Phosphonate-functionalized chromatographic stationary phases, methods of making and using the same

Abstract

The application relates to a phosphate functionalized chromatographic stationary phase and a preparation method and application thereof, a structural formula of the phosphate functionalized chromatographic stationary phase comprising: or; Sil represents silica gel, R1 is selected from C1-C10 linear or branched alkylene or C1-C10 linear or branched alkylene containing an ether bond, and R2 is selected from a phosphate group or an organic structure containing at least one phosphoric acid group and / or at least one phosphate group connected by a phosphate. The phosphate functionalized chromatographic stationary phase provided by the application has a high sample load, exhibits excellent separation selectivity for the separation and analysis of a full series of 16 rare earth elements and the removal of radioactive nuclides such as U and Th in the rare earth elements, and the preparation method is simple to operate and can be applied in industrialization.

Description

Technical Field

[0001] This application relates to the field of chromatography technology, specifically to a phosphate ester functionalized chromatographic stationary phase, its preparation method, and its application. Background Technology

[0002] Rare earth elements, as important strategic resources, have significant applications in high-end fields such as national defense, new materials, aerospace, and communications. Furthermore, with the development of science and technology, some high-end applications of rare earth elements require increasingly higher purity levels. For example, ultra-high purity rare earth elements with a purity of 5N (>99.999%) or higher are needed in semiconductor fabrication and optical sensing devices for high-power lasers. Therefore, the efficient separation and preparation of rare earth elements and the removal of trace impurities are crucial.

[0003] However, due to the lanthanide contraction leading to similar ionic radii and extremely similar physicochemical properties, rare earth elements often contain various impurities, including radioactive and transition metal impurities, making their separation and ultra-high purity extremely difficult and challenging to achieve efficient separation and purification using conventional chemical methods. Currently, commonly used rare earth separation methods include solvent extraction, ion exchange resin methods, precipitation, adsorption, and membrane separation. Solvent extraction is currently the most commonly used method in industry for obtaining single ultra-high purity rare earth elements, but it also suffers from problems such as cumbersome operation, the need for multi-stage extraction, the use of large amounts of organic extractants, and the inability to deeply remove trace impurities. While resin methods can obtain single high-purity rare earth elements, the resin particles currently used are large, resulting in low separation coefficients, small throughput, and unsuitability for continuous production. Chromatography, especially high-performance liquid chromatography (HPLC), offers advantages such as speed, efficiency, high sensitivity, simple operation, automation, and ease of industrial scale-up, making it suitable for single rare earth element separation and high purification, as well as the deep removal of radioactive impurities.

[0004] In high-performance liquid chromatography (HPLC), the stationary phase is the core component for separating rare earth elements. Currently, commonly used stationary phases mainly rely on the principle of cation exchange for separation and can be classified into strong cation exchange (sulfonic acid type), medium-strong cation exchange (phosphate type), and weak cation exchange (carboxylic acid type). However, the above-mentioned chromatographic packing materials still have disadvantages such as low resolution between rare earth elements and associated impurity elements, long separation time, large peak broadening, and low column efficiency.

[0005] Therefore, it is of great significance to develop a chromatographic packing material that can perform separation analysis and high purification of the entire range of rare earth elements, as well as deep removal of radionuclides from rare earth elements. Summary of the Invention

[0006] To address the above issues, the purpose of this application is to provide a phosphate ester functionalized chromatographic stationary phase, its preparation method, and its application. Compared with the prior art, the phosphate ester functionalized chromatographic stationary phase provided in this application has the advantage of high surface phosphate ester group modification. It exhibits excellent separation selectivity for the separation and analysis of all 16 rare earth elements and the removal of associated radionuclides such as U and Th from rare earth elements. Furthermore, the preparation method is simple to operate and can be applied industrially.

[0007] To achieve this objective, the present application adopts the following technical solution: In a first aspect, this application provides a phosphate ester functionalized chromatographic stationary phase, the structural formula of which includes: or ; Wherein, Sil represents silica gel, R1 is selected from C1 to C10 straight-chain or branched alkylene groups or C1 to C10 straight-chain or branched alkylene groups containing ether bonds, and R2 is selected from phosphate ester groups or organic structures containing at least one phosphate group and / or at least one phosphate ester group linked by phosphate esters.

[0008] The phosphate-functionalized chromatographic stationary phase provided in this application contains phosphate ester groups and / or phosphate groups, which creates a difference in adsorption stability between the stationary phase and ions, thereby achieving stable adsorption of rare earth elements and nuclides through ion exchange or chelation. Therefore, the phosphate-functionalized chromatographic stationary phase provided in this application has good separation and analysis effects on the entire range of rare earth elements, and can also remove associated radionuclides such as U and Th.

[0009] In this application, the specific forms of phosphate ester functionalized chromatographic stationary phases include, but are not limited to, the following, which are merely examples: Formula 1: ; Formula 2: ; Formula 3: ; Formula 4: ; Formula 5: .

[0010] Secondly, this application provides a method for preparing a phosphate ester functionalized chromatographic stationary phase as described in the first aspect of this application, the preparation method comprising the following steps: (1) The bare silica gel is immersed in an acidic aqueous solution for activation treatment, and then washed and dried to obtain activated silica gel; (2) The activated silica gel obtained in step (1) is dispersed in a first solvent, an epoxy silane coupling agent is added to react, and then washed and dried to obtain epoxy functionalized silica gel. (3) The epoxy-functionalized silica gel obtained in step (2) is dispersed in a second solvent, and a phosphorus-containing functionalizing modifier is added to carry out a ring-opening reaction. After washing and drying, a phosphate-functionalized chromatographic stationary phase is obtained.

[0011] In this application, epoxy-functionalized silica gel is obtained by reacting activated silica gel with an epoxy-silane coupling agent. Subsequently, the epoxy-functionalized silica gel is reacted with a phosphorus-containing functionalizing modifier. The phosphorus-containing functionalizing modifier attacks the epoxy-functionalized silica gel through a nucleophilic reaction, causing the epoxy groups to open and further hydrolyze, to obtain a phosphate ester functionalized chromatographic stationary phase.

[0012] In some embodiments, the pore size of the bare silicone in step (1) is 80~200Å, for example, it can be 90Å, 100Å, 120Å, 150Å, 180Å or 200Å, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] In some embodiments, the average particle size of the bare silica gel is 1 to 10 μm, for example, it can be 1 μm, 1.5 μm, 1.8 μm, 3 μm, 5 μm or 10 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0014] In this application, it is preferable to control the average particle size of the bare silica gel within a specific range to maintain high column efficiency in high-performance liquid chromatography (HPLC). Excessive average particle size will lead to a significant decrease in resolution.

[0015] In this application, the cleaning described in steps (2) and (3) is preferably performed using the first solvent or the second solvent used in the reaction of these steps, or multiple solvents such as methanol and / or ethanol can be used for cleaning in sequence.

[0016] In some embodiments, the acid used in the acidic aqueous solution of step (1) includes any one or a combination of at least two of hydrochloric acid, nitric acid, or sulfuric acid.

[0017] In this application, the hydrochloric acid, nitric acid, or sulfuric acid is of analytical grade.

[0018] In some embodiments, the mass ratio of acid to water in the acidic aqueous solution is 1:(1.0~10.0), for example, it can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] In some embodiments, the activation treatment time is 12 to 24 hours, for example, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] In some embodiments, the cleaning in step (1) includes washing the silica gel with water until it is neutral.

[0021] In this application, the water used for washing is generally deionized water.

[0022] In some embodiments, step (2) of the first solvent includes any one or a combination of at least two of toluene, xylene, or n-heptane.

[0023] In some embodiments, the solid-liquid ratio of the activated silica gel to the first solvent is 1g:(10~50)mL, for example, it can be 1g:10mL, 1g:20mL, 1g:30mL, 1g:40mL or 1g:50mL, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] In some embodiments, the ratio of activated silica gel to epoxy silane coupling agent is 1 g:(1.0~1.8) mL, for example, it can be 1:1 g / mL, 1:1.1 g / mL, 1:1.2 g / mL, 1:1.3 g / mL, 1:1.4 g / mL, 1:1.5 g / mL, 1:1.6 g / mL, 1:1.7 g / mL or 1:1.8 g / mL, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0025] In this application, the preferred method is to control the ratio of activated silica gel to epoxy silane coupling agent to control the amount of epoxy modification on the surface. Excessive use of epoxy silane coupling agent may lead to silica gel agglomeration, while insufficient use may result in inadequate modification, affecting the subsequent phosphate ester functionalization.

[0026] In some embodiments, the epoxy silane coupling agent comprises any one or a combination of at least two of the following: triethoxy(3-epoxypropyloxypropyl)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3-epoxypropoxypropyl)dimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethoxysilane, or 5,6-epoxyhexyltriethoxysilane.

[0027] In some embodiments, the reaction temperature is 50~110°C, for example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or 110°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] In some embodiments, the reaction time is 12 to 96 hours, for example, 12 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours, 50 hours, 55 hours, 60 hours, 65 hours, 70 hours, 75 hours, 80 hours, 85 hours, 90 hours, or 96 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] In some embodiments, the reaction is carried out under a protective atmosphere, which includes nitrogen and / or an inert gas, including argon.

[0030] In some embodiments, the drying temperature in step (2) is 60~100℃, for example, it can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] In some embodiments, the second solvent in step (3) includes a polar solvent.

[0032] In some embodiments, the second solvent includes any one or a combination of at least two of water, methanol, ethanol, or acetonitrile.

[0033] In some embodiments, the ratio of the epoxy-functionalized silica gel to the second solvent is 1 g:(10~50) mL, for example, it can be 1:10 g / mL, 1:20 g / mL, 1:30 g / mL, 1:40 g / mL or 1:50 g / mL, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] In some embodiments, the mass ratio of the epoxy-functionalized silicone to the phosphorus-containing functionalized modifier is 1:(1~30), for example, it can be 1:1, 1:5, 1:10, 1:15, 1:20, 1:25 or 1:30, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] In some embodiments, the temperature of the ring-opening reaction is 40~120°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] In some embodiments, the ring-opening reaction time is 12 to 24 hours, for example, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] In some embodiments, the phosphorus-containing functionalized modifier includes any one or a combination of at least two of disodium hydrogen phosphite, hypophosphite, sodium phytate, sodium alendronate, tetrasodium aminotrimethylene phosphonate, sodium hydroxyethylidene diphosphonate, sodium ethylenediaminetetramethylene phosphonate, or pentasodium diethylenetriaminepentamethylidene phosphonate.

[0038] In some embodiments, the drying temperature in step (3) is 60~100℃, for example, it can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Thirdly, this application provides an application of the phosphate ester functionalized chromatographic stationary phase as described in the first aspect of this application, wherein the phosphate ester functionalized chromatographic stationary phase is used for chromatographic separation.

[0040] In some embodiments, the phosphate-functionalized chromatographic stationary phase is used for the separation and analysis of rare earth elements and / or the separation and removal of associated radionuclides in rare earth elements, wherein the rare earth elements include any one or a combination of at least two of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, or Y, and the radionuclides include U and / or Th.

[0041] In some embodiments, the chromatographic separation conditions include: a mobile phase comprising phase A and phase B, using gradient elution; phase A being water (generally deionized water); and phase B having a pH of 2.5–4.5, for example, 2.5, 3, 3.5, 4, or 4.5, with a concentration of 100–800 mmol. α Aqueous solutions of hydroxyisobutyric acid, for example, can be 100 mmol, 200 mmol, 400 mmol, 600 mmol or 800 mmol, with azoarsine solution as the post-column derivatization solution and a UV-Vis detector, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] In some embodiments, the column temperature for chromatographic separation is 20~50°C, for example, it can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C or 50°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] In some embodiments, the detection wavelength of the detector is 645~668nm, for example, it can be 645nm, 650nm, 655nm, 660nm or 668nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] In some embodiments, the total flow rate of the mobile phase is 0.6 to 1.5 mL / min, for example, it can be 0.6 mL / min, 0.8 mL / min, 1.0 mL / min, 1.2 mL / min or 1.5 mL / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] In some embodiments, the concentration of the azoarsine solution is (1.0~2.0)×10⁻⁶. -4 mol / L, for example, could be 1.0 × 10⁻⁶. -4 mol / L, 1.5×10 -4 mol / L or 2.0×10 -4 The values ​​are mol / L, but not limited to those listed; other unlisted values ​​within the range also apply.

[0046] In some embodiments, the flow rate of the azoarsine solution is 0.2 to 0.8 mL / min, for example, 0.2 mL / min, 0.4 mL / min, 0.6 mL / min or 0.8 mL / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] Compared with the prior art, this application has the following advantages: (1) The phosphate ester functionalized chromatographic stationary phase provided in this application has a high sample loading capacity and can be used for the separation of a full range of rare earth elements. It has a high separation effect on 16 rare earth elements, especially on the two rare earth elements Dy / Y, which solves the problem that existing weak cation exchange chromatographic stationary phases are difficult to separate Dy / Y.

[0048] (2) The phosphate-functionalized chromatographic stationary phase provided in this application can separate and remove radionuclides U and Th associated with rare earth elements, which is of great significance for the separation and purification of rare earth elements.

[0049] (3) The preparation method of the phosphate ester functionalized chromatographic stationary phase provided in this application is simple and conducive to industrial application. Attached Figure Description

[0050] Figure 1 This is the X-ray photoelectron spectrum of the phosphate ester functionalized chromatographic stationary phase provided in Example 1 of this application. Figure 1In the image, 'a' represents the high-resolution XPS spectrum of P 2p. Figure 1 b is the high-resolution XPS spectrum of O 1s; Figure 2 These are the nuclear magnetic resonance spectra of the epoxy-functionalized silica gel and phosphate-functionalized chromatographic stationary phases provided in Example 1 of this application, wherein... Figure 2 In the image, a and b are the carbon spectra of Sil-GPTMS and Sil-PCX, respectively. Figure 2 c and d are the phosphorus spectra of Sil-GPTMS and Sil-PCX, respectively. Figure 2 In the image, e and f are the proton NMR spectra of Sil-GPTMS and Sil-PCX, respectively. Figure 3 These are Fourier transform infrared spectra of the bare silica gel, epoxy-functionalized silica gel, and phosphate-functionalized chromatographic stationary phases provided in Example 1 of this application; Figure 4 These are structural diagrams of the phosphate ester functionalized chromatographic stationary phases provided in Examples 1-3 and 6-7 of this application. Figure 4 Images (a) through (c) are structural diagrams of the phosphate-functionalized chromatographic stationary phases provided in Examples 1 through 3, respectively. Figure 4 (d) to (e) are structural diagrams of the phosphate ester functionalized chromatographic stationary phases provided in Examples 6 and 7, respectively. Figure 5 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 1 of this application; Figure 6 This is a separation chromatogram of 16 rare earth elements by a phosphate ester functionalized chromatographic stationary phase provided in Example 2 of this application; Figure 7 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 3 of this application; Figure 8 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 4 of this application; Figure 9 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 5 of this application; Figure 10 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 6 of this application; Figure 11 This is the separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 7 of this application; Figure 12 This is the separation chromatogram of 16 rare earth elements and U and Th provided in Example 5 of this application for the phosphate ester functionalized chromatographic stationary phase; Figure 13 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 8 of this application; Figure 14 This is a separation chromatogram of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Example 9 of this application; Figure 15 This is a separation chromatogram of 16 rare earth elements by a phosphate ester functionalized chromatographic stationary phase provided in Example 10 of this application; Figure 16 This is a separation chromatogram of 16 rare earth elements by a phosphate ester functionalized chromatographic stationary phase provided in Example 11 of this application; Figure 17 This is a separation chromatogram of 16 rare earth elements by a phosphate ester functionalized chromatographic stationary phase provided in Example 12 of this application; Figure 18 This is a chromatogram of the separation of 16 rare earth elements by the phosphate ester functionalized chromatographic stationary phase provided in Comparative Example 1 of this application. Detailed Implementation

[0051] The technical solution of this application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely to help understand this application and should not be regarded as specific limitations on this application.

[0052] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this application will not exhaustively list the specific point values ​​included in the range.

[0053] Example 1 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase, the preparation method comprising the following steps: (1) Bare silica gel (average particle size 10 μm, pore size 100 Å) was immersed in a hydrochloric acid aqueous solution with an acid-water mass ratio of 1:4 for 24 h for activation treatment, then washed with water until neutral, and dried to obtain activated silica gel; (2) Disperse 5g of the activated silica gel obtained in step (1) in 50mL of anhydrous toluene after the molecular sieve has been pre-dried and place it in a three-necked flask for mechanical stirring and dispersion. Slowly add 5mL of 3-glycidyloxypropyltrimethoxysilane under nitrogen protection and react for 24h under mechanical stirring at 60℃. The ratio of activated silica gel to epoxy silane coupling agent is 1:1g / mL. Then wash with toluene and ethanol in sequence and dry under vacuum at 60℃ to obtain epoxy functionalized silica gel. (3) Disperse 5g of the epoxy-functionalized silica gel obtained in step (2) in 50mL of water, add 15g of disodium hydrogen phosphite, and carry out the ring-opening reaction at 40℃ for 24h with mechanical stirring. The mass ratio of epoxy-functionalized silica gel to disodium hydrogen phosphite is 1:3. Then wash with water and ethanol in sequence, and dry under vacuum at 60℃ to obtain the phosphate ester functionalized chromatographic stationary phase.

[0054] Example 2 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The difference between the preparation method and Example 1 is that 3-glycidyloxypropyltrimethoxysilane is replaced with triethoxy(3-epoxypropyloxypropyl)silane, and the reaction temperature in step (2) is 110°C, while other conditions remain unchanged, to obtain a phosphate ester functionalized chromatographic stationary phase.

[0055] Example 3 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 1 is that 3-glycidyloxypropyltrimethoxysilane is replaced with 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane, while other conditions remain unchanged, to obtain the phosphate ester functionalized chromatographic stationary phase.

[0056] Example 4 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 1 is that the bare silica gel is replaced with silica gel with an average particle size of 5 μm and a pore size of 120 Å, while other conditions remain unchanged, to obtain the phosphate ester functionalized chromatographic stationary phase.

[0057] Example 5 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 1 is that the bare silica gel is replaced with silica gel with an average particle size of 3 μm and a pore size of 110 Å, while other conditions remain unchanged, to obtain the phosphate ester functionalized chromatographic stationary phase.

[0058] Example 6 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 5 is that disodium hydrogen phosphite is replaced with sodium phytate, while other conditions remain unchanged, to obtain the phosphate ester functionalized chromatographic stationary phase.

[0059] Example 7 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 5 is that disodium hydrogen phosphite is replaced with sodium ethylenediaminetetramethylenephosphonate, while other conditions remain unchanged, to obtain the phosphate ester functionalized chromatographic stationary phase.

[0060] Example 8 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 1 is that the amount of 3-glycidyloxypropyltrimethoxysilane used is 7.5 ml, the ratio of activated silica gel to epoxysilane coupling agent is 1:1.5 g / mL, and other conditions remain unchanged, thus obtaining a phosphate ester functionalized chromatographic stationary phase.

[0061] Example 9 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 1 is that the amount of 3-glycidyloxypropyltrimethoxysilane used is 9 ml, and the ratio of activated silica gel to epoxysilane coupling agent is 1:1.8 g / mL. Other conditions remain unchanged, and a phosphate ester functionalized chromatographic stationary phase is obtained.

[0062] Examples 10-11 Examples 10 and 11 provide a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between the preparation method and Example 1 is that the volume of 3-glycidyloxypropyltrimethoxysilane is 4 mL and 10 mL, respectively, that is, the ratio of activated silica gel to epoxysilane coupling agent is 1:0.8 g / mL and 1:2.0 g / mL, respectively.

[0063] Example 12 This embodiment provides a method for preparing a phosphate ester functionalized chromatographic stationary phase. The only difference between this method and Example 1 is that the ring-opening reaction time is 48 hours, while other conditions remain unchanged.

[0064] Comparative Example 1 This embodiment provides a method for preparing a stationary phase. The difference between this method and Example 1 is that steps (2) and (3) are omitted, and the resulting stationary phase is activated silica gel.

[0065] Application Example 1 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase, which was prepared in Example 1 and packed into a 4.6×250mm stainless steel column using a column packer to obtain a chromatographic column. The column was then used in conjunction with a Shimadzu HPLC-LC40 high-performance liquid chromatograph for the separation of 16 rare earth elements.

[0066] Sample solution preparation: Take 1 mL each of Sc standard solution with a concentration of 1 g / L and mixed standard solution of 15 rare earth elements (each rare earth element has a concentration of 1 g / L), and dilute them with deionized water to 10 mL. At this time, the sample concentration is 100 mg / L.

[0067] The chromatographic conditions were as follows: the mobile phase consisted of phase A and phase B. Phase A was deionized water, and phase B was an aqueous solution of α-hydroxyisobutyric acid with a concentration of 400 mmol at pH 3.6. The total flow rate of the mobile phase was 1.0 mL / min. A 0.15 mmol azoarsine solution was used as the post-column derivatization solution at a flow rate of 0.6 mL / min. The column temperature was 30 °C. The detector was a UV-Vis detector with a detection wavelength of 658 nm. Gradient elution program 1 was used, as detailed in Table 1.

[0068] Table 1 Application Example 2 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase, which differs from Application Example 1 only in that the phosphate ester functionalized chromatographic stationary phase is prepared in Example 2.

[0069] Application Example 3 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase, which differs from Application Example 1 only in that the phosphate ester functionalized chromatographic stationary phase is prepared in Example 3.

[0070] Application Example 4 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase, which differs from Application Example 1 only in that the phosphate ester functionalized chromatographic stationary phase is prepared in Example 4.

[0071] Application Example 5 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase, which differs from Application Example 1 only in that the phosphate ester functionalized chromatographic stationary phase is prepared in Example 5.

[0072] Application Example 6 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase, which differs from Application Example 1 only in that the phosphate ester functionalized chromatographic stationary phase was prepared in Example 6 and uses gradient elution program 2, as shown in Table 2.

[0073] Table 2 Application Example 7 This application example provides an application of a phosphate ester functionalized chromatographic stationary phase. The only difference from Application Example 1 is that the phosphate ester functionalized chromatographic stationary phase was prepared in Example 7, and the elution gradient uses gradient elution program 3, as shown in Table 3.

[0074] Table 3 Application Example 8 This application example provides an application of a phosphate ester-functionalized chromatographic stationary phase, differing from Application Example 5 only in that the phosphate ester-functionalized chromatographic stationary phase is prepared in Example 5, and in mobile phase A... α The pH of the hydroxyisobutyric acid aqueous solution is 3.80. The sample solution is prepared as follows: take 1 mL of standard solutions of U, Th, and Sc elements with a concentration of 1 g / L and 1 mL of mixed standard solutions of 15 rare earth elements (each rare earth element has a concentration of 1 g / L). Dilute with deionized water to 10 mL. At this time, the concentration of the 16 rare earth elements and U and Th elements is 100 mg / L. Other conditions remain unchanged.

[0075] Application Examples 9-13 Application Examples 9-13 provide an application of phosphate ester functionalized chromatographic stationary phases, which differ from Application Example 1 only in that the phosphate ester functionalized chromatographic stationary phases are prepared in Examples 8-12.

[0076] Application Comparative Example 1 This application example provides an application of a stationary phase, which differs from Application Example 1 only in that the stationary phase is prepared using Comparative Example 1.

[0077] Characterization of phosphate ester functionalized chromatographic stationary phase: X-ray photoelectron spectroscopy analysis Taking Example 1 as an example, the obtained phosphate ester functionalized chromatographic stationary phase was subjected to X-ray photoelectron spectroscopy (XPS) analysis, and its chemical composition was analyzed. Its high-resolution XPS spectra for P 2p and O 1s were obtained. Figure 1 The results show characteristic peaks at binding energies of 532.57 eV, 530.72 eV, and 529.87 eV, which are attributed to Si-O-Si bonds, PO bonds, and P=O bonds, respectively. These results confirm that phosphate ester groups have been successfully grafted onto the surface of the silica stationary phase.

[0078] [Nuclear Magnetic Resonance Imaging Test] Taking Example 1 as an example, NMR spectroscopy (CMR), NMR spectroscopy (PMR), and NMR spectroscopy were performed on epoxy-functionalized silica gel (Sil-GPTMS) and phosphate-functionalized chromatographic stationary phase (Sil-PCX). Figure 2 As shown. Figure 2 As can be seen in a and b, there is a significant change in the C5 and C6 chemical shifts of the epoxide group, proving that the epoxide group has undergone ring opening. Simultaneously, through... Figure 2 As can be seen from d, there is a P signal peak, indicating that the phosphorus-containing functionalized modifier was successfully modified onto the surface of the chromatographic stationary phase.

[0079] Infrared Spectroscopy Analysis Taking Example 1 as an example, bare silica gel (denoted as Sil), epoxy-functionalized silica gel (denoted as Sil-GPTMS), and phosphate-functionalized chromatographic stationary phase (denoted as Sil-PCX) were subjected to infrared spectroscopy analysis, such as... Figure 3 As shown. From Figure 3 It can be seen that, compared with bare silica gel and phosphate ester functionalized chromatographic stationary phases, epoxy-functionalized silica gel has a higher performance at 905 cm⁻¹. -1 A distinct absorption peak appeared at [location], corresponding to the symmetric stretching vibration of CO in the epoxy group. Furthermore, the symmetric stretching vibration of CO in the epoxy group disappeared in the phosphate-functionalized chromatographic stationary phase, indicating that the epoxy group of the epoxy-functionalized silica gel was attacked and ring-opened by disodium hydrogen phosphite, thus successfully synthesizing the phosphate-functionalized chromatographic stationary phase.

[0080] In summary, the structural formulas of the phosphate ester functionalized chromatographic stationary phases provided in Examples 1-3 and 6-7 above are as follows: Figure 4 As shown.

[0081] Chromatographic separation data: The separation chromatograms of the phosphate ester functionalized chromatographic stationary phases provided in Examples 1-12 for the 16 rare earth elements described in the above application examples 1-13 are as follows: Figures 5-17 As shown. Comparative Example 1 uses the stationary phase provided in Comparative Example 1, and the separation chromatogram is as follows. Figure 18 As shown.

[0082] Comparing Example 1 with Examples 2-3, from Figure 5 , Figure 6 and Figure 7 It can be seen that, compared with epoxy silane coupling agents such as 3-glycidyloxypropyltrimethoxysilane, triethoxy(3-epoxypropyloxypropyl)silane, and triethoxy(3-epoxypropyloxypropyl)silane, the type of coupling agent has less impact on the separation effect of rare earth elements, and all of them can achieve the separation of rare earth elements. Among them, 3-glycidyloxypropyltrimethoxysilane has the best effect.

[0083] Comparing Example 1 with Examples 4-5, from Figure 5 , Figure 8 and Figure 9 It can be seen that when the average particle size is within the range of this application, as the particle size decreases, the overall retention time of rare earth elements increases, and the resolution between rare earth elements is improved.

[0084] Comparing Example 5 with Examples 6-7, from Figure 9 , Figure 10 and Figure 11 It can be seen that, compared with sodium hydrogen phosphite, sodium phytate, and sodium ethylenediaminetetramethylene phosphate, the inorganic phosphate sodium hydrogen phosphite is more effective.

[0085] The chromatograms of the separation of 16 rare earth elements and radionuclides such as U and Th from the phosphate ester functionalized stationary phase prepared in Example 5 above are shown in the figure. Figure 12 As shown, the phosphate-functionalized chromatographic stationary phase provided in this application can separate rare earth elements from associated radionuclides U and Th.

[0086] Comparing Example 1 with Examples 8-11, from Figure 5 , Figure 13 , Figure 14 , Figure 15 and Figure 16 It can be seen that this application can achieve better separation effect for 16 rare earth elements by controlling the ratio of activated silica gel to epoxy silane coupling agent. In Examples 10-11, the ratio was too large or too small, resulting in poor separation effect.

[0087] Comparing Example 1 and Example 12, from Figure 5 and Figure 17 It can be seen that this application stably separates 16 rare earth elements by controlling the time of the ring-opening reaction, while the time in Example 13 was too long, resulting in poor separation.

[0088] Comparing Example 1 with Comparative Example 1, from Figure 5 and Figure 18 As can be seen, by sequentially modifying the bare silica gel with epoxy and phosphate functionalization, this application can effectively separate 16 rare earth elements compared with unmodified activated silica gel, while unmodified activated silica gel has no effect on retaining rare earth elements.

[0089] In summary, the phosphate-functionalized chromatographic stationary phase provided in this application has a high sample loading capacity, exhibits excellent separation selectivity for the separation and analysis of all 16 rare earth elements and the removal of associated radionuclides such as U and Th from rare earth elements, and the preparation method is simple to operate and can be applied industrially.

[0090] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A phosphate ester functionalized chromatographic stationary phase, characterized in that, The structural formula of the phosphate ester functionalized chromatographic stationary phase includes: or ; Wherein, Sil represents silica gel, R1 is selected from C1 to C10 straight-chain or branched alkylene groups or C1 to C10 straight-chain or branched alkylene groups containing ether bonds, and R2 is selected from phosphate ester groups or organic structures containing at least one phosphate group and / or at least one phosphate ester group linked by phosphate esters.

2. A method for preparing a phosphate ester functionalized chromatographic stationary phase as described in claim 1, characterized in that, The preparation method includes the following steps: (1) The bare silica gel is immersed in an acidic aqueous solution for activation treatment, and then washed and dried to obtain activated silica gel; (2) The activated silica gel obtained in step (1) is dispersed in a first solvent, an epoxy silane coupling agent is added to react, and then washed and dried to obtain epoxy functionalized silica gel. (3) The epoxy-functionalized silica gel obtained in step (2) is dispersed in a second solvent, and a phosphorus-containing functionalizing modifier is added to carry out a ring-opening reaction. After washing and drying, a phosphate-functionalized chromatographic stationary phase is obtained.

3. The preparation method according to claim 2, characterized in that, The pore size of the bare silicone in step (1) is 80~200Å; And / or, the average particle size of the bare silica gel is 1~10μm.

4. The preparation method according to claim 2 or 3, characterized in that, The acid used in the acidic aqueous solution in step (1) includes any one or a combination of at least two of hydrochloric acid, nitric acid, or sulfuric acid; And / or, the mass ratio of acid to water in the acid-water solution is 1:(1.0~10.0); And / or, the activation treatment time is 12~24h; And / or, the cleaning in step (1) includes washing the silica gel with water until it is neutral.

5. The preparation method according to any one of claims 2 to 4, characterized in that, Step (2) The first solvent includes any one or a combination of at least two of toluene, xylene or n-heptane; And / or, the solid-liquid ratio of the activated silica gel to the first solvent is 1 g:(10~50) mL; And / or, the ratio of the activated silica gel to the epoxy silane coupling agent is 1 g: (1.0~1.8) mL; And / or, the epoxy silane coupling agent comprises any one or a combination of at least two of the following: triethoxy(3-epoxypropyloxypropyl)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3-epoxypropoxypropyl)dimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethoxysilane, or 5,6-epoxyhexyltriethoxysilane. And / or, the temperature of the reaction is 50~110℃; And / or, the reaction time is 12~96h; And / or, the reaction is carried out under a protective atmosphere, which includes nitrogen and / or an inert gas, including argon; And / or, the drying temperature in step (2) is 60~100℃.

6. The preparation method according to any one of claims 2 to 5, characterized in that, Step (3) The second solvent includes a polar solvent; And / or, the second solvent includes any one or a combination of at least two of water, methanol, ethanol or acetonitrile; And / or, the ratio of the epoxy-functionalized silica gel to the second solvent is 1 g: (10~50) mL; And / or, the mass ratio of the epoxy-functionalized silicone to the phosphorus-containing functionalized modifier is 1:(1~30); And / or, the ring-opening reaction is carried out at a temperature of 40~120°C; And / or, the ring-opening reaction takes 12-24 hours; And / or, the phosphorus-containing functionalized modifier includes any one or a combination of at least two of the following: disodium hydrogen phosphite, hypophosphite, sodium phytate, sodium alendronate, tetrasodium aminotrimethylene phosphonate, sodium hydroxyethylidene diphosphonate, sodium ethylenediaminetetramethylene phosphonate, or pentasodium diethylenetriaminepentamethylenephosphonate. And / or, the drying temperature in step (3) is 60~100℃.

7. An application of the phosphate ester functionalized chromatographic stationary phase as described in claim 1, characterized in that, The phosphate-functionalized chromatographic stationary phase is used for chromatographic separation.

8. The application according to claim 7, characterized in that, The phosphate-functionalized chromatographic stationary phase is used for the separation and analysis of rare earth elements and / or the separation and removal of associated radionuclides in rare earth elements. The rare earth elements include any one or a combination of at least two of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, or Y. The radionuclides include U and / or Th.

9. The application according to claim 7 or 8, characterized in that, The chromatographic separation conditions include: the mobile phase consists of phase A and phase B, gradient elution is used, phase A is water, phase B is an aqueous solution of α-hydroxyisobutyric acid with a pH of 2.5 to 4.5 and a concentration of 100 to 800 mmol, azoarsine solution is used as the post-column derivatization solution, and the detector is a UV-Vis detector.

10. The application according to claim 9, characterized in that, The column temperature for the chromatographic separation is 20~50℃; And / or, the detection wavelength of the detector is 645~668nm; And / or, the total flow rate of the mobile phase is 0.6~1.5 mL / min; And / or, the concentration of the azoarsine solution is (1.0~2.0)×10⁻⁶. -4 mol / L; And / or, the flow rate of the azoarsine solution is 0.2~0.8 mL / min.

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