Synthesis of crown ether-based covalent organic framework adsorption materials and their targeted adsorption and extraction methods for indium

Abstract

The invention discloses the synthesis of crown ether-based covalent organic framework adsorption materials and a method for targeted adsorption and extraction of indium, and belongs to the technical field of nonferrous metal metallurgy. The synthesis of the crown ether-based covalent organic framework adsorption materials and the method for targeted adsorption and extraction of indium of the invention are aimed at the problem that low-concentration indium in acidic multi-component complex systems is difficult to be separated and extracted efficiently. According to the bonding coordination characteristics of indium ions, crown ether supramolecules with specifically matched spatial configuration and highly complementary electronic states are selected as basic units. A series of crown ether-based covalent organic framework adsorption materials with specific topological structures are constructed through efficient polycondensation reactions with "self-correction" and "self-repairing" characteristics. The materials have the characteristics of strong selectivity for indium, large complex affinity, high chemical stability, etc., and can realize efficient selective adsorption, separation and extraction of low-concentration indium in acidic multi-component complex systems.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal metallurgy, and more specifically, relates to a method for synthesizing a crown ether-based covalent organic framework adsorption material and extracting indium by targeted adsorption. Background Art

[0002] As a strategic metal, indium occupies a pivotal position in modern industry and is a key raw material supporting the development of the top ten emerging industries. Its application in new energy technology, new generation information technology, aerospace, and national defense is particularly prominent. With its unique conductivity and light transmittance, about 80% of indium is used to manufacture ITO (indium tin oxide) targets, which are then converted into core components of liquid crystal displays through a magnetron sputtering process, which constitutes the main area of ​​current indium application. In addition, due to its excellent semiconductor properties, indium plays an important role in the production of high-performance semiconductor materials such as indium phosphide, which have a far-reaching impact on promoting the miniaturization of electronic devices and improving energy efficiency.

[0003] With the development of strategic emerging industries, a large amount of secondary resources containing indium are generated every year. After pretreatment and enrichment, these resources are usually treated by wet leaching to form an acidic complex solution system containing indium. However, due to the low indium content in the solution system, the wide variety of impurity elements and serious interference, the efficient and selective separation and extraction of indium faces great challenges. To this end, the development of efficient and selective indium adsorption materials is particularly critical.The application with Chinese patent application number 201811102086.3 discloses a method for preparing an impregnating resin for adsorbing scattered metal indium (III), wherein styrene-divinylbenzene macroporous resin is placed in a mixed system of N1923, phytic acid mixed extractant and anhydrous ethanol to react to prepare an impregnating resin, which has the characteristics of fast adsorption rate, large adsorption capacity, good stability and easy recovery; the application with Chinese patent application number 201911296945.1 discloses a hyperbranched polyethyleneimine modified carbon fiber adsorption material and preparation method for adsorbing indium (III), wherein the modified carbon fiber is prepared from activated carbon fiber and hyperbranched polyethyleneimine (HPEI), and the adsorption and separation of indium (III) in an acidic solution system is realized; the application with Chinese patent application number 201610249106.4 discloses a method for recovering indium from indium-containing smoke, wherein a polyvinylidene fluoride adsorption functional membrane is used to treat the leaching liquid The indium in the waste liquid crystal panel is adsorbed and enriched, thereby realizing the efficient recovery of indium in the smoke dust; the application case with Chinese patent application number 201210321309.1 discloses a method for recovering indium from waste liquid crystal panels by an acid leaching-cation exchange resin adsorption process, and a strong acid cation exchange resin column is used to countercurrently adsorb the waste liquid crystal panel leachate, thereby realizing the effective separation of indium in the solution; the application case with Chinese patent application number 201010280023.4 discloses an indium adsorbent, a method for manufacturing an indium adsorbent, and an indium adsorption method, wherein the adsorbent is a polymer material having a template structure for indium, and can achieve an indium adsorption selectivity of more than 2.0 relative to zinc; the application case with Chinese patent application number 201910069823.2 discloses a method for adsorbing and separating indium using a metal organic framework material UiO-66, wherein UiO-66 is used as an adsorbent at a pH of 2 to 4 and an indium ion concentration of 1 to 100 The selective adsorption and separation of indium was achieved under the conditions of 0.1% to 0.1% mg / L and a temperature of 25 to 45°C; the application case with Chinese patent application number 201910851278.2 discloses a synthesis of a P204 composite UiO-66 material and a method for using it to adsorb and separate indium from a liquid crystal panel. The synthesized P204 / UiO-66 composite material is used as an adsorbent. Under the conditions of a shaking table temperature of 25 to 45°C, a rotation speed of 200-300 rpm, and a pH value of 0 to 3, more than 95% of the indium in the waste liquid crystal panel leachate can be recovered; the application case with Chinese patent application number 201610421206.0 discloses a synthesis method and application of polysulfone microcapsules for adsorbing indium. Polysulfone is used as a raw material, the microcapsule technology is combined with the extraction technology, and the extractant is coated by a microencapsulation method. The prepared polysulfone microcapsule material achieves a good indium adsorption effect. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that low-concentration indium in an acidic multi-component complex system is difficult to be efficiently separated and extracted, and to solve the problems of poor selectivity, low adsorption depth, limited recovery rate, etc. of traditional indium adsorption materials, and to provide a method for synthesizing a crown ether-based covalent organic framework adsorption material and for targeted adsorption and extraction of indium. According to the bonding coordination characteristics of indium ions, crown ether supramolecules with a specifically matched spatial configuration and highly complementary electronic states are selected as basic units, and a series of crown ether-based covalent organic framework adsorption materials with specific topological structures are constructed through efficient polycondensation reactions with "self-correcting" and "self-repairing" characteristics. The crown ether-based covalent organic framework adsorption materials have the characteristics of strong selectivity for indium, large complex affinity, high chemical stability, etc., and can realize efficient selective adsorption, separation and extraction of low-concentration indium in an acidic multi-component complex system.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] The synthesis of the crown ether-based covalent organic framework adsorption material and the method for targeted adsorption and extraction of indium of the present invention are as follows:

[0007] (1) Add benzo-15-crown-5 and tetramethylethylenediamine to a n-hexane solution and stir to dissolve, then dropwise add a n-hexane solution containing n-butyl lithium in a dry ice ethanol bath, and react at room temperature; then dropwise add a n-hexane solution containing elemental iodine in a dry ice ethanol bath, and continue to react at room temperature; after the reaction is completed, quench with water, separate the liquids, perform vacuum rotary evaporation, and purify in sequence to obtain 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1;

[0008] (2) dissolving the intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH in a mixed solution of 1,4-dioxane and water, and reacting at a constant temperature; after the reaction, diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, and purification are performed in sequence to obtain a crown ether precursor, i.e., intermediate product 2;

[0009] (3) adding the intermediate product 2 obtained in step (2) and the linker to a mixed solution of 1,4-dioxane and mesitylene, degassing the reactor and sealing it under vacuum; placing the sealed reactor in an oil bath ultrasonic machine and reacting at a constant temperature under ultrasonic oscillation conditions; after the reaction, washing the product with N,N-dimethylformamide, tetrahydrofuran and acetone in sequence to finally obtain the target product, i.e., a crown ether-based covalent organic framework adsorption material;

[0010] (4) The synthesized crown ether-based covalent organic framework adsorption material is added to an indium-containing acidic solution system for constant temperature reaction to achieve targeted adsorption, separation and extraction of indium.

[0011] Preferably, in step (1), the molar ratio of benzo-15-crown-5 to tetramethylethylenediamine is (1:2) to (1:8), the molar ratio of benzo-15-crown-5 to n-butyllithium is (1:4) to (1:12), the molar ratio of benzo-15-crown-5 to elemental iodine is (1:2) to (1:8), and the reaction time is 6 to 36 h.

[0012] Preferably, the molar ratio of the intermediate product 1 in step (2) to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)benzaldehyde is (1:2) to (1:8), the molar ratio to Pd(dppf)Cl2 is (1:0.1) to (1:1), and the molar ratio to KOH is (1:2) to (1:8), the reaction temperature is 70 to 140 °C, and the reaction time is 6 to 36 h.

[0013] Preferably, in step (3), the linker is one of tetrakis-(4-aminophenyl)-ethylene, tetrakis-(p-aminophenyl)-porphyrin, tris(4-aminophenyl)amine, and 4,4',4'',4'''-(3a1,5-dihydropyrene-1,3,6,8-tetrayl)tetraphenylamine, the molar ratio of the intermediate product 2 to the linker is (1:1) to (5:1), the molar ratio of 1,4-dioxane to mesitylene is (1:1) to (5:1), the reaction temperature is 100 to 140 °C, and the reaction time is 6 to 36 h.

[0014] Preferably, in step (4), the acidity of the solution is 0.005 to 5 mol / L, the reaction temperature is 20 to 95° C., and the reaction time is 0.5 to 4 h.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention relates to the synthesis of crown ether-based covalent organic framework adsorbent materials and a method for targeted adsorption and extraction of indium. Aiming at the efficient separation and extraction of low-concentration indium in acidic multi-component complex systems, a series of crown ether-based covalent organic framework structures with specific topological structures are designed, and a synthesis route with "self-correcting" and "self-repairing" properties is proposed. In the synthesis process of the adsorbent material, benzo-15-crown-5 is directly used as the raw material, and 1,4-diiodobenzo-15-crown-5 can be obtained by a one-step iodination substitution reaction. The crown ether precursor is obtained by selecting suitable reaction raw materials and synthesis conditions, and finally an efficient and short-process preparation of crown ether-based covalent organic framework adsorbent materials is achieved.

[0017] (2) The synthesis of the crown ether-based covalent organic framework adsorbent material and the method for targeted adsorption and extraction of indium of the crown ether-based covalent organic framework adsorbent material of the present invention. The crown ether unit is stably present in the skeleton of the covalent organic framework adsorbent material, and the degree of structural pre-organization is high. During the complexation with indium ions, the energy loss caused by conformational transition can be effectively reduced, which is conducive to the formation of a stable complex. In addition, the crown ether-based covalent organic framework adsorbent material has a rigid π-type skeleton, which can provide additional ion-dipole electrostatic force for the complexation process, further strengthening the complexation process.

[0018] (3) The synthesis of the crown ether-based covalent organic framework adsorbent material of the present invention and the method for targeted adsorption and extraction of indium. The crown ether moiety in the adsorbent material realizes selective recognition of indium ions through non-covalent weak interactions. This weak interaction is not only directional and synergistic, but also has good reversibility, which is an important basis for achieving efficient adsorption-desorption. The topological dimension and pore shape and size of the covalent organic framework adsorbent material can be flexibly controlled by changing the synthesis conditions, thereby improving the permeability and transportability of metal ions during the adsorption-desorption process, so that it has excellent recycling performance. DETAILED DESCRIPTION

[0019] The synthesis of the crown ether-based covalent organic framework adsorption material of the present invention and the method for targeted adsorption and extraction of indium, according to the bonding coordination characteristics of indium ions, selects crown ether supramolecules with specific spatial configuration matching and highly complementary electronic states as basic units, and constructs a series of crown ether-based covalent organic framework adsorption materials with specific topological structures through efficient polycondensation reactions with "self-correction" and "self-repairing" characteristics, which have the characteristics of strong selectivity for indium, large complex affinity, high chemical stability, etc., and can achieve efficient selective adsorption, separation and extraction of low-concentration indium in acidic multi-component complex systems. The treatment process of the present invention specifically includes the following steps:

[0020] (1) Benzo-15-crown-5 and tetramethylethylenediamine (TMEDA) were added to a n-hexane solution in a molar ratio of (1:2) to (1:8) and stirred to dissolve. Then, a n-hexane solution containing n-butyl lithium (the molar ratio of benzo-15-crown-5 to n-butyl lithium was (1:4) to (1:12)) was added dropwise under a dry ice ethanol bath, and the reaction was continued at room temperature for 6 to 36 hours. Then, a n-hexane solution containing iodine (the molar ratio of benzo-15-crown-5 to iodine was (1:2) to (1:8)) was added dropwise under a dry ice ethanol bath, and the reaction was continued at room temperature for 6 to 36 hours. After the reaction was completed, quenching with water, separation, vacuum rotary evaporation, purification and other steps were carried out in sequence to obtain 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1.

[0021] (2) The intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH are dissolved in a mixed solution of 1,4-dioxane and water (the molar ratio of the intermediate product 1 to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde is (1:2) to (1:8), the molar ratio of the intermediate product 1 to Pd(dppf)Cl2 is (1:0.1) to (1:1), and the molar ratio of the intermediate product 1 to KOH is (1:2) to (1:8)), and the mixture is refluxed at 70 to 140°C for 6 to 36 hours. After the reaction is completed, the intermediate product 1 is subjected to diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, purification, and other steps to obtain a crown ether precursor, namely, the intermediate product 2. Among them, Pd(dppf)Cl2 is a chemical substance, the full name of which is palladium(II) chloride-1,1'-bis(diphenylphosphino)ferrocene, and is a commonly used transition metal catalyst.

[0022] (3) The intermediate product 2 obtained in step (2) and a linker (one of tetrakis-(4-aminophenyl)-ethylene, tetrakis-(p-aminophenyl)-porphyrin, tris(4-aminophenyl)amine, 4,4',4'',4'''-(3a1,5-dihydropyrene-1,3,6,8-tetrayl)tetraphenylamine) are added in a molar ratio of (1:1) to (5:1) to a mixed solution of 1,4-dioxane and mesitylene (the molar ratio of 1,4-dioxane to mesitylene is (1:1) to (5:1)), and the reactor is degassed and vacuum-sealed; the sealed reactor is further placed in an oil bath ultrasonic machine and subjected to ultrasonic oscillation reaction at a temperature of 100 to 140°C for 12 to 92 hours. After the reaction is completed, the product is washed with N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and acetone in sequence to finally obtain the target product, namely the crown ether-based covalent organic framework adsorption material.

[0023] (4) The synthesized crown ether-based covalent organic framework adsorbent material is added to an indium-containing solution system with an acidity of 0.005 to 5 mol / L and reacted at a temperature of 20 to 95°C for 0.5 to 4 h to achieve targeted adsorption, separation and extraction of indium.

[0024] The present invention is further described below in conjunction with specific embodiments.

[0025] Example 1

[0026] The synthesis of the crown ether-based covalent organic framework adsorption material and the method for targeted adsorption and extraction of indium in this embodiment specifically include the following steps:

[0027] (1) Benzo-15-crown-5 and tetramethylethylenediamine (TMEDA) were added to a n-hexane solution in a molar ratio of 1:2 and stirred to dissolve. Then, a n-hexane solution containing n-butyl lithium (the molar ratio of benzo-15-crown-5 to n-butyl lithium was 1:4) was added dropwise under a dry ice ethanol bath, and the mixture was reacted at room temperature for 6 h. Then, a n-hexane solution containing iodine (the molar ratio of benzo-15-crown-5 to iodine was 1:2) was added dropwise under a dry ice ethanol bath, and the mixture was reacted at room temperature for 6 h. After the reaction was completed, quenching with water, separation, vacuum rotary evaporation, purification and other steps were performed in sequence to obtain 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1.

[0028] (2) The intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH were dissolved in a mixed solution of 1,4-dioxane and water (the molar ratio of the intermediate product 1 to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde was 1:2, the molar ratio of the intermediate product 1 to Pd(dppf)Cl2 was 1:0.1, and the molar ratio of the intermediate product 1 to KOH was 1:2), and the mixture was refluxed at 70°C for 6 h. After the reaction was completed, the intermediate product 1 was subjected to diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, purification, and other steps to obtain a crown ether precursor, namely, the intermediate product 2.

[0029] (3) The intermediate product 2 obtained in step (2) and the linker tetra-(4-aminobenzene)-ethylene are added to a mixed solution of 1,4-dioxane and mesitylene (the molar ratio of 1,4-dioxane to mesitylene is 1:1) in a molar ratio of 1:1, and the reactor is degassed and vacuum-sealed; the sealed reactor is further placed in an oil bath ultrasonic machine and ultrasonically shaken at 100 °C for 12 h. After the reaction is completed, the product is washed with N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and acetone in sequence to finally obtain the target product, i.e., the crown ether-based covalent organic framework adsorption material.

[0030] (4) The synthesized crown ether-based covalent organic framework adsorbent material was added to an indium-containing solution system with an acidity of 0.005 mol / L and reacted at 20 °C for 4 h to achieve targeted adsorption, separation and extraction of indium. The adsorption rate of indium was 99.12%.

[0031] The adsorption rate can be calculated by the following formula:

[0032] Adsorption rate = (C0 - Ce) / C0 × 100%

[0033] Where: (C0) is the initial concentration of indium ions in the solution (mol / L); (Ce) is the remaining indium ion concentration in the solution at equilibrium (i.e. after the reaction is completed) (mol / L).

[0034] Example 2

[0035] The synthesis of the crown ether-based covalent organic framework adsorption material and the method for targeted adsorption and extraction of indium in this embodiment specifically include the following steps:

[0036] (1) Benzo-15-crown-5 and tetramethylethylenediamine (TMEDA) were added to a n-hexane solution in a molar ratio of 1:8 and stirred to dissolve. Then, a n-hexane solution containing n-butyl lithium (the molar ratio of benzo-15-crown-5 to n-butyl lithium was 1:12) was added dropwise under a dry ice ethanol bath, and the mixture was reacted at room temperature for 36 h. Then, a n-hexane solution containing iodine (the molar ratio of benzo-15-crown-5 to iodine was 1:8) was added dropwise under a dry ice ethanol bath, and the mixture was reacted at room temperature for 36 h. After the reaction was completed, 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1, was obtained by sequentially performing the steps of quenching with water, separation, vacuum rotary evaporation, and purification.

[0037] (2) The intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH are dissolved in a mixed solution of 1,4-dioxane and water (the molar ratio of the intermediate product 1 to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde is 1:8, the molar ratio of the intermediate product 1 to Pd(dppf)Cl2 is 1:1, and the molar ratio of the intermediate product 1 to KOH is 1:8), and the mixture is refluxed at 140°C for 36 h. After the reaction is completed, the intermediate product 1 is subjected to diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, purification, and other steps to obtain a crown ether precursor, namely, the intermediate product 2.

[0038] (3) The intermediate product 2 obtained in step (2) and the linker tetra-(p-aminophenyl)-porphyrin are added to a mixed solution of 1,4-dioxane and mesitylene (the molar ratio of 1,4-dioxane to mesitylene is 5:1) at a molar ratio of 5:1, and the reactor is degassed and vacuum-sealed; the sealed reactor is further placed in an oil bath ultrasonic machine and ultrasonically shaken at 140 °C for 92 h. After the reaction is completed, the product is washed with N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and acetone in sequence to finally obtain the target product, i.e., the crown ether-based covalent organic framework adsorption material.

[0039] (4) The synthesized crown ether-based covalent organic framework adsorbent material was added to an indium-containing solution system with an acidity of 5 mol / L and reacted at 95 °C for 0.5 h to achieve targeted adsorption, separation and extraction of indium. The adsorption rate of indium was 99.27%.

[0040] Example 3

[0041] The synthesis of the crown ether-based covalent organic framework adsorption material and the method for targeted adsorption and extraction of indium in this embodiment specifically include the following steps:

[0042] (1) Benzo-15-crown-5 and tetramethylethylenediamine (TMEDA) were added to a n-hexane solution in a molar ratio of 1:3 and stirred to dissolve. Then, a n-hexane solution containing n-butyl lithium (the molar ratio of benzo-15-crown-5 to n-butyl lithium was 1:6) was added dropwise under a dry ice ethanol bath, and the reaction was continued at room temperature for 12 h. Then, a n-hexane solution containing iodine (the molar ratio of benzo-15-crown-5 to iodine was 1:3) was added dropwise under a dry ice ethanol bath, and the reaction was continued at room temperature for 12 h. After the reaction was completed, quenching with water, separation, vacuum rotary evaporation, purification and other steps were carried out in sequence to obtain 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1.

[0043] (2) The intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH are dissolved in a mixed solution of 1,4-dioxane and water (the molar ratio of the intermediate product 1 to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde is 1:3, the molar ratio of the intermediate product 1 to Pd(dppf)Cl2 is 1:0.3, and the molar ratio of the intermediate product 1 to KOH is 1:3), and the mixture is refluxed at 90°C for 12 h. After the reaction is completed, the intermediate product 1 is subjected to diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, purification, and other steps to obtain a crown ether precursor, namely, the intermediate product 2.

[0044] (3) The intermediate product 2 obtained in step (2) and the linker tri(4-aminophenyl)amine are added to a mixed solution of 1,4-dioxane and mesitylene in a molar ratio of 2:1 (the molar ratio of 1,4-dioxane to mesitylene is 2:1), the reactor is degassed and vacuum-sealed; the sealed reactor is further placed in an oil bath ultrasonic machine and ultrasonically shaken at 110 °C for 24 h. After the reaction is completed, the product is washed with N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and acetone in sequence to finally obtain the target product, i.e., the crown ether-based covalent organic framework adsorption material.

[0045] (4) The synthesized crown ether-based covalent organic framework adsorbent material was added to an indium-containing solution system with an acidity of 1 mol / L and reacted at 45 °C for 1 h to achieve targeted adsorption, separation and extraction of indium. The adsorption rate of indium was 99.38%.

[0046] Example 4

[0047] The synthesis of the crown ether-based covalent organic framework adsorption material and the method for targeted adsorption and extraction of indium in this embodiment specifically include the following steps:

[0048] (1) Benzo-15-crown-5 and tetramethylethylenediamine (TMEDA) were added to a n-hexane solution in a molar ratio of 1:5 and stirred to dissolve. Then, a n-hexane solution containing n-butyl lithium (the molar ratio of benzo-15-crown-5 to n-butyl lithium was 1:8) was added dropwise under a dry ice ethanol bath, and the reaction was continued at room temperature for 18 h. Then, a n-hexane solution containing iodine (the molar ratio of benzo-15-crown-5 to iodine was 1:5) was added dropwise under a dry ice ethanol bath, and the reaction was continued at room temperature for 18 h. After the reaction was completed, quenching with water, separation, vacuum rotary evaporation, purification and other steps were carried out in sequence to obtain 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1.

[0049] (2) The intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH are dissolved in a mixed solution of 1,4-dioxane and water (the molar ratio of the intermediate product 1 to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde is 1:5, the molar ratio of the intermediate product 1 to Pd(dppf)Cl2 is 1:0.5, and the molar ratio of the intermediate product 1 to KOH is 1:5), and the mixture is refluxed at 110°C for 18 h. After the reaction is completed, the intermediate product 1 is subjected to diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, purification, and other steps to obtain a crown ether precursor, namely, the intermediate product 2.

[0050] (3) The intermediate product 2 obtained in step (2) and the linker 4,4',4'',4'''-(3a1,5-dihydropyrene-1,3,6,8-tetrayl)tetraphenylamine are added to a mixed solution of 1,4-dioxane and mesitylene (the molar ratio of 1,4-dioxane to mesitylene is 3:1) at a molar ratio of 3:1, and the reactor is degassed and vacuum-sealed; the sealed reactor is further placed in an oil bath ultrasonic machine and ultrasonically shaken at 120°C for 48 hours. After the reaction is completed, the product is washed with N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and acetone in sequence to finally obtain the target product, i.e., the crown ether-based covalent organic framework adsorption material.

[0051] (4) The synthesized crown ether-based covalent organic framework adsorption material was added to an indium-containing solution system with an acidity of 2.5 mol / L and reacted at 60 °C for 2 h to achieve targeted adsorption, separation and extraction of indium. The adsorption rate of indium was 99.11%.

[0052] Example 5

[0053] The synthesis of the crown ether-based covalent organic framework adsorption material and the method for targeted adsorption and extraction of indium in this embodiment specifically include the following steps:

[0054] (1) Benzo-15-crown-5 and tetramethylethylenediamine (TMEDA) were added to a n-hexane solution in a molar ratio of 1:7 and stirred to dissolve. Then, a n-hexane solution containing n-butyl lithium (the molar ratio of benzo-15-crown-5 to n-butyl lithium was 1:10) was added dropwise under a dry ice ethanol bath, and the mixture was reacted at room temperature for 24 h. Then, a n-hexane solution containing iodine (the molar ratio of benzo-15-crown-5 to iodine was 1:7) was added dropwise under a dry ice ethanol bath, and the mixture was reacted at room temperature for 24 h. After the reaction was completed, 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1, was obtained by sequentially performing the steps of quenching with water, separation, vacuum rotary evaporation, and purification.

[0055] (2) The intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH are dissolved in a mixed solution of 1,4-dioxane and water (the molar ratio of the intermediate product 1 to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde is 1:7, the molar ratio of the intermediate product 1 to Pd(dppf)Cl2 is 1:0.7, and the molar ratio of the intermediate product 1 to KOH is 1:7), and the mixture is refluxed at 130°C for 24 h. After the reaction is completed, the intermediate product 1 is subjected to diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, purification, and other steps to obtain a crown ether precursor, namely, the intermediate product 2.

[0056] (3) The intermediate product 2 obtained in step (2) and the linker tri(4-aminophenyl)amine are added to a mixed solution of 1,4-dioxane and mesitylene in a molar ratio of 4:1 (the molar ratio of 1,4-dioxane to mesitylene is 4:1), the reactor is degassed and vacuum-sealed; the sealed reactor is further placed in an oil bath ultrasonic machine and ultrasonically shaken at 130 °C for 72 h. After the reaction is completed, the product is washed with N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and acetone in sequence to finally obtain the target product, i.e., the crown ether-based covalent organic framework adsorption material.

[0057] (4) The synthesized crown ether-based covalent organic framework adsorbent material was added to an indium-containing solution system with an acidity of 4 mol / L and reacted at 75 °C for 3 h to achieve targeted adsorption, separation and extraction of indium. The adsorption rate of indium was 99.41%.

Claims

1. A method for synthesizing a crown ether-based covalent organic framework adsorption material, characterized in that: The specific process operations are: (1) Add benzo-15-crown-5 and tetramethylethylenediamine to a n-hexane solution and stir to dissolve, then dropwise add a n-hexane solution containing n-butyl lithium in a dry ice ethanol bath, and react at room temperature; then dropwise add a n-hexane solution containing elemental iodine in a dry ice ethanol bath, and continue to react at room temperature; after the reaction is completed, quench with water, separate the liquids, perform vacuum rotary evaporation, and purify in sequence to obtain 1,4-diiodobenzo-15-crown-5, i.e., intermediate 1; (2) dissolving the intermediate product 1 obtained in step (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, Pd(dppf)Cl2, and KOH in a mixed solution of 1,4-dioxane and water, and reacting at a constant temperature; after the reaction, diatomaceous earth adsorption, liquid separation, vacuum rotary evaporation, and purification are performed in sequence to obtain a crown ether precursor, i.e., intermediate product 2; (3) The intermediate product 2 obtained in step (2) and the linker are added to a mixed solution of 1,4-dioxane and mesitylene, and the reactor is degassed and sealed by vacuum pumping; the sealed reactor is placed in an ultrasonic machine in an oil bath, and reacted at a constant temperature under ultrasonic oscillation conditions; after the reaction is completed, the product is washed with N,N-dimethylformamide, tetrahydrofuran and acetone in sequence to finally obtain the target product, i.e., a crown ether-based covalent organic framework adsorption material.

2. The method for synthesizing the crown ether based covalent organic framework adsorption material according to claim 1, characterized in that: In the step (1), the molar ratio of benzo-15-crown-5 to tetramethylethylenediamine is (1:2) to (1:8), the molar ratio of benzo-15-crown-5 to n-butyllithium is (1:4) to (1:12), and the molar ratio of benzo-15-crown-5 to iodine is (1:2) to (1:8). The reaction time is 6 to 36 hours.

3. The method for synthesizing the crown ether based covalent organic framework adsorption material according to claim 1, characterized in that: The molar ratio of the intermediate product 1 in step (2) to 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)benzaldehyde is (1:2) to (1:8). The molar ratio of is (1:0.1) to (1:1), the molar ratio of is (1:2) to (1:8) with KOH, the reaction temperature is 70 to 140 °C, and the reaction time is 6 to 36 h.

4. The method for synthesizing the crown ether based covalent organic framework adsorption material according to claim 1, characterized in that: The linker in step (3) is tetrakis-(4-aminophenyl)-ethylene, tetrakis-(p-aminophenyl)-porphyrin, tris(4-aminophenyl)amine, -(3a1,5-dihydropyrene-1,3,6,8-tetrayl)tetraphenylamine, the molar ratio of the intermediate 2 to the linker is (1:1) to (5:1), the molar ratio of 1,4-dioxane to mesitylene is (1:1) to (5:1), the reaction temperature is 100 to 140 °C, and the reaction time is 6 to 36 h.

5. A method for targeted adsorption and extraction of indium using a crown ether-based covalent organic framework adsorption material synthesized by the method of any one of claims 1 to 4, characterized in that: The synthesized crown ether-based covalent organic framework adsorption material is added to an indium-containing acidic solution system for constant temperature reaction to achieve targeted adsorption, separation and extraction of indium.

6. The method for targeted adsorption and extraction of indium according to claim 5, characterized in that: The solution acidity is 0.005-5 mol / L, the reaction temperature is 20-95°C, and the reaction time is 0.5-4 h.