Process for the preparation of phosphate crosslinked organic porous uranium extractants

Abstract

The application belongs to the technical field of polymer materials and engineering, and discloses a preparation method of a phosphate cross-linked organic porous uranium extractant. A phenylacetylene is cross-linked with 1,4-dithioerythritol through a click chemistry reaction by using a photo-induced cross-linking method. Compared with common mercaptans, 1,4-dithioerythritol contains an adsorption group. The cross-linking reaction is carried out under the condition that the ratio is 1:3 and the light irradiation time is 1h. An organic polymer PCM with a porous structure is synthesized. After the synthesized polymer is subjected to Soxhlet extraction for 48h, the polymer is modified by phosphating with phosphorus oxychloride to prepare a porous polymer containing a phosphate group. After the synthesized polymer is subjected to Soxhlet extraction for 48h and is dried, a purple black powder P-PCM is obtained. The target polymer can be synthesized only through three steps of reactions. The polymer preparation is relatively simple under the photo-induced cross-linking, which is of great significance to improving the uranium adsorption capacity. The preparation is simple, the reaction is stable, the safety is high, and the cost is low through the click chemistry reaction.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials and engineering technology, specifically relating to a method for preparing a phosphate-crosslinked organic porous uranium extractant. Background Technology

[0002] Oceans and salt lakes contain large amounts of uranium. Recovering uranium from natural waters can not only solve the problem of radioactive contamination in water but also sustain the fuel supply for nuclear power plants. Adsorption processes offer a promising route for efficient uranium extraction. Uranium extraction from water can be achieved through various methods, including ion exchange, coprecipitation, membrane separation, and adsorption. Adsorption is one of the most commonly used methods for uranium extraction from water due to its advantages of low cost, simple operation, and good efficiency. The preparation of high-performance adsorbents is a major challenge in adsorption technology. Therefore, developing inexpensive and high-performance adsorbents to remove uranium from seawater is crucial. Extensively studied porous organic polymers include covalent organic polymers (POPs), covalent organic frameworks (COFs), conjugated microporous polymers (CMPs), covalent triazine frameworks (CTFs), and porous aromatic frameworks (PAFs). However, most of these porous organic polymers are synthesized using noble metal catalysts, which limits their practical applications.

[0003] Crosslinked polymers are a class of porous organic polymers with rigid benzene ring structures, large specific surface areas, and abundant permanent pores. Their large specific surface area and greater stability make them suitable for adsorbing and treating heavy metals, especially uranium. Phosphorylation is an effective method for sample functionalization because the chelation of P=O with uranyl ions can be achieved through solid covalent bonding. Therefore, uranium can be extracted from seawater through crosslinking reactions combined with phosphate esterification. This method improves adsorption capacity and selectivity, thus a method for preparing phosphate-crosslinked organic porous uranium extractants is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a phosphate-crosslinked organic porous uranium extractant, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a phosphate-crosslinked organic porous uranium extractant, comprising the following steps:

[0006] S1. Under nitrogen protection, 1,3,5-tribromobenzene, bis(triphenylphosphine)palladium dichloride, triphenylphosphine and cuprous iodide were added sequentially to a 250 mL three-necked flask, triethylamine was injected, trimethylsilylacetylene was added, and the mixture was stirred in an oil bath to obtain the reactants.

[0007] S2. Add the reactants and anhydrous potassium carbonate to a 50 mL three-necked flask, then add methanol and tetrahydrofuran in sequence, stir at room temperature for 12 h, and dry to obtain mixture a;

[0008] S3. Mixture a obtained by dissolving S2 in tetrahydrofuran, add photoinitiator 1,4-dithiothreitol, irradiate with ultraviolet light, wash the reaction solution with methanol and dichloromethane, and vacuum dry for 48 h to obtain polymer b.

[0009] S4. Add anhydrous AlCl3 and POCl3 to polymer b obtained in S3 in a three-necked flask, and heat at 115°C for 48 hours. Filter the mixture, wash it several times with distilled water and dry it to obtain a purplish-black powder containing phosphate polymer P-PCM.

[0010] Preferably, in step S1, the amount of 1,3,5-tribromobenzene added is 2.00 g with a concentration of 6.40 mmol, the amount of bis(triphenylphosphine)palladium dichloride added is 227 mg with a concentration of 320 μmol, the amount of triphenylphosphine added is 86.9 mg with a concentration of 320 μmol, the amount of cuprous iodide added is 64.8 mg with a concentration of 320 μmol, the amount of triethylamine added is 73.0 mL, and the amount of trimethylsilylacetylene added is 2.90 mL with a concentration of 19.2 mmol.

[0011] Preferably, in step S2, the amount of anhydrous potassium carbonate added is 97.0 mg, the concentration is 702 μmol, the amount of methanol added is 7.50 mL, and the amount of tetrahydrofuran added is 24.5 mL.

[0012] Preferably, in step S3, the amount of tetrahydrofuran added is 2 mL, the amount of photoinitiator added is 17.6 mg, the amount of 1,4-dithiothreitol added is 155.0 mg, and the concentration is 1.00 mmol / L.

[0013] Preferably, in step S4, the amount of anhydrous AlCl3 added is 70 mg, and the amount of POCl3 added is 10 mL.

[0014] Preferably, in S1, the molar ratio of bis(triphenylphosphine)palladium dichloride, triphenylphosphine, and cuprous iodide is 1:1:1.

[0015] Preferably, in S1, the molar ratio of 1,3,5-tribromobenzene and trimethylsilylacetylene is 1:3.

[0016] Preferably, in step S1, the heating temperature of the oil bath stirring is 89.5°C, and the stirring time is 16 hours.

[0017] Preferably, in step S3, the duration of ultraviolet light irradiation is 1 hour.

[0018] Preferably, in step S4, the drying environment is a vacuum at 70°C, and the drying time is 24 hours.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The preparation method provided by this invention only requires three steps to synthesize the target polymer. The reaction system is under photo-induced crosslinking, which makes polymer preparation relatively simple and is of great significance for improving uranium adsorption capacity. Furthermore, through click chemistry, the preparation is simple, the reaction is stable, safe, low-cost, and recyclable, which is in line with the concept of green chemistry and has significant research significance and scientific value in the field of adsorption. Attached Figure Description

[0021] Figure 1 The infrared spectrum of the P-PCM of this invention;

[0022] Figure 2 This is a schematic diagram showing the effect of adsorption time on uranium adsorption by P-PCM according to the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-2 As shown, the present invention provides the following technical solution: a method for preparing a phosphate-crosslinked organic porous uranium extractant, comprising the following steps:

[0025] S1. Under nitrogen protection, 1,3,5-tribromobenzene, bis(triphenylphosphine)palladium dichloride, triphenylphosphine and cuprous iodide were added sequentially to a 250 mL three-necked flask, triethylamine was injected, trimethylsilylacetylene was added, and the mixture was stirred in an oil bath to obtain the reactants.

[0026] S2. Add the reactants and anhydrous potassium carbonate to a 50 mL three-necked flask, then add methanol and tetrahydrofuran in sequence, stir at room temperature for 12 h, and dry to obtain mixture a;

[0027] S3. Mixture a obtained by dissolving S2 in tetrahydrofuran, add photoinitiator 1,4-dithiothreitol, irradiate with ultraviolet light, wash the reaction solution with methanol and dichloromethane, and vacuum dry for 48 h to obtain polymer b.

[0028] S4. Add anhydrous AlCl3 and POCl3 to polymer b obtained in S3 in a three-necked flask, and heat at 115°C for 48 hours. Filter the mixture, wash it several times with distilled water and dry it to obtain a purplish-black powder containing phosphate polymer P-PCM.

[0029] The chemical reaction steps for the above reaction are as follows:

[0030]

[0031] In addition, in this invention, in S1, the amount of 1,3,5-tribromobenzene added is 2.00 g with a concentration of 6.40 mmol, the amount of bis(triphenylphosphine)palladium dichloride added is 227 mg with a concentration of 320 μmol, the amount of triphenylphosphine added is 86.9 mg with a concentration of 320 μmol, the amount of cuprous iodide added is 64.8 mg with a concentration of 320 μmol, the amount of triethylamine added is 73.0 mL, and the amount of trimethylsilylacetylene added is 2.90 mL with a concentration of 19.2 mmol.

[0032] Furthermore, in this invention, regarding the above-mentioned S2, the amount of anhydrous potassium carbonate added is 97.0 mg, the concentration is 702 μmol, the amount of methanol added is 7.50 mL, and the amount of tetrahydrofuran added is 24.5 mL.

[0033] Furthermore, in this invention, regarding the above-mentioned S3, the amount of tetrahydrofuran added is 2 mL, the amount of photoinitiator added is 17.6 mg, the amount of 1,4-dithiothreitol added is 155.0 mg, and the concentration is 1.00 mmol / L.

[0034] Furthermore, in this invention, regarding the above-mentioned S4, the amount of anhydrous AlCl3 added is 70 mg, and the amount of POCl3 added is 10 mL.

[0035] Furthermore, in this invention, regarding the above-mentioned S1, the molar ratio of bis(triphenylphosphine)palladium dichloride, triphenylphosphine, and cuprous iodide is 1:1:1.

[0036] Furthermore, in this invention, the molar ratio of S1,1,3,5-tribromobenzene and trimethylsilylacetylene is 1:3.

[0037] Furthermore, in this invention, regarding the above-mentioned S1, the heating temperature of the oil bath stirring is 89.5°C, and the stirring time is 16 hours.

[0038] Furthermore, in this invention, regarding the above-mentioned S3, the duration of ultraviolet light irradiation is 1 hour.

[0039] Furthermore, in this invention, regarding the above-mentioned S4, the drying environment is a vacuum at 70°C, and the drying time is 24 hours.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of phosphate crosslinked organic porous uranium extractant, characterized in that: The method comprises the following steps: S1. Under the protection of nitrogen, 1, 3, 5-tribromobenzene, bis-triphenylphosphine palladium dichloride, triphenylphosphine and cuprous iodide are sequentially added into a 250ml three-necked flask, triethylamine is injected, and trimethylsilylethynyl is added after oil bath stirring to obtain a reaction mixture; the addition amount of the 1, 3, 5-tribromobenzene is 2.00g, the concentration is 6.40mmol, the addition amount of the bis-triphenylphosphine palladium dichloride is 227mg, the concentration is 320μmol, the addition amount of the triphenylphosphine is 86.9mg, the concentration is 320μmol, the addition amount of the cuprous iodide is 64.8mg, the concentration is 320μmol, the addition amount of the triethylamine is 73.0ml, and the addition amount of the trimethylsilylethynyl is 2.90ml, the concentration is 19.2mmol; S2. The reaction mixture and anhydrous potassium carbonate are added into a 50ml three-necked flask, and then methanol and tetrahydrofuran are sequentially injected, stirring is carried out at room temperature for 12h, and then drying is carried out to obtain a mixture a; the addition amount of the anhydrous potassium carbonate is 97.0mg, the concentration is 702μmol, the addition amount of the methanol is 7.50ml, and the addition amount of the tetrahydrofuran is 24.5ml; S3. The mixture a obtained in S2 is dissolved in tetrahydrofuran, a photoinitiator and 1, 4-dithiothreitol are added, ultraviolet light irradiation is carried out, the reaction solution is washed with methanol and dichloromethane, and then vacuum drying is carried out for 48h to obtain a polymer b; the addition amount of the tetrahydrofuran is 2ml, the addition amount of the photoinitiator is 17.6mg, and the addition amount of the 1, 4-dithiothreitol is 155.0mg, the concentration is 1.00mmol; S4. Anhydrous AlCl3 and POCl3 are added into the polymer b obtained in S3 in a three-necked flask, and then the mixture is filtered, washed with distilled water for multiple times and dried to obtain a purple black powder phosphorus-containing polymer P-PCM; the addition amount of the anhydrous AlCl3 is 70mg, and the addition amount of the POCl3 is 10ml.

2. The method for preparing the phosphate-crosslinked organic porous uranium extractant according to claim 1, characterized in that: In S1, the molar ratio of bis-triphenylphosphine palladium dichloride, triphenylphosphine and cuprous iodide is 1:1:

1.

3. The method for preparing the phosphate-crosslinked organic porous uranium extractant according to claim 1, characterized in that: In S1, the molar ratio of the 1, 3, 5-tribromobenzene and trimethylsilylethynyl is 1:

3.

4. The method for preparing the phosphate-crosslinked organic porous uranium extractant according to claim 1, characterized in that: In S1, the heating temperature of the oil bath stirring is 89.5℃, and the stirring time is 16h.

5. The method for preparing the phosphate-crosslinked organic porous uranium extractant according to claim 1, characterized in that: In S3, the ultraviolet light irradiation time is 1h.

6. The method for preparing the phosphate-crosslinked organic porous uranium extractant according to claim 1, characterized in that: In S4, the drying environment is 70℃ vacuum, and the drying time is 24h.

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