Separation membrane and separation method of tanshinone homologues

Abstract

The invention discloses a separation membrane and a separation method of tanshinone homologues, and belongs to the technical field of separation membranes. The separation membrane takes a nylon membrane as a basement membrane, spherical polyion liquid (PILs) nanoparticles are loaded on the nylon membrane, and a preparation method of the spherical PILs nanoparticles comprises the following steps: by taking 1-vinyl-3-octyl-imidazole bromide, acrylonitrile, divinyl benzene and 2-hydroxy-4 '-(2-hydroxyethoxy)-2-methylallyl ketone as raw materials and 1-octanol as a solvent, carrying out a reaction at the temperature of 50-80 DEG C for 2-4 hours at the temperature of 50-60 DEG C for 1-2 hours to obtain the spherical PILs nanoparticles. Uniformly mixing; pouring the mixture into water, stirring to form an emulsion, and irradiating under 365nm ultraviolet light to carry out photo-initiation polymerization; and pouring the solution into ethanol to form a precipitate, filtering, washing and drying to obtain the PILs nano-particles. The separation membrane disclosed by the invention is high in water flux and has a relatively good separation effect on tanshinone homologues.

Description

Technical Field

[0001] The present invention belongs to the technical field of separation membranes, and more specifically, relates to a separation membrane and a separation method for tanshinone homologues. Background Art

[0002] In recent years, the separation of compounds in traditional Chinese medicines has received increasing attention. These compounds have important market prospects due to their medical and pharmaceutical values. The homologues of tanshinone in Salvia miltiorrhiza have also received extensive attention. Tanshinone IIA is the main lipophilic component, with anti-inflammatory, antioxidant and anti-SARS-CoV-2 activities. Tanshinone I also has good pharmacological activities, including antioxidant stress activity and regulation of autophagy. However, due to the similar physical sizes and chemical properties of tanshinone IIA and tanshinone I, their separation is challenging.

[0003] Traditional methods for separating homologues are based on chromatography, liquid-liquid extraction, recyclable liquid-liquid extraction, solid-phase adsorption and membrane separation, etc. Among them, membranes with rich weak interactions are considered as alternatives to membranes with equal pore sizes for separating molecules with small size differences, but the common channel-like internal structure cannot greatly amplify the difference in the interaction between the membrane and the target compound. Therefore, it is necessary to develop new membrane structures to solve this problem.

[0004] In the prior art, polymer membranes based on ionic liquids have membrane filtration differences for tanshinone I and tanshinone IIA, and the difference in the rejection rate of the membrane for tanshinone is 14.1%. Existing problems are as follows: 1. The pore size of pure polyionic liquid membranes is small, and a sufficiently large pressure (above 0.6 MPa) is required during operation, resulting in very high energy consumption and requirements for equipment, and the pure water flux of the membrane is small (333 Lm -2 h -1 ). 2. There are only weak differences in the effects of static adsorption and dynamic membrane permeation of the membrane between the two homologues, and the effects are not significant. Summary of the Invention

[0005] Aiming at the technical problem of difficult separation of tanshinone homologues, the present invention provides a separation membrane and a separation method for tanshinone homologues. An emulsion polymerization ionic liquid-loaded membrane is used to replace the traditional polyionic liquid nanofiltration membrane, and a special microchromatographic structure is used to amplify the separation effect. At the same time, it has a high water flux, can reduce the requirement for operating pressure, and realizes low-energy consumption and efficient membrane separation of tanshinone homologues.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: A separation membrane for tanshinone homologues, the separation membrane includes a substrate membrane, on which spherical polyionic liquid (PILs) nanoparticles are loaded. The preparation method of the spherical PILs nanoparticles includes: using 1-vinyl-3-R-imidazole halide (chloride or bromide), acrylonitrile, divinylbenzene, 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone as raw materials, and 1-octanol as a solvent, mixing them evenly; pouring the mixture into water and stirring to form an emulsion, and irradiating it under 365 nm ultraviolet light for photoinitiated polymerization; then pouring the solution into ethanol to form a precipitate, filtering, washing and drying to obtain PILs nanoparticles; wherein, R = C n H 2n , n is an integer, and n = 4 - 10.

[0007] For separating other homologues, corresponding anions can be selected. For example, for amino acid homologues, amino acid anion-substituted ionic liquids can be selected.

[0008] Preferably, the dosage ratio of the 1-vinyl-3-octyl-imidazole halide, acrylonitrile, divinylbenzene, and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone is 2 - 4 g : 2 - 4 mL : 0.2 - 0.4 mL : 0.03 - 0.12 g.

[0009] Preferably, the irradiation time is 20 - 40 min.

[0010] Preferably, the loading amount of the spherical PILs nanoparticles is 0.2 - 0.6 mg / cm 2 .

[0011] A preparation method of the above-mentioned separation membrane for tanshinone homologues, dispersing the spherical PILs nanoparticles in an ethanol aqueous solution, pouring the solution onto the substrate membrane installed on a vacuum filter, and forming a loaded membrane by means of vacuum filtration after the solvent is completely filtered.

[0012] A separation method for tanshinone homologues, fixing the above-mentioned separation membrane on a vacuum filtration device under reduced pressure, and enabling the mixed solution of two tanshinones to pass through the membrane through the action of pressure, thereby achieving separation.

[0013] Preferably, the pressure ≤ 0.1 MPa.

[0014] The mechanism of the present invention is:

[0015] In a manner similar to column chromatography, there is an adsorption and desorption process of the compound on the surface of each PILs particle. During this process, there is a slight difference in the flow rates of the two compounds. After passing through a membrane channel composed of a large number of such particles, this slight difference is amplified to form the final separation effect.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] The membrane constructed by loading with poly(ionic liquid) microparticles in the present invention has a high water flux, low energy consumption, and high efficiency, and can achieve the separation of tanshinone homologues at a relatively low pressure. At 0.1 Mpa, the water flux can reach 800 Lm -2 h -1 or more. The separation efficiency is high, and the separation efficiency for tanshinone homologues can reach 60.7%. Description of the Drawings

[0018] Figure 1 It is the test result of the water flux of the separation membranes with different loadings in the present invention.

[0019] Figure 2 It is the SEM of the separation membrane prepared in Example 1 of the present invention. Detailed Embodiments

[0020] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0021] A separation membrane for tanshinone homologues, the separation membrane includes a substrate membrane, on which spherical PILs nanoparticles are loaded. The preparation method of the spherical PILs nanoparticles includes: using 1-vinyl-3-R-imidazolium halide (chloride or bromide), acrylonitrile, divinylbenzene, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone as raw materials, and 1-octanol as a solvent, mixing them evenly; pouring the mixture into water and stirring to form an emulsion, and irradiating with 365 nm ultraviolet light for photoinitiated polymerization; then pouring the solution into ethanol to form a precipitate, filtering, washing, and drying to obtain PILs nanoparticles; wherein, R = C n H 2n , n is an integer, and n = 4 - 10.

[0022] For separating other homologues, corresponding anions can be selected. For example, for amino acid homologues, amino acid anion-substituted ionic liquids can be selected.

[0023] Further, the dosage ratio of the 1-vinyl-3-R-imidazole halide salt, acrylonitrile, divinylbenzene, and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone is 2-4 g: 2-4 mL: 0.2-0.4 mL: 0.03-0.12 g.

[0024] In the examples of this application, 1-vinyl-3-octyl-imidazole bromide salt is taken as an example. It can be understood that other 1-vinyl-3-R-imidazole halide salts also have the same or similar effects.

[0025] Further, the irradiation time is 20-40 min. More specifically, the irradiation time is 30 min.

[0026] Further, the loading amount of the spherical PILs nanoparticles is 0.2-0.6 mg / cm 2 .

[0027] A method for preparing a separation membrane of the above-mentioned tanshinone homolog. The spherical PILs nanoparticles are dispersed in an ethanol aqueous solution, and the solution is poured onto a substrate membrane installed on a vacuum filter. By means of vacuum filtration, after the solvent is completely filtered, a loaded membrane is formed.

[0028] A method for separating tanshinone homologs. The above-mentioned separation membrane is fixed on a vacuum filtration device under reduced pressure, and a mixed solution of two tanshinones is passed through the membrane under the action of pressure, thereby achieving separation.

[0029] Further, the pressure ≤ 0.1 MPa.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the specification of this invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. It should be noted that the reagents and the like used in this example are all ordinary commercially available products.

[0031] Example 1

[0032] Add 3 g of 1-vinyl-3-octylimidazolium bromide, 3 mL of acrylonitrile, 0.4 mL of divinylbenzene, and 0.06 g of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone into a flask, and then add 1-octanol and mix evenly. Then pour the mixture into 200 mL of water and form an emulsion with mechanical stirring. Continuously stir the emulsion and irradiate it under ultraviolet light at 365 nm for 30 min. Then pour the solution into a large amount of ethanol at room temperature to form a precipitate. Wash and dry the precipitate in a vacuum oven to obtain PILs nanoparticles. Disperse 0.02 mg, 0.1 mg, and 0.12 mg of PILs nanoparticles in an aqueous ethanol solution (75%) respectively to form a uniform turbid liquid. After vacuum filtering a certain amount of the liquid, form a layer of stacked loose spherical PILs nanoparticles on a 50-mm nylon membrane, and the SEM images are as shown in Figure 1 shown.

[0033] Perform a water flux test on the separation membrane prepared in Example 1, and measure the water flux of the membrane using a vacuum solution filtration device (Jinteng, China). Use a certain amount of PILs (0 - 0.12 mg) to construct a membrane with a diameter of 50 mm. The filtrate volume is 20 mL, and record the filtration time. The water flux NWP (Lh -1 m -2 ) is calculated by the following formula:

[0034]

[0035] where: NWP----pure water flux, L / (m 2 h)

[0036] V——water throughput, L

[0037] A——effective membrane area, m 2

[0038] T——time, h

[0039] The results are as shown in Figure 2 shown. When the loading amount is 0.6 mg / cm 2 , the lowest water flux of the membrane is measured to be 103.29 Lm -2 h -1 . The structure formed by the microsphere packing promotes the transfer of the solvent through the membrane, which is the potential reason for the high water flux of the membrane. When the loading amount is 0.2 mg / cm 2 , the water flux is 833.12 Lm -2 h -1 .

[0040] For the membrane (loading amount is 0.2 mg / cm 2)Fixed on the decompression filtration device, the mixture of two tanshinones is passed through the membrane under reduced pressure. The solutions before and after passing through the membrane are taken respectively, and the tanshinone concentration is measured by high performance liquid chromatography, and the selectivity of the polyionic liquid microparticle membrane for the two tanshinones is calculated. The results are shown in Table 1 and Table 2. The selectivity is reflected by the apparent rejection rate, and the calculation formula is:

[0041]

[0042] S = |R1 - R2|

[0043] In the formula: R—the rejection rate %,

[0044] C2—the concentration of the permeate solution mol / L,

[0045] C1—the concentration of the feed solution mol / L,

[0046] S—selectivity.

[0047] Table 1

[0048]

[0049] As can be seen from Table 1, at lower tanshinone concentrations, the separation rate of tanshinones is higher. When tanshinone I is 2.0 μg / mL -1 , tanshinone IIa is 4.5 μg / mL -1 , the separation effect is the best, and the rejection rate of tanshinone I is 100%, indicating that the number of adsorption sites of tanshinone I at this concentration matches that of PIL.

[0050] Membrane filtration is a dynamic adsorption - desorption process. Therefore, the volume of the solvent used to dissolve the sample can also elute the sample, which has an important impact on the separation process. The influence of different solvent volumes on the separation process is shown in Table 2.

[0051] Table 2

[0052]

[0053] As can be seen from Table 2, at the same sample content, the removal rates of both tanshinones decrease with the increase of the solvent volume, and the decrease rate of the removal rate of tanshinone IIA is greater than that of tanshinone I. Different rejection rate decline rates lead to changes in the separation effect. At 4.0 mL, the separation effect reaches the maximum value (60.7%).

[0054] Through screening experiments on different concentrations of two homologues and different volumes of the filtrate, finally 1.0 μg / mL of tanshinone I, 2.25 μg / mL of tanshinone IIA and a filtrate volume of 4 mL are selected as the optimal membrane separation conditions.

[0055] The adsorption thermodynamics of PILs particles was simultaneously determined and compared with dynamic membrane separation. The results are shown in Table 3.

[0056] Table 3

[0057]

[0058] It shows that the static adsorption capacity of PIL for tanshinone I exceeds that for tanshinone IIA, but the difference is very small. Comparing the dynamic membrane separation data in Table 1 and Table 2, it shows that this membrane system has significant advantages in separating the structurally similar tanshinones.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A separation membrane for tanshinone homologues, characterized in that: The separation membrane comprises a substrate membrane on which spherical PILs nanoparticles are loaded. The preparation method of the spherical PILs nanoparticles comprises: using 1-vinyl-3-R-imidazole halogenated salt, acrylonitrile, divinylbenzene, and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropenone as raw materials and 1-octanol as solvent, and mixing them uniformly; pouring the mixture into water and stirring to form an emulsion, and irradiating it under 365nm ultraviolet light for photoinitiated polymerization; then pouring the solution into ethanol to form a precipitate, filtering, washing and drying to obtain PILs nanoparticles; wherein R=C n H 2n , n is an integer, and n=4-10.

2. The separation membrane of tanshinone homologues according to claim 1, characterized in that The usage ratio of the 1-vinyl-3-R-imidazole halogenated salt, acrylonitrile, divinylbenzene and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropenone is 2-4g:2-4ml:0.2-0.4ml:0.03-0.12g.

3. The separation membrane of tanshinone homologues according to claim 1, characterized in that The irradiation time is 20-40 minutes.

4. The separation membrane of tanshinone homologues according to claim 1, characterized in that The base film includes any one of a nylon film and a polytetrafluoroethylene film.

5. The separation membrane of tanshinone homologues according to claim 1, characterized in that: The loading amount of the spherical PILs nanoparticles is 0.2-0.6 mg / cm 2 .

6. The method for preparing a separation membrane for tanshinone homologues according to any one of claims 1 to 5, characterized in that: The spherical PILs nanoparticles are dispersed in an ethanol aqueous solution, and the solution is poured onto a base membrane mounted on a vacuum filter. After the solvent is completely filtered out by vacuum filtration, a separation membrane is formed.

7. A method for separating tanshinone homologues, characterized in that: The separation membrane described in any one of claims 1 to 6 is fixed on a vacuum filtration device, and the mixed solution of the two tanshinones is passed through the separation membrane by pressure, thereby achieving separation.

8. The separation method according to claim 7, characterized in that The pressure is ≤0.1MPa.

9. The separation method according to claim 7, characterized in that The concentration of tanshinone I in the mixed solution is 0.25-2 μg / mL, and the concentration of tanshinone II is 0.5-2.5 μg / mL.

Images