 5:5.

[0101] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 2310 poise, and the weight-average molecular weight of the polyamide was 368329 g mol. -1 Its molecular weight distribution index (PDI) is 3.22. The remaining experimental and application procedures are the same as those in Comparative Example 1.

[0102] Comparative Example 4

[0103] (1) Under nitrogen atmosphere and ice bath conditions, 50 ml of N,N-dimethylacetamide (DMAc) was added to a three-necked round-bottom flask containing 3,5-diaminobenzoic acid (DABA) (3.0430 g, 0.020 mol). After complete dissolution, isophthaloyl chloride (IPC) (2.2181 g, 0.006 mol) was added. After 20 min, terephthaloyl chloride (TPC) (2.8423 g, 0.014 mol) was added, followed by the remaining 66 ml of N,N-dimethylacetamide (DMAc). After complete dissolution, propylene oxide (7 ml, 0.100 mol) was added. The reaction was carried out for 12 hours to obtain a viscous reaction solution. The viscous reaction solution was poured into 1000 ml of methanol to obtain a fibrous polymer. After three precipitation and washing, the fibrous solid polymer was filtered and then filtered again. The obtained polymer was dried in a vacuum drying oven at 120 °C for 12 h and then weighed, with a yield of 95%. The molar ratio of IPC to TPC in the reaction system was 3:7.

[0104] (2) At room temperature, the above polymer was dissolved in N,N-dimethylacetamide (DMAc) to prepare a polyamide solution. The polymer concentration of the solution was 5 wt% (polymer concentration is calculated by dividing the mass of the polymer by the total mass of the polymer and solvent), the rotational viscosity was 2710 poise, and the weight-average molecular weight of the polyamide was 263147 g mol. -1 Its molecular weight distribution index (PDI) is 2.32. The remaining experimental and application procedures are the same as those in Comparative Example 1.

[0105] Table 1 lists the measured results of water vapor permeability, H2O / N2 selectivity, mechanical strength, and hydrolytic stability of the furan-based gas separation dehumidification membranes of the examples and comparative examples. For example, the water vapor permeability of the furan-based aromatic polyamide gas separation membrane of Example 5 was 13850 Barrer, the H2O / N2 selectivity was 18000, and the hydrolytic stability remained at 98% after seven consecutive days of testing under extreme conditions. Simultaneously, this membrane also exhibited excellent mechanical properties and thermal stability. Compared to Comparative Example 1, the water vapor permeability and H2O / N2 selectivity of the furan-based aromatic polyamide gas separation membranes of Examples 1-5 significantly exceeded those of the aromatic polyamide gas separation membrane. This is because the furan five-membered heterocycle in the furan-based aromatic polyamide gas separation membrane provides a larger free volume and hydrophilicity, increasing the affinity of water vapor for the membrane, thereby achieving a significant improvement in dehumidification performance.

[0106] The furan-based gas separation and dehumidification membrane of this invention exhibits excellent water vapor permeability and H2O / N2 selectivity, as well as superior mechanical strength, thermal stability, and hydrolytic stability. The furan-based gas separation and dehumidification membrane of this invention is low in manufacturing cost, easy to process, and easy to recycle, making it environmentally friendly and suitable for large-scale production applications.

[0107] Table 1

[0108]

[0109] Note: The units for P^H2O and P^N2 are Barrers; the unit for tensile strength is MPa; the unit for elongation at break is %; hot water resistance is the retention rate of elongation at break after 7 days of hot water treatment at 80°C, expressed as %.

[0110] The parts of this invention not described in detail are well-known to those skilled in the art. The embodiments described above are merely preferred embodiments of the invention, and do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Various modifications and improvements to the technical solutions of this invention made by those skilled in the art without departing from the spirit of the invention should fall within the protection scope defined by the claims of this invention.

Claims

1. The application of a furanyl aromatic polyamide gas separation membrane in air dehumidification, characterized in that, The separation membrane is made of furanyl aromatic polyamide, and the general structural formula of the furanyl aromatic polyamide is as follows: Ar1 is the aromatic unit structure that forms an aromatic diamine, and Ar2 is the aromatic unit structure that forms an aromatic diacyl chloride; where x and y are the molar percentages of Ar2 and furanyl diacyl chloride moieties in the polymer, respectively, x + y = 100, and 1 ≤ x < 100 1≤y<100; n represents the degree of polymerization, n is a positive integer from 10 to 200, and the weight-average molecular weight of the aromatic polyamide is between 5000 and 800000; Ar1 is selected from one or more of the following structures: ； ； Ar2 is selected from one or more of the following structures: ； 。 2. The application according to claim 1, characterized in that, The furanyl aromatic polyamide gas separation membrane is prepared by the following steps: (1) Under nitrogen atmosphere and ice bath conditions, N,N-dimethylacetamide DMAc was added to the aromatic diamine monomer. After complete dissolution, Ar2-structured aromatic dichloride and furanyl dichloride were added in batches. After complete dissolution, propylene oxide PO was added, and the reaction was carried out for 12-24 h to obtain the reaction solution. The aromatic diamine monomer was 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl TFDB or 3,5-diaminobenzoic acid DABA; the Ar2-structured aromatic dichloride was terephthaloyl chloride TPC; and the furanyl dichloride was 2,5-furandicarboxylic acid FDCC. (2) The reaction solution was precipitated in methanol solution to obtain a white fibrous polymer. After washing, the obtained polymer was vacuum dried to remove excess solvent and obtain a dry white fibrous polymer. (3) Dissolve the dried white fibrous polymer in N,N-dimethylacetamide (DMAc) solvent to obtain a polyamide solution; (4) The polyamide solution was poured onto a clean glass substrate and allowed to flow naturally. It was then dried overnight in an oven at 80-90 ºC to allow the solvent to evaporate completely, resulting in a transparent membrane with a thickness of 20-50 μm. The prepared membrane was then immersed in anhydrous methanol for 12-20 h and dried in a vacuum oven at 120-130 ºC for 6-12 h and 180-190 ºC for 6-12 h to obtain the furanyl aromatic polyamide gas separation membrane described above.

3. The application according to claim 2, characterized in that, In step (1), the molar ratio of aromatic diamine monomer to (aromatic dichloride of Ar2 + furanyl dichloride) is 1:1, and the molar amount of propylene oxide is 5 times the amount of aromatic diamine monomer.

4. The application according to claim 2, characterized in that, In step (1), the molar ratio of furanyl dichloride to Ar2 aromatic dichloride is 2.1-0.5:0.1-2.

1.

5. The application according to claim 2, characterized in that, In step (2), the vacuum drying temperature is 120-180℃ and the vacuum drying time is 12-24 hours.

6. The application according to claim 2, characterized in that, In step (3), the concentration of the polyamide solution is 5-15 wt%.

7. The application according to claim 2, characterized in that, In step (4), the thickness of the gas separation membrane is 20~50 μm.

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