A carbazole-based amine extractant, its preparation method and use

Abstract

The application discloses a kind of amine extractant based on carbazole, and provides its synthesis method, is expected to realize the selective separation of ReO4 − / TcO4 − In water, belong to radioactive waste water treatment, medical Mo / Tc separation and Mo / Re separation technical field.Extractant is synthesized by four-step reaction, and process is simple.The extractant only contains CHN element, can be completely incinerated to discharge in the form of CO2.Under the extract system involved in the application, the extractant has excellent extraction performance on ReO4 − , is easy to back extraction, and has excellent separation performance on ReO4 − / M (Pd 2+ , Eu 3+ , Th 4+ , UO2 2+ , MoO4 2− ).The application provides a new idea for the recovery of TcO4 − In radioactive waste liquid, Mo / Tc separation and Mo / Re separation.

Description

Technical Field

[0001] This invention pertains to the fields of spent fuel reprocessing, Mo / Tc separation in medical Mo / Tc generators, and Mo / Re separation in molybdenite, and relates to the use of TcO4. − / ReO4 − The extraction system for separation and recovery specifically involves a 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant, the preparation method of this extractant, and its application in the highly selective separation of TcO4. − / ReO4 − Its uses in this area. Background Technology

[0002] I. Background: 1) Technetium production is relatively high in nuclear power reactors (6%), mainly in the form of pertechnetate (TcO4). − It exists in the form of TcO4. − It will severely disrupt the spent fuel reprocessing process. Secondly, TcO4 − The high solubility and high migration of TcO4 make it possible for... − It readily diffuses into the environment, posing a threat to natural ecosystems and human health. Therefore, the identification, separation, and recovery of TcO4 is crucial. − It is of great significance to nuclear energy safety, ecological safety, and sustainable development. 2) In nuclear medicine, 99m Tc is one of the most commonly used radionuclides in imaging diagnostics. 99m Tc mainly through 99 Mo / 99m Tc generators are being used. Due to the restrictions of the Nuclear Non-Proliferation Treaty, there is an urgent need to develop new [technology / equipment]. 99m Tc preparation methods. Such as based on 98 Mo(n, γ) 99 Mo reaction or 100 Mo(γ, n) 99 Production methods such as the Mo reaction, however, yield... 99 Mo contains a large number of Mo isotope carriers, and classic alumina chromatography column generators are difficult to obtain suitable results. 99mTc eluent. How to efficiently and safely separate Mo / Tc is key to the development of this method. 3) Rhenium is a high-melting-point rare metal. It has important applications in cutting-edge high-tech fields such as national defense, aerospace, nuclear energy, and the electronics industry. Its application, especially in ultra-high-temperature components such as rockets and engines in the aerospace field, has attracted great attention from materials scientists worldwide. Since rhenium is a scarce metal, research on its extraction and recovery technologies is of great significance for its applications. Molybdenite is the most important ore source of molybdenum and also the mineral with the highest rhenium content. In nature, about 99% of molybdenum exists as molybdenite. In molybdenite, because the ionic radius of rhenium is close to that of molybdenum, some rhenium can exist in the mineral in an isomorphous form (ReS2). Therefore, Mo / Re separation technology is crucial for the extraction and recovery of molybdenum and rhenium.

[0003] II. Technology: Currently, TcO4 is separated. − / ReO4 − Common methods include precipitation, ion exchange, solid-phase adsorption, and liquid-phase extraction. However, the precipitants currently used in precipitation methods cannot completely precipitate TcO4. − (k sp Below 10 -10 Ion exchange methods typically utilize ion exchange resins that suffer from elution difficulties, poor radiation stability, and relatively slow absorption kinetics. Pure inorganic anion exchange framework materials in TcO4... − / ReO4 − Solid-phase adsorption exhibits relatively poor selectivity, low capacity, and instability. The adsorbents used in solid-phase adsorption also have their own drawbacks and limitations. For example, metal-organic frameworks (MOFs) are critically unstable in acids, and CPNs do not follow the "CHON" rule, easily causing secondary pollution. These shortcomings prevent a fundamental solution to the removal of technetium. Liquid-phase extraction, with its advantages of good separation effect, ease of rapid and continuous operation, large production capacity, small storage volume during the process, high safety factor, and ease of automatic control, has been applied to TcO4. − / ReO4 − Separation. In recent years, researchers have developed numerous techniques for the extraction and separation of TcO4. − / ReO4 − Extractants. For liquid-phase extraction, although many methods have been developed for the extraction and separation of TcO4... − / ReO4 −While various extractants exist, they all suffer from different problems, such as inability to be used under acidic conditions, low extraction capacity, poor selectivity, and susceptibility to emulsification or three-phase formation. Among these extractants, amine extractants can be used in acidic environments, are simple to synthesize, and offer a certain degree of selectivity. Furthermore, by modifying amine extractants to increase their solubility in diluents and the solubility of their complexes with acids and anions, the problems of emulsification or three-phase formation can be effectively solved or mitigated. However, most amine extractants suffer from low extraction capacity, and almost all of them exhibit problems such as decreased extraction performance due to increased acidity, which urgently need to be addressed. Summary of the Invention

[0004] To address the problems of low selectivity and decreased extraction performance with increasing acidity in current amine extractants, this invention aims to provide a novel carbazole-based amine extractant that maintains a high extraction partition ratio (1~3 mol·L⁻¹) even under high acidity conditions in the sulfuric acid-chloroform system. −1 H2SO4, D Re (200~400). This invention provides a method for synthesizing 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant and achieving the extraction of TcO4. − / ReO4 − Highly selective extraction and separation. This invention relates to a 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant, whose synthesis is relatively simple and yields a high rate (approximately 50% overall yield across four steps). This extractant contains only CHN elements and can be completely incinerated, emitting CO2 with minimal environmental impact. The sulfuric acid-chloroform extraction system involved in this invention also provides a highly selective extraction method for ReO4. − It has a high distribution ratio (1~3 mol·L). −1 H2SO4, D Re (200~400), and 0.1 mol·L −1 Na₂CO₃ aqueous solution can be completely back-extracted in one step. This extractant is effective for ReO₄⁻. − / M(Pd) 2+ Eu 3+ ,Th 4+ UO2 2+ MoO4 2 − It exhibited excellent separation performance at 1.5 mol·L⁻¹. −1 H2SO4 SF Re(VII) / M It can reach over 8000.

[0005] The present invention has the following beneficial effects:

[0006] 1. The prepared extractant 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) contains only CHN elements and can be completely incinerated and emitted as CO2, which has little environmental harm.

[0007] 2. In the sulfuric acid-chloroform system, the extractant 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) is effective against ReO4. − The extraction partition ratio increases with increasing acidity, then decreases slightly, and then tends to remain constant above 200. This improves upon the limitations of current amine extractants in treating ReO4 at high acidity. − The disadvantage of a significantly reduced extraction distribution ratio.

[0008] 3. In the sulfuric acid-chloroform system, the extractant 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) is effective against ReO4. − / M(Pd 2+ Eu 3+ ,Th 4+ UO2 2+ MoO4 2− It exhibited excellent separation performance at 1.5 mol·L⁻¹. −1 Under H2SO4, its extraction separation factor can reach over 8000.

[0009] 4. In the sulfuric acid-chloroform system, MoO4 2− The concentration of the extractant 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) was used to extract ReO4. − The extraction partition ratio was almost unaffected, and the separation factor was high. Detailed Implementation

[0010] The present invention will be further described in detail below through specific embodiments.

[0011] Example 1

[0012] Synthesis method of 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant (see figure below):

[0013]

[0014] Synthesis and characterization of intermediate compound 2: Compound 1 (0.99 g, 3 mmol) and dry THF (50 mL) were added to a 250 mL single-necked round-bottom flask equipped with a constant-pressure dropping funnel. A lithium aluminum hydride THF solution (30 mL, 1 mol·L⁻¹) was then added to the constant-pressure dropping funnel. −1 Under N2 protection, the mixture was cooled to 0 °C using an ice-water bath, and a THF solution of lithium aluminum hydride was slowly added dropwise. After the addition was complete, the mixture was stirred overnight. 50 mL of THF:H2O (19:1) was added dropwise to quench the reaction. The solvent was removed under vacuum, and the mixture was washed thoroughly successively with 200 mL of 2N HCl aqueous solution and 100 mL of petroleum ether. The solution was then dried under an infrared lamp to obtain a pale yellow powdery solid (1.02 g, 82.9%). Characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ11.67 (s, 1H), 8.62 (s, 6H), 8.24 (d, J = 1.6 Hz, 2H), 7.65 (d, J = 1.6 Hz, 2H), 4.50 (d, J = 4.8 Hz, 4H), 1.43 (s, 18H). 13 C NMR (101 MHz, DMSO) δ 141.98,137.33, 125.28, 123.55, 117.48, 116.43, 35.06, 32.33, 32.22.HRMS (m / z):338.2556([M+H] + ); Calcd: 338.2591.

[0015] Synthesis and characterization of intermediate compound 3: Compound 2 (2.05 g, 5 mmol), triethylamine (5 mL), and EtOH (50 mL) were added to a 100 mL single-necked flask. After stirring for 1 h, benzaldehyde (2.12 g, 20 mmol) was added. Stirring for 12 h resulted in the precipitation of a white precipitate. The reaction mixture was filtered, and the residue was washed successively with 10 mL EtOH and 50 mL petroleum ether. The residue was dried under an infrared lamp to obtain a white solid powder (2.21 g, 86.0%). Characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ10.75 (s, 1H), 8.62 (s, 2H), 8.09 (d, J = 1.7 Hz, 2H), 7.79 (dd, J= 7.9, 1.6Hz, 4H), 7.52 – 7.33 (m, 8H), 5.21 (s, 4H), 1.40 (s, 18H). 13 C NMR (101 MHz, DMSO) δ 162.03, 141.61, 137.30, 136.57, 131.17, 129.16, 128.38, 123.42,123.17, 121.95, 115.49, 61.21, 34.87, 32.41.HRMS (m / z): 514.3189([M+H] + );Calcd: 514.3217.

[0016] Synthesis and characterization of intermediate compound 4: Compound 3 (1.03 g, 2 mmol) and CH3OH (50 mL) were added to a 100 mL single-necked round-bottom flask. The mixture was cooled to 0 °C in an ice-water bath, and sodium borohydride (0.76 g, 20 mmol) was added. The mixture was stirred overnight under N2 protection. The reaction solution was quenched with 10 mL of water. The solvent CH3OH was removed under vacuum, and the mixture was thoroughly stirred with 100 mL of 2N HCl aqueous solution. The mixture was filtered, and the residue was washed with 50 mL of petroleum ether and dried under an infrared lamp to obtain a white solid powder (1.10 g, 92.7%). Characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 12.33 (s, 1H), 9.59 (s, 4H), 8.29 (d, J = 1.9 Hz, 2H), 7.73 – 7.53 (m, 6H), 7.42 (dd, J = 5.0, 1.8 Hz, 6H), 4.78 (s, 4H), 4.42 (s, 4H), 1.43 (s, 18H). 13 C NMR (101 MHz, DMSO) δ141.82, 138.32, 132.71, 130.83, 129.22, 128.85, 127.07, 123.52, 118.03,114.20, 50.38, 47.69, 35.03, 32.34.HRMS (m / z): 518.3571([M+H] + ); Calcd: 518.3530.

[0017] Synthesis and characterization of the target compound 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant: In a 250 mL single-necked round-bottom flask, compound 4 (1.18 g, 2 mmol), KI (0.17 g, 1 mmol), triethylamine (3 mL), dried CH3CN (100 mL), and benzyl bromide (1.71 g, 10 mmol) were added. The mixture was refluxed for 24 h under N2 protection. The solvent CH3CN was removed from the reaction solution under vacuum, and 200 mL of CH2Cl2 was added. The organic phase was washed successively with 100 mL of distilled water and 100 mL of saturated NaCl aqueous solution. The solution was dried over anhydrous Na2SO4, filtered, and the solvent was removed under vacuum. The resulting oily substance was separated by column chromatography (petroleum ether / ethyl acetate), further washed by reflux in MeOH (50 mL), filtered, and dried under an infrared lamp to obtain a white powdery solid (1.03 g, 73.6%). Characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 9.84 (s, 1H), 8.02 (d, J = 1.8 Hz, 2H), 7.62 (d, J = 1.8 Hz, 2H), 7.44 – 7.38 (m, 8H), 7.32(t, J = 7.4 Hz, 8H), 7.27 – 7.22 (m, 4H), 3.92 (s, 4H), 3.65 (s, 8H), 1.40 (s, 18H). 13 C NMR (101 MHz, DMSO) δ 141.79, 139.36, 137.29, 129.02, 128.81,127.52, 123.30, 122.99, 121.14, 115.21, 57.72, 54.28, 34.87, 32.37.HRMS (m / z): 698.4421([M+H] + ); Calcd: 698.4469.

[0018] Application Example 1

[0019] ReO4 was separated by extraction with 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant. − : 0.01 mol·L⁻¹ of organic phase as extractant −1 Chloroform solution; aqueous phase is ReO4 − ([Re(VII)] = 50 mg·L)−1 ) and sulfuric acid (H2SO4: 0.05 – 3 mol·L −1 An aqueous solution of rhenium was prepared. The organic phase was pre-equilibrated with an equal volume of sulfuric acid solution of the appropriate concentration, and then mixed with an equal volume of aqueous phase and stirred for 1 h. The aqueous phase was separated by centrifugation, and the rhenium concentration was detected by ICP-AES. The results showed that with increasing sulfuric acid concentration, rhenium concentration decreased. D Re The concentration initially increases, then decreases slightly, and then maintains equilibrium. When the H₂SO₄ concentration is 1.5 mol·L⁻¹ −1 hour, D Re It reached its highest level, exceeding 400. Even at 3 mol·L⁻¹ −1 Under H2SO4, D Re It remains above 200.

[0020] ReO4 was separated by extraction with 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant. − Subsequent back-extraction: The organic phase obtained after centrifugation is back-extracted using an alkaline aqueous solution, which can be completely back-extracted in 1-2 times. (The remaining text appears to be incomplete and possibly contains errors. A more accurate translation would require the full context.) −1 The back-extraction effect of Na2CO3 is better than that of 0.1 mol·L⁻¹. −1 (NH4)2CO3 can achieve complete back-extraction in one step, as shown in Table 1.

[0021] Table 1. ReO4 back-extraction in different alkaline solutions −

[0022]

[0023] (The loaded organic phase of 0.01 mol·L −1 L in CHCl3 contacted with the aqueous phase containing Re(VII)(50 mg / L) in H2SO4 solution.)

[0024] Application Example 2

[0025] ReO4 − / M(M = Pd 2+ UO2 2+ Eu 3+ ,Th 4+ Extraction and separation study of 0.01 mol·L⁻¹ organic phase as extractant −1 Chloroform solution; aqueous phase is ReO4 − / Pd2+ / UO2 2+ / Eu 3+ / Th 4+ Sulfuric acid (H2SO4: 0.5 – 1.5 mol·L⁻¹) −1 The organic phase was pre-equilibrated with an equal volume of sulfuric acid solution of the appropriate concentration, and then mixed with an equal volume of aqueous phase and stirred for 1 h. The aqueous phase was separated by centrifugation, and the concentration of the corresponding ions was detected by ICP-AES. The processed data are shown in Table 2. With increasing acidity, the concentration of Pd... 2+ UO2 2+ Eu 3+ ,Th 4+ The extraction partition ratios decreased to varying degrees. The extractant's effect on Pd... 2+ UO2 2+ Eu 3 + ,Th 4+ The extraction partition ratios were low, all less than 0.1. SF Re / M The separation factors are summarized in Table 2. At 1.5 mol·L⁻¹ −1 Under H2SO4, its extraction separation factor can reach over 8000.

[0026] Table 2 Extraction partition ratios of different metal ions by the extractant and related separation factors

[0027]

[0028] Application Example 3

[0029] ReO4 − / MoO4 2− Extraction and separation studies: 0.01 mol·L⁻¹ organic phase as extractant −1 Chloroform solution; aqueous phase is ReO4 − / MoO4 − Sulfuric acid (H2SO4: 0.5 – 1.5 mol·L⁻¹) −1 The organic phase was pre-equilibrated with an equal volume of sulfuric acid solution of the appropriate concentration, and then mixed with an equal volume of aqueous phase and stirred for 1 h. The aqueous phase was separated by centrifugation, and the concentration of the corresponding ions was detected by ICP-AES. The results showed that with increasing acidity, the concentration of MoO4- ions decreased. 2− The extraction partition ratio decreased significantly at 1.5 mol·L⁻¹. −1 At H2SO4, its partition ratio is only 0.016. At 1.5 mol·L⁻¹ −1 When H2SO4 is used, the separation factor can reach 25000.

[0030] The organic phase is 0.01 mol·L⁻¹ of extractant.−1 Chloroform solution; aqueous phase is ReO4 − / MoO4 − (MoO4) − 1 – 5 mmol·L −1 Sulfuric acid (H2SO4: 1.5 mol·L⁻¹) −1 The organic phase was pre-equilibrated with an equal volume of sulfuric acid solution of the corresponding concentration, and then mixed with an equal volume of aqueous phase and stirred for 1 h. The aqueous phase was separated by centrifugation, and the concentration of the corresponding ions was detected by ICP-AES. The results showed that when MoO4... 2− The concentration increased from 1 to 5 mmol·L −1 hour, D Re It remains almost unchanged, indicating that MoO4 2− The effect of ReO4 concentration change − The extraction process was almost unaffected. D Mo It first increases, then tends to balance, reaching 0.2. The separation factor decreases from 25000 to 2500, and then tends to balance.

Claims

1. A carbazole-based amine extractant, 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine), characterized in that... The structural formula of the extractant is as follows: 。 2. The extractant according to claim 1 in ReO4 Its applications in highly selective extraction and separation.

3. The use according to claim 2, characterized in that... Using the 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant for ReO4 An extraction and recovery system is provided, comprising an equal volume mixture of an organic phase and an aqueous phase. The organic phase contains 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) as an extractant at a molar concentration of 0.005–0.05 mol / L. The aqueous phase contains ReO4 to be recovered. The solution.

4. The use according to claim 2, characterized in that... Using the 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant for ReO4 Pd and other metal cations in radioactive nuclear waste 2+ Eu 3 + ,Th 4+ UO2 2+ A highly selective extraction and separation system.

5. The use according to claim 2, characterized in that... Using the 1,1'-(3,6-di-tert-butyl-9H-carbazole-1,8-diyl)bis(N,N-dibenzylmethylamine) extractant for ReO4 With MoO4 A highly selective extraction and separation system.

Images