A method for separating and extracting lanthanum / actinides using a class of asymmetric extractants, the asymmetric extractants and their preparation

Abstract

This invention discloses a novel method for separating and extracting lanthanide / actinide elements using a novel asymmetric extractant, the asymmetric extractant itself, and its preparation method. The method includes the following steps: using an asymmetric triazine amide o-phenanthroline as the extractant, mixing it with a diluent to form an organic phase, and extracting and separating trivalent actinide ions and trivalent lanthanide ions from an acidic aqueous solution. The asymmetric triazine amide o-phenanthroline has the following structure, which is used by the extractant to extract and separate trivalent actinide ions and trivalent lanthanide ions. This extractant simultaneously contains an o-phenanthroline skeleton, a 1,2,4-triazine ring, and an amide side chain. Both the o-phenanthroline skeleton and the triazine side chain contain N-coordinating atoms with high selectivity for An(III) ions. The O-coordinating atoms in the amide side chain can improve the extraction capacity, resulting in a high extraction rate for actinide ions but a weaker extraction capacity for lanthanide ions. It exhibits excellent actinide / lanthanide element separation capabilities and has good application prospects in the field of spent fuel reprocessing.

Description

Technical Field

[0001] This invention relates to the field of spent fuel reprocessing technology, specifically to a method for separating and extracting lanthanum / actinide elements using a class of asymmetric extractants, the asymmetric extractants themselves, and their preparation methods. Background Technology

[0002] Nuclear energy, as a clean and efficient energy source, has significant advantages in reducing coal use and greenhouse gas emissions. However, the sustainable development of nuclear energy faces the challenge of safely disposing of spent fuel. While uranium (U) and plutonium (Pu) contained in spent fuel can be recovered using the PUREX process, highly radioactive and toxic minor actinide (MA) elements such as americium (Am) and curium (Cm) remain in high-level radioactive waste (HLLW). Therefore, researchers have proposed a separation-transmutation (P&T) strategy to address this issue, aiming to convert long-lived minor actinides into short-lived or stable elements.

[0003] Because lanthanides, as fission products, have large neutron resonance cross sections, they need to be separated before transmutation. Trivalent actinides (An(III)) and trivalent lanthanides (Ln(III)) have similar chemical properties, making their complete separation a challenging task. To recover valuable actinides as target products, lanthanides are purified into fission products (FPs). In practical applications, solvent extraction is used to separate trivalent actinides and lanthanides. Solvent extraction offers advantages such as high separation efficiency, low production cost, simple operation, and ease of large-scale industrial application.

[0004] Actinides have a higher degree of 5f electron dispersion, making them more likely to bind with extractants containing soft donor atoms such as S and N. Therefore, o-phenanthroline triazine extractants (BTPhen) with pure N coordination in the o-phenanthroline skeleton have shown a certain degree of selective separation ability between An(III) and Ln(III). However, its high extraction rate for Ln(III), easy protonation, slow extraction rate, and difficulty in back-extraction still limit its further application (J. Am. Chem. Soc., 133 (2011) 13093-13102.).

[0005] Subsequent researchers developed a series of N,O mixed-coordinate o-phenanthroline amide extractants (DAPhen) with o-phenanthroline skeletons and amide side chains, and confirmed that they have a certain selective separation ability of Am(III) / Eu(III) (Inorg. Chem., 53(2014) 1712-1720.). However, subsequent experiments showed that these extractants have a strong extraction ability for light lanthanides such as La(III) and Ce(III), thus reducing the separation factor between them and Am(III) (Inorg. Chem., 60(2021) 9745-9756.). Existing research still lacks methods and extractants for efficient extraction and separation of actinides and lanthanides. Summary of the Invention

[0006] This invention addresses the difficulty in extracting and separating trivalent actinides and trivalent lanthanides by providing an asymmetric extractant. This extractant exhibits strong selectivity for Am(III) but weak extraction ability for impurity elements Ln(III). It can efficiently separate and extract trivalent actinides and lanthanides under strong acid conditions, and has promising application prospects in the field of high-level radioactive waste treatment.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for separating and extracting lanthanide / actinide elements using a class of asymmetric extractants includes the following steps: using asymmetric triazine amide o-phenanthroline as the extractant, mixing it with a diluent to form an organic phase, and extracting and separating trivalent actinide ions and trivalent lanthanide ions from an acidic aqueous solution;

[0009] The structure of the asymmetric triazine amide o-phenanthroline is as follows:

[0010]

[0011] R1 and R2 are independently selected from straight-chain or branched alkyl substituents of C2-C10 or aromatic substituents of C6-C12; R3 and R4 are straight-chain, branched or cyclic alkyl substituents of C2-C10 or aromatic substituents of C6-C12.

[0012] This invention uses asymmetric triazine amide o-phenanthroline as an extractant to extract and separate trivalent actinide and trivalent lanthanide ions. This extractant simultaneously contains an o-phenanthroline skeleton, a 1,2,4-triazine ring, and an amide side chain. Unlike previous methods using side-linking grafts in other extractants with an o-phenanthroline skeleton, this series of extractants employs a de novo o-phenanthroline skeleton construction method, improving the generality of the synthesis and enabling the effective synthesis of asymmetric extractants with different side chains. The pre-organized o-phenanthroline skeleton provides coordination cavities for the target metal ions, thus avoiding the energy barriers required for significant configurational inversion and effectively increasing the extraction rate. Both the o-phenanthroline skeleton and the triazine side chain contain N-coordinating atoms with high selectivity for An(III) ions, while the O-coordinating atoms in the amide side chain enhance the extraction capability.

[0013] This series of extractants avoids the drawbacks of BTPhen-type extractants, such as slow extraction kinetics and difficulty in back-extraction, and DAPhen-type extractants, such as their poor co-extraction of light Ln(III). The target extractant exhibits high extraction efficiency for actinide ions but weaker extraction ability for lanthanide ions, demonstrating excellent actinide / lanthanum element separation capabilities and promising application prospects in the field of spent fuel reprocessing.

[0014] In some embodiments, R1 and R2 are selected from ethyl, butyl, phenyl, or tolyl; and R3 and R4 are selected from phenyl, tolyl, or tetramethylcyclohexyl. Alkyl groups such as ethyl, butyl, and tetramethylcyclohexyl can improve the solubility of the extractant in organic solvents, while aromatic groups such as phenyl and tolyl are electron-donating groups that can increase the electron cloud density on the coordinating atoms, thereby enhancing the extractant's ability to extract metal ions.

[0015] In some embodiments, R1 and R2 are ethyl or tolyl, and R3 and R4 are selected from phenyl or tetramethylcyclohexyl.

[0016] In some embodiments, the asymmetric triazine amide o-phenanthroline has any one of the following structures:

[0017]

[0018] In some embodiments, the diluent includes one or more of 3-nitrotrifluorotoluene, kerosene, n-dodecane, and n-octanol.

[0019] In some embodiments, the trivalent actinide ions include one or more of Ac(III), Am(III), Cm(III), Bk(III), Cf(III), Es(III), Fm(III), Md(III), No(III), and Lr(III);

[0020] In some embodiments, the trivalent actinide ion is241 Am(III) and / or 243 A mixture of Am(III);

[0021] The trivalent lanthanide ions include one or more of La(III), Ce(III), Pr(III), Nd(III), Pm(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Lu(III); in some embodiments, the trivalent lanthanide ions are radioactive. 152,154 Eu is a mixture of one or more non-radioactive lanthanides.

[0022] The concentration of trivalent actinide ions in the acidic aqueous solution is 10. -9 Above mol / L.

[0023] The molar concentration of the extractant in the organic phase is 0.001-0.1 mol / L; such as 0.002 mol / L, 0.004 mol / L, 0.005 mol / L, 0.006 mol / L, 0.008 mol / L, 0.01 mol / L, 0.012 mol / L, 0.015 mol / L, 0.016 mol / L, 0.018 mol / L, 0.02 mol / L, 0.025 mol / L, 0. 0.03 mol / L, 0.035 mol / L, 0.04 mol / L, 0.045 mol / L, 0.05 mol / L, 0.055 mol / L, 0.06 mol / L, 0.065 mol / L, 0.07 mol / L, 0.075 mol / L, 0.08 mol / L, 0.085 mol / L, 0.09 mol / L, 0.09 mol / L, 0.1 mol / L, or any value between them.

[0024] The volume ratio of the organic phase to the acidic aqueous solution is 0.1-10:1; in some embodiments, the volume ratio of the organic phase to the acidic aqueous solution is 0.5-5:1, and more preferably 0.5-2:1.

[0025] The acidic aqueous solution is an aqueous solution of nitric acid, hydrochloric acid, or sulfuric acid; preferably, an aqueous solution of nitric acid; the molar concentration of the acid in the acidic aqueous solution is 0.1-4 mol / L. In this invention, the extractant exhibits excellent extraction and separation effects across the entire acidity range of 0.1-4 mol / L, such as 0.1 mol / L, 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, 1.6 mol / L, 1.8 mol / L, 2.0 mol / L, 2.2 mol / L, 2.5 mol / L, 2.8 mol / L, 3.0 mol / L, 3.2 mol / L, 3.5 mol / L, 3.8 mol / L, 4.0 mol / L, or any value between them. The separation effect is particularly excellent at concentrations of 0.5-4 mol / L.

[0026] The extraction temperature is 0–50℃, and the mixture is shaken and mixed for 1–120 min to reach extraction equilibrium. Temperatures such as 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, or any temperature in between, and the mixing time is shaken for 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, or any time in between, are used to reach extraction equilibrium. The preferred mixing time is 1–60 min at a temperature of 10–35℃.

[0027] This invention also provides a class of asymmetric extractants, wherein the asymmetric extractant is an asymmetric triazine amide o-phenanthroline, having the following structure:

[0028]

[0029] R1 and R2 are independently selected from straight-chain or branched alkyl substituents of C2-C10 or aromatic substituents of C6-C12; R3 and R4 are straight-chain, branched or cyclic alkyl substituents of C2-C10 or aromatic substituents of C6-C12.

[0030] In some embodiments, R1 and R2 are selected from ethyl, phenyl, or tolyl; and R3 and R4 are selected from phenyl, tolyl, or tetramethylcyclohexyl.

[0031] In some embodiments, R1 and R2 are ethyl or tolyl, and R3 and R4 are selected from phenyl or tetramethylcyclohexyl.

[0032] In some embodiments, the asymmetric triazine amide o-phenanthroline has any one of the following structures:

[0033]

[0034] The present invention also provides a method for preparing the aforementioned asymmetric extractant, comprising the steps of: condensing compound 1 (8-amino-7-formylquinoline-2-nitrile) and compound 2 to obtain intermediate 3, and then adding hydrazine hydrate to react and obtain compound 4; and subjecting compound 4 to a side-chain cyclization reaction with compound 5 to obtain the aforementioned asymmetric extractant.

[0035]

[0036] The reaction can be represented as follows:

[0037]

[0038] The conditions for the condensation reaction of compound 1 and compound 2 are as follows: compound 1 and compound 2 are refluxed at 0℃-100℃ in a molar ratio of 1:0.5-1:3 for 1-12 hours.

[0039] In some embodiments, the condensation reaction uses one or more solvents including methanol, ethanol, acetonitrile, chloroform, or dichloromethane;

[0040] In some embodiments, the condensation reaction also includes a base catalyst, such as one or more of potassium hydroxide, sodium hydroxide, sodium ethoxide, or triethylamine.

[0041] In some embodiments, the step of reacting with hydrazine hydrate to obtain compound 4 specifically includes: drying the product of intermediate 3 by rotary evaporation, dissolving it in one or more solvents such as tetrahydrofuran, ethanol or methanol, adding 85% hydrazine hydrate at a molar ratio of 1:5 to 1:20 with intermediate 3, refluxing for 1 to 12 hours at a reaction temperature of 0°C to 100°C, and then separating and purifying by column chromatography to obtain product 4.

[0042] In some embodiments, the side-chain cyclic closure reaction conditions are as follows: the molar ratio of compound 4 to compound 5 is 1:1.2-1:3, the reaction is carried out under acid-binding agent conditions, refluxed in solvent at 0℃-100℃ for 1-12 hours, the organic solvent is evaporated, and the final product is obtained by column chromatography.

[0043] In some embodiments, the solvent in the side-chain cyclic closure reaction includes one or more of tetrahydrofuran, methanol, DMF, and DMSO; the acid-binding agent includes one or more of triethylamine and ethylenediamine.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The asymmetric triazine amide o-phenanthroline extractant of this invention has the advantages of novel structure, high solubility, and strong chemical stability. It can efficiently extract and separate trivalent actinides and lanthanides from a wide range of nitric acid solutions, with relatively weak overall extraction ability for trivalent lanthanides but strong separation ability. It has strong novelty and good application prospects in the field of nuclear fuel reprocessing. Currently, no similar compounds have been reported in the extraction and separation of trivalent actinides and lanthanides.

[0046] The asymmetric triazine amide o-phenanthroline extractant of this invention adopts a de novo o-phenanthroline skeleton construction synthesis method, which improves the universality of the synthesis and can effectively synthesize asymmetric extractants with different side chains. Attached Figure Description

[0047] Figure 1 The 8-amino-7-formylquinoline-2-nitrile raw material prepared in Example 1 1 H NMR data graph.

[0048] Figure 2 The 8-amino-7-formylquinoline-2-nitrile raw material prepared in Example 1 13 C NMR data graph.

[0049] Figure 3 The N-ethyl-2-oxo-N-(p-tolyl)propionamide raw material prepared in Example 1 1 HNMR data graph.

[0050] Figure 4 The CyMe4-Et-Tol-ATPhen extractant prepared in Example 2 1 H NMR data graph.

[0051] Figure 5 ESI-MS data of the CyMe4-Et-Tol-ATPhen extractant prepared in Example 2.

[0052] Figure 6 The Ph2-Et-Tol-ATPhen extractant prepared in Example 3 1 H NMR data graph.

[0053] Figure 7 ESI-MS data of the Ph2-Et-Tol-ATPhen extractant prepared in Example 3.

[0054] Figure 8 The effect of nitric acid concentration on the extraction of Am(III) and Eu(III) by CyMe4-Et-Tol-ATPhen.

[0055] Figure 9The effect of nitric acid concentration on the extraction of Am(III) and Eu(III) by Ph2-Et-Tol-ATPhen.

[0056] Figure 10 The effect of extractant concentration on the extraction of Am(III) and Eu(III) by CyMe4-Et-Tol-ATPhen.

[0057] Figure 11 The effect of extractant concentration on the extraction of Am(III) and Eu(III) by Ph2-Et-Tol-ATPhen.

[0058] Figure 12 The effect of nitric acid concentration on the extraction of Ln(III) by CyMe4-Et-Tol-ATPhen.

[0059] Figure 13 The effect of nitric acid concentration on the extraction of Ln(III) by Ph2-Et-Tol-ATPhen. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0061] Compounds 1 and 2 were synthesized in-house, while other chemical raw materials were purchased commercially.

[0062] Example 1

[0063] The reaction formula for the synthesis of compound 1 (8-amino-7-formylquinoline-2-nitrile) is shown below:

[0064]

[0065] First, 7-methylquinoline (5 g, 35 mmol) was dissolved in dichloromethane (DCM), and m-chloroperoxybenzoic acid (6.6 g, 38.5 mmol) was added. The reaction was carried out at room temperature for 7–12 hours. The reaction was quenched with sodium bicarbonate solution, extracted with dichloromethane, and dried over Na₂SO₄ to obtain 7-methylquinoline oxide, which was used directly in the next reaction. Next, 7-methylquinoline oxide (5 g, 31.4 mmol) was dissolved in anhydrous dichloromethane, and benzoyl chloride (6.6 g, 47.1 mmol) and trimethylcyanosilane (4.6 g, 47.1 mmol) were slowly added. The reaction was carried out at room temperature for 7–12 hours. The reaction was quenched with sodium bicarbonate solution, extracted with dichloromethane, dried over Na₂SO₄, and separated by column chromatography to obtain 2-cyano-7-methylquinoline.

[0066] 2-Cyano-7-methylquinoline (5 g, 29.7 mmol) was dissolved in sulfuric acid solution (15 mL), and nitric acid (6.5 mL) was slowly added in an ice bath. The reaction was allowed to proceed for 1 hour. The reaction solution was then quenched in ice, extracted with dichloromethane, dried over Na₂SO₄, and separated by column chromatography to obtain 2-cyano-7-methyl-8-nitroquinoline. 2-Cyano-7-methyl-8-nitroquinoline (5 g, 23.4 mmol) was dissolved in DMF (25 mL), and N,N-dimethylformamide dimethyl acetal (4.2 g, 35.1 mmol) was added. The reaction was allowed to proceed for 7–12 hours. After the reaction was stopped, the reaction solution was poured into water, and a solid precipitated. Filtration yielded 2-cyano-7-(N,N-dimethylamine-vinyl)-8-nitro-quinoline solid, which was then directly reacted in the next step.

[0067] 2-Cyano-7-(N,N-dimethylamine-vinyl)-8-nitro-quinoline (2.7 g, 10.0 mmol) was dissolved in a solution of tetrahydrofuran and water (v:v = 1:1, 60 mL), and sodium periodate (3.2 g, 15.0 mmol) was added. The reaction was allowed to proceed for 6–8 hours. The reaction was quenched with water, extracted with ethyl acetate, dried over Na₂SO₄, and separated by column chromatography to obtain 2-cyano-7-aldehyde-8-nitro-quinoline. 2-Cyano-7-aldehyde-8-nitro-quinoline (2.3 g, 10.0 mmol) was added to a solution of ethanol and acetic acid (v:v = 4:1, 40 mL), and iron powder (2.8 g, 50.0 mmol) was added. The mixture was heated to 50–80°C and reacted for 4–8 hours. The mixture was then filtered while hot, extracted with ethyl acetate, dried over Na₂SO₄, and separated by column chromatography to obtain 8-amino-7-formylquinoline-2-nitrile (compound 1).

[0068] The 1H NMR spectrum of the prepared 8-amino-7-formylquinoline-2-nitrile (compound 1) is as follows: Figure 1 As shown, the carbon NMR spectrum is as follows: Figure 2 As shown: 1H NMR (500MHz, CDCl3) δ10.01 (s, 1H), 8.15 (d, J = 8.5Hz, 1H), 7.78 (d, J = 8.5Hz, 1H), 7.68 (d, J = 8.5Hz, 1H), 7.05 (d, J = 8.5Hz, 1H).

[0069] 13 C NMR (125MHz, CDCl3) δ192.88,148.66,138.88,137.10,133.71,132.13,130.37,126.50,117.32,114.02,112.67.

[0070] The synthetic reaction formula for N-ethyl-2-oxo-N-(p-tolyl)propionamide (compound 2) is shown below:

[0071]

[0072] Pyruvic acid (1.0 g, 11.4 mmol) was added to DCM (20 mL), followed by oxaloyl chloride (1.4 g, 11.4 mmol) and 2 drops of DMF solution. The mixture was stirred until no gas was produced. Then, p-tolylethylamine (1.4 g, 11.4 mmol) was dissolved in dichloromethane (10 mL) and slowly added to the reaction mixture. The reaction was allowed to proceed overnight at room temperature. The reaction was quenched with water, extracted with ethyl acetate, dried over Na2SO4, and separated by column chromatography to obtain N-ethyl-2-oxo-N-(p-tolyl)propionamide (compound 2). The 1H NMR spectrum of the prepared N-ethyl-2-oxo-N-(p-tolyl)propionamide raw material is shown below. Figure 3 As shown:

[0073] 1 H NMR (500MHz, CDCl3) δ7.17 (d, J = 8.0 Hz, 2H), 7.04 (d, J = 8.0 Hz, 2H), 3.79 (q, J = 7.0 Hz, 2H), 2.35 (s, 3H), 2.17 (s, 3H), 1.16 (t, J = 7.0 Hz, 3H).

[0074] Example 2

[0075] The synthetic method of 9-([6,6,9,9]-tetramethylcyclohexyl-[3,10]-[1,2,4]triazine-3-yl)-2-N-ethyl(p-tolyl)formamide-1,10-o-phenanthroline (CyMe4-Et-Tol-ATPhen) extractant is represented by the following reaction formula:

[0076]

[0077] The preparation process includes the following steps:

[0078] The 8-amino-7-formylquinoline-2-onitrile (compound 1) (0.4 g, 2 mmol) prepared in Example 1 and N-ethyl-2-oxo-N-(p-tolyl)propionamide (compound 2) (0.4 g, 2.0 mmol) were added to 30 mL of ethanol solution, followed by the dropwise addition of 0.2 mL of saturated KOH ethanol solution. The mixture was heated to 50 °C and reacted for 5 hours. The reaction was then stopped, allowed to stand at room temperature, and used directly in the next reaction without any post-treatment.

[0079] The solution obtained in the previous step was directly added to 8 mL of 85% hydrazine hydrate solution, and the reaction was carried out overnight at room temperature. After the reaction was completed, the solution was diluted with aqueous solution and extracted with ethyl acetate (30 mL × 3 times). The organic phases were combined, dried over anhydrous sodium sulfate, and separated by column chromatography (DCM:MeOH = 5:1) to give a yellow solid 4.

[0080] Compound 4 (0.4 g, 1.0 mmol) and 3,3,6,6-tetramethylcyclohexanedione (compound 5) were placed in 20 mL of a mixed solution of tetrahydrofuran and triethylamine (v / v = 10:1), and the mixture was heated to reflux for 8 hours. Heating was then stopped, and the mixture was cooled to room temperature. The mixture was then diluted with water, extracted three times with ethyl acetate (20 mL), dried over anhydrous sodium sulfate, and separated by column chromatography (DCM:MeOH = 10:1) to give a pale yellow solid, which was the product.

[0081] The 1H NMR spectrum of the prepared CyMe4-Et-Tol-ATPhen extractant is as follows: Figure 4 As shown, 1 H NMR (500MHz, Methanol-d4) δ8.82(d,J=8.5Hz,1H),8.71(d,J=8.0Hz,1H),8.23(d,J=7.5Hz,1H),8.10(d,J=8.5Hz,1H),8.00(d,J=8.5Hz,1H),7.39 (d,J=7.5Hz,1H),7.14(d,J=8.0Hz,2H),6.94(d,J=7.0Hz,2H),3.81(q,J =7.0Hz,2H),2.19(s,3H),1.79(d,J=25Hz,4H),1.40(s,6H),0.90(s,9H).

[0082] Mass spectrometry, such as Figure 5 As shown, ESI-HRMS:[C 33 H 34 N6O+H] + Theoretical value: m / z = 531.2867; Actual value: 531.2862; [C] 33 H34 N6O+Na] + Theoretical value: m / z = 553.2686; Actual value: 553.2681.

[0083] Organic elemental analysis: C 31 H 34 Theoretical N6O values: C = 73.49%, H = 6.76%, N = 16.59%; Actual values: C = 74.64%, H = 6.15%, N = 15.82%.

[0084] Example 3

[0085] The synthetic method of 9-([5,6]-diphenyl-[1,2,4]triazine-3-yl)-2-N-ethyl(p-tolyl)formamide-1,10-phenanthroline (Ph2-Et-Tol-ATPhen) extractant is shown in the following reaction formula:

[0086]

[0087] The preparation process includes the following steps:

[0088] 8-Amino-7-formylquinoline-2-onitrile (compound 1) (0.4 g, 2 mmol) and N-ethyl-2-oxo-N-(p-tolyl)propionamide (compound 2) (0.4 g, 2.0 mmol) were added to 30 mL of ethanol solution, followed by the dropwise addition of 0.2 mL of saturated KOH ethanol solution. The mixture was heated to 50 °C and reacted for 5 hours. The reaction was then stopped, allowed to stand at room temperature, and used directly in the next reaction without any post-treatment.

[0089] The solution obtained in the previous step was directly added to 8 mL of 85% hydrazine hydrate solution, and the reaction was carried out overnight at room temperature. After the reaction was completed, the solution was diluted with aqueous solution and extracted with ethyl acetate (30 mL × 3 times). The organic phases were combined, dried over anhydrous sodium sulfate, and separated by column chromatography (DCM:MeOH = 5:1) to give a yellow solid 4.

[0090] Compound 4 (0.4 g, 1.0 mmol) and benzoyl (compound 5') were placed in 20 mL of a mixed solution of tetrahydrofuran and triethylamine (v / v = 10:1), and the mixture was heated to reflux for 8 hours. Heating was then stopped, and the mixture was cooled to room temperature. The mixture was then diluted with water, extracted three times with ethyl acetate (20 mL), dried over anhydrous sodium sulfate, and separated by column chromatography (DCM:MeOH = 10:1) to obtain a deep yellow solid, which was the product.

[0091] The 1H NMR spectrum of the prepared Ph2-Et-Tol-ATPhen extractant is as follows: Figure 6 As shown, 1H NMR (500MHz, Methanol-d4) δ8.90(d,J=8.5Hz,1H),8.65(d,J=8.5Hz,1H),8.23(d,J=8.0Hz,1H),8.02(d,J=8.0Hz,1H),7.94(d,J=9.0Hz,1H),7.65(d,J =7.5Hz,2H),7.52(d,J=8.0Hz,2H),7.36(m,8H),7.12(q,J=8.0Hz,2H),6.79 (q, J=8.0Hz, 2H), 3.80 (d, J=7.0Hz, 2H), 2.04 (s, 3H), 0.99 (t, J=6.5Hz, 3H).

[0092] Mass spectrometry, such as Figure 7 As shown, ESI-HRMS:[C 37 H 28 N6O+H] + Theoretical value: m / z = 573.2397; Actual value: 573.2398; [C] 37 H 28 N6O+Na] + Theoretical value: m / z = 595.2217; Actual value: 595.2216.

[0093] Organic elemental analysis: C 37 H 28 Theoretical N6O values: C = 77.60%, H = 4.93%, N = 14.68%; Actual values: C = 77.32%, H = 4.35%, N = 14.86%.

[0094] Example 4

[0095] Step 1: Dissolve CyMe4-Et-Tol-ATPhen or Ph2-Et-Tol-ATPhen extractant in 3-nitrotrifluorotoluene solvent to prepare a 20 mmol / L solution as the organic phase in the extraction experiment. (The text then abruptly shifts to a seemingly unrelated topic: "Containing radioactive elements...") 241,243 Am(III) and 152,154 Eu(III) (concentration of 0.001 mmol / L) was added to nitric acid solutions with concentrations of 0.1, 0.5, 1.0, 2.0, 3.0, and 4.0 mol / L as the aqueous phase in the extraction experiments.

[0096] Step 2: In the radioactive extraction experiment, 1 mL of each of the aqueous and organic phases were added to centrifuge tubes and thoroughly mixed using a vortex mixer (2000 rpm, 10 min). The experimental temperature was 25℃, and the mixing time was 60 min. After the extraction reached equilibrium, the mixture was centrifuged to separate the phases (3000 rpm, 1 min). 100 μL of each phase was then collected. 241,243 Am and 152,154 The aqueous and organic phase solutions of Eu(III) were added to a scintillation flask containing the scintillation solution and mixed thoroughly. The concentrations of Eu(III) in the aqueous and organic phases after extraction were measured using an ultra-low background scintillation analyzer. 241,243 Am(III) and 152,154 The radioactivity of Eu(III) can be used to determine the concentrations of nitric acid in the aqueous phase at 0.1, 0.5, 1.0, 2.0, 3.0, and 4.0 mol / L. 241,243 Am(III) and 152, 154 Extraction partition ratio D of Eu(III).

[0097] The results are as follows Figure 8 , Figure 9 As shown in Tables 1 and 2, it can be seen that with the increase of nitric acid concentration, CyMe4-Et-Tol-ATPhen and Ph2-Et-Tol-ATPhen have different effects on... 241,243 Am(III) and 152,154 The extraction partition ratio D of Eu(III) showed a trend of first increasing and then decreasing. Within the solution acidity range of 0.5-4.0 M, the extraction partition ratios of both for Am(III) exceeded 15, with extraction rates higher than 90%. The extraction partition ratios of Eu(III) were all below 1, and the separation factors of Am(III) / Eu(III) both exceeded 50. When the nitric acid concentration was 2 mol / L, the extraction partition ratios of both for Am(III) and Eu(III) were... 241 The extraction partition ratios of Am(III) reached their maximum values ​​of 44.58 and 40.33, respectively, with extraction rates exceeding 97%. The separation factors of Am(III) / Eu(III) were 50.14 and 63.50, respectively. Both extractants maintained strong Am(III) / Eu(III) extraction and separation effects even at high acidity, indicating their strong chemical stability and resistance to decomposition or protonation under strong acid conditions.

[0098] Table 1. Effects of nitric acid concentration on CyMe4-Et-Tol-ATPhen extraction 241,243 Am(III) and 152,154 Effects of Eu(III)

[0099] Nitric acid concentration (mol / L) <![CDATA[D Am(III) ]]> <![CDATA[D Eu(III) ]]> <![CDATA[SF Am / Eu ]]> 0.1 7.62 0.13 56.43 0.5 28.30 0.32 88.18 1 37.64 0.68 55.19 2 44.58 0.89 50.14 3 33.07 0.64 51.49 4 28.13 0.55 50.54

[0100] Table 2. Effects of nitric acid concentration on Ph2-Et-Tol-ATPhen extraction 241,243 Am(III) and 152,154 The effects of Eu(III).

[0101]

[0102]

[0103] Example 5

[0104] Step 1: Dissolve CyMe4-Et-Tol-ATPhen or Ph2-Et-Tol-ATPhen extractants in 3-nitrotrifluorotoluene to prepare solutions with extractant concentrations of 2, 4, 8, 12, 16, and 20 mmol / L, which will be used as the organic phase in the extraction experiment. (The text then abruptly shifts to a seemingly unrelated topic: "Containing radioactive elements...") 241,243 Am(III) and 152,154 Eu(III) feed solutions (all concentrations of 0.001 mmol / L) were added to 1.0 mol / L nitric acid solutions as the aqueous phase in the extraction experiment.

[0105] Step 2: In the radioactive extraction experiment, 1 mL of each of the aqueous and organic phases were added to centrifuge tubes and thoroughly mixed using a vortex mixer (2000 rpm, 10 min). The experimental temperature was 25℃, and the mixing time was 60 min. After the extraction reached equilibrium, the mixture was centrifuged to separate the phases (3000 rpm, 1 min). 100 μL of each phase was then collected. 241,243 Am and 152,154 The aqueous and organic phase solutions of Eu(III) were added to a scintillation flask containing the scintillation solution and mixed thoroughly. The concentrations of Eu(III) in the aqueous and organic phases after extraction were measured using an ultra-low background scintillation analyzer. 241 Am(III) and 152,154 The radioactivity of Eu(III) can be obtained when the extractant concentration is 2, 4, 8, 12, 16, and 20 mmol / L, respectively. 241,243 Am(III) and 152,154 Extraction partition ratio D of Eu(III).

[0106] The results are as follows Figure 10 , Figure 11As shown in Tables 3 and 4, with the increase of extractant concentration, the extraction partition ratios (D) of Am(III) and Eu(III) gradually increased, and the partition ratio of Am(III) was consistently higher than that of Eu(III), confirming that both have good Am(III) / Eu(III) separation capabilities. Slope analysis revealed a linear relationship between Log[D] and Log[extractant concentration], thus determining the number of extractant molecules in the extract. The slopes for Am(III) and Eu(III) in CyMe4-Et-Tol-ATPhen were 1.84 and 1.45, respectively, confirming the simultaneous presence of 1-2 extractant molecules in the extract. The slopes for Am(III) and Eu(III) in Ph2-Et-Tol-ATPhen were 1.75 and 1.39, respectively, confirming the simultaneous presence of 1-2 extractant molecules in the extract. The final results obtained in different experimental processes may have slight errors, such as the partition ratio fluctuating within ±5.

[0107] Table 3. Effects of extractant concentration on CyMe4-Et-Tol-ATPhen extraction 241,243 Am(III) and 152,154 The effects of Eu(III).

[0108] Extractant concentration (mmol / L) <![CDATA[D Am(III) ]]> <![CDATA[D Eu(III) ]]> 2 0.52 0.02 4 1.99 0.07 8 6.89 0.18 12 16.93 0.24 16 24.83 0.42 20 35.58 0.79

[0109] Table 4. Effects of extractant concentration on Ph2-Et-Tol-ATPhen extraction 241,243 Am(III) and 152,154 The effects of Eu(III).

[0110] Extractant concentration (mmol / L) <![CDATA[D Am(III) ]]> <![CDATA[D Eu(III) ]]> 2 0.48 0.01 4 1.59 0.03 8 6.33 0.07 12 11.99 0.10 16 19.12 0.21 20 24.48 0.33

[0111] Example 6

[0112] Step 1: Dissolve CyMe4-Et-Tol-ATPhen or Ph2-Et-Tol-ATPhen extractants in 3-nitrotrifluorotoluene to prepare a 20 mmol / L solution as the organic phase in the extraction experiment. Add feed solutions containing non-radioactive Ln(III) (each ion concentration of 0.1 mmol / L) to nitric acid solutions with concentrations of 0.1, 0.5, 1.0, 2.0, 3.0, and 4.0 mol / L to prepare the aqueous phase in the extraction experiment.

[0113] Step 2, in the non-radioactive extraction experiment, 1 mL of the aqueous and organic phases were added to a centrifuge tube and thoroughly mixed using a vortex mixer (2000 rpm, 10 min). The experimental temperature was 25℃, and the mixing time was 60 min. After the extraction reached equilibrium, the mixture was centrifuged to separate the phases (3000 rpm, 1 min). 500 μL of the aqueous solution containing Ln(III) was taken out and diluted to 3 mL with 1 mol / L dilute nitric acid. The concentrations of Ln(III) in the aqueous and organic phases after extraction were measured using inductively coupled plasma atomic emission spectrometry (ICP-AES). The extraction partition ratio D of Ln(III) was obtained when the nitric acid concentrations in the aqueous phase were 0.1, 0.5, 1.0, 2.0, 3.0, and 4.0 mol / L.

[0114] The results are as follows Figure 12 , Figure 13 As shown in Tables 5 and 6, with increasing nitric acid concentration, the extraction partition ratio (D) of CyMe4-Et-Tol-ATPhen and Ph2-Et-Tol-ATPhen for Ln(III) first increases and then decreases, with slightly stronger extraction effects for light lanthanides than for heavy lanthanides. Within a solution acidity range of 0.1-4.0 M, the extraction partition ratios of both for Ln(III) are below 0.3, indicating generally weak extraction effects.

[0115] Table 5. Effect of nitric acid concentration on CyMe4-Et-Tol-ATPhen extraction of Ln(III).

[0116]

[0117] Table 6. Effect of nitric acid concentration on Ph2-Et-Tol-ATPhen extraction of Ln(III).

[0118]

[0119]

[0120] The above results indicate that this type of extractant has excellent extraction and separation capabilities for trivalent actinides and lanthanides over a wide range of nitric acid concentrations.

Claims

1. A method for separating and extracting lanthanum / actinides using a class of asymmetric extractants, characterized in that, The steps include: using asymmetric triazine amide o-phenanthroline as the extractant, mixing it with a diluent to form the organic phase, and extracting and separating trivalent actinide ions and trivalent lanthanide ions from an acidic aqueous solution; The structure of the asymmetric triazine amide o-phenanthroline is as follows: R1 and R2 are independently selected from straight-chain or branched alkyl substituents of C2-C10 or aromatic substituents of C6-C12; R3 and R4 are straight-chain, branched or cyclic alkyl substituents of C2-C10 or aromatic substituents of C6-C12.

2. The method for separating and extracting lanthanum / actinides using an asymmetric extractant according to claim 1, characterized in that, R1 and R2 are selected from ethyl, phenyl, or tolyl; R3 and R4 are selected from phenyl, tolyl, or tetramethylcyclohexyl.

3. The method for separating and extracting lanthanum / actinides using the asymmetric extractant according to claim 1, characterized in that, The diluent includes one or more of 3-nitrotrifluorotoluene, kerosene, n-dodecane, and n-octanol.

4. The method for separating and extracting lanthanum / actinides using an asymmetric extractant according to claim 1, characterized in that, The trivalent actinide ions include one or more of Ac(III), Am(III), Cm(III), Bk(III), Cf(III), Es(III), Fm(III), Md(III), No(III) and Lr(III); And / or, the trivalent lanthanide ions include one or more of La(III), Ce(III), Pr(III), Nd(III), Pm(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Lu(III); And / or, the concentration of trivalent actinide ions in the acidic aqueous solution is 10 -9 Above mol / L.

5. The method for separating and extracting lanthanum / actinides using an asymmetric extractant according to claim 1, characterized in that, The molar concentration of the extractant in the organic phase is 0.001-0.1 mol / L; And / or, the volume ratio of the organic phase to the acidic aqueous solution is 0.1-10:

1.

6. The method for separating and extracting lanthanum / actinides using an asymmetric extractant according to claim 1, characterized in that, The acidic aqueous solution is an aqueous solution of nitric acid, hydrochloric acid, or sulfuric acid; the molar concentration of the acid in the acidic aqueous solution is 0.1-4 mol / L.

7. The method for separating and extracting lanthanum / actinides using the asymmetric extractant according to claim 1, characterized in that, The extraction temperature is 0–50℃, and the mixture is shaken and mixed for 1–60 min to reach extraction equilibrium.

8. A class of asymmetric extractants, characterized in that, The asymmetric extractant is asymmetric triazineamide o-phenanthroline, having the following structure: R1 and R2 are independently selected from straight-chain or branched alkyl substituents of C2-C10 or aromatic substituents of C6-C12; R3 and R4 are straight-chain, branched or cyclic alkyl substituents of C2-C10 or aromatic substituents of C6-C12.

9. The method for preparing the asymmetric extractant according to claim 8, characterized in that, The steps include: condensing compound 1 and compound 2 to obtain intermediate 3, then adding hydrazine hydrate to react and obtain compound 4; and reacting compound 4 with compound 5 to undergo a side-chain cyclization reaction to obtain the asymmetric extractant.

10. The method for preparing the asymmetric extractant according to claim 9, characterized in that, The conditions for the condensation reaction are as follows: compound 1 and compound 2 are refluxed at a molar ratio of 1:0.5-1:3 at 0℃-100℃ for 1-12 hours. And / or, the condensation reaction uses one or more solvents including methanol, ethanol, acetonitrile, chloroform or dichloromethane; And / or, the condensation reaction also includes a base catalyst, said base catalyst including one or more of potassium hydroxide, sodium hydroxide, sodium ethoxide or triethylamine; The specific steps for reacting with hydrazine hydrate to obtain compound 4 include: drying the product of intermediate 3 by rotary evaporation, dissolving it in one or more solvents such as tetrahydrofuran, ethanol or methanol, adding 85% hydrazine hydrate at a molar ratio of 1:5 to 1:20 with intermediate 3, refluxing for 1 to 12 hours at a reaction temperature of 0℃ to 100℃, and separating and purifying to obtain compound 4. And / or, the side chain cyclic closure reaction conditions are: the molar ratio of compound 4 and compound 5 is 1:1.2-1:3, under an acid-binding agent environment, the reaction is refluxed in a solvent at 0℃-100℃ for 1-12 hours, and the asymmetric extractant is obtained by separation; And / or, the solvent in the side-chain cyclic closure reaction includes one or more of tetrahydrofuran, methanol, DMF, and DMSO; the acid-binding agent includes one or more of triethylamine and ethylenediamine.

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