An ester-based organic film, a method for preparing the same, and an application thereof

Abstract

The application discloses an ester organic membrane and a preparation method and application thereof, relates to the technical field of separation membranes, and solves the technical problem that the existing separation membrane has poor tolerance to sulfolane, which greatly influences the permeation flux and separation performance of the separation membrane; the preparation method of the organic membrane comprises the following steps: reacting allyl itaconate, ethylene glycol dimethacrylate and tert-butyl hydroperoxide to prepare an acrylate-ethylene glycol dimethacrylate polymer; mixing the allyl itaconate-ethylene glycol dimethacrylate polymer, polytoluene acrylate, a pore former and a solvent to prepare a casting solution; coating the casting solution on a support body, and cooling and solidifying to obtain the organic membrane; the organic membrane prepared by the application has high stability in sulfolane, high tolerance, high rejection rate of organic impurities in sulfolane, and good organic impurity removal effect.

Description

Technical Field

[0001] This invention relates to the field of separation membrane technology, specifically to an ester-based organic membrane, its preparation method, and its application. Background Technology

[0002] Sulfolane is widely used in the oil and gas industry, mainly for aromatics extraction and natural gas purification. During aromatics extraction and natural gas purification, sulfolane's performance deteriorates due to feedstock contamination or its own degradation, generating various impurities. Therefore, there is a significant demand in the oil and gas production sector for purification technologies that can remove impurities from deteriorated sulfolane and restore its performance.

[0003] Existing online purification technologies for deteriorated sulfolane employ methods such as ion exchange resins, activated carbon, activated clay, and mechanical filtration, which are effective at removing inorganic and particulate impurities from sulfolane, but less effective at removing organic impurities. Microporous membrane separation can remove all organic impurities larger than sulfolane molecules, making it the most effective method to address the decomposition, polymerization, and subsequent performance degradation and clogging of the equipment caused by sulfolane decomposition and polymerization. However, this method requires microporous membranes with special properties. Since some organic impurities in sulfolane are very close in size to sulfolane molecules, the separation membrane must have highly precise molecular size discrimination at the nanoscale. Microporous inorganic membranes have complex preparation processes and poor controllability at the nanoscale, making it difficult to achieve such high discrimination, resulting in low separation rates for organic impurities in sulfolane and an inability to restore its performance. While organic membranes offer rich controllability at the nanoscale and can produce separation membranes with extremely high discrimination, they suffer from drawbacks such as poor resistance to organic solvents and susceptibility to swelling, leading to membrane failure. Existing organic films resistant to various organic solvents can withstand methanol, ethanol, N,N-dimethylformamide, tetrahydrofuran, and carbon tetrachloride, but they are not resistant to sulfolane, which has a greater swelling effect, and will quickly fail when used with sulfolane.

[0004] The existing related technologies are as follows:

[0005] (1) Patent document CN118320644A discloses an organic solvent-resistant separation membrane and its preparation method: polyimide, reinforcing agent, N-methylpyrrolidone, pore-forming agent, and loading agent are added to a beaker, stirred at room temperature until the system dissolves, filtered, and the filtrate is allowed to stand for 5-8 hours to obtain a casting solution; this document prepares a casting solution by combining the prepared reinforcing agent with polyimide and polyethylene glycol, and modifies the casting solution after coating it onto a pretreated substrate to prepare a support layer, and then prepares a separation membrane after modifying the outside of the support layer with a coating, which not only effectively improves the permeate flux and rejection rate of the separation membrane, but also improves the solvent resistance of the separation membrane. The separation membrane provided by this patent is resistant to methanol and N,N-dimethylformamide. After being immersed in N,N-dimethylformamide solvent for 7 days, the permeate flux to methanol organic dyes can still reach 19.8 L / (m2 The permeability was 98.8% (h·bar), but after soaking in sulfolane for 7 days, the permeation flux was <0.1 L / (m²). 2 h·bar).

[0006] (2) Patent document CN117619168A discloses an organic solvent-resistant nanofiltration composite membrane, its preparation method, and its application: the composite membrane includes a base membrane and a separation layer, wherein the crosslinked polymer of the separation layer comprises structural units provided by amino-substituted polycyclic aromatic hydrocarbons, the amino-substituted polycyclic aromatic hydrocarbons being selected from 4,4'-diaminobiphenyl and / or 4,4'-diaminoterphenyl; the thickness of the separation layer is ≤80nm, the roughness is ≤20nm, and the degree of crosslinking of the crosslinked polymer is 20-70%. The composite membrane provided in this document exhibits stable performance after 100h operation in a methanol solution containing dye, but after immersion in sulfolane for 100h, the permeation flux of sulfolane is <0.1L / (m). 2 (h·bar), intolerant to sulfolane.

[0007] (3) Patent document CN117065577A discloses a method for preparing an organic solvent-resistant nanofiltration membrane: a polymer is dissolved in an ionic liquid and heated to dissolve, forming a homogeneous casting solution. Then, an ultrafiltration base membrane is prepared by a non-solvent-induced reverse method. The polymer is one or more of polyacrylonitrile, poly(p-phenylene terephthalamide), poly(m-phenylene isophthalamide), and polyetheretherketone. A multifunctional amine substance is mixed with water to obtain an aqueous solution. The multifunctional amine substance includes m-phenylene diamine, p-phenylene diamine, polyethyleneimine, and 3,5-diamino-N-(4-aminophenyl)benzene. The nanofiltration membrane contains at least two of the following: formamide and m-phenylenediamine-4-methyl; a monomer containing an acyl chloride group is dissolved in an ionic liquid and heated to obtain an oil phase solution; the monomer containing the acyl chloride group includes at least two of phthaloyl chloride, isophthaloyl chloride, trimesoyl chloride, 5-chloro-methoxyisophthaloyl chloride, 5-isocyanoisophthaloyl chloride, and biphenyltetracarboxylic acid chloride; the ultrafiltration membrane is first immersed in an aqueous phase solution for wetting treatment, and then immersed in an oil phase solution for interfacial polymerization reaction to generate a nascent polyamide membrane layer; the nascent polyamide membrane layer is heat-treated to obtain a nanofiltration membrane resistant to organic solvents. The nanofiltration membrane provided by this patent maintains excellent permeate flux and retention performance after being immersed in methanol, N,N-dimethylformamide, tetrahydrofuran, and carbon tetrachloride for 15 days, but after being immersed in sulfolane for 7 days, the retention rate of impurities in sulfolane decreases to <20%, indicating insensitivity to sulfolane. However, after soaking in sulfolane for 100 hours, the permeation flux of sulfolane was <0.1 L / (m²). 2 It is not resistant to sulfolane (h·bar) and has an initial rejection rate of less than 50% for organic impurities in sulfolane.

[0008] (4) CN114588792A A polyvinylidene chloride membrane reinforced with polyvinyl butyral and its preparation method. The patented membrane is prepared from the following components: 10-30 wt% polyvinylidene chloride, 0.1-10 wt% polyvinyl butyral, 0.5-20 wt% porogen, 0.5-10 wt% additive and 50-80 wt% solvent; the porogen is one or a mixture of two of polyvinylpyrrolidone and polyethylene glycol, the additive is one or a mixture of two of water, ethanol, ethylene glycol, diethylene glycol and ethylene glycol monomethyl ether, and the solvent is one of N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone. This patent uses polyvinyl butyral blended with polyvinylidene chloride to enhance the tensile elongation at break of polyvinylidene chloride membrane and improve the mechanical properties of polyvinylidene chloride membrane, but does not improve the membrane's resistance to organic solvents, and the initial rejection rate of organic impurities in sulfolane is less than 50%.

[0009] In summary, existing separation membranes provided by similar technologies have poor tolerance to sulfolane. After prolonged immersion in sulfolane, the permeation flux or separation performance will decrease significantly or even fail. Summary of the Invention

[0010] This invention aims to address the technical problem that existing separation membranes have poor tolerance to sulfolane, which greatly affects the permeation flux and separation performance of the membranes. The purpose is to provide an ester-based organic membrane, its preparation method, and its application. This organic membrane exhibits high stability and strong tolerance in sulfolane, high retention rate of organic impurities in sulfolane, and good removal effect of organic impurities.

[0011] This invention is achieved through the following technical solution:

[0012] The first objective of this invention is to provide a method for preparing an ester-based organic membrane, comprising the following steps:

[0013] An acrylate-dimethacrylate polymer was prepared by reacting itaconic acid allyl ester, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide.

[0014] A casting solution is prepared by mixing allyl itaconic acid-ethylene dimethacrylate polymer, polytoluene acrylate, pore-forming agent and solvent;

[0015] The casting solution is coated onto the support and then cooled and solidified to obtain an organic film.

[0016] Furthermore, the mass ratio of itaconic acid allyl ester, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide is (0.8–2):1:(0.002–0.06).

[0017] Preferably, the mass ratio of itaconic acid allyl ester, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide is 1.2:1:0.03.

[0018] Furthermore, the specific preparation method of the acrylate-ethylene glycol dimethacrylate polymer is as follows:

[0019] Allyl itaconic acid, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide were mixed in a certain mass ratio to obtain a mixture. The mixture was then added to saturated brine and heated to 80-90°C. The mixture was stirred for 7-9 hours to obtain an allyl itaconic acid-ethylene glycol dimethacrylate polymer.

[0020] Furthermore, the pore-forming agent is a mixture of toluene and butanone.

[0021] Furthermore, the mass ratio of toluene to butanone is 1:(1-3).

[0022] Preferably, the mass ratio of toluene to butanone is 1:3.

[0023] Furthermore, the composition of the casting solution includes:

[0024] The mass ratio of itaconic acid allyl ester-dimethacrylate ethylene glycol polymer, polytoluene acrylate, pore-forming agent and solvent is 1:(1.2~1.6):(1.5~2):(4~6).

[0025] Preferably, the mass ratio of itaconic acid allyl ester-ethylene dimethacrylate polymer, polytoluene acrylate, pore-forming agent and solvent is 1:1.3:1.8:5.

[0026] Furthermore, the solvent is N,N-dimethylformamide.

[0027] Furthermore, the method for preparing the casting solution is as follows:

[0028] The itaconic acid allyl ester-dimethacrylate ethylene glycol polymer, polytoluene acrylate, pore-forming agent and solvent are mixed in proportion and heated to 60℃~65℃, stirred for 12~16h, and then heated to 110℃~120℃ and evacuated for 4~8h to obtain the casting solution.

[0029] Furthermore, the support is a polytetrafluoroethylene hollow fiber membrane.

[0030] Furthermore, the cooling and curing temperature is 1℃~9℃, and the curing time is 12~24h.

[0031] A second objective of this invention is to provide an ester-based organic membrane prepared by the method described above.

[0032] A third object of the present invention is to provide the application of the organic membrane in aromatic hydrocarbon extraction and natural gas purification, specifically, the organic membrane is used to separate impurities from sulfolane.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. The organic membrane of the present invention has high stability and strong tolerance in sulfolane, improving the tolerance of the organic membrane to sulfolane from <7 days in the prior art to 70 days.

[0035] 2. The organic membrane of the present invention has a high rejection rate for organic impurities in sulfolane and a good removal effect for organic impurities, increasing from <62% in the prior art to >95%. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0037] The following details embodiments of an ester-based organic membrane, its preparation method, and its applications according to the present invention. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art.

[0038] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. The range defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0040] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0041] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other substances not listed may also be included, or that only the listed substances may be included.

[0042] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0043] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0044] It should be noted that:

[0045] 1. The test solution used in the following examples was prepared by adding 2 mol / m³ each of decane, n-docosahexanes, polyoxyethylene alkyl alcohol ether-20, sodium dodecyl sulfonate, sodium dodecyl alcohol sulfate, sodium butylnaphthalene sulfonate, sodium isooctanoate, sodium butylnaphthalene sulfonate, sodium dodecylbenzene sulfonate, sodium diisooctyl succinate sulfonate, sodium perfluorononenoxybenzene sulfonate, dodecylammonium chloride, dodecyltrimethylammonium chloride, and dodecylpyridine bromide to sulfolane. 3 The test solution was obtained.

[0046] 2. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels.

[0047] Example 1

[0048] A method for preparing an ester-based organic membrane:

[0049] Step 1: Mix allyl itaconic acid, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide in a mass ratio of 2:1:0.06 and add them to saturated brine. The volume of brine should be 4 times the volume of the mixture. Heat the mixture to 85°C and stir continuously for 8 hours. Then filter out the polymer, rinse it with brine, and dry it at 100°C for 4 hours to obtain the allyl itaconic acid-ethylene glycol dimethacrylate polymer.

[0050] Step 2: Mix toluene and butanone in a mass ratio of 1:1 to prepare a mixed reagent;

[0051] Step 3: The dried itaconic acid allyl ester-ethylene glycol dimethacrylate polymer is mixed with polybutylene terephthalate, mixed reagents and N,N-dimethylformamide in a mass ratio of 1:1.6:2:6 and heated to 65°C and stirred for 12 hours. Then the temperature is raised to 120°C and the gas is evacuated for 4 hours to obtain the casting solution.

[0052] Step 4: Apply the casting solution evenly to the polytetrafluoroethylene hollow fiber membrane (average pore size 0.05–1.0 μm), cool to 1°C, and cure for 12 hours to obtain 1. # Organic membrane.

[0053] Test 1 with test solution # The initial flux and organic impurity rejection rate of the organic membrane, and then 1 # The organic membrane was tested with a test solution after being immersed in sulfolane for 70 days. # The flux and organic impurity rejection rate of the organic membrane after immersion are shown in Table 1.

[0054] Table 1.1 # Organic membrane flux and rejection rate

[0055] project initial Soak for 7 days <![CDATA[Flow rate L / (m 2 h·bar)]]> 6.2 6.2 Organic impurity rejection rate % 90.3 90.5

[0056] Example 2

[0057] A method for preparing an ester-based organic membrane:

[0058] Step 1: Allyl itaconic acid, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide were mixed in a mass ratio of 0.8:1:0.002 and then added to saturated brine. The volume of the brine was 4 times the volume of the mixture. The mixture was heated to 85°C and stirred continuously for 8 hours. The product was then filtered out, rinsed with brine, and dried at 100°C for 4 hours to obtain the allyl itaconic acid-ethylene glycol dimethacrylate polymer.

[0059] Step 2: Mix toluene and butanone at a mass ratio of 1:2 to prepare a mixed reagent;

[0060] Step 3: The dried itaconic acid allyl ester-dimethacrylate ethylene glycol polymer is mixed with polyethylene terephthalate, mixed reagents and N,N-dimethylformamide in a mass ratio of 1:1.2:1.5:4 and heated to 60°C and stirred for 16 hours. Then the temperature is raised to 110°C and the gas is evacuated for 8 hours to obtain the casting solution.

[0061] Step 4: The casting solution is evenly coated onto the polytetrafluoroethylene hollow fiber membrane (average pore size 0.02–0.5 μm), and cooled to 9°C for 24 hours to cure, yielding 2 # Organic membrane.

[0062] Test 2 with test solution. #Initial flux and organic impurity rejection rate of organic membrane, and then 2 # The organic membrane was tested with a test solution after being immersed in sulfolane for 70 days. # The flux and organic impurity rejection rate of the organic membrane after immersion are shown in Table 2.

[0063] Table 2, 2 # Organic membrane flux and rejection rate

[0064] project initial Soaking for 70 days <![CDATA[Flow rate L / (m 2 h·bar)]]> 6.1 6.1 Organic impurity rejection rate % 92.9 92.8

[0065] Example 3

[0066] A method for preparing an ester-based organic membrane:

[0067] Step 1: Allyl itaconic acid, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide were mixed in a mass ratio of 1.2:1:0.03 and then added to saturated brine. The volume of brine was 4 times the volume of the mixture. The mixture was heated to 85°C and stirred continuously for 8 hours. The product was then filtered out, rinsed with brine, and dried at 100°C for 4 hours to obtain the allyl itaconic acid-ethylene glycol dimethacrylate polymer.

[0068] Step 2: Mix toluene and butanone at a mass ratio of 1:3 to prepare a mixed reagent;

[0069] Step 3: The dried itaconic acid allyl ester-ethylene glycol dimethacrylate polymer is mixed with polybutylene terephthalate, mixed reagents, and N,N-dimethylformamide in a mass ratio of 1:1.3:1.8:5 and heated to 65°C and stirred for 12 hours. Then the temperature is raised to 120°C and the gas is evacuated for 4 hours to obtain the casting solution.

[0070] Step 4: The casting solution is uniformly coated onto polytetrafluoroethylene (PTFE) hollow fiber membranes (average pore size 0.05–1.0 μm), PTFE hollow fiber membranes (average pore size 0.02–0.5 μm), and PTFE hollow fiber membranes (average pore size 0.05–0.3 μm), respectively. The membranes are then cooled to 1°C and cured for 12 hours to obtain 3-1. # 3-2 # 3-3 # Organic membrane.

[0071] Test 3-1 with the test solution. # 3-2 # 3-3 # Initial flux and organic impurity rejection rate of organic membrane, then 3-1 # 3-2 # 3-3 # The organic membrane was tested with a test solution after being immersed in sulfolane for 70 days. # 3-2 # 3-3# The flux and organic impurity rejection rate of the organic membrane after immersion are shown in Table 3.

[0072] Table 3, 3-1 # 3-2 # 3-3 # Organic membrane flux and rejection rate

[0073]

[0074]

[0075] The experimental results of Examples 1-3 show that the organic membranes prepared according to the methods and conditions provided by the present invention remain stable in performance after being immersed in sulfolane for 70 days. Among them, the organic membrane prepared according to the conditions of Example 3 has the highest retention rate and also a higher flow rate. The experimental results of Example 3 also show that the pore size of the polytetrafluoroethylene hollow fiber membrane support has no effect on the performance of the organic membrane.

[0076] Comparative Example

[0077] The following are organic membranes produced using existing similar technologies.

[0078] (1) Preparation of organic membrane according to CN118320644A: ① Weigh 25.1g of 4,4'-dichlorobenzophenone, 20.0g of 4,4-dihydroxydiphenylmethane, 21.2g of 4,4'-dihydroxybenzophenone, 12.55g of potassium carbonate, and 376.5mL of dimethyl sulfoxide into a three-necked flask under nitrogen protection and stir. Raise the temperature of the three-necked flask to 130℃ and stir until the system dissolves. Raise the temperature of the three-necked flask to 305℃ and keep the reaction at this temperature for 2.5h. After the reaction is complete, lower the temperature of the three-necked flask to room temperature and slowly add the reaction solution into another three-necked flask containing 1500mL of purified water and stir. Filter by suction. Use a filter cake made of... A mixture of acetone and ethanol in a volume ratio of 1:2 was boiled and kept at that temperature for 40 minutes. The mixture was then cooled to room temperature and filtered. The filter cake was transferred to a drying oven at 75°C and dried to constant weight to obtain intermediate I. Intermediate I was pulverized to a particle size of less than 0.1 mm. 10 g of the pulverized intermediate I and 100 mL of 88 wt% sulfuric acid were weighed and added to a three-necked flask. The mixture was stirred at room temperature for 11 hours. The reaction solution was slowly added to 1000 mL of deionized water at 3°C. The mixture was filtered, the filter cake was pulverized, and the cake was washed with deionized water until neutral. The cake was then dried at 75°C to constant weight to obtain intermediate II. Intermediate II was weighed... 70g of 3-aminophthalimide, 10g of N-methylpyrrolidone, 250mL of toluene, 200mL of toluene, and 30g of molecular sieve were added to a three-necked flask under nitrogen protection and stirred. The temperature of the three-necked flask was raised to reflux, and the reaction was maintained at this temperature for 11 hours. The temperature of the three-necked flask was lowered to room temperature, and the mixture was filtered. The molecular sieve was removed, and the filtrate was transferred to a three-necked flask. The temperature of the three-necked flask was raised to 135℃, and the solvent was removed by vacuum distillation. The distilled solid was pulverized to a particle size of less than 0.1mm. The solid was soaked in toluene at room temperature for 10 hours, filtered, and the filter cake was washed three times with toluene and then dried. The filter cake was transferred to a drying oven at 80℃ and dried to constant weight to obtain the reinforcing agent. ② Weigh 50g of polyimide, 15g of reinforcing agent, 425mL of N-methylpyrrolidone, 4.0g of polyethylene glycol 400, and 2.5g of zinc nitrate into a beaker. Stir at room temperature until the system dissolves, filter, and let the filtrate stand for 6.5h to remove air bubbles, obtaining the casting solution. ③ Completely immerse the PP nonwoven fabric in N-methylpyrrolidone at room temperature for 50min. Remove the PP nonwoven fabric and spread it flat to obtain the pretreated substrate. Apply the casting solution evenly to the pretreated substrate to form a 55μm thick coating layer on the surface of the pretreated substrate. Cure at room temperature for 8min to obtain the coated nonwoven fabric. ④ Mix hexamethylenediamine, 2-methylimidazole and isopropanol at a ratio of 4g:3g:100mL to obtain a modified solution; immerse the coated nonwoven fabric in the modified solution at a temperature of 75℃ and keep it warm for 11 hours. After the reaction is complete, remove the submerged coated nonwoven fabric from the modified solution, wash it three times with isopropanol, and then dry it with compressed air to obtain the support layer.⑤ Mix 1,2,4-triaminobenzene hydrochloric acid, triethylamine, and purified water at a ratio of 5g:2g:30mL to obtain a mixed solution; mix trimesoyl chloride and cumene at a ratio of 1g:3mL to obtain a coating solution; place the support layer in the mixed solution and soak it at room temperature for 2.5min; immerse the support layer in the coating solution and keep it completely submerged for 45s; remove the support layer from the coating solution and drain it; transfer the support layer with the coating solution drained to a drying oven at 85℃ and keep it at that temperature for 13min; transfer the membrane to a 10wt% sodium hydroxide solution at 70℃ and keep it at that temperature for 20min; transfer the membrane to deionized water and ultrasonically disperse it at room temperature for 50min; transfer the membrane to a drying oven at 60℃ and vacuum dry it to constant weight to obtain 4. # Organic membrane.

[0079] (2) Preparation of organic membrane according to CN117619168A: ① Polyimide (P84) was dissolved in N,N-dimethylformamide and stirred at room temperature for 6 hours until completely dissolved to obtain a P84 casting solution with a concentration of 22wt%. The prepared casting solution was allowed to stand to remove bubbles. Under the conditions of room temperature and 70% humidity, the casting solution was coated onto a polyester nonwoven fabric, with the coating thickness controlled at 150μm and the coating speed controlled at 150mm / s. After coating, it was quickly transferred to pure water for phase inversion and soaked for 5 minutes. The prepared P84 ultrafiltration membrane was transferred to pure water and soaked for 2 hours, and then transferred to isopropanol solvent and soaked for 2 hours to remove any possible residual solvent and water. The P84 ultrafiltration membrane was immersed in isopropanol solvent containing 120g / L hexamethylenediamine and crosslinked at 25℃ for 20 hours. The crosslinked ultrafiltration membrane was then rinsed with isopropanol and water. ② Dissolve 4,4′-diaminobiphenyl in a mixed solvent of tetrahydrofuran and water to obtain a first solution. The volume ratio of tetrahydrofuran to water is 4:6, and the concentration of 4,4′-diaminobiphenyl is 0.2 wt%. The resulting mixed solution is sonicated for 30 min and centrifuged at 12000 r / min for 10 min to obtain a clear mixed solution. Dissolve the crosslinking agent trimesoyl chloride in the organic phase solvent B, n-hexane, to obtain a second solution. The concentration of the crosslinking agent is 0.1 w / v%. ③ Immerse the crosslinked base film in the first solution containing the amine monomer for 5 min. After removing surface droplets with an air knife, immerse it in the second solution containing the crosslinking agent for 10 min at 60°C. After the reaction, rinse the film surface with n-hexane and further dry and cure it in a 60°C oven for 10 min. ④ After further immersing the composite film obtained from interfacial polymerization in step ③ in N,N-dimethylformamide solvent for 1 hour, it is then rinsed with methanol for 1 hour to remove residual N,N-dimethylformamide. After immersion in a 35% glycerol aqueous solution and air drying, 5 # Organic membrane.

[0080] (3) Prepare organic membrane according to CN117065577A: ① Add poly(m-phenylene isophthalamide) to 1-ethyl-3-methylimidazolium acetate ([EMIM][OAC]) ionic liquid, heat and dissolve at 85°C under magnetic stirring, let stand to degas, and prepare homogeneous casting solution; the concentration of poly(m-phenylene isophthalamide) in the homogeneous casting solution is 16wt%; pour the homogeneous casting solution onto the nonwoven fabric support layer, adjust the coating thickness with a doctor blade, coat the homogeneous casting solution onto the nonwoven fabric support layer, after coating, immerse in a room temperature coagulation bath for curing, the homogeneous casting solution precipitates at the interface, completes the phase inversion, forms a porous layer structure, and obtains ultrafiltration base membrane. ② Polyethyleneimine and m-phenylenediamine are mixed with water and stirred until homogeneous to obtain an aqueous solution; the concentration of polyethyleneimine in the aqueous solution is 1 wt%, and the concentration of m-phenylenediamine is 0.5 wt%. Tristyrene chloride monomer and isophthaloyl chloride monomer are dissolved in an ionic liquid of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([BMIM]Tf2N), heated to 85°C and stirred until dissolved to obtain an oil solution; the concentration of tristyrene chloride monomer in the oil solution is 0.1 wt%, and the concentration of isophthaloyl chloride monomer is 0.5 wt%. The concentration was 0.1 wt%. The ultrafiltration membrane was first immersed in an aqueous solution for 2 minutes, then the aqueous solution was discarded. The remaining droplets on the ultrafiltration membrane were removed using an air gun to ensure uniform impregnation with the aqueous solution. Then, it was immersed in an oil solution for interfacial polymerization for 0.5 minutes. After the reaction, the impregnation was stopped, resulting in a nascent polyamide membrane layer. The ultrafiltration membrane with the nascent polyamide membrane layer was then heat-treated at 60°C for 5 minutes to form a polyamide separation layer. Finally, it was rinsed with ethanol to remove residues, yielding 6... # Organic membrane.

[0081] (4) Organic membrane preparation according to CN114588792A: 360g of PVDC with a degree of polymerization of 1900, 40g of PVB with a viscosity of 400mPa.s, 200g of polyvinylpyrrolidone with a molecular weight of 10000, 100g of ethylene glycol, and 1300g of dimethylacetamide were uniformly mixed at 50℃ and stirred for 24h to dissolve. After degassing, a casting solution was obtained. The casting solution was coated onto a clean glass plate at 40℃ using a 100μm thick doctor blade. After standing for 10s, the membrane was completely immersed in a 40℃ mixed solution of ethylene glycol and dimethylacetamide to gel and solidify for 60s. Then, it was removed and soaked in pure water at room temperature for 12 hours, and then transferred to an oven to dry at 40℃ for 12 hours to obtain 7 # Organic membrane.

[0082] Test 3-3 with the test solution. # 4 # 5 # 6 # 7 #The initial flux and organic impurity rejection rate of the organic membrane, and then 3-3 # 4 # 5 # 6 # 7 # After the organic membranes were immersed in sulfolane for 70 days, the flow rate and organic impurity rejection rate of the organic membranes after immersion were tested with a test solution. The experimental results are shown in Table 4.

[0083] Table 4. Comparative Experiment Results

[0084]

[0085] As can be seen from the experimental results in Table 4, the 4 prepared by the existing method # 5 # 6 # 7 # The organic membrane failed after being soaked in sulfolane for 70 days, becoming clogged and losing flow, indicating it was intolerant to sulfolane; while the 3-3 membrane prepared according to the method of this invention... # The organic membrane remained stable after being immersed in sulfolane for 70 days, demonstrating significantly stronger tolerance to sulfolane than existing technologies.

[0086] Finally, it should be noted that the above specific embodiments are only used to describe the purpose, technical solution, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation of the present invention and is not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing specific embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions or improvements can be made to some or all of the technical features. Such modifications, equivalent substitutions, and improvements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for preparing an ester-based organic membrane, characterized in that, Includes the following steps: An acrylate-dimethacrylate polymer was prepared by reacting itaconic acid allyl ester, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide. A casting solution is prepared by mixing allyl itaconic acid-ethylene glycol dimethacrylate polymer, polytoluene acrylate, pore-forming agent and solvent; The casting solution is coated onto the support and then cooled and solidified to obtain an organic film.

2. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The mass ratio of itaconic acid allyl ester, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide is (0.8–2):1:(0.002–0.06).

3. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The mass ratio of itaconic acid allyl ester, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide is 1.2:1:0.

03.

4. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The specific preparation method of the acrylate-ethylene glycol dimethacrylate polymer is as follows: Allyl itaconic acid, ethylene glycol dimethacrylate, and tert-butyl hydroperoxide were mixed in a certain mass ratio to obtain a mixture. The mixture was then added to saturated brine and heated to 80–90°C. The mixture was stirred for 7–9 hours to obtain an allyl itaconic acid-ethylene glycol dimethacrylate polymer.

5. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The porogen is a mixture of toluene and butanone.

6. The method for preparing an ester-based organic membrane according to claim 5, characterized in that, The mass ratio of toluene to butanone is 1:(1-3).

7. The method for preparing an ester-based organic membrane according to claim 6, characterized in that, The mass ratio of toluene to butanone is 1:

3.

8. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The casting solution comprises: The mass ratio of itaconic acid allyl ester-dimethacrylate ethylene glycol polymer, polytoluene acrylate, pore-forming agent and solvent is 1:(1.2~1.6):(1.5~2):(4~6).

9. The method for preparing an ester-based organic membrane according to claim 8, characterized in that, The mass ratio of itaconic acid allyl ester-ethylene dimethacrylate polymer, polytoluene acrylate, pore-forming agent and solvent is 1:1.3:1.8:

5.

10. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The solvent used is N,N-dimethylformamide.

11. The method for preparing an ester-based organic membrane according to claim 1, characterized in that, The method for preparing the casting solution is as follows: The itaconic acid allyl ester-dimethacrylate ethylene glycol polymer, polytoluene acrylate, pore-forming agent and solvent are mixed in proportion and heated to 60℃~65℃, stirred for 12~16h, and then heated to 110℃~120℃ and evacuated for 4~8h to obtain the casting solution.

12. A method for preparing an ester-based organic membrane according to any one of claims 1-11, characterized in that, The support is a polytetrafluoroethylene hollow fiber membrane.

13. A method for preparing an ester-based organic membrane according to any one of claims 1-11, characterized in that, The cooling and curing temperature is 1℃~9℃, and the curing time is 12~24h.

14. An ester-based organic membrane, characterized in that, It is prepared by the method described in any one of claims 1-13.

15. The application of the ester-based organic membrane as described in claim 14 in aromatic hydrocarbon extraction and natural gas purification.

16. The application as described in claim 15, wherein the ester-based organic membrane is used to separate impurities from sulfolane.

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