Binaphthylamine-based chiral intrinsic microporous polymer composite membranes and preparation and use thereof

Abstract

The present application relates to the technical field of separation membrane, and particularly relates to a kind of binaphthyl amine-based chiral inherent microporous polymer composite membrane and its preparation and application, with DMAc-H2O mixed solvent system as the dissolving medium of binaphthyl amine, n-hexane as the solvent of trimesoyl chloride, interface polymerization is carried out on polyacrylonitrile-based membrane, and S-BINAM / PAN chiral inherent microporous polymer composite membrane is self-assembled.The DMAc-H2O mixed solvent is used to replace traditional aqueous solvent, and the problem of low reaction activity of inherent microporous polymer monomer caused by hydrophobicity is solved;The polar aprotic property of DMAc enhances the solubility of binaphthyl amine, and the introduction of H2O optimizes the interface polymerization kinetics;The solvent system breaks through the dependence of traditional interface polymerization on hydrophilic monomer, provides a new path for efficient reaction of hydrophobic chiral monomer, and significantly improves the chemical stability and separation efficiency of the membrane.

Description

Technical Field

[0001] This invention relates to the field of separation membrane technology, and in particular to a binaphthylamine-based chiral intrinsically microporous polymer composite membrane and its preparation and application. Background Technology

[0002] Traditional interfacial polymerization typically involves the reaction of hydrophilic amine monomers (such as m-phenylenediamine, piperazine, or phenolic compounds) with acyl chloride compounds at the water / n-hexane interface. This technique suffers from limited monomer selection, leading to a limited variety of film structures and severely hindering the development of high-performance separation membranes. Based on a deep understanding of polymerization kinetics, researchers have proposed multidimensional performance control strategies, including: film thinning, microporous structure control, introduction of functional additives, surface engineering modification, and precise stoichiometric control. Notably, in recent years, intrinsically microporous polymer (PIM) monomers with non-planar topologies have shown unique advantages—their rigid framework can construct high free volume channels, theoretically enabling ultrafast solvent transport and precise sieving. However, due to their inherent hydrophobicity, the reactivity of these monomers is significantly reduced in conventional water / oil interfacial polymerization systems. To address this bottleneck, research has shifted towards developing novel solvent systems. Polar aprotic solvents such as tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) have attracted considerable attention due to their excellent solubility (especially for aromatic compounds), cost-effectiveness, and volatility. Experiments show that using this type of solvent instead of the traditional aqueous phase for interfacial polymerization results in polyamide films that not only maintain excellent chemical stability but also have significantly improved separation selectivity.

[0003] However, during the synthesis process, the phase interface of the organic solvent often fails to stably form a polyamide membrane, and existing separation membranes have poor separation effects on chiral chemicals. To address these technical problems, the inventors have proposed a new synthesis scheme for polyamide composite membranes to improve the separation effect on chiral chemicals. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention aims to provide a binaphthylamine-based chiral microporous polymer composite membrane, its preparation, and its application; and solves the technical problems of low reactivity and poor separation effect of separation membranes on chiral chemical substances in conventional water / oil interface polymerization systems.

[0005] According to an embodiment of the present invention, the first embodiment is provided as follows:

[0006] A method for preparing a binaphthylamine-based chiral intrinsically microporous polymer composite membrane includes the following steps:

[0007] S1. Preparation of reaction solution:

[0008] An aqueous solution was prepared by fully dissolving the aqueous monomer in a mixture of N,N-dimethylacetamide and H₂O.

[0009] The aqueous phase monomers include S-naphthylamine and NaOH.

[0010] An oil phase solution was prepared by dissolving the oil phase monomer in n-hexane.

[0011] The oil phase monomer is pyromellitic trimethylol chloride;

[0012] S2. Substrate pretreatment:

[0013] The polyacrylonitrile film is fixed in place using a mold, which limits the polymerization reaction area on the polyacrylonitrile film. The polyacrylonitrile film is fixed and kept horizontal in the mold.

[0014] After soaking the polyacrylonitrile membrane in an aqueous solution, the residual liquid on the surface is removed.

[0015] S3, Chiral polymerization step:

[0016] An oil-phase solution is dropped onto the surface of the polyacrylonitrile membrane soaked in the aqueous solution obtained in step S2. An interfacial polymerization reaction occurs on the surface of the polyacrylonitrile membrane. After the polymerization reaction time is reached, the reaction solution is removed.

[0017] After soaking the polyacrylonitrile membrane in hexane for a second time, the hexane solution was removed.

[0018] A thermal crosslinking treatment was performed, and after the thermal crosslinking was completed, the mold was removed to obtain a binaphthylamine-based chiral intrinsically microporous polymer composite membrane.

[0019] Furthermore, in S1, the volume ratio of N,N-dimethylacetamide to H2O used in the N,N-dimethylacetamide and H2O mixture is 7:3.

[0020] Furthermore, in step S2, the polyacrylonitrile film is pretreated before being fixed with a mold.

[0021] The pretreatment steps for polyacrylonitrile membrane are as follows: immerse the polyacrylonitrile membrane in deionized water, and after immersion, use absorbent paper to dry the surface moisture of the polyacrylonitrile membrane.

[0022] Furthermore, in S3, the polymerization reaction time is 1.5-3 min;

[0023] The thermal crosslinking process involves placing the mold in a forced-air drying oven after the reagent on the surface of the polyacrylonitrile film has completely evaporated. The thermal crosslinking temperature is 55-65℃ and the thermal crosslinking time is 5-8 minutes.

[0024] Furthermore, the binaphthylamine-based chiral microporous polymer composite membrane was immersed in deionized water and stored in a refrigerated environment at a temperature of 2-8°C for later use.

[0025] According to an embodiment of the present invention, utilizing the preparation method of the binaphthylamine-based chiral intrinsically microporous polymer composite membrane in the first embodiment of the present invention, a second embodiment is provided as follows:

[0026] A binaphthylamine-based chiral microporous polymer composite membrane is prepared by the aforementioned method for preparing a binaphthylamine-based chiral microporous polymer composite membrane.

[0027] Furthermore, the separation layer has sub-nanometer pore sizes, ranging from 0.8 to 1.4 nm; and a specific surface area greater than 50. .

[0028] According to an embodiment of the present invention, utilizing the naphthylamine-based chiral microporous polymer composite membrane in the second embodiment provided by the present invention, a third embodiment is provided as follows:

[0029] Naphthylamine-based chiral microporous polymer composite membranes are used for the separation of chiral compounds.

[0030] Compared with the prior art, the technical solution provided in this application has the following beneficial effects.

[0031] By using a DMAc-H2O mixed solvent to replace the traditional aqueous solvent, this solvent system breaks through the dependence of traditional interfacial polymerization on hydrophilic monomers, providing a new pathway for the efficient reaction of hydrophobic chiral monomers, and significantly improving the chemical stability and separation efficiency of the membrane.

[0032] The synthesized polymer composite membrane possesses a three-dimensional structure that provides high free volume channels, high permeation flux, and mechanical stability, thus solving the "trade-off" effect that traditional membrane materials struggle to balance permeability and selectivity.

[0033] It provides an efficient and low-energy-consumption solution for the continuous separation of chiral compounds in the pharmaceutical industry, and has the potential for large-scale production. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] in:

[0036] Figure 1This is a flowchart of a method for preparing a binaphthylamine-based chiral intrinsically microporous polymer composite membrane in one embodiment;

[0037] Figure 2 This is a diagram illustrating the film formation mechanism of a binaphthylamine-based chiral microporous polymer composite membrane in one embodiment.

[0038] Figure 3 This is a SEM comparison image of a binaphthylamine-based chiral intrinsically microporous polymer composite membrane from one embodiment.

[0039] Figure 4 XPS and XRD patterns of a binaphthylamine-based chiral intrinsically microporous polymer composite membrane in one embodiment;

[0040] Figure 5 AFM three-dimensional morphology image of a binaphthylamine-based chiral intrinsically microporous polymer composite membrane in one embodiment;

[0041] Figure 6 This is a comparison chart of the chiral recognition ability of the binaphthylamine-based chiral microporous polymer composite membrane in one embodiment.

[0042] Figure 7 This is a comparison of the circular dichroism spectra of S-BINAM monomer and S-BINAM-CPIM3 film in one embodiment.

[0043] Figure 8 The image shows a wide-angle X-ray scattering curve and BET test pattern of a binaphthylamine-based chiral microporous polymer composite membrane in one embodiment. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] A binaphthylamine-based chiral intrinsically microporous polymer composite membrane was prepared according to the technical solution of this application, comprising:

[0046] A polyacrylonitrile (PAN) membrane substrate and a polymer release layer on the PAN membrane substrate, the release layer covering the surface and pores of the PAN membrane substrate. The release layer is polymerized from S-naphthylamine and trimesoyl chloride.

[0047] Furthermore, the preparation method of the binaphthylamine-based chiral intrinsically microporous polymer composite membrane is illustrated by means of examples.

[0048] Figure 2 The rationale for selecting reactants and solvents is presented, along with the synthetic mechanism of this synthesis scheme.

[0049] like Figure 2 As shown in (b), since both reactants are in organic solvents, trimesoyl chloride (TMC) can directly enter the N,N-dimethylacetamide (DMAc) solvent, resulting in the inability to form a stable S-binaphthylamine (S-BINAM)-trisoyl chloride (TMC) polymer film.

[0050] like Figure 2 As shown in (c), this scheme inhibits the entry of trimesoyl chloride (TMC) by adding a certain amount of deionized water to the N,N-dimethylacetamide (DMAc) solvent, thereby enabling the formation of a stable S-binaphthylamine (S-BINAM)-trimethylammonium chloride (TMC) polymer film at the interface of the N,N-dimethylacetamide (DMAc) and H2O mixture with n-hexane.

[0051] Figure 1 The preparation process of the binaphthylamine-based chiral intrinsically microporous polymer composite membrane is demonstrated, and the specific steps include:

[0052] S1. Prepare the reaction solution;

[0053] Prepare an aqueous solution: Dissolve the aqueous monomers S-binaphthylamine (S-BINAM) and NaOH thoroughly in a mixture of N,N-dimethylacetamide (DMAc) and H2O to prepare an aqueous solution. The volume ratio of N,N-dimethylacetamide (DMAc) to H2O is 7:3.

[0054] Prepare an oil phase solution; dissolve the oil phase monomer, trimesoyl chloride (TMC), in n-hexane.

[0055] S2, Substrate pretreatment;

[0056] Soak the polyacrylonitrile (PAN) membrane in deionized water. After soaking, use absorbent paper to dry the surface of the polyacrylonitrile membrane and set it aside.

[0057] Lay the polyacrylonitrile film flat on a clean plate, use a mold to fix the polyacrylonitrile film, limit the range of the polymerization reaction, and ensure that the film is fixed and kept horizontal in the mold.

[0058] After soaking the polyacrylonitrile membrane in an aqueous solution, the residual liquid on the surface is removed.

[0059] S3, chiral polymerization;

[0060] An oil phase solution is dropped onto the surface of the polyacrylonitrile membrane soaked in the aqueous phase solution obtained in step S2. An interfacial polymerization reaction occurs on the surface of the polyacrylonitrile membrane. After the polymerization reaction time is reached, the reaction solution is removed.

[0061] After soaking the polyacrylonitrile membrane in hexane for a second time, the hexane solution was removed.

[0062] After the reagents on the surface of the polyacrylonitrile film have completely evaporated, the mold is placed in a forced-air drying oven for thermal crosslinking treatment.

[0063] After the thermal cross-linking is completed, the mold is removed to obtain the composite film. The composite film is then taken out and soaked in deionized water.

[0064] Example 1

[0065] 1. Preparation of aqueous phase solution: Add S-BINAM (1 wt%) and sodium hydroxide (0.2 wt%) to N,N-dimethylacetamide / deionized water mixed solution (7:3, v:v) and sonicate for 5 min to completely dissolve it; Preparation of organic phase solution: Dissolve trimesoyl chloride (TMC) (0.1 wt%) in n-hexane.

[0066] 2. Soak the purchased polyacrylonitrile (PAN) film in deionized water for 24 hours. After soaking, wipe it clean with absorbent paper and set aside. Cut the PAN film to the appropriate size as needed, lay it flat on a clean glass plate, install the rubber gasket and PTFE mold in sequence, and clamp it with fixing clips to ensure that the film is fixed in the mold and kept horizontal.

[0067] Next, using a plastic pipette, add 5 mL of DMAc / H2O mixed solution along the edge of the mold, soak the polyacrylonitrile membrane for 5 minutes, and then pour the solution into a waste bottle; then remove the molds one by one, and use a rubber roller to roll off the residual solvent on the membrane surface; then reassemble each mold in the original order.

[0068] 3. After ensuring the mold is placed horizontally, add 5 mL of n-hexane solution along the edge of the mold to induce interfacial polymerization on the polyacrylonitrile film surface for 3 minutes. Then, pour the solution into a waste bottle, and subsequently add an appropriate amount of n-hexane solution along the edge to stop the reaction. After standing for 1 minute, pour out the solution and wait for the surface reagents to completely evaporate. Then, place the mold in a forced-air drying oven for thermal crosslinking treatment at 60℃ for 7 minutes. After thermal crosslinking, remove the molds sequentially, take out the prepared composite film, and immerse it in deionized water. Finally, store it in a refrigerator at 2℃ for later use.

[0069] Example 2

[0070] The polyacrylonitrile membrane, aqueous solution, and oil solution used were the same as in Example 1. The difference in control parameters was that in step S3, the chiral polymerization step, the polymerization reaction time was 1.5 min, the thermal crosslinking temperature was 65°C, the thermal crosslinking time was 5 min, the membrane was removed and immersed in deionized water, and stored in a refrigerator at 6°C for later use.

[0071] We also characterized the synthesized polymer membrane.

[0072] like Figure 3 As shown, SEM images of S-BINAM / PAN chiral intrinsically microporous polymer (CPIM) composite membranes with different polymerization reaction times are presented. The polymerization time in images c and e is 1.5 min; the polymerization time in images d and f is 3 min. From images c and d, it can be seen that the synthesized composite membrane is continuous and defect-free, and from images e and f, it can be seen that a stable pore structure has been formed.

[0073] Figure 4 XPS and XRD patterns of the prepared composite membrane are shown. The figures show that the polyacrylonitrile membrane was not damaged, and the S-BINAM chiral microporous polymer component is stably present in the composite membrane, proving that the preparation of the binaphthylamine chiral microporous polymer composite membrane was successful.

[0074] Figure 5 The figure shows the AFM three-dimensional morphology of self-supporting S-BINAM-CPIM3 membranes prepared with different polymerization reaction times.

[0075] The height distribution curves for different polymerization times show that when the polymerization time is 1.5 min, the average thickness of the separation layer is about 15 nm; when the polymerization time is 3 min, the thickness of the separation layer increases significantly to 30 nm, an increase of 100%. Extending the reaction time before the reactants are completely reacted can effectively increase the thickness of the separation layer. Composite membranes with different separation layer thicknesses can be prepared by controlling the reaction time according to actual needs to meet different separation effect requirements.

[0076] Application examples

[0077] The application of the synthesized S-BINAM / PAN chiral intrinsically microporous polymer (CPIM) composite membrane in the continuous separation of chiral compounds was verified.

[0078] Figure 6 The separation performance of S-BINAM / PAN chiral intrinsically microporous polymer (CPIM) composite membranes with polymerization times of 1.5 min and 3 min was demonstrated using an ethanol solution of the ibuprofen / phenylethanol racemic mixture as a model system.

[0079] Under the influence of concentration gradient without external pressure, the S-BINAM / PAN composite membrane exhibited excellent chiral recognition ability in the permeation experiment. High performance liquid chromatography (HPLC) detection showed that the enantiomeric excess (ee) of racemic ibuprofen could reach the theoretical limit of 100%.

[0080] It is worth noting that the composite membrane also exhibits excellent cycling stability, maintaining extremely high selectivity even after five consecutive separation cycles. These characteristics provide important technical support for its application in the continuous separation of chiral compounds in the pharmaceutical industry.

[0081] This method uses a DMAc-H2O mixed solvent system as the dissolution medium for benzidine (S-BINAM) and n-hexane as the solvent for trimesoyl chloride (TMC) to carry out interfacial polymerization on a polyacrylonitrile (PAN) membrane. The resulting membrane is then self-assembled into an S-BINAM / PAN chiral intrinsically microporous polymer (CPIM) composite membrane. By optimizing the interfacial polymerization process parameters, a chiral intrinsically microporous polyamide film material with a three-dimensional rigid twisted topology was constructed. The use of the DMAc-H2O mixed solvent instead of the traditional aqueous solvent solves the problem of low reactivity of intrinsically microporous polymer (PIM) monomers due to hydrophobicity. The polar aprotic properties of DMAc enhance the solubility of benzidine, while the introduction of H2O optimizes the interfacial polymerization kinetics. This solvent system breaks through the dependence of traditional interfacial polymerization on hydrophilic monomers, providing a new pathway for the efficient reaction of hydrophobic chiral monomers, and significantly improving the chemical stability and separation efficiency of the membrane.

[0082] like Figure 7 As shown, through experimental verification, the axial chiral center of binaphthylamine was successfully introduced. The Cotton effect was confirmed by CD spectroscopy to show a significant signal at λ=350 nm, which endows the membrane material with excellent chiral recognition ability.

[0083] The composite membrane also exhibited characteristic chiral signal peaks similar to those of the monomer, and in-depth analysis revealed that this stemmed from the effective chiral transfer from the chiral spirocyclic monomer to the polymer matrix. These findings reveal the structure-property relationship of chiral functional materials at the molecular level, providing important theoretical support for the rational design of novel chiral separation membranes.

[0084] Figure 8 Figures a and b show the wide-angle X-ray scattering curves of the S-BINAM and S-BINAM-CPIM3 self-supporting films, respectively. Figure c shows the CO2 adsorption isotherm of the S-BINAM-CPIM3 self-supporting film. Figure d shows the pore size distribution of the S-BINAM-CPIM3 self-supporting film fitted by nonlocal density functional theory (NLDFT).

[0085] A comparison of figures a and b shows that the S-BINAM monomer exhibits distinct Bragg diffraction peaks at 2θ = 15.6° and 22.5°, indicating its typical crystal structure. In contrast, the S-BINAM-CPIM3 film shows only broad peaks (the 33° peak is a characteristic glass peak of the test sample stage) within the 2θ = 5°–50° range, confirming the successful construction of an amorphous network structure. The d-interval calculated based on the Bragg equation is 0.347 nm. This parameter not only reflects the tightness of the molecular chain stacking but also directly reveals the existence of sub-nanometer microporous channels within the material.

[0086] As shown in Figures c and d, the CO2 adsorption curve (77 K) exhibits a steep upward trend in the low-pressure range. This characteristic is highly consistent with the Type I adsorption isotherm, confirming that the material possesses a well-developed microporous structure. The BET specific surface area calculated using the Langmuir model reaches 57.12. Compared to traditional polyamide films, the efficiency is approximately 3-5 times higher, providing an important structural basis for efficient mass transport. Further analysis of the adsorption isotherm using nonlocal density functional theory (NLDFT) revealed that the film exhibits a multi-pore size distribution, with sub-nanometer pore sizes ranging from 0.8 to 1.4 nm.

[0087] This unique microporous structure originates from the synergistic effect of the steric hindrance effect of the binaphthyl structure in the S-BINAM molecule and the rigid aromatic ring structure of the TMC crosslinking agent: ① The V-shaped configuration of binaphthyl diamine hinders the regular stacking of molecular chains, promoting the formation of an amorphous structure; ② The controllable crosslinking of the acyl chloride groups constructs relatively uniform molecular sieve channels at the sub-nanometer scale. This sub-nanometer pore system, along with the previously characterized surface charge properties and hydrophilic gradient, forms a functional synergy, providing theoretical support for the preparation of novel separation membranes with high selectivity (pore size sieving) and high throughput (short microporous path).

[0088] Meanwhile, through continuous separation experiments of chiral compounds, the experimental results show that the S-BINAM / PAN chiral intrinsically microporous polymer (CPIM) composite membrane prepared by this method exhibits excellent chiral sieving performance and long-term stability.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A method for preparing a binaphthylamine-based chiral intrinsically microporous polymer composite membrane, characterized in that, Includes the following steps: S1. Preparation of reaction solution: An aqueous solution was prepared by fully dissolving the aqueous monomer in a mixture of N,N-dimethylacetamide and H2O. The aqueous phase monomers include S-naphthylamine and NaOH. An oil phase solution was prepared by dissolving the oil phase monomer in n-hexane. The oil phase monomer is pyromellitic trimethylol chloride; S2. Substrate pretreatment: The polyacrylonitrile film is fixed in place using a mold, which limits the polymerization reaction area on the polyacrylonitrile film. The polyacrylonitrile film is fixed and kept horizontal in the mold. After soaking the polyacrylonitrile membrane in an aqueous solution, the residual liquid on the surface is removed. S3, Chiral polymerization step: An oil-phase solution is dropped onto the surface of the polyacrylonitrile membrane soaked in the aqueous solution obtained in step S2. An interfacial polymerization reaction occurs on the surface of the polyacrylonitrile membrane. After the polymerization reaction time is reached, the reaction solution is removed. After soaking the polyacrylonitrile membrane in hexane for a second time, the hexane solution was removed. A thermal crosslinking treatment was performed, and after the thermal crosslinking was completed, the mold was removed to obtain a binaphthylamine-based chiral intrinsically microporous polymer composite membrane.

2. The method for preparing the binatamine-based chiral intrinsically microporous polymer composite membrane according to claim 1, characterized in that, In S1, the volume ratio of N,N-dimethylacetamide to H2O used in the N,N-dimethylacetamide and H2O mixture is 7:

3.

3. The method for preparing the binatamine-based chiral intrinsically microporous polymer composite membrane according to claim 1, characterized in that, In S2, the polyacrylonitrile film is pretreated before being fixed using a mold. The pretreatment steps for polyacrylonitrile membrane are as follows: immerse the polyacrylonitrile membrane in deionized water, and after immersion, use absorbent paper to dry the surface moisture of the polyacrylonitrile membrane.

4. The method for preparing the binatamine-based chiral intrinsically microporous polymer composite membrane according to claim 1, characterized in that, In S3, the polymerization reaction time is 1.5-3 minutes. The thermal crosslinking process involves placing the mold in a forced-air drying oven after the reagent on the surface of the polyacrylonitrile film has completely evaporated. The thermal crosslinking temperature is 55-65℃ and the thermal crosslinking time is 5-8 minutes.

5. The method for preparing the binatamine-based chiral intrinsically microporous polymer composite membrane according to claim 1, characterized in that, The binaphthylamine-based chiral microporous polymer composite membrane was immersed in deionized water and stored in a refrigerated environment at a temperature of 2-8℃ for later use.

6. A binaphthylamine-based chiral intrinsically microporous polymer composite membrane, characterized in that, It is prepared by the preparation method according to any one of claims 1-5.

7. The binaphthylamine-based chiral intrinsically microporous polymer composite membrane according to claim 6, characterized in that, The separation layer has sub-nanometer pore sizes, ranging from 0.8 to 1.4 nm; its specific surface area is greater than 50. .

8. The application of the binaphthylamine-based chiral intrinsically microporous polymer composite membrane of claim 6 for the separation of chiral compounds.

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