Preparation method of crosslinked benzimidazole and imine connected polymer membrane for methanol / organic matter separation

Abstract

The invention relates to a preparation method of a crosslinked benzimidazole and imine connected polymer membrane for methanol / organic matter separation. Cross-linking the benzimidazole and imine connected polymer base membrane prepared on the support in a solution containing a cross-linking agent; the crosslinking time is 0.1 to 72 hours; the crosslinking temperature is 40-80 DEG C; putting the polymer film obtained after crosslinking treatment into a drying oven at 80-300 DEG C, carrying out heat treatment for 1-72 hours, and then naturally cooling to room temperature, so as to obtain a crosslinked benzimidazole and imine connected polymer film; and the thickness of the benzimidazole and imine connection polymer film is 20-2000nm. The method is applied to separation of mixtures such as methanol / dimethyl carbonate, methanol / toluene, methanol / methyl tert-butyl ether and the like for the first time. And for methanol / dimethyl carbonate and methanol / methyl tert-butyl ether, the mass fractions of methanol in the penetrating fluid can respectively reach 98.8% and 99.9% or above.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic polymer membrane preparation, and is a preparation method of a cross-linked benzimidazole and imine connected polymer membrane for methanol / organic separation. BACKGROUND

[0002] The separation of methanol (MeOH) containing organic mixture systems is crucial in the chemical industry. As one of the most versatile basic chemicals, MeOH can be used as a liquid fuel and a raw material for various chemical products, reducing dependence on fossil fuels. At the same time, it can be synthesized from renewable resources such as carbon dioxide and synthesis gas, which can realize carbon cycle, and is the core material in the methanol economy proposed by George A. Olah (Nobel Prize winner in Chemistry, 1994). Methyl tert-butyl ether (MTBE) and dimethyl carbonate (DMC) are important ways for MeOH diversification in the methanol economy, promoting the development of the methanol economy. MTBE, as an octane enhancer in unleaded gasoline, can improve the anti-knock performance and combustion efficiency of gasoline, thereby improving energy utilization efficiency and reducing harmful gas emissions. In addition, MTBE is also used as a synthetic raw material for important chemicals and an intermediate for biological medicines, with broad application prospects and large market demand. It is mainly generated by the reaction of MeOH and isobutene. However, the reaction usually requires excess MeOH to increase the yield, resulting in the generation of MeOH / MTBE mixture which is difficult to separate. DMC, as a low-toxicity, safe and green organic solvent, is easy to transport and can replace toxic substances such as phosgene in organic synthesis. The current commercial production process of DMC involves MeOH reaction, and the final product contains DMC and MeOH, making separation difficult. At the same time, both of them can form azeotrope with MeOH at normal pressure, further increasing the difficulty of mixture separation. Pervaporation, as one of the most widely used membrane separation technologies, uses the difference in vapor pressure of components on both sides of the membrane as driving force, relies on the different solubility and diffusion rates of components in the membrane to realize the separation of mixtures, and has the advantages of high efficiency, no need for additional additives and easy operation, showing potential in liquid phase molecular separation. This provides a theoretical basis for the separation of MeOH / MTBE, MeOH / DMC and other azeotropic or near-boiling organic systems.

[0003] Polymer is the first material applied in membrane separation technology due to its low cost, easy scale-up and high processability, and dominates the membrane market. The polymer membrane materials for pervaporation include cellulose acetate (CA), polyimide (PI), chitosan (CS) and so on. However, the lower free volume and disordered cross-linked network structure of polymer itself, and the swelling of polymer chains by polar solvents such as MeOH, lead to lower performance of polymer membranes for organic system separation. For example, the flux of commercial polymer membrane PERVAP 2256 is less than 1.00 kg·m⁻²·h⁻¹ and the selectivity is less than 100 for MeOH / MTBE separation. Cross-linking, heat treatment, surface modification and other methods can improve the pore size distribution of polymer, limit the movement of polymer chains, and improve the separation performance of the membrane.

[0004] Benzimidazole and imine linked polymer membrane is a kind of heterocyclic network polymer generated by the polycondensation reaction of amine and aldehyde, which belongs to a new type of polybenzimidazole. Due to the unique tetrahedral core branched structure, compared with ordinary linear structure polymer, benzimidazole and imine linked polymer has higher microporosity and free volume. At the same time, the strong hydrogen bond and π-π stacking interaction in the main chain and the existence of benzimidazole ring endow benzimidazole and imine linked polymer with excellent thermal and chemical stability, good hydrophilicity and rigidity. However, due to the absence of fixed chemical crosslinking structure between the molecular chains of benzimidazole and imine linked polymer, when applied to the separation of polar organic solvents, the polymer chain swells, and the separation performance is poor. The patent specification with publication number CN115400617B discloses a preparation method of a high-temperature-resistant benzimidazole and imine linked polymer membrane for hydrogen purification. The method prepares a benzimidazole and imine linked polymer base membrane on the surface of an Al2O3 ceramic sheet through interfacial polymerization, and then crosslinks the base membrane by 1,3,5-benzene tricarboxylic acid chloride (TMC) solution in n-hexane at room temperature to obtain a dense, defect-free and high-selectivity gas separation membrane. The patent specification with publication number CN113101815B discloses a preparation method of a bacteria-resistant benzimidazole and imine linked polymer for dye / salt wastewater treatment. The method prepares a benzimidazole and imine linked polymer membrane on the surface of polyacrylonitrile (PAN) through interfacial polymerization, realizes high efficiency and high flux separation of dye wastewater, and has excellent desalination. Wang et al. (Sep. Purif. Technol., 2023, 316, 123802) crosslink the benzimidazole and imine linked polymer membrane by TMC n-hexane solution at room temperature for ethyl acetate dehydration, realizing high separation performance. The above crosslinking modification methods of benzimidazole and imine linked polymer membrane are all concentrated in n-hexane solution at room temperature. However, due to the non-polarity of n-hexane molecules and the non-violent movement of polymer chains at room temperature, the system cannot effectively swell the polymer chains during crosslinking treatment, and the crosslinking agent only reacts on the surface of the membrane, which cannot further diffuse into the interior of the polymer membrane to realize overall crosslinking and improve the crosslinking degree. Therefore, when used for gas and weakly polar molecule separation, it has good performance, but for MeOH and other strong polar solvents, surface crosslinking cannot effectively inhibit the overall swelling of MeOH to the polymer membrane, and has no good effect on the separation of MeOH and other polar solvent systems. SUMMARY

[0005] The application provides a new temperature and solvent assisted crosslinking method for preparing a crosslinked benzimidazole and imine linked polymer film, and is applied to pervaporation separation of an organic mixture containing MeOH for the first time, so that MeOH is recovered and other organic substances are purified. The benzimidazole and imine linked polymer base film prepared by an interfacial polymerization method is subjected to temperature and solvent assisted crosslinking and heat treatment, so that special mass transfer channels are created and polymer chain spacing is adjusted. The crosslinking range and crosslinking density of the polymer are improved due to the rapid diffusion and reaction of the temperature and solvent assisted crosslinking agent, the polymer chain spacing is adjusted and the movement of the polymer chain is limited, the crosslinking agent introduces carboxyl groups, and MeOH preferential adsorption sites are provided, and the heat treatment promotes the ring formation of the benzimidazole and improves the rigidity of the polymer. The crosslinked benzimidazole and imine linked polymer film has good MeOH separation and recovery performance.

[0006] The technical scheme of the application is as follows:

[0007] A preparation method of a crosslinked benzimidazole and imine linked polymer film for methanol / organic substance separation, comprising the following steps:

[0008] 1) crosslinking the benzimidazole and imine linked polymer base film prepared on a support in a solution containing a crosslinking agent; the crosslinking agent is one or more of 1,4-benzene dicarbonyl chloride, succinyl chloride, 1,3,5-benzene tricarbonyl chloride, adipoyl chloride, malonyl chloride, 1,3,5-benzene trisulfonyl chloride, 1,3-benzene disulfonyl chloride, pyromellitic dianhydride and 3,3',4,4'-biphenyl tetracarboxylic anhydride; the crosslinking time is 0.1-72 h; and the crosslinking temperature is 40-80 DEG C.

[0009] 2) placing the polymer film obtained after the crosslinking treatment in step 1) into an oven, naturally cooling to room temperature after heat treatment, and obtaining a crosslinked benzimidazole and imine linked polymer film; the thickness of the benzimidazole and imine linked polymer film is 20-2000 nm.

[0010] The support in step 1) comprises one of an Al2O3 ceramic sheet, a ZrO2 ceramic sheet, SiO2, TiO2, a ceramic tube, polysulfone, polyacrylonitrile, polyether sulfone or a stainless steel support.

[0011] The solvent of the crosslinking agent comprises one or more of hexane, octane, heptane, ethyl acetate, benzene, toluene, trimethylbenzene, tetrahydrofuran and N,N-dimethylformamide; and the mass percentage concentration of the crosslinking agent in the solvent is 0.100-30.0wt%.

[0012] Preferably, the mass percentage concentration of the crosslinking agent in the solvent is 0.500-10.0wt%.

[0013] The crosslinking temperature is preferably 40-65℃;

[0014] The polymer film obtained after the crosslinking treatment is placed in an oven at 80-300℃ and heat treated for 1-72h.

[0015] The crosslinked benzimidazole and imine-linked polymer membrane prepared by the method of the present application is used for separating mixtures of methanol / dimethyl carbonate, methanol / toluene and methanol / methyl tert-butyl ether.

[0016] In the application, the crosslinked benzimidazole and imine-linked polymer membrane material is used for separating organic mixtures with a kinetic diameter smaller than that of methanol (0.380nm) and larger than that of dimethyl carbonate (0.496nm).

[0017] The specific description is as follows:

[0018] Any benzimidazole and imine-linked polymer reported in the prior art or purchased can be used; or a benzimidazole and imine-linked polymer base film is prepared on different supports according to the method of Wang et al. (Sep. Purif. Technol., 2023, 316, 123802) and is crosslinked by immersion in a solution containing a crosslinking agent, wherein the organic phase for interfacial polymerization in the preparation method is replaced with toluene.

[0019] The crosslinked benzimidazole and imine-linked polymer membrane obtained after the crosslinking treatment is a porous organic polymer connected by benzimidazole and imine groups, has a reticular structure crosslinked with each other and selective channels for preferentially permeating MeOH; and the thickness of the benzimidazole and imine-linked polymer membrane is 20-2000nm.

[0020] The post-treatment crosslinking method and application system of the crosslinked benzimidazole and imine-linked polymer membrane prepared by the present application are innovative. That is, the crosslinked reticular polymer membrane connected by benzimidazole and imine is prepared for the first time by a temperature and solvent-assisted crosslinking method, and is applied for the first time in the pervaporation separation of MeOH / organic systems.

[0021] The present application is used for preparing complete and dense crosslinked benzimidazole and imine-linked polymer membranes by adjusting parameters such as crosslinking temperature, crosslinking solvent and crosslinking time. Benefiting from suitable interchain distance, porosity and good MeOH affinity, the obtained crosslinked benzimidazole and imine-linked polymer membranes are used for separating MeOH / DMC, MeOH / toluene, MeOH / MTBE and other organic mixtures containing MeOH. Good MeOH / organic pervaporation separation performance is achieved.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The benzimidazole and imine connected polymer base film is first chemically crosslinked and heat treated at a certain temperature and in a crosslinking solvent system for different times, the complex solvent promotes the swelling of the polymer chain, which is beneficial to the diffusion of the crosslinking agent into the base film, improves the crosslinking range, and the crosslinking rate is accelerated at a proper temperature, which improves the crosslinking degree, so that the crosslinked benzimidazole and imine connected polymer film has high MeOH / MTBE and MeOH / DMC separation performance and good stability. 4 The total flux is 2.80 kg·m⁻²·h⁻¹, which is better than most existing polymer films.

[0024] The advantages of the present application are:

[0025] The interfacial polymerization method is a method for preparing a film material, which is simple and effective, fast in reaction speed, easy to scale up, low in requirements for concentration and purity, capable of generating a benzimidazole and imine connected polymer film with controllable thickness, and reducing the mass transfer resistance. Figure 3 As shown in the X-ray diffraction characterization, after the reaction of the crosslinking agent and the polymer chain, the interchain distance of the polymer is reduced, the molecular sieving ability is improved, and the swelling is inhibited. Figure 4 As shown in the infrared spectrogram and Figure 5 As shown in the X-ray photoelectron spectroscopy, the carboxyl group is introduced by the crosslinking agent, the MeOH site is increased, the selective mass transfer channel is created, the benzimidazole ring is promoted by heat treatment, the rigidity and thermal stability of the polymer film are improved, and finally the crosslinked benzimidazole and imine connected polymer film has a complex crosslinked network structure and excellent stability.

[0026] The crosslinked benzimidazole and imine connected polymer film prepared by the method has high permeation flux and separation factor, good selectivity at high test temperature and MeOH concentration, and can be applied to the pervaporation separation of MeOH / organic matter under actual industrial conditions, effectively saving energy and reducing emissions. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The surface SEM image of the crosslinked benzimidazole and imine connected polymer film prepared in Example 1 of the present application.

[0028] Figure 2 The cross-sectional SEM image of the crosslinked benzimidazole and imine connected polymer film prepared in Example 1 of the present application.

[0029] Figure 3 The X-ray diffraction pattern of the crosslinked benzimidazole and imine connected polymer film prepared in Example 6 of the present application.

[0030] Figure 4 The infrared spectrum is shown for the cross-linked benzimidazole and imine-linked polymer film prepared in Example 6 of this invention.

[0031] Figure 5 The image shows the X-ray photoelectron spectrum of the cross-linked benzimidazole and imine-linked polymer film prepared in Example 6 of this invention.

[0032] Figure 6 The graph shows the separation performance of the cross-linked benzimidazole and imine-linked polymer membrane prepared in Example 6 of this invention for MeOH / MTBE at different test temperatures (feed concentration of 50 wt%).

[0033] Figure 7 The graph shows the separation performance of the cross-linked benzimidazole and imine-linked polymer membrane prepared in Example 6 of this invention for MeOH / MTBE at different feed concentrations (feed temperature of 50°C).

[0034] Figure 8 The graph shows the performance stability of the cross-linked benzimidazole and imine-linked polymer membrane prepared in Example 6 of this invention on MeOH / MTBE during a test of ≥120h (feeding conditions: 50wt% MeOH / MTBE at 50℃). Detailed Implementation

[0035] The following specific embodiments illustrate the content of the present invention in detail. These embodiments are merely preferred embodiments of the present invention, and the claims of the present invention are not limited to these limited embodiments.

[0036] Example 1

[0037] Step 1) Weigh 0.100 g of 1,3,5-benzenetricarboxylic acid chloride (TMC) and dissolve it in 19.9 g of n-hexane. Sonicate the solution until completely dissolved to obtain a 0.500 wt% TMC crosslinking solution. Place the benzimidazole and imine-linked polymer base film prepared on γ-Al2O3 into the TMC crosslinking solution and crosslink at 40 °C for 24 h.

[0038] Step 2) After crosslinking is completed, take out the crosslinked film and air dry it until there are no droplets on the surface. Then, put it in a 120℃ oven for heat treatment for 24 hours, take it out and cool it to room temperature.

[0039] like Figure 1 As shown, SEM characterization of the prepared membrane surface reveals a continuous, defect-free cross-linked benzimidazole and imine-linked polymer membrane formed on the γ-Al₂O₃ support surface. Figure 2As shown, by SEM characterization of the cross-section of the prepared membrane, it can be seen that the γ-A12O3 support surface successfully loaded a layer of uniform thickness, about 80 nm. The prepared cross-linked benzimidazole and imine-linked polymer membrane was subjected to pervaporation test. At 30°C, 10wt% MeOH / MTBE was separated, the membrane permeation flux was 0.420 kg·m⁻²·h⁻¹, and the separation factor was 256.

[0040] Example 2

[0041] Step 1) 0.200 g of TMC was weighed into 19.8 g of n-hexane and ultrasonically dissolved to obtain a 1.00wt% TMC cross-linking solution. The benzimidazole and imine-linked polymer-based membrane prepared on γ-A12O3 was placed in the TMC cross-linking solution and cross-linked at 40°C for 12 h.

[0042] Step 2) After cross-linking was completed, the cross-linked membrane was taken out and air-dried until the surface was completely free of droplets, then placed in a 120°C oven for heat treatment for 24 h, and taken out and cooled to room temperature.

[0043] The prepared cross-linked benzimidazole and imine-linked polymer membrane was subjected to pervaporation test. At 30°C, 50wt% MeOH / MTBE was separated, the membrane permeation flux was 0.126 kg·m⁻²·h⁻¹, and the separation factor was 1.30×10 4 .

[0044] Example 3

[0045] Step 1) 0.100 g of TMC was weighed into 19.9 g of a mixed solvent of n-hexane and ethyl acetate and ultrasonically dissolved to obtain a 0.500wt% TMC cross-linking solution. The benzimidazole and imine-linked polymer-based membrane prepared on γ-A12O3 was placed in the TMC cross-linking solution and cross-linked at 65°C for 12 h.

[0046] Step 2) After cross-linking was completed, the cross-linked membrane was taken out and air-dried until the surface was completely free of droplets, then placed in a 120°C oven for heat treatment for 24 h, and taken out and cooled to room temperature.

[0047] The prepared cross-linked benzimidazole and imine-linked polymer membrane was subjected to pervaporation test. At 30°C, 50wt% MeOH / MTBE was separated, the membrane permeation flux was 0.011 kg·m⁻²·h⁻¹, and the separation factor was 103.

[0048] Example 4

[0049] Step 1) 0.100 g of TMC was weighed into 19.9 g of n-hexane and sonicated until completely dissolved to give a 0.500 wt% TMC crosslinking solution. The benzimidazole and imine-linked polymer membrane prepared on a polyacrylonitrile organic support was placed into the TMC crosslinking solution and crosslinked at 40 °C for 10 h.

[0050] Step 2) After crosslinking was complete, the crosslinked membrane was removed and allowed to air dry until the surface was completely free of droplets. The membrane was then placed into a 120 °C oven for 24 h, removed and allowed to cool to room temperature.

[0051] The crosslinked benzimidazole and imine-linked polymer membrane prepared was tested for pervaporation. At 30 °C, 30 wt% MeOH / MTBE was separated with a membrane flux of 0.005 kg m"2h"1and a separation factor of 154.

[0052] Example 5

[0053] Step 1) 2.00 g of TMC was weighed into 18.0 g of n-hexane and sonicated until completely dissolved to give a 10.0 wt% TMC crosslinking solution. The benzimidazole and imine-linked polymer membrane prepared on a γ- AI2O3 support was placed into the TMC crosslinking solution and crosslinked at 40 °C for 12 h.

[0054] Step 2) After crosslinking was complete, the crosslinked membrane was removed and allowed to air dry until the surface was completely free of droplets. The membrane was then placed into a 120 °C oven for 24 h, removed and allowed to cool to room temperature.

[0055] The crosslinked benzimidazole and imine-linked polymer membrane prepared was tested for pervaporation. At 40 °C, 30 wt% MeOH / MTBE was separated with a membrane flux of 2.07 kg m"2h"1and a separation factor of 8.00 x 10 3 .

[0056] Example 6

[0057] Step 1) 0.100 g of TMC was weighed into 19.9 g of n-hexane and sonicated until completely dissolved to give a 0.500 wt% TMC crosslinking solution. The benzimidazole and imine-linked polymer membrane prepared on a γ- AI2O3 support was placed into the TMC crosslinking solution and crosslinked at 40 °C for 10 h.

[0058] Step 2) After crosslinking was complete, the crosslinked membrane was removed and allowed to air dry until the surface was completely free of droplets. The membrane was then placed into a 120 °C oven for 24 h, removed and allowed to cool to room temperature.

[0059] The crosslinked benzimidazole and imine-linked polymer membrane prepared was tested for pervaporation. The separation performance of the membrane for MeOH / MTBE was investigated at different feed temperatures and concentrations. As shown in Table 2, the separation factor increased with increasing feed temperature.Figure 3 As shown, the X-ray diffraction characterization showed that the interchain distance of the polymer was reduced after the crosslinker reacted with the polymer chain. As shown, Figure 4 As shown, the infrared spectrum successfully proved the successful synthesis of the crosslinked benzimidazole and imine connected polymer membrane. As shown, Figure 5 As shown, the X-ray photoelectron spectroscopy showed that the crosslinker introduced carboxyl groups, increasing the affinity for MeOH sites. The separation performance of the membrane for MeOH / MTBE at different feed temperatures, as shown, Figure 6 As shown, as the temperature increased, both the membrane flux and separation performance improved. At 50°C, the membrane permeation flux was 2.80 kg·m⁻²·h⁻¹, and the separation factor was 4.80×10 4 The separation performance of the membrane for MeOH / MTBE at different feed concentrations Figure 7 As shown, the membrane had good separation performance for raw material liquid in a wide concentration range. As shown, Figure 8 As shown, the membrane showed stability in the performance test for ≥120 h.

[0060] Example 7

[0061] Step 1) 0.150 g of pyromellitic dianhydride was weighed into 19.85 g of ethyl acetate, and ultrasonic was used to completely dissolve it, obtaining a 0.750 wt% pyromellitic anhydride crosslinking solution. The benzimidazole and imine connected polymer membrane prepared on γ-Al2O3 was placed in the pyromellitic dianhydride crosslinking solution, and crosslinked at 40°C for 24 h.

[0062] Step 2) After the crosslinking was completed, the crosslinked membrane was taken out and dried until the surface was completely free of droplets, and then placed in a 120°C oven for heat treatment for 12 h, and then taken out and cooled to room temperature.

[0063] The prepared crosslinked benzimidazole and imine connected polymer membrane was subjected to pervaporation test. At 40°C, the membrane permeation flux was 0.650 kg·m⁻²·h⁻¹, and the separation factor was 45.

[0064] Example 8

[0065] Step 1) 0.100 g of TMC was weighed into 19.9 g of n-hexane and ethyl acetate mixed solvent, and ultrasonic was used to completely dissolve it, obtaining a 0.500 wt% TMC crosslinking solution. The benzimidazole and imine connected polymer membrane prepared on γ-Al2O3 was placed in the TMC crosslinking solution, and crosslinked at 40°C for 24 h.

[0066] Step 2) After the crosslinking was completed, the crosslinked membrane was taken out and dried until the surface was completely free of droplets, and then placed in a 120°C oven for heat treatment for 12 h, and then taken out and cooled to room temperature.

[0067] The prepared crosslinked benzimidazole and imine linked polymer membranes were subjected to pervaporation tests. At 40°C, 30wt% MeOH / DMC was separated with a membrane permeate flux of 0.650 kg-m-2-h-1 and a separation factor of 273.

[0068] The above only describes some embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the scope of the present application should be included in the protection scope of the present application.

[0069] The technical solutions disclosed and proposed in the present application can be realized by referring to the content of the present application and appropriately changing the condition routes and other links by those skilled in the art. Although the methods and preparation technologies of the present application have been described by means of preferred embodiments, it is obvious for those skilled in the art to modify or recombine the methods and technical routes described in the present application without departing from the content, spirit and scope of the present application, so as to realize the final preparation technology. It should be particularly pointed out that all similar replacements and modifications are obvious for those skilled in the art, and they are regarded as being included in the spirit, scope and content of the present application.

Claims

1. A method for preparing a cross-linked benzimidazole and imine-linked polymer membrane for methanol / organic matter separation, characterized in that, Includes the following steps: 1) The benzimidazole and imine-linked polymer base film prepared on the support is crosslinked in a solution containing a crosslinking agent; the crosslinking agent is one or more of 1,4-phenylenediol chloride, succinyl chloride, 1,3,5-phenyltricarboxylic acid chloride, adipic acid chloride, malonyl chloride, 1,3,5-phenyltrisulfonyl chloride, 1,3-phenyldisulfonyl chloride, pyromellitic dianhydride, and 3,3',4,4'-biphenyltetracarboxylic anhydride; the crosslinking time is 0.1~72h; the crosslinking temperature is 40~80℃; 2): Place the polymer film obtained after the crosslinking treatment in step 1) into an oven, heat-treat it, and then naturally cool it to room temperature to obtain a crosslinked benzimidazole and imine-linked polymer film; the thickness of the benzimidazole and imine-linked polymer film is 20~2000nm.

2. The method for preparing the crosslinked benzimidazole and imine-linked polymer membrane according to claim 1; characterized in that, Step 1) The support includes one of the following: Al2O3 ceramic sheet, ZrO2 ceramic sheet, SiO2, TiO2, ceramic tube, polysulfone, polyacrylonitrile, polyethersulfone, or stainless steel support.

3. The method for preparing the crosslinked benzimidazole and imine-linked polymer membrane according to claim 1; characterized in that, The solvent for the crosslinking agent includes one or more of hexane, octane, heptane, ethyl acetate, benzene, toluene, trimethylbenzene, tetrahydrofuran, and N,N-dimethylformamide; the mass percentage concentration of the crosslinking agent in the solvent is 0.100~30.0 wt%.

4. The method for preparing the crosslinked benzimidazole and imine-linked polymer membrane according to claim 1; characterized in that, The mass percentage concentration of the crosslinking agent in the solvent is 0.500~10.0 wt%.

5. The method for preparing a crosslinked benzimidazole and imine-linked polymer membrane according to claim 1; characterized in that, The cross-linking temperature is 40~65℃.

6. The method for preparing the crosslinked benzimidazole and imine-linked polymer membrane according to claim 1; characterized in that, The polymer film obtained after crosslinking treatment is placed in an oven at 80~300℃ and heat-treated for 1~72h.

7. The cross-linked benzimidazole and imine-linked polymer membrane prepared according to claim 1 is used to separate mixtures of methanol / dimethyl carbonate, methanol / toluene, and methanol / methyl tert-butyl ether.

8. The application according to claim 7, wherein the cross-linked benzimidazole and imine-linked polymer membrane material is used to separate organic mixtures with a kinetic diameter smaller than that of methanol (0.380 nm) and a kinetic diameter larger than that of dimethyl carbonate (0.496 nm).

Images