Compound as well as preparation method and application thereof

Abstract

The invention provides a compound as well as a preparation method and application thereof. The compound is represented by the following formula (I) wherein R is a C1 to C14 alkyl group. The compound can efficiently extract tetravalent plutonium in a spent fuel post-treatment process, and is wide in applicable nitric acid concentration, fast in extraction kinetics, high in extraction efficiency and short in extraction equilibrium time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of spent fuel reprocessing, in particular to a compound, a preparation method and application thereof. BACKGROUND

[0002] In a closed nuclear fuel cycle system, selective extraction and separation of plutonium is one of the key problems, which is not only related to the sustainable development of nuclear energy, but also closely related to the wide application of plutonium isotopes. At present, a large amount of plutonium is mainly obtained from spent fuel dissolution solution, and the plutonium is separated from other fission products and minor actinides in the dissolution solution, and then a high-purity plutonium product can be obtained after further purification. However, the plutonium content in the spent fuel dissolution solution is low, and other elements such as uranium are the main components of the dissolution solution. In addition, the extractant for extracting metal ions currently used is usually tri-butyl phosphate, which has good affinity for uranium and plutonium. Therefore, in order to obtain a high-purity plutonium product, a large number of chemical separation processes are usually required, and the valence state of plutonium needs to be accurately adjusted to reduce its affinity with tri-butyl phosphate and separate it from uranium.

[0003] Moreover, tri-butyl phosphate also contains phosphorus element, and therefore cannot be completely incinerated, which does not meet the carbon-nitrogen-oxygen-hydrogen CNOH principle of green and sustainable development. Therefore, developing a new type of environmentally friendly CNOH principle and high selectivity for tetravalent plutonium to obtain a high-purity plutonium product through simple chemical separation not only can effectively reduce the complexity of the process flow, but also reduce the use amount of some toxic and harmful chemicals such as nitric acid and kerosene in the plutonium extraction process, which has important practical significance for the efficient, green and sustainable development of nuclear energy. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a compound, a preparation method and application thereof. The compound can efficiently extract tetravalent plutonium in the spent fuel reprocessing process, has a wide applicable nitric acid concentration, fast extraction kinetics, high extraction efficiency and short extraction equilibrium time.

[0005] The first aspect of the present application provides a compound represented by formula (I),

[0006]

[0007] wherein R is a C1 to C14 alkyl group.

[0008] In some embodiments, R is a C6 to C10 alkyl group.

[0009] The second aspect of the present application provides a method for preparing the compound of the first aspect, which comprises the following steps:

[0010] Step 1: reacting a dialkylamine NH(R)2with a chloroacetyl chloride in the presence of 4-dimethylaminopyridine and triethylamine in a solvent to obtain a compound represented by formula (II), wherein R is as defined above;

[0011] ClCH2CON(R)2(II)

[0012] Step 2: reacting 1,4,7,10-tetraazacyclododecane with ethylene oxide in the presence of an inert gas in a solvent to obtain a compound represented by formula (III);

[0013]

[0014] Step 3: reacting the compound represented by formula (II) with the compound represented by formula (III) in the presence of sodium hydride in a solvent under an inert gas atmosphere to obtain a compound represented by formula (I).

[0015] In some embodiments, in step 1, the reaction temperature is 0-5°C, and / or the reaction time is 6-12 hours, and / or the solvent is selected from one or more of anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous dimethylformamide, anhydrous acetonitrile.

[0016] In some embodiments, in step 2, the reaction temperature is 0-5°C, and / or the reaction time is 6-18 hours, and / or the solvent is selected from one or more of anhydrous ethanol, anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous dimethylformamide, anhydrous acetonitrile.

[0017] In some embodiments, in step 3, the reaction temperature is 10-60°C, and / or the reaction time is 6-24 hours, and / or the solvent is selected from one or more of anhydrous tetrahydrofuran, anhydrous dichloromethane, anhydrous dimethylformamide, anhydrous acetonitrile.

[0018] The third aspect of the present application provides an application of the compound of the first aspect in the extraction of tetravalent plutonium in a spent fuel reprocessing process, characterized in that the application comprises the following steps:

[0019] Step 11: dissolving the compound represented by formula (I) in an organic solvent to obtain an organic phase;

[0020] Step 12: mixing the spent fuel with an aqueous nitric acid solution to obtain an aqueous phase;

[0021] Step 13: mixing the organic phase and the aqueous phase and stirring for 0.5-15 minutes; and

[0022] Step 14: after the end of stirring, separating the organic phase and the aqueous phase, so that the tetravalent plutonium is partially or completely extracted in the organic phase.

[0023] In some embodiments, in step 12, the concentration of nitric acid in the aqueous nitric acid solution is 1.0-8.0 mol / L.

[0024] In some embodiments, in step 11, the organic solvent is selected from one or more of alkanes, alcohol organic solvents.

[0025] In some embodiments, in step 11, the concentration of the compound represented by formula (I) in the organic phase is 0.01-0.2 mol / L.

[0026] The compound of the present application can be used as an extractant for extracting tetravalent plutonium in spent fuel reprocessing process. Compared with the extractant tributyl phosphate commonly used in the related art, the compound of the present application does not contain non-incinerable phosphorus element, and meets the green and sustainable carbon-nitrogen-oxygen-hydrogen CNOH principle. The compound of the present application includes tetraazacycloalkane structure, amide group and flexible ether oxygen chain structure in the structure. Through the joint action of these structures, efficient extraction of tetravalent plutonium in the acidic aqueous solution of spent fuel can be achieved, and the extraction distribution ratio can be as high as 25.9. The extractant is suitable for acidic aqueous solution with a nitric acid concentration of 1.0-8.0 mol / L. The applicable nitric acid concentration is wide, the extraction kinetics is fast, the extraction efficiency is high, and the extraction equilibrium time is short, which can reach equilibrium within half a minute. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the compound represented by formula (I-1) prepared in Preparation Example 1 is shown.

[0028] Figure 2 The nuclear magnetic resonance carbon spectrum of the compound represented by formula (I-1) prepared in Preparation Example 1 is shown. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described in detail below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] Throughout the specification, unless otherwise specifically indicated, the terms used herein are to be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as generally understood by those skilled in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0031] It is to be understood that the terms "including", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or method that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such product or method. An element proceeded by "comprises a... " does not, without more constraints, exclude the presence of additional elements of the product or method that contains the element.

[0032] In the related art, the extractant for extracting metal ions from the spent fuel dissolution solution is tributyl phosphate, which has good affinity for uranium and plutonium. Therefore, in order to obtain a plutonium product with high purity, a large number of chemical separation processes are required, and the valence state of plutonium needs to be accurately adjusted to reduce its affinity with tributyl phosphate and separate it from uranium.

[0033] Moreover, tributyl phosphate also contains phosphorus elements, and therefore cannot be completely incinerated, which does not meet the carbon-nitrogen-oxygen-hydrogen CNOH principle of green and sustainable development. Therefore, developing a new type of environmentally friendly CNOH principle and high selectivity extractant for tetravalent plutonium to obtain a plutonium product with high purity through simple chemical separation can not only effectively reduce the complexity of the process flow, but also reduce the amount of use of some toxic and harmful chemicals such as nitric acid and kerosene in the plutonium extraction process. This has important practical significance for the efficient, green and sustainable development of nuclear energy.

[0034] Therefore, the first aspect of the present application provides a compound. The compound is represented by formula (I):

[0035]

[0036] wherein R is a C1 to C14 alkyl group.

[0037] The compound of the present application can be used as an extractant for extracting tetravalent plutonium in the spent fuel reprocessing process. Compared with the commonly used extractant tributyl phosphate in the related art, the compound of the present application does not contain non-incinerable phosphorus elements, and meets the carbon-nitrogen-oxygen-hydrogen CNOH principle of green and sustainable development. The structure of the compound of the present application includes a tetraazacycloalkane structure, an amide group and a flexible ether oxygen chain structure. Through the combined action of these structures, efficient extraction of tetravalent plutonium in the acidic aqueous solution of spent fuel can be achieved, and the extraction distribution ratio can be as high as 25.9. The extractant is suitable for acidic aqueous solutions with a nitric acid concentration of 1.0-8.0 mol / L. The applicable nitric acid concentration is wide, the extraction kinetics is fast, the extraction efficiency is high, and the extraction equilibrium time is short, which can reach equilibrium within half a minute.

[0038] The term "alkyl" refers to a branched, straight-chain or cyclic saturated aliphatic hydrocarbon group, which can be represented as -Cn H 2n+1 wherein n represents the number of carbon atoms. "C1 to C14 alkyl" represents an alkyl group having 1 to 14 carbon atoms, for example, C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14 alkyl or an alkyl group in a range between any two of these values. Examples of the alkyl group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, or n-decyl.

[0039] In some embodiments, R in formula (I) can be a C6 to C10 alkyl group, and optionally R can be a linear C8 alkyl group. In this way, the alkyl chain on the nitrogen atom of the amide group has an appropriate length and flexibility, which is advantageous for the complexation of the compound of formula (I) with tetravalent plutonium, and thus for the extraction efficiency.

[0040] A second aspect of the present application provides a method for preparing the compound of the first aspect of the present application. The method comprises the following steps:

[0041] Step 1: reacting dialkylamine NH(R)2 with chloroacetyl chloride in the presence of 4-dimethylaminopyridine and triethylamine in a solvent to obtain a compound of formula (II), wherein R is as defined above;

[0042] ClCH2CON(R)2 (II)

[0043] Step 2: reacting 1,4,7,10-tetraazacyclododecane with ethylene oxide in a solvent under an inert gas atmosphere to obtain a compound of formula (III);

[0044]

[0045] Step 3: reacting the compound of formula (II) with the compound of formula (III) in the presence of sodium hydride in a solvent under an inert gas atmosphere to obtain a compound of formula (I).

[0046] The preparation method of the present application is schematically shown by the following reaction formula.

[0047]

[0048]

[0049] In some embodiments, in step 1, the reaction temperature can be 0-5°C, optionally 0°C, 1°C, 2°C, 3°C, 4°C or 5°C. In some embodiments, in step 1, the reaction time can be 6-12 hours, optionally 8-12 hours, optionally 8 hours. In some embodiments, in step 1, the solvent can be selected from one or more of anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous dimethylformamide, anhydrous acetonitrile, optionally anhydrous dichloromethane. In step 1, triethylamine is mainly used to provide alkalinity, and 4-dimethylaminopyridine is used as a catalyst for the reaction of acyl chloride with amine compounds to form amide compounds. In the presence of these substances, the reaction is promoted to proceed towards the target reactant.

[0050] In some embodiments, in step 2, the reaction temperature can be 0-5°C, optionally 0°C, 1°C, 2°C, 3°C, 4°C or 5°C, but not limited to. In some embodiments, in step 2, the reaction time can be 6-18 hours, optionally 8-16 hours, optionally 12 hours, but not limited to. In some embodiments, in step 2, the solvent can be selected from one or more of anhydrous ethanol, anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous dimethylformamide, anhydrous acetonitrile.

[0051] In some embodiments, in step 3, the reaction temperature can be 10-60°C, optionally 10°C, 20°C, 30°C, 40°C, 50°C, 55°C or 60°C, but not limited to. In some embodiments, in step 3, the reaction time can be 6-24 hours, optionally 8-20 hours, optionally 8-16 hours, optionally 12 hours, but not limited to. In some embodiments, in step 3, the solvent can be selected from one or more of anhydrous tetrahydrofuran, anhydrous dichloromethane, anhydrous dimethylformamide, anhydrous acetonitrile, optionally anhydrous tetrahydrofuran.

[0052] When the reaction needs to be carried out under an inert gas atmosphere, the inert gas can be selected from helium, nitrogen, argon, etc. Optionally, the inert gas is selected from argon. By carrying out the reaction under an inert gas atmosphere, the reaction system can be prevented from being disturbed by external gases such as oxygen and moisture.

[0053] The third aspect of the present application provides the use of the compound of the first aspect in the extraction of tetravalent plutonium in the spent fuel reprocessing process. The use comprises the following steps:

[0054] Step 11: dissolving the compound represented by formula (I) in an organic solvent to obtain an organic phase;

[0055] Step 12: mixing the spent fuel with an aqueous nitric acid solution to obtain an aqueous phase;

[0056] Step 13: mixing the organic phase and the aqueous phase and stirring for 0.5-15 minutes; and

[0057] Step 14: after the stirring is completed, separating the organic phase and the aqueous phase, so that the tetravalent plutonium is partially or completely extracted in the organic phase.

[0058] In some embodiments, in step 12, the concentration of nitric acid in the aqueous nitric acid solution can be 1.0-8.0 mol / L. Illustratively, the concentration of nitric acid in the aqueous nitric acid solution can be 1.0 mol / L, 2.0 mol / L, 3.0 mol / L, 4.0 mol / L, 5.0 mol / L, 6.0 mol / L, 7.0 mol / L, 8.0 mol / L, or a value between any two of the above values, but is not limited thereto. The compound of formula (I) has high stability in a wide range of concentrations of nitric acid, reducing the possibility of decomposition reaction, and facilitating effective extraction of tetravalent plutonium.

[0059] In some embodiments, in step 13, the organic phase and the aqueous phase are mixed and stirred for 0.5-15 minutes. Illustratively, the stirring time can be 0.5 minutes, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 10 minutes, 15 minutes, or a value between any two of the above values, but is not limited thereto. By stirring for the above time, the organic phase and the aqueous phase can reach extraction equilibrium.

[0060] In some embodiments, in step 11, the organic solvent is selected from one or more of alkanes, alcohol organic solvents, 3-nitro-trifluorotoluene, hydrogenated tetrapropylene, and the like. The alkanes can be selected from one or more of alkanes having 8-14 carbon atoms, and optionally, alkanes having 12 carbon atoms. The alcohol organic solvents can be selected from one or more of n-octanol, n-decanol, isodecanol, nonanol, and the like. Alternatively, the organic solvent is a mixed solvent of n-dodecane and isodecanol. Alternatively, the volume ratio of n-dodecane to isodecanol is 95:5. The above solvents are not miscible with water and have low solubility in water. The density difference between the solvents and water facilitates phase separation of the solvents from water, thereby facilitating improved extraction efficiency.

[0061] In some embodiments, in step 11, the concentration of the compound of formula (I) in the organic phase can be 0.01-0.2 mol / L. Illustratively, the concentration of the compound of formula (I) in the organic phase can be 0.01 mol / L, 0.02 mol / L, 0.04 mol / L, 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, 0.2 mol / L, or a value between any two of the above values, but is not limited thereto.

[0062] The present application will be described in further detail below with reference to specific examples, which are merely illustrative and not intended to limit the scope of the present disclosure.

[0063] In the following examples, the components used are commercially available products unless otherwise specifically stated. In addition, the equipment and instruments involved are also commercially available standard products, and the operating conditions and parameter settings are in accordance with the standard instructions provided by the equipment manufacturers.

[0064] Preparation Example 1: Preparation of a compound represented by formula (I-1)

[0065] A compound represented by formula (I-1) is prepared according to the following reaction formula.

[0066]

[0067]

[0068] 1. Preparation of a compound ClCH2CON(n-C8H 17 )2

[0069] (1) 10.0 g of dioctylamine is dissolved in 50 mL of anhydrous dichloromethane under argon protection;

[0070] (2) 0.1 g of 4-dimethylaminopyridine and 10 mL of triethylamine are added to the system of (1), and the temperature of the system is lowered to 0°C;

[0071] (3) 10.0 g of chloroacetyl chloride is slowly added dropwise to 20 mL of anhydrous dichloromethane in the system of (2) and stirred for 12 hours;

[0072] (4) The solvent is rotary evaporated to obtain a compound ClCH2CON(n-C8H 17 )2.

[0073] 2. Preparation of a compound represented by formula (III)

[0074] (1) 5.0 g of 1,4,7,10-tetraazacyclododecane is dissolved in 50 mL of anhydrous ethanol under argon protection;

[0075] (2) The temperature of the system is lowered to -10°C;

[0076] (3) 14.0 g of ethylene oxide is added to the system and the temperature is raised to 5°C, and the reaction is carried out for 12 hours;

[0077] (4) The solvent is rotary evaporated to obtain a compound represented by formula (III).

[0078] 3. Preparation of a compound represented by formula (I-1)

[0079] (5) Under argon protection, 1.6 g of sodium hydride with 60% content was added into 40 mL of anhydrous tetrahydrofuran;

[0080] (6) The temperature of the system was reduced to 0°C;

[0081] (7) 2.0 g of compound represented by formula (III) was slowly added into the reaction system and stirred for 60 minutes;

[0082] (8) 11.4 g of compound ClCH2CON(n-C8H 17 )2 was dissolved in 20 mL of anhydrous tetrahydrofuran;

[0083] (9) The solution of step (8) was slowly dropped into the solution of step (7) and slowly stirred until it rose to room temperature;

[0084] (10) The liquid obtained in step (9) was heated to 55°C in an oil bath and continuously stirred to reflux for 12 hours;

[0085] (11) The reaction was quenched by slowly adding saturated aqueous sodium bicarbonate solution;

[0086] (12) Ethyl acetate was added;

[0087] (13) The organic phase was separated and washed with saturated sodium chloride solution for 3 times;

[0088] (14) The organic phase was separated and dried with anhydrous magnesium sulfate;

[0089] (15) The organic phase was rotary evaporated to be thick;

[0090] (16) Column chromatography purification was performed with dichloromethane:methanol as the mobile phase with a volume ratio of 50:1 to obtain the compound represented by formula (I-1) with a yield of 86%.

[0091] The compound represented by formula (I-1) was tested by nuclear magnetic resonance hydrogen spectrum and carbon spectrum (400 MHz). The solvent used in the test was deuterated chloroform. The test results are shown in Figure 1 and Figure 2 .

[0092] Example 1

[0093] Take 0.1 mol of the compound shown in formula (I-1) as an extractant, dissolve it in 1 L of n-dodecane solution containing 5% isodecanol to prepare an organic phase of 0.1 mol / L. Take 1 mL of the organic phase and mix it with an equal volume of an aqueous phase containing 4.0 mol / L nitric acid and 1 mg / L tetravalent plutonium, stir for 5 minutes, then separate the organic phase and the aqueous phase, measure the concentration of plutonium in the aqueous phase and the organic phase respectively, and calculate the distribution ratio. The resulting distribution ratio is 7.5.

[0094] The calculation formula of the distribution ratio is: distribution ratio = concentration of plutonium in the organic phase ÷ concentration of plutonium in the aqueous phase.

[0095] The test method of the concentration of plutonium in the aqueous phase and the organic phase is as follows: after the aqueous phase and the organic phase are separated, heat them to dryness on an electric furnace at 300°C to obtain radioactive sources containing only metal elements, then analyze the activity of the aqueous phase and the organic phase radioactive sources by α spectrometer, and compare with the standard source to obtain the original concentration of plutonium in the aqueous phase and the organic phase.

[0096] Example 2

[0097] Take 0.1 mol of the compound shown in formula (I-1) as an extractant, dissolve it in 1 L of n-dodecane solution containing 5% isodecanol to prepare an organic phase of 0.1 mol / L. Take 1 mL of the organic phase and mix it with an equal volume of an aqueous phase containing 4.0 mol / L nitric acid and 1 mg / L tetravalent plutonium, stir for 5 minutes, then separate the organic phase and the aqueous phase, measure the concentration of plutonium in the aqueous phase and the organic phase respectively, and calculate the distribution ratio. The resulting distribution ratio is 7.5.

[0098] Example 3

[0099] Take 0.1 mol of the compound shown in formula (I-1) as an extractant, dissolve it in 1 L of n-dodecane solution containing 5% isodecanol to prepare an organic phase of 0.1 mol / L. Take 1 mL of the organic phase and mix it with an equal volume of an aqueous phase containing 4.0 mol / L nitric acid and 1 mg / L tetravalent plutonium, stir for 5 minutes, then separate the organic phase and the aqueous phase, measure the concentration of plutonium in the aqueous phase and the organic phase respectively, and calculate the distribution ratio. The resulting distribution ratio is 7.5.

[0100] Example 4

[0101] Take 0.1 mol of the compound shown in formula (I-1) as an extractant, dissolve it in 1 L of n-dodecane solution containing 5% isodecanol to prepare an organic phase of 0.1 mol / L. Take 1 mL of the organic phase and mix it with an equal volume of an aqueous phase containing 4.0 mol / L nitric acid and 1 mg / L tetravalent plutonium, stir for 5 minutes, then separate the organic phase and the aqueous phase, measure the concentration of plutonium in the aqueous phase and the organic phase respectively, and calculate the distribution ratio. The resulting distribution ratio is 7.5.

[0102] Example 5

[0103] Example 5

[0104] Example 5

[0105] Example 5

[0106] Example 5

[0107] Table 1

[0108]

[0109] Example 5

[0110] As can be seen from Table 1, compared with Comparative Example 1, Examples 1 to 5 of the present application all have significantly higher extraction distribution ratios, especially the extraction distribution ratio of Example 3 is as high as 25.9. This shows that the compound of the present application can efficiently extract tetravalent plutonium in a wide range of nitric acid concentrations. In particular, as the concentration of nitric acid increases, the extraction distribution ratio increases. This shows that the compound of the present application has higher stability at higher concentrations of nitric acid, reducing the possibility of decomposition reaction, and is conducive to efficient extraction of tetravalent plutonium. It is worth noting that in Example 4, the extraction reached equilibrium only after 0.5 minutes of stirring time, and also showed a higher extraction distribution ratio than Comparative Example 1. This shows that the compound of the present application can reach extraction equilibrium in a shorter time, which is conducive to improving the extraction efficiency. Among them, the extraction equilibrium is determined by testing the extraction distribution ratio at different time points, and when the change in the extraction distribution ratio is observed to be less than 1%, it is determined that the extraction has reached equilibrium.

[0111] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation or direct / indirect application in other related technical fields made by using the content of the present application is included in the patent protection scope of the present application.

Claims

1. A compound, characterized in that, The compound is represented by formula (I): Wherein, R is a C1 to C14 alkyl group.

2. The compound according to claim 1, wherein, R is a C6 to C10 alkyl group.

3. A method for preparing the compound of claim 1, characterized in that, The method includes the following steps: Step 1: In the presence of 4-dimethylaminopyridine and triethylamine, dialkylamine NH(R)2 is reacted with chloroacetyl chloride in a solvent to give the compound shown in formula (II), wherein R is as defined in claim 1; ClCH2CON(R)2(II) Step 2: Under an inert gas atmosphere, 1,4,7,10-tetraazacyclododecane reacts with ethylene oxide in a solvent to obtain the compound shown in formula (III); Step 3: In an inert gas atmosphere and in the presence of sodium hydride, the compound shown in formula (II) reacts with the compound shown in formula (III) in a solvent to obtain the compound shown in formula (I).

4. The method according to claim 3, wherein, In step 1, the reaction temperature is 0–5°C, and / or the reaction time is 6–12 hours, and / or the solvent is selected from one or more of anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous dimethylformamide, and anhydrous acetonitrile.

5. The method according to claim 3 or 4, wherein, In step 2, the reaction temperature is 0–5°C, and / or the reaction time is 6–18 hours, and / or the solvent is selected from one or more of anhydrous ethanol, anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous dimethylformamide, and anhydrous acetonitrile.

6. The method according to any one of claims 3 to 5, wherein, In step 3, the reaction temperature is 10–60°C, and / or the reaction time is 6–24 hours, and / or the solvent is selected from one or more of anhydrous tetrahydrofuran, anhydrous dichloromethane, anhydrous dimethylformamide, and anhydrous acetonitrile.

7. The application of the compound of claim 1 in the extraction of tetravalent plutonium in spent fuel reprocessing, characterized in that, The application includes the following steps: Step 11: Dissolve the compound shown in formula (I) in an organic solvent to obtain an organic phase; Step 12: Mix spent fuel with an aqueous nitric acid solution to obtain an aqueous phase; Step 13: Mix the organic phase and the aqueous phase, and stir for 0.5–15 minutes; and Step 14: After stirring, separate the organic phase and the aqueous phase to extract tetravalent plutonium partially or completely in the organic phase.

8. The application according to claim 7, wherein, In step 12, the concentration of nitric acid in the nitric acid aqueous solution is 1.0 to 8.0 mol / L.

9. The application according to claim 7 or 8, wherein, In step 11, the organic solvent is selected from one or more of alkane and alcohol organic solvents.

10. The application according to any one of claims 7 to 9, wherein, In step 11, the concentration of the compound represented by formula (I) in the organic phase is 0.01 to 0.2 mol / L.

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