Preparation of COF-based separation material and application of COF-based separation material in purification of active ingredients of natural products

Abstract

The invention relates to the technical field of membrane material preparation, in particular to preparation of a COF-based separation material and application of the COF-based separation material in purification of active ingredients of natural products. The invention particularly relates to preparation of a fish-line-shaped COF (FLL-COF) material. The preparation method comprises the following steps: physically blending the prepared FLL-COF and polyvinylidene fluoride (PVDF) powder, and preparing a mixed membrane through phase inversion; the prepared FLL-COF-coated PVDF mixed membrane has the advantages that materials are easy to recycle, pollution is avoided, energy consumption is low, separation performance is excellent, and the mixed membrane can be applied to the continuous separation process. The affinity acting force of FLL-COF rich in nitrogen and oxygen elements on acteoside (ACT) is similar to a'fishhook ', and a'centipede hook' structure similar to RL-COF is constructed to improve the selective separation of the RL-COF coated PVDF mixed membrane on ACT. The mixed membrane combines the COF and the membrane and is expected to provide a new application thought and method for efficient separation of phenylethanoid glycosides in effective components of natural products.

Description

Technical Field

[0001] The present invention relates to the technical field of material separation, and in particular to the preparation of a COF-based separation material and its application in the purification of active components of natural products. Technical Background

[0002] Cistanche tubulosa is cylindrical or slightly flat, with thick flesh. Its surface is usually gray-brown or brown, with dense longitudinal wrinkles and ring nodes. Cistanche tubulosa is known as the "desert ginseng" and is a multi-purpose medicinal plant. Modern research shows that Cistanche tubulosa has many effects such as anti-Alzheimer's disease, anti-aging, anti-fatigue, and immune function regulation, and has the effects of tonifying the kidney, nourishing the essence, moisturizing dryness, and laxative. It has broad application prospects in the fields of medicine, health care, and food; studies have shown that the biologically active ingredients in cultivated and wild Cistanche tubulosa are basically the same, mainly phenylethanol glycosides, polysaccharides, oligosaccharides, flavonoids, polyphenols, and proteins.

[0003] At present, the methods for separation and purification of phenylethanoid glycosides mainly include macroporous adsorption resin method, high-speed countercurrent chromatography, molecular imprinting technology and membrane separation method. The membrane separation method can highly enrich the effective ingredients of natural products with fewer impurities, and has the advantages of mild operating conditions and low energy consumption. However, the membrane materials currently available for purification of phenylethanoid glycosides are limited in application due to their small variety, easy contamination and low selectivity. Based on this, it is necessary to design a hybrid membrane for the efficient separation of phenylethanoid glycosides. Summary of the invention

[0004] In view of the above-mentioned technical limitations, the present invention proposes a preparation of a COF-based separation material and its application in the purification of active ingredients of natural products, which overcomes the shortcomings and defects mentioned in the background technology.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention point of the present invention is to provide a preparation of a COF-based separation material and its application in the purification of active ingredients of natural products. The fish line-shaped COF (FLL-COF) prepared by the present invention is used as a filler and polyvinylidene fluoride (PVDF) is used as a base material. The preparation steps of FLL-COF and the separation material are as follows.

[0007] Optionally, in the above-mentioned COF-based separation material, the filler of the separation material is FLL-COF.

[0008] The second invention of the present invention is to provide a method for preparing the above-mentioned separation material, comprising the following steps: (1) Preparation of FLL-COF: 4,4',4"-(1,3,5-triazine-2,4,6-triyl) tribenzaldehyde and 2,5-bis(allyloxy) terephthalate were added to acetonitrile and mixed evenly by ultrasonication, and then acetic acid solution was slowly added and reacted at room temperature for 3 days. The mixture was washed with tetrahydrofuran, ethanol and water, and freeze-dried; (2) Preparation of hybrid membrane: PVDF powder, polyvinyl pyrrolidone (PVP) and the filler FLL-COF prepared in step S2 are dissolved in N-methylpyrrolidone (NMP), stirred in an oil bath, and allowed to stand for degassing. After degassing, the membrane is scraped, and the scraped membrane is placed in deionized water for phase inversion reaction to obtain a FLL-COF@PVDF hybrid membrane, which is stored in deionized water for standby use;

[0009] Optionally, in the above preparation method, in the step (1), the ratio of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde to 2,5-bis(allyloxy)ethylene terephthalate is: (9mg-12mg): (12mg-14mg), the volume of acetonitrile is 1.5-2.5mL, the ultrasonic dispersion power is 200-250W, the ultrasonic dispersion time is 5-12min, the concentration of the acetic acid solution is 4-8mol / L, the mixture is washed with tetrahydrofuran 2-3 times, with ethanol 2-3 times, and with water 2-3 times.

[0010] Optionally, in the above-mentioned preparation method, in step (2), the oil bath temperature is 45-55°C, the stirring time is 24-25h, the static degassing temperature is 45-55°C, and the time is 12-14h; the dosage ratio of PVDF powder, PVP, filler FLL-COF and NMP is (7.0-9.0g): (0.1-0.2g): (0.1-0.3g): (22-24g).

[0011] In a specific embodiment, the present invention also provides the preparation of the above COF-based separation material and its application in the purification of active ingredients of natural products.

[0012] In a specific embodiment, the present invention also provides a mixed membrane, wherein the mixed membrane uses FLL-COF as a filler and polyvinylidene fluoride as a base material, and the filler and the base material are formed by physical blending and phase transformation; the phenylethanol glycoside compound is verbascoside.

[0013] A method for preparing a COF-based separation material, and using the prepared FLL-COF as a filler to physically blend with a PVDF matrix to form a mixed membrane. The preparation process of the FLL-COF@PVDF mixed membrane prepared by the method of the present invention is simple, and the reaction is controllable. FLL-COF is rich in nitrogen and has a high affinity for verbascoside, which can improve the separation of verbascoside by the mixed membrane. In addition, FLL-COF has the advantages of a large specific surface area and a porous structure, which can expose more affinity sites, thereby improving the separation and purification of verbascoside in phenylethanoid glycoside. Membrane separation technology is an efficient and recyclable technology, and is one of the more ideal methods for separating the effective components of natural products.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The preparation of a COF-based separation material provided by the present invention and its application in the purification of active ingredients of natural products have the advantages of easy material recovery, no pollution, low energy consumption, excellent separation performance, and can be applied to continuous separation processes, and effectively solve the shortcomings and disadvantages of few types, low selectivity, difficult recovery, high energy consumption, and easy secondary pollution. Studies have shown that the adsorption amount of the mixed membrane to verbascoside is 155.19 mg / g, and the selectivity is 4.29. This mixed membrane is expected to provide a new application idea and method for the efficient separation of phenylethanol glycosides in the active ingredients of natural products. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 This is a scanning electron microscope image of the FLL-COF material prepared in Example 1.

[0017] Figure 2 This is a scanning electron microscope image of the FLL-COF@PVDF-250 mixed membrane prepared in Example 1.

[0018] Figure 3 This is a scanning electron microscope image of the FLL-COF@PVDF-1000 mixed membrane prepared in Example 2.

[0019] Figure 4 This is a scanning electron microscope image of the FLL-COF@PVDF-150 mixed membrane prepared in Example 3.

[0020] Figure 5 This is a scanning electron microscope image of the FLL-COF@PVDF-200 mixed membrane prepared in Example 4.

[0021] Figure 6This is a scanning electron microscope image of the FLL-COF@PVDF-300 mixed membrane prepared in Example 6.

[0022] Figure 7 This is a scanning electron microscope image of the PVDF membrane prepared in Comparative Example 1. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below. However, it should be understood that the description herein is only used to explain the present invention and is not used to limit the scope of the present invention.

[0024] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention, and the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The reagents and instruments used herein are all commercially available, and the characterization means involved can refer to the relevant descriptions in the prior art, which will not be repeated herein.

[0025] In order to further understand the present invention, the present invention is further described in detail below in conjunction with the best embodiment. Example 1

[0026] A COF-based separation material for separating and purifying active ingredients of natural products was developed. Specific recognition was used to separate and purify phenylethanoid glycosides from Cistanche tubulosa.

[0027] A method for preparing a COF-based separation material comprises the following steps:

[0028] Step 1: Add 10.5 mg of 4,4',4"-(1,3,5-triazine-2,4,6-triyl) tribenzaldehyde and 12.3 mg of 2,5-bis(allyloxy) terephthalate into a 5 mL beaker containing 2 mL of acetonitrile and ultrasonicate for 8 min until mixed evenly. Then slowly add 0.6 mL of HAc (6 mol / L) solution, further ultrasonicate for 5 min, and then seal the beaker to prevent solvent evaporation and react at room temperature for 3 days. Wash with THF, ethanol and water in turn. Finally, freeze-dry for 24 h to obtain FLL-COF.

[0029] Step 2: Dissolve 8 g of PVDF powder, 0.1 g of polyvinyl pyrrolidone and 250 mg of FLL-COF in 23 g of N-methylpyrrolidone, stir mechanically in an oil bath at 50 °C for 24 h, and then stand at 50 °C for 12 h for degassing;

[0030] Step 3: After the above reaction is completed, use a film casting knife to take out the casting solution and start scraping the film. Place the scraped film in deionized water for phase inversion reaction, and finally obtain the FLL-COF@PVDF mixed membrane. The doping amount of FLL-COF in the FLL-COF@PVDF mixed membrane is 250 mg, so it is named FLL-COF@PVDF-250 mixed membrane and stored in deionized water for use;

[0031] Please refer to Figure 1 As shown: FLL-COF presents a fish line morphology, and mapping clearly shows that N and O elements are evenly distributed on FLL-COF. The N and O elements contained in FLL-COF can form various types of intermolecular interactions, such as hydrogen bonds, π-π interactions, and dipole-dipole interactions. These interactions can enhance the binding force between FLL-COF and ACT. FLL-COF, which is rich in nitrogen and oxygen elements, has an affinity for verbascoside (ACT) like a "fish hook", and a "centipede hook" structure similar to RL-COF is constructed to improve the selective separation of ACT by RL-COF@PVDF hybrid membrane.

[0032] Please refer to Figure 2 As shown: Under the conditions of pH = 5, 35°C, and ACT / ECH concentration of 0.8 mg / mL, FLL-COF@PVDF-250 was used for selective separation test. The study showed that the adsorption capacity of ACT by the FLL-COF@PVDF-250 hybrid membrane reached 155.19 mg / g, and the selectivity was 4.29. Example 2

[0033] Preparation of FLL-COF@PVDF-100 mixed membrane: The preparation method is consistent with Example 1, except that the addition amount of FLL-COF is 100 mg.

[0034] Please refer to Figure 3 As shown: Adsorption selectivity experiment of FLL-COF@PVDF-100 hybrid membrane for 0.5mg / mL ACT / ECH mixed solution: FLL-COF@PVDF-100 was placed in a 50mL conical flask, 20mL of 0.5mg / mL ACT / ECH mixed solution was added, sealed and placed on a 150rpm shaker, and shaken and adsorbed at 30℃ for 24h. The content of ACT after adsorption was determined by HPLC. The adsorption amount of ACT after adsorption was 56.06mg / g, and the selectivity was 2.02. Example 3

[0035] Preparation of FLL-COF@PVDF-150 mixed membrane: The preparation method is consistent with Example 1, except that the addition amount of FLL-COF is 150 mg.

[0036] Please refer to Figure 4 As shown: FLL-COF@PVDF-150 hybrid membrane adsorption selectivity experiment for 0.5 mg / mL ACT / ECH mixed solution (30°C). The prepared FLL-COF@PVDF-150 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 83.37 mg / g, and the selectivity was 2.23. Example 4

[0037] Preparation of FLL-COF@PVDF-200 mixed membrane: The preparation method is consistent with Example 1, except that the addition amount of FLL-COF is 200 mg.

[0038] Please refer to Figure 5 As shown: FLL-COF@PVDF-200 hybrid membrane adsorption selectivity experiment for 0.5 mg / mL ACT / ECH mixed solution (30°C). The prepared FLL-COF@PVDF-200 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 94.04 mg / g, and the selectivity was 2.68. Example 5

[0039] Preparation of FLL-COF@PVDF-250 mixed membrane: The preparation method is consistent with Example 1, except that the addition amount of FLL-COF is 250 mg.

[0040] Please refer to Figure 2 As shown: FLL-COF@PVDF-250 hybrid membrane adsorption selectivity experiment for 0.5 mg / mL ACT / ECH mixed solution (30°C). The prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 106.10 mg / g, and the selectivity was 3.0. Example 6

[0041] Preparation of FLL-COF@PVDF-300 mixed membrane: The preparation method is consistent with Example 1, except that the addition amount of FLL-COF is 300 mg.

[0042] Please refer to Figure 6 As shown: FLL-COF@PVDF-300 hybrid membrane adsorption selectivity experiment for 0.5 mg / mL ACT / ECH mixed solution (30°C). The prepared FLL-COF@PVDF-300 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 98.01 mg / g, and the selectivity was 2.49. Example 7

[0043] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg and the pH was 4.

[0044] In the adsorption selectivity experiment (30°C) of 0.5 mg / mL ACT / ECH mixed solution, the prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 109.54 mg / g, and the selectivity was 3.95. Example 8

[0045] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg and the pH was 5.

[0046] In the adsorption selectivity experiment (30°C) of 0.5 mg / mL ACT / ECH mixed solution, the prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 123.36 mg / g, and the selectivity was 3.83. Example 9

[0047] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg and the pH was 6.

[0048] In the adsorption selectivity experiment (30°C) of 0.5 mg / mL ACT / ECH mixed solution, the prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption amount for ACT was 114.84 mg / g, and the selectivity was 3.43. Example 10

[0049] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg, the pH was 5, and the ACT concentration was 0.6 mg / mL.

[0050] At 30°C, the prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption capacity for ACT was 131.65 mg / g with a selectivity of 3.70. Embodiment 11

[0051] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg, the pH was 5, and the ACT concentration was 0.8 mg / mL.

[0052] At 30 °C, the prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption capacity for ACT was 139.29 mg / g and the selectivity was 3.59. Example 12

[0053] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg, the pH was 5, and the ACT concentration was 1.0 mg / mL.

[0054] At 30 °C, the prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption capacity for ACT was 143.37 mg / g with a selectivity of 3.25. Embodiment 13

[0055] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg, the pH was 5, the ACT concentration was 0.8 mg / mL, and the temperature was 30°C.

[0056] The prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption capacity for ACT was 139.29 mg / g and the selectivity was 3.59. Embodiment 14

[0057] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg, the pH was 5, the ACT concentration was 0.8 mg / mL, and the temperature was 35°C.

[0058] The prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption capacity for ACT was 155.19 mg / g and the selectivity was 4.29. Embodiment 15

[0059] The preparation method was consistent with that in Example 1, except that the amount of FLL-COF added was 250 mg, the pH was 5, the ACT concentration was 0.8 mg / mL, and the temperature was 40°C.

[0060] The prepared FLL-COF@PVDF-250 hybrid membrane was used to separate phenylethanoid glycosides, and its adsorption capacity for ACT was 148.70 mg / g and the selectivity was 3.83. Comparative Example 1:

[0061] Preparation of PVDF membrane: 8g of PVDF powder and 0.1g of polyvinyl pyrrolidone were dissolved in 23g of N-methylpyrrolidone, mechanically stirred in an oil bath at 50°C for 24h, and then allowed to stand at 50°C for 12h for degassing. The casting solution was taken out with a casting knife and the film was scraped. The scraped film was placed in deionized water for phase inversion reaction, and finally the obtained PVDF mixed membrane was obtained.

[0062] Please refer to Figure 7As shown: The selective adsorption experiment of 0.8 mg / mL phenylethanoid glycosides by PVDF membrane: The PVDF membrane was placed in a 50 mL conical flask, and 20 mL of phenylethanoid glycosides solution (C ACT , C ECH The mixture was sealed and placed on a shaker at 150 rpm for 24 h at 35°C. The ACT content before and after adsorption was determined by HPLC. The adsorption amount of ACT after adsorption reached 27.32 mg / g, and the selectivity was 1.13.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Preparation of a COF-based separation material and its application in the purification of active ingredients of natural products, characterized in that: The preparation method comprises the steps of: (1) Preparation of FLL-COF: 4,4',4"-(1,3,5-triazine-2,4,6-triyl) tribenzaldehyde and 2,5-bis(allyloxy) terephthalate were added to acetonitrile and mixed evenly by ultrasonication, and then acetic acid solution was slowly added and reacted at room temperature for 3 days. The mixture was washed with tetrahydrofuran, ethanol and water, and freeze-dried; (2) Preparation of mixed membrane: polyvinylidene fluoride powder, polyvinyl pyrrolidone and the filler FLL-COF prepared in step S1 are dissolved in N-methylpyrrolidone, stirred in an oil bath, and allowed to stand for degassing. After degassing, the membrane is scraped and placed in deionized water for phase inversion reaction to obtain a FLL-COF@PVDF blended membrane. The blended membrane is stored in deionized water for later use.

2. The preparation method according to claim 2, characterized in that: (1) The amount ratio of 4,4',4"-(1,3,5-triazine-2,4,6-triyl) tribenzaldehyde and 2,5-bis(allyloxy) terephthalate described in step (1) is: (9 mg-12 mg): (12 mg-14 mg), the volume of acetonitrile is 1.5-2.5 mL, the ultrasonic dispersion power is 200-250 W, the ultrasonic dispersion time is 5-12 min, the concentration of acetic acid solution is 4-8 mol / L, and the mixture is washed with tetrahydrofuran 2-3 times, ethanol 2-3 times, and water 2-3 times. (2) In step (2), the oil bath temperature is 45-55°C, the stirring time is 24-25h, the static degassing temperature is 45-55°C, and the time is 12-14h; the dosage ratio of polyvinylidene fluoride powder, polyvinyl pyrrolidone, filler FLL-COF and N-methylpyrrolidone is (7.0-9.0g): (0.1-0.2g): (0.1-0.3g): (22-24g).

3. The preparation of a COF-based separation material according to claim 1 and its application in the purification of active ingredients of natural products.

4. A mixed membrane, wherein FLL-COF is used as a filler and polyvinylidene fluoride is used as a base material, and the filler and the base material are transformed through physical blending to form a mixed membrane; and the phenylethanol glycoside compound is verbascoside.

5. Use of the hybrid membrane according to claim 4 in the purification of active ingredients of natural products.

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