Liquid chromatographic column, application thereof and separation method of succinic acid diester isomeride

Abstract

The invention relates to the field of chemical analysis, and discloses a liquid chromatographic column and application thereof and a separation method of succinic acid diester isomeride, and chromatographic column filler comprises titanium dioxide coated silicon dioxide microspheres. The liquid chromatographic column can effectively separate the isomers of the succinic acid diester, the purity of the two separated isomers of the succinic acid diester exceeds 99%, and the preparation raw materials are simple in component, easy to obtain, low in cost, simple in preparation process, free of environmental pollution and high in chromatographic column consistency.

Description

Technical Field

[0001] This invention relates to the field of chemical analysis, specifically to a liquid chromatography column for separating succinate diester isomers, its application, and a method for separating succinate diester isomers. Background Technology

[0002] To date, most industrial propylene polymerization plants worldwide use fourth-generation Ziegler-Natta (ZN) catalysts. This type of catalytic system uses magnesium chloride as a support, phthalate compounds as internal electron donors, alkoxysilanes as external electron donors, and trialkylaluminum as a co-catalyst during propylene polymerization. The catalytic activity reaches 30 kg PP / (gcat·h), and the isotactic index of the resulting polymer is greater than 98%. In the ZN propylene polymerization catalytic system, the internal electron donor compound has a significant impact on catalyst activity, stereoregulation, hydrogen sensitivity, copolymerization performance, and the molecular weight distribution of the resulting polymer, making it a key element in ZN polypropylene catalyst research. Whether considering the development history of ZN catalysts or the development of polypropylene catalyst technology, one of the key focuses of propylene polymerization catalyst research has been the continuous search for ideal electron donor compounds.

[0003] In recent years, with the increasing emphasis on green environmental protection worldwide, the potential harm of plasticizers to human health has received significant attention. Phthalate-based internal electron-donating compounds used in fourth-generation Zn catalysts are a type of plasticizer; therefore, the development of non-phthalate-based internal electron-donating compounds has become a key focus in propylene polymerization catalyst research. Succinate diester-based internal electron-donating polypropylene catalysts can produce polymers with excellent mechanical properties when used in propylene polymerization, and their plasticizer-free nature makes them promising candidates for use in polypropylene catalysts.

[0004] Succinate diesters typically generate two or three isomers during synthesis. Different isomers, acting as electron donors within polypropylene catalysts, exhibit varying activities and hydrogen sensitivity. Since isomers generally share the same boiling point, separation based on boiling point is not feasible. Currently available chromatographic columns are not effective at separating succinate diester isomers. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem in existing technologies that cannot effectively separate succinate diester isomers, thus making it difficult to improve the purity of dimethyl succinate. A liquid chromatography column is provided for separating succinate diester isomers, which can effectively separate succinate diester isomers.

[0006] To achieve the above objectives, the first aspect of the present invention provides a liquid chromatography column for separating succinate diester isomers, wherein the column packing comprises titanium dioxide coated silica microspheres.

[0007] A second aspect of the present invention provides the application of the above-described liquid chromatography column in the separation of succinate diester isomers.

[0008] A third aspect of the present invention provides a method for separating succinate diester isomers, the method comprising: injecting a sample containing succinate diester isomers into the above-mentioned liquid chromatography column for liquid chromatography column separation.

[0009] Through the above technical solution, the present invention can achieve at least the following beneficial effects:

[0010] (1) The liquid chromatography column of the present invention can effectively separate the isomers of succinate diester, and the purity of the two isomers of succinate diester after separation exceeds 99%.

[0011] (2) The raw materials for preparing the liquid chromatography column of the present invention are simple in composition, easy to obtain, low in cost, simple in preparation process, no environmental pollution, and have high consistency of chromatography column. Attached Figure Description

[0012] Figure 1 The image shown is a scanning electron microscope image of titanium dioxide-coated silica microspheres in Example 1 of the present invention;

[0013] Figure 2 The liquid chromatogram of the mixture of dimethyl succinate isomers separated in Example 1 of the present invention is shown.

[0014] Figure 3 The following is a racemic liquid chromatography chromatogram of the isomers of dimethyl succinate separated in Example 2 of the present invention;

[0015] Figure 4 The following is a racemic liquid chromatography chromatogram of the isomers of dimethyl succinate separated in Example 3 of the present invention;

[0016] Figure 5 The liquid chromatogram of the mixture of dimethyl succinate isomers separated in Comparative Example 1 of the present invention is shown.

[0017] Figure 6 The liquid chromatogram of the mixture of dimethyl succinate isomers separated in Comparative Example 2 of the present invention is shown.

[0018] Figure 7 The following is a racemic liquid chromatography chromatogram of the isomers of dimethyl succinate separated in Comparative Example 3 of the present invention.

[0019] Figure 8 The in vitro racemic liquid chromatography chromatogram of the isomers of dimethyl succinate separated in Comparative Example 4 of the present invention is shown. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] The first aspect of the present invention provides a liquid chromatography column for separating succinate diester isomers, wherein the column packing comprises titanium dioxide coated silica microspheres.

[0022] In this invention, preferably, the column packing density can be 0.2-2 g / mL, more preferably 0.5-0.8 g / mL (e.g., 0.5 g / mL, 0.6 g / mL, 0.7 g / mL, 0.8 g / mL, and any two of the above values ​​forming a range and points within that range).

[0023] In this invention, preferably, the pore size of the titanium dioxide-coated silica microspheres can be [missing information]. More preferably (For example,

[0024] And the range formed by any two of the above values, and the values ​​within that range).

[0025] In this invention, preferably, the elemental mass ratio of the titanium dioxide coating on the surface of the silica microspheres can be Ti:Si:O = (50-55):(5-10):40.

[0026] In this invention, preferably, the shell thickness of the titanium dioxide-coated silica microspheres is 5-25 nm (for example, it can be any two values ​​formed by 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, or any value within that range), and the average particle size of the core layer is 0.5-8 μm, preferably 1-6 μm (for example, it can be any two values ​​formed by 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, or any value within that range).

[0027] It is understood that, since the shell thickness is at the nanometer level, the shell thickness is generally ignored when measuring the average particle size of the titanium dioxide-coated silica microspheres in this invention. That is, the average particle size of the titanium dioxide-coated silica microspheres is 0.5-8 μm, preferably 1-6 μm.

[0028] In this invention, preferably, the encapsulation rate of the titanium dioxide-coated silica microspheres is 70-90% (for example, it can be any two values ​​from 70%, 72%, 75%, 78%, 80%, 83%, 85%, 87%, 90% and values ​​within that range).

[0029] In this invention, preferably, the liquid chromatography column packing material further includes: C8 packing material or C18 packing material.

[0030] In this invention, preferably, the C8 filler is octylsilane and the C18 filler is octadecylsilane.

[0031] In this invention, preferably, the average particle size of the C8 or C18 filler is 0.5-8 μm, more preferably 3-6 μm (e.g., 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, and any two of the above values).

[0032] In this invention, preferably, the pore size of the C8 packing or C18 packing is [missing information]. More preferably (For example,

[0033] And the range formed by any two of the above values, and the values ​​within that range).

[0034] In this invention, preferably, the mass ratio of titanium dioxide-coated silica microspheres to C8 or C18 packing material in the chromatographic column packing is 1-10:1 (for example, it can be any two ratios from 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and the ratio within that range).

[0035] In this invention, preferably, the titanium dioxide-coated silica microspheres can be obtained commercially or in-house.

[0036] In this invention, preferably, the method for preparing the titanium dioxide-coated silica microspheres includes: blending silica with a titanium-containing premixed liquid.

[0037] In a preferred embodiment of the present invention, the blending is performed in a stepwise manner, that is, the silica carrier is added to the titanium source-containing premixed solution in a stepwise manner with a concentration gradient.

[0038] In a preferred embodiment of the present invention, the titanium-containing premixed liquid can be obtained by premixing a titanium source and a solvent.

[0039] In a preferred embodiment of the present invention, after the blending is completed, solid-liquid separation is performed, and the separated solid phase is kept at a temperature of 100-200°C for 10-20 hours. Preferably, the temperature can be 140-180°C (for example, it can be any two values ​​formed by 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, and 180°C, or any value within that range); the time can be 14-18 hours (for example, it can be any two values ​​formed by 14 hours, 14.5 hours, 15 hours, 15.5 hours, 16 hours, 16.5 hours, 17 hours, 17.5 hours, and 18 hours, or any value within that range).

[0040] In this invention, preferably, the titanium source is a titanium source commonly used in the art for preparing titanium dioxide-coated silica microspheres, such as tetrabutyl titanate (i.e., tetrabutyl titanate); the solvent is a solvent commonly used in the art for dissolving the titanium source, such as at least one of ethanol, acetonitrile, isopropanol, acetone and n-butanol.

[0041] In this invention, preferably, the silicon dioxide can be obtained commercially or in-house.

[0042] In a preferred embodiment of the present invention, the method for preparing silicon dioxide involves mixing a silicon source, a solvent, and ammonia water, followed by solid-liquid separation, wherein the solid phase is silicon dioxide.

[0043] In this invention, preferably, the silicon source can be a commonly used silicon source in the art for preparing titanium dioxide-coated silica microspheres, such as tetraethyl silicate; the solvent can be a commonly used solvent in the art for dissolving silicon sources, such as at least one of ethanol, acetonitrile, isopropanol, acetone or n-butanol; and the ammonia concentration can be 25-28 wt%.

[0044] In this invention, preferably, the volume ratio of the silicon source, solvent and ammonia is 1:50-300:2-5.

[0045] In this invention, preferably, after the solid-liquid separation is completed during the preparation of silicon dioxide, the solid phase is further washed and dried.

[0046] In this invention, preferably, the conditions for preparing silicon dioxide can be those commonly used in the art, for example, a temperature of 25-50°C and a time of 6-12 hours.

[0047] A second aspect of the present invention provides the application of the above-described liquid chromatography column in the separation of succinate diester isomers.

[0048] A third aspect of the present invention provides a method for separating succinate diester isomers, the method comprising: injecting a sample containing succinate diester isomers into the above-mentioned liquid chromatography column for liquid chromatography column separation.

[0049] In this invention, preferably, during the separation by the liquid chromatography column, the temperature of the chromatographic column is 25-40℃ (for example, it can be any two values ​​formed by 25℃, 28℃, 30℃, 33℃, 35℃, 37℃, and 40℃, or values ​​within that range).

[0050] In this invention, preferably, when performing liquid chromatography column separation, the mobile phase comprises: 30-60 wt% tetrahydrofuran, 30-60 wt% acetonitrile, and 10-30 wt% water.

[0051] In this invention, preferably, the flow rate of the liquid chromatography column is 0.05-10 BV / h (for example, it can be any two values ​​formed by 0.05 BV / h, 0.5 BV / h, 1 BV / h, 1.5 BV / h, 2 BV / h, 2.5 BV / h, 3 BV / h, 3.5 BV / h, 4 BV / h, 4.5 BV / h, 5 BV / h, 5.5 BV / h, 6 BV / h, 6.5 BV / h, 7 BV / h, 7.5 BV / h, 8 BV / h, 8.5 BV / h, 9 BV / h, 9.5 BV / h, 10 BV / h, or a value within that range).

[0052] In this invention, the unit "BV" refers to the volume of material to be adsorbed (e.g., a liquid containing succinate diester isomers) treated per unit volume of adsorbent (e.g., packing material of a liquid chromatography column); similarly, the unit "BV / h" refers to the volume of material to be adsorbed (e.g., a liquid containing succinate diester isomers) flowing through a unit volume of adsorbent (e.g., packing material of a liquid chromatography column) per hour.

[0053] In this invention, preferably, the succinate diester isomers include: meso-optical succinate diester with ester groups at positions 2 and 3 and exo-optical succinate diester with ester groups at positions 2 and 3.

[0054] In this invention, the method is particularly suitable for the separation of optical isomers, and preferably, the succinate diester isomers have the following structural formulas: Wherein, R is selected from C1-C8 alkyl groups, and R1, R2, R3, and R4 are each independently selected from at least one of H or C1-C8 alkyl groups.

[0055] The present invention will be described in detail below through examples. In the following examples, the liquid chromatograph is an Agilent Technologies 1290 model. The mobile phase is a commercially available product from Merkel, brand name Sigma-Aldrich.

[0056] The commercial C8 stationary phase column was a commercially available product from Agilent Technologies under the brand name Poroshell.

[0057] The commercial C18 stationary phase column used was a commercially available product from Agilent Technologies under the brand name Zorbax.

[0058] The silica microsphere chromatographic column was a commercially available product from Merkel under the brand name Sigma-Aldrich.

[0059] Column analysis revealed that the following dimethyl succinate isomers consist of 10 wt% racemic dimethyl succinate and 90 wt% meso dimethyl succinate.

[0060] The method for measuring the pore size of titanium dioxide-coated silica microspheres is: physical adsorption (BET).

[0061] The average particle size of titanium dioxide-coated silica microspheres was measured using a physical adsorption analyzer (BET).

[0062] The elemental detection method for titanium dioxide-coated titanium dioxide structures is X-ray fluorescence spectroscopy (XRF).

[0063] The shell thickness of titanium dioxide-coated silica microspheres was measured using X-ray powder diffraction (XRD).

[0064] The average particle size of the core layer of titanium dioxide-coated silica microspheres was measured using a physical adsorption analyzer (BET).

[0065] The encapsulation efficiency of titanium dioxide-coated silica microspheres was measured using X-ray fluorescence spectroscopy (XRF).

[0066] The packing density of a liquid chromatography column is calculated as follows: ρ = m / V; where ρ is the packing density, m is the packing mass, and V is the packing volume.

[0067] Resolution (R): R = 2(T2 - T1) / (W1 + W2), where: T2 is the retention time of the peak after two adjacent peaks, T1 is the retention time of the peak before two adjacent peaks, W1 is the peak base width of the peak before two adjacent peaks, and W2 is the peak base width of the peak after two adjacent peaks. When the resolution R > 1.5, the two substances are considered to be completely separated.

[0068] Purity of a single component after separation = Peak area of ​​pure substance / Total peak area (peak area after solvent removal).

[0069] Example 1

[0070] 1. Preparation of silica support:

[0071] Add 100 ml of anhydrous ethanol, 30 ml of deionized water, and 10 ml of ammonia to a 500 ml three-necked flask in sequence. Stir for 30 min to mix the solution evenly. Then add tetraethyl silicate dropwise at a constant rate for 60 min. Reflux the reaction in a 30 °C water bath with a constant stirring speed for 6 h. After the reaction is complete, centrifuge for 20 min to separate the solid. Wash the solid product three times with anhydrous ethanol by centrifugation. Dry the solid product at 40 °C to obtain the silica carrier.

[0072] 2. Preparation of titanium dioxide-coated silica microspheres:

[0073] Add 100 mL of acetonitrile and 100 mL of n-butanol solution to a 500 mL beaker. While stirring with a magnetic stirrer, add 7.16 mL of tetrabutyl titanate dropwise and continue stirring until the solution is clear (time is 20 ± 5 min). This solution is marked as No. 1. In a separate beaker, add 100 mL of acetonitrile and 100 mL of n-butanol solution, 3.6 mL of deionized water, 2.7 mL of ammonia, and 0.2 g, 0.5 g, and 0.8 g of silica carrier (labeled a, b, and c, respectively). After ultrasonic stirring, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 2 hours. Divide the solution evenly into four 50 mL centrifuge tubes and centrifuge at 3500 rpm for 10 minutes to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication, centrifuge under the same conditions, remove the supernatant, add 15 mL of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 mL of deionized water. After ultrasonic dispersion, transfer the mixture to a 50 mL reaction vessel and react at 100 °C for 14 hours to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface elemental mass ratio is Ti:Si:O = 50:10:40. The shell thickness of the titanium dioxide-coated silica microspheres is 25 nm, the average particle size of the core layer is 1 μm, and the encapsulation efficiency is 75%. Scanning electron microscopy images of the titanium dioxide-coated silica microspheres are shown below. Figure 1 As shown.

[0074] 3. Preparation of chromatographic column

[0075] A stainless steel chromatographic column with dimensions of 50 mm × 4.6 mm was selected. The modified TiO2@SiO2 microspheres and commercially available C8 particles (1 μm) were then used. The chromatographic column was packed with a 5:1 mass ratio of acetone and tetrahydrofuran (v = 1:1) at a packing density of 0.8 g / mL. The selected pressurizing solution was a mixture of acetone and tetrahydrofuran (v = 1:1), and the packing pressure was 35 MPa. After packing, the column was connected to a high-pressure pump and flushed with chromatographically pure acetone at a flow rate of 0.1 mL / min for at least 2 hours to equilibrate the column.

[0076] 4. Application of chromatographic columns

[0077] Sample preparation: The dimethyl succinate isomer was dissolved in acetonitrile before injection;

[0078] Detection wavelength: 240nm;

[0079] Column temperature: 35℃;

[0080] Injection volume: 1.0 μL;

[0081] Mobile phase: 45% tetrahydrofuran + 45% acetonitrile + 10% water;

[0082] Flow rate: 0.3 BV / h;

[0083] The liquid chromatogram of a mixture of dimethyl succinate isomers is shown below. Figure 2 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0084] Example 2

[0085] 1. Preparation of silica support:

[0086] Add 100 ml of anhydrous ethanol, 30 ml of deionized water, and 10 ml of ammonia to a 500 ml three-necked flask in sequence. Stir for 30 min to mix the solution evenly. Then add tetraethyl silicate dropwise at a constant rate for 240 min. Reflux the reaction in a 30 °C water bath with a constant stirring speed for 12 h. After the reaction is complete, centrifuge for 20 min to separate the solid. Wash the solid product three times with anhydrous ethanol by centrifugation. Dry the solid product at 60 °C to obtain the silica carrier.

[0087] 2. Preparation of titanium dioxide-coated silica microspheres:

[0088] Add a solution of 200 ml acetonitrile and 100 ml n-butanol to an 800 ml beaker. While stirring with a magnetic stirrer, add 9.46 ml tetrabutyl titanate dropwise and stir until the solution is clear (time is 30 ± 5 min). This solution is marked as No. 1. In a separate beaker, add 200 mL of acetonitrile and 100 mL of n-butanol solution, 5.4 mL of deionized water, 4.1 mL of ammonia, and 0.3 g, 0.6 g, and 1.0 g of silica carrier (denoted as a / b / c, respectively). After ultrasonic stirring, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 2.5 h. Divide the solution evenly into four 50 mL centrifuge tubes and centrifuge at 3500 rpm for 10 min to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication, centrifuge under the same conditions, remove the supernatant, add 15 mL of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 mL of deionized water. After ultrasonic dispersion, transfer the mixture to a 50 mL reaction vessel and react at 180 °C for 18 h to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface element mass ratio is Ti(55):Si(5):O(40). The shell thickness of the titanium dioxide-coated silica microspheres is 5 nm, the average particle size of the core layer is 5 μm, and the encapsulation efficiency is 90%.

[0089] 3. Preparation of chromatographic column

[0090] The chromatographic column was prepared according to the method in Example 1, except that a 150 mm × 19 mm column was used. The modified TiO2@SiO2 microspheres and commercial C8 particles (5 μm) were then used. The chromatographic column was filled with packing material at a mass ratio of 1:1, with a packing density of 0.5 g / mL.

[0091] 4. Application of chromatographic columns

[0092] Sample preparation: The dimethyl succinate isomer was dissolved in acetonitrile before injection;

[0093] Detection wavelength: 240nm;

[0094] Column temperature: room temperature (25℃);

[0095] Injection volume: 200 μL;

[0096] Mobile phase: 40% tetrahydrofuran + 50% acetonitrile + 10% water;

[0097] Flow rate: 5 BV / h;

[0098] The in vitro racemic liquid chromatography chromatogram of dimethyl succinate isomers is shown below. Figure 3 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0099] Example 3

[0100] 1. Preparation of silica support:

[0101] Add 100 ml of anhydrous ethanol, 30 ml of deionized water, and 10 ml of ammonia to a 500 ml three-necked flask in sequence. Stir for 30 min to mix the solution evenly. Then add tetraethyl silicate dropwise at a constant rate for 120 min. Reflux the reaction in a 30 °C water bath with a constant stirring speed for 6 h. After the reaction is complete, centrifuge for 20 min to separate the solid. Wash the solid product three times with anhydrous ethanol by centrifugation. Dry the solid product at 40 °C to obtain the silica carrier.

[0102] 2. Preparation of titanium dioxide-coated silica microspheres:

[0103] Add 100 ml of acetonitrile and 100 ml of n-butanol solution to a 500 ml beaker. While stirring with a magnetic stirrer, add 8.03 ml of tetrabutyl titanate dropwise and continue stirring until the solution is clear (time is 20 ± 5 min). This solution is marked as No. 1. In a separate beaker, add 100 mL of acetonitrile and 100 mL of n-butanol solution, 4.2 mL of deionized water, 3.4 mL of ammonia, and 0.26 g, 0.54 g, and 0.9 g of silica carrier (denoted as a / b / c, respectively). After ultrasonic stirring, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 2 hours. Divide the solution evenly into four 50 mL centrifuge tubes and centrifuge at 3500 rpm for 10 minutes to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication, centrifuge under the same conditions, remove the supernatant, add 15 mL of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 mL of deionized water. After ultrasonic dispersion, transfer the mixture to a 50 mL reaction vessel and react at 150 °C for 16 hours to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface elemental mass ratio is Ti:Si:O = 52:8:40. The shell thickness of the titanium dioxide-coated silica microspheres is 15 nm, the average particle size of the core layer is 3 μm, and the encapsulation efficiency is 80%.

[0104] 3. Preparation of chromatographic column

[0105] A stainless steel chromatographic column with dimensions of 100 mm × 10 mm was selected. The modified TiO2@SiO2 microspheres and commercially available C8 particles (3 μm) were then used. The chromatographic column was packed with a 2:1 mass ratio of acetone and tetrahydrofuran (v = 1:1) at a packing density of 0.7 g / mL. The selected pressurizing solution was a mixture of acetone and tetrahydrofuran (v = 1:1), and the pressure during packing was 35 MPa. After packing, the column was connected to a high-pressure pump, and the column was flushed with chromatographically pure acetone at a flow rate of 0.1 mL / min for at least 2 hours to equilibrate the column.

[0106] 4. Application of chromatographic columns

[0107] Sample preparation: The dimethyl succinate isomer was dissolved in acetonitrile before injection;

[0108] Detection wavelength: 240nm;

[0109] Column temperature: 35℃;

[0110] Injection volume: 500 μL;

[0111] Mobile phase: 90% tetrahydrofuran + 10% water;

[0112] Flow rate: 10 BV / h;

[0113] The in vivo racemic liquid chromatography chromatogram of dimethyl succinate isomers is shown below. Figure 4 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0114] Example 4

[0115] The chromatographic column was prepared according to the method in Example 1, except that:

[0116] 2. Preparation of titanium dioxide-coated silica microspheres:

[0117] Add 200ml of acetonitrile and 100ml of n-butanol solution to an 800ml beaker. While stirring with a magnetic stirrer, add 10.25ml of tetrabutyl titanate dropwise and stir until the solution is clear (time is 30±5min). This solution is marked as No. 1. In a separate beaker, add 200 ml of acetonitrile and 100 ml of n-butanol solution, 5.4 ml of deionized water, 4.5 ml of ammonia, and 0.4 g, 0.7 g, and 1.0 g of silica carrier (denoted as a / b / c, respectively). After ultrasonic stirring, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 3.0 h. Divide the solution evenly into four 50 ml centrifuge tubes and centrifuge at 3500 rpm for 10 min to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication, centrifuge under the same conditions, remove the supernatant, add 15 ml of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 ml of deionized water. After ultrasonic dispersion, transfer the mixture to a 50 ml reaction vessel and react at 200 °C for 18 h to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface element mass ratio is Ti(55):Si(5):O(40). The shell thickness of the titanium dioxide-coated silica microspheres is 5 nm, the average particle size of the core layer is 8 μm, and the encapsulation efficiency is 90%.

[0118] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0119] Example 5

[0120] The chromatographic column was prepared according to the method in Example 1, except that:

[0121] 2. Preparation of titanium dioxide-coated silica microspheres:

[0122] Add 100 ml of acetonitrile and 100 ml of n-butanol solution to a 500 ml beaker. While stirring with a magnetic stirrer, add 6.02 ml of tetrabutyl titanate dropwise and continue stirring until the solution is clear (time is 20 ± 5 min). This solution is marked as No. 1. In a separate beaker, add 100 mL of acetonitrile and 100 mL of n-butanol solution, 3.6 mL of deionized water, 2.5 mL of ammonia, and 0.2 g, 0.5 g, and 0.7 g of silica carrier (denoted as a / b / c, respectively). After ultrasonic stirring until homogeneous, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 2 hours. Divide the solution evenly into four 50 mL centrifuge tubes and centrifuge at 3500 rpm for 10 minutes to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication. Centrifuge again under the same conditions, remove the supernatant, add 15 mL of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 mL of deionized water. After homogeneous ultrasonic dispersion, transfer the mixture to a 50 mL reaction vessel and react at 170 °C for 12 hours to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface elemental mass ratio is Ti:Si:O = 45:20:35. The shell thickness of the titanium dioxide-coated silica microspheres is 25 nm, the average particle size of the core layer is 1 μm, and the encapsulation efficiency is 70%.

[0123] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0124] Example 6

[0125] The chromatographic column was prepared according to the method in Example 1, except that:

[0126] 2. Preparation of titanium dioxide-coated silica microspheres:

[0127] Add 100 ml of acetonitrile and 100 ml of n-butanol solution to a 500 ml beaker. While stirring with a magnetic stirrer, add 10.05 ml of tetrabutyl titanate dropwise and continue stirring until the solution is clear (time is 20 ± 5 min). This solution is marked as No. 1. In a separate beaker, add 100 mL of acetonitrile and 100 mL of n-butanol solution, 6.0 mL of deionized water, 5.5 mL of ammonia, and 0.3 g, 0.6 g, and 0.9 g of silica carrier (denoted as a / b / c, respectively). After ultrasonic stirring, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 2 hours. Divide the solution evenly into four 50 mL centrifuge tubes and centrifuge at 3500 rpm for 10 minutes to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication. Centrifuge under the same conditions, remove the supernatant, add 15 mL of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 mL of deionized water. After ultrasonic dispersion, transfer the mixture to a 50 mL reaction vessel and react at 150 °C for 16 hours to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface elemental mass ratio is Ti:Si:O = 50:10:40. The shell thickness of the titanium dioxide-coated silica microspheres is 30 nm, the average particle size of the core layer is 10 μm, and the encapsulation efficiency is 64%.

[0128] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0129] Example 7

[0130] The chromatographic column was prepared according to the method in Example 1, except that:

[0131] 2. Preparation of titanium dioxide-coated silica microspheres:

[0132] Add 100 ml of acetonitrile and 100 ml of n-butanol solution to a 500 ml beaker. While stirring with a magnetic stirrer, add 6.02 ml of tetrabutyl titanate dropwise and continue stirring until the solution is clear (time is 20 ± 5 min). This solution is marked as No. 1. In a separate beaker, add 100 mL of acetonitrile and 100 mL of n-butanol solution, 4.4 mL of deionized water, 3.0 mL of ammonia, and 0.2 g, 0.4 g, and 0.6 g of silica carrier (denoted as a / b / c, respectively). After ultrasonic stirring, add the solutions from beakers a, b, and c sequentially to beaker 1. The solution quickly turns white. Continue stirring for 2 hours. Divide the solution evenly into four 50 mL centrifuge tubes and centrifuge at 3500 rpm for 10 minutes to obtain the centrifugation precursor. Disperse the precursor once with anhydrous ethanol using ultrasonication, centrifuge under the same conditions, remove the supernatant, add 15 mL of ethanol to each centrifuge tube, ultrasonically disperse, then add 15 mL of deionized water. After ultrasonic dispersion, transfer the mixture to a 50 mL reaction vessel and react at 140 °C for 14 hours to obtain the titanium dioxide-coated silica structure. The pore size of the titanium dioxide-coated silica microspheres is [not specified]. The surface elemental mass ratio is Ti:Si:O = 50:10:40. The shell thickness of the titanium dioxide-coated silica microspheres is 25 nm, the average particle size of the core layer is 1 μm, and the encapsulation efficiency is 75%.

[0133] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0134] Example 8

[0135] The chromatographic column was prepared according to the method in Example 1, except that the C8 particles were replaced with C18 particles (5 μm). ).

[0136] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0137] Example 9

[0138] The chromatographic column was prepared according to the method in Example 1, except that the C8 particles were replaced with modified TiO2@SiO2 microspheres (5 μm). ).

[0139] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0140] Example 10

[0141] The chromatographic column was applied according to the method of Example 1, except that the mobile phase was replaced with 70% tetrahydrofuran + 30% water;

[0142] The dimethyl succinate isomers were separated using the liquid chromatography column prepared above. The resolution and the purity of the separated individual components are shown in Table 1.

[0143] Comparative Example 1

[0144] The chromatographic column application scheme of Example 1 was followed, except that a commercial C8 stationary phase column was used to separate the dimethyl succinate isomers. The liquid chromatogram of the dimethyl succinate isomer mixture is shown below. Figure 5 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0145] Comparative Example 2

[0146] The chromatographic column application protocol of Example 1 was followed, except that a commercial C18 stationary phase column was used to separate the dimethyl succinate isomers. The liquid chromatogram of the dimethyl succinate isomer mixture is shown below. Figure 6 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0147] Comparative Example 3

[0148] The chromatographic column application scheme of Example 1 was followed, except that a silica microsphere column (1 μm) was used. The in vitro racemic liquid chromatography chromatogram of dimethyl succinate isomers is shown below. Figure 7 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0149] Comparative Example 4

[0150] The chromatographic column application scheme of Example 1 was followed, except that a silica microsphere column (5 μm) was used. The in vitro racemic liquid chromatography chromatogram of dimethyl succinate isomers is shown below. Figure 8 As shown in Table 1, the degree of separation and the purity of the separated individual components are as follows.

[0151] Table 1

[0152]

[0153]

[0154] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A liquid chromatography column for separating succinate diester isomers, characterized in that, The chromatographic column packing material comprises titanium dioxide-coated silica microspheres.

2. The liquid chromatography column according to claim 1, wherein, The column packing density is 0.2-2 g / mL, preferably 0.5-0.8 g / mL.

3. The liquid chromatography column according to claim 1 or 2, wherein, The pore size of the titanium dioxide-coated silica microspheres is... Preferred And / or, the elemental mass ratio of the titanium dioxide coating on the surface of the silica microspheres is Ti:Si:O = (50-55):(5-10):

40.

4. The liquid chromatography column according to claim 1 or 2, wherein, The shell thickness of the titanium dioxide-coated silica microspheres is 5-25 nm, and the average particle size of the core layer is 0.5-8 μm, preferably 1-6 μm; And / or, the encapsulation rate of the titanium dioxide-coated silica microspheres is 70-90%.

5. The liquid chromatography column according to claim 1, wherein, The liquid chromatography column packing material further includes: C8 packing material or C18 packing material; Preferably, the average particle size of the C8 or C18 packing is 0.5-8 μm, more preferably 3-6 μm; Preferably, the pore size of the C8 or C18 packing is [missing information]. More preferably Preferably, in the chromatographic column packing, the mass ratio of titanium dioxide-coated silica microspheres to C8 or C18 packing is 1-10:

1.

6. The use of the liquid chromatography column according to any one of claims 1-5 in the separation of succinate diester isomers.

7. A method for separating succinate diester isomers, characterized in that, The method includes injecting a sample containing succinate diester isomers into a liquid chromatography column according to any one of claims 1-5 for liquid chromatography column separation.

8. The method according to claim 7, wherein, During the separation process of the liquid chromatography column, the temperature of the column is 25-40℃.

9. The method according to claim 7 or 8, wherein, When performing liquid chromatography column separation, the mobile phase comprises: 30-60 wt% tetrahydrofuran, 30-60 wt% acetonitrile and 10-30 wt% water; Preferably, the flow rate of the liquid chromatography column is 0.05-10 BV / h.

10. The method according to claim 7 or 8, wherein, The succinate diester isomers include: meso-optical succinate diester with ester groups at positions 2 and 3 and exo-optical succinate diester with ester groups at positions 2 and 3.

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