Benzodiimidazole bonded covalent organic framework material as well as preparation method and application thereof
The preparation of benzodiimidazole-bonded covalent organic frame materials through solid phase synthesis method solves the problems of environmental pollution and low efficiency in traditional synthesis methods, and achieves efficient and environmentally friendly preparation of covalent organic frame materials and high catalytic activity.
Patent Information
- Application Number
- CN202510560714.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2025-08-05
AI Technical Summary
The synthesis method of traditional covalent organic frameworks relies on solution phase reactions, resulting in environmental pollution and low efficiency, making it difficult to control the crystallinity and pore size distribution of the material.
By using solid phase synthesis method, a covalent organic frame material with benzodiimidazole bonded is prepared by solid phase reaction between organic carboxylic acid ligand and tetraaminobenzene ligand compounds in benzoic anhydride medium, reducing the use of reaction medium and improving crystallinity and synthesis efficiency.
The preparation of covalent organic frame materials with high crystallinity and uniform pore structure has been achieved, which reduces production costs and waste liquid generation, improves reaction efficiency, and shows high catalytic activity in the catalytic reaction of carbon dioxide and epoxy compounds, and the yield of cyclic carbonate reaches more than 98%.
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Figure CN120424327A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of catalyst synthesis, and in particular to a benzimidazole-linked covalent organic framework material, a preparation method, and applications thereof. Background Art
[0002] Covalent organic frameworks (COFs) are a class of porous crystalline materials composed of organic monomers linked by covalent bonds. Due to their high surface area, excellent chemical stability, and tunable pore size, they have shown widespread application in gas storage, catalysis, and separation. However, traditional COF synthesis methods rely primarily on solution-phase reactions, requiring the use of large amounts of organic reaction media, which increases the environmental burden. Furthermore, the reaction process is complex and difficult to control the crystallinity and pore size distribution of the material.
[0003] Therefore, the development of green and environmentally friendly synthesis methods has become the current research focus. As a rigid heterocyclic structure, benzodiimidazole has excellent π-π interaction and nitrogen atom coordination ability, and is often used to design high-performance COF materials. Although benzodiimidazole-based covalent organic frameworks have been shown to have good effects in the fields of gas adsorption and catalysis, most existing synthesis methods rely on reaction medium systems, which have problems such as pollution and low efficiency. Solid-phase synthesis, as a green chemical method, can be carried out in the absence of reaction medium or with a small amount of reaction medium, reducing environmental impact while improving the crystallinity and synthesis efficiency of the material.
[0004] Therefore, the solid-phase synthesis of benzodiimidazole-based covalent organic frameworks has important research and application value. Summary of the Invention
[0005] The present application provides a benzimidazole-linked covalent organic framework material, a preparation method and its application, to solve the above-mentioned problems mentioned in the background technology.
[0006] In a first aspect, the present application provides a benzimidazole-linked covalent organic framework material, which is obtained by solid-phase reaction of an organic carboxylic acid ligand and a tetraaminobenzene ligand compound; and comprises a structural unit shown in Formula 1 or Formula 2:
[0007]
[0008] Wherein, R includes any one of the organic carboxylic acid ligands shown in Formula 3 to Formula 9:
[0009]
[0010] Optionally, the tetraaminobenzene ligand compound is 2,3,5,6-tetrakis(amino)-p-benzoquinone or 1,2,4,5-phenylenetetramine.
[0011] In a second aspect, the present application provides a method for preparing a benzimidazole-linked covalent organic framework material, which is used to prepare the above-mentioned covalent organic framework material, and the method comprises the following steps:
[0012] A carboxylic acid organic ligand, a tetraaminobenzene ligand compound, and a reaction medium are added to the polytetrafluoroethylene liner of a high-pressure reactor in a proportion, mixed, and the high-pressure reactor is transferred to a constant temperature oven for heating and reaction. After the reaction is completed, the high-pressure reactor is naturally cooled to room temperature to obtain a crude covalent organic framework material;
[0013] The crude covalent organic framework material is filtered, the precipitate is collected, and the precipitate is washed with an organic solvent and dried to obtain the covalent organic framework material.
[0014] Optionally, the molar ratio of the organic carboxylic acid ligand to the tetraaminobenzene ligand compound is 1:2-5.
[0015] Optionally, the reaction medium is benzoic anhydride, and the ratio of the amount of the reaction medium added to the sum of the amounts of the organic carboxylic acid ligand and the tetraaminobenzene ligand compound is 0.5-5:1.
[0016] Optionally, during the heating reaction process, the reaction temperature is 60-400 degrees Celsius and the reaction time is 6-120 hours.
[0017] In a third aspect, the present application provides an application of a benzimidazole-linked covalent organic framework material in catalyzing the reaction of carbon dioxide and epoxy compounds to prepare cyclocarbonates. The covalent organic framework material is the above-mentioned covalent organic framework material, or a covalent organic framework material obtained by the above-mentioned preparation method.
[0018] Optionally, a method for preparing cyclic carbonate comprises the following steps:
[0019] A covalent organic framework material connected by benzdiimidazole, an epoxy compound and tetrabutylammonium bromide are mixed in proportion to obtain a mixture; carbon dioxide gas is introduced into the mixture, and the mixture is stirred and reacted for 0.5-72 hours at a temperature of 25-200 degrees Celsius and a pressure of 0.1-6 MPa to obtain a cyclocarbonate.
[0020] Optionally, the molar ratio of the benzimidazole-linked covalent organic framework material to the epoxy compound is 1:1-25;
[0021] The molar ratio of tetrabutylammonium bromide to the epoxy compound is 1:5-1000.
[0022] Optionally, the epoxy compound includes: ethylene oxide, propylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,2-epoxyhexane, phenyl ethylene oxide, 1,2-epoxydodecane, 1,2,7,8-diepoxyoctane, 1,2-epoxy-2-methylpropane, trans-2,3-epoxybutane, trans-1,2-stilbene oxide, 1-allyloxy-2,3-epoxypropane, 1,2-epoxy-3-phenoxypropane, 3,3,3-trifluoropropylene oxide, butylene oxide and any one of their corresponding chlorinated or fluorinated epoxy compounds.
[0023] The present application provides a benzodiimidazole-linked covalent organic framework material, a preparation method, and its application, which realizes the preparation of a benzodiimidazole-linked covalent organic framework material and has the following beneficial effects compared to the prior art:
[0024] (1) The benzodiimidazole-linked covalent organic framework material provided in the present application is obtained by solid-phase reaction of an organic carboxylic acid ligand and a tetraaminobenzene ligand compound. The covalent organic framework material has different topological structures such as HCB, SQL, and HXL. The covalent organic framework material also has high crystallinity, high specific surface area, uniform pore structure, absorption in the visible light range, excellent thermal stability, and a uniform two-dimensional layered morphology.
[0025] (2) The benzodiimidazole-linked covalent organic framework material provided in the present application is synthesized by solid-phase reaction, and a small amount of reaction medium is used in the preparation process, which not only saves production costs and improves reaction efficiency, but also significantly reduces the generation of reaction medium waste liquid during the subsequent purification process of the product, and has good economic and environmental benefits.
[0026] (3) The synthesis method of the covalent organic framework material prepared in this application is universal. Through organic carboxylic acid ligands and tetraaminobenzene ligand compounds, crystalline covalent organic framework materials with different topological structures including HCb, SPL, KGM, HXL, etc. can be synthesized.
[0027] (4) The synthesis conditions of the benzodiimidazole-linked covalent organic framework material provided in this application are mild, which is convenient for large-scale synthesis in factories and can achieve the preparation of kilogram-scale covalent organic framework materials.
[0028] (5) The covalent organic framework material linked by benzimidazole provided in the present application has high catalytic activity when used as a catalyst to catalyze the reaction of carbon dioxide and epoxy compounds to prepare cyclocarbonates, so that the yield of cyclocarbonates reaches more than 98%. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0030] Figure 1 The X-ray powder diffraction pattern of the covalent organic framework material provided in Example 1 of the present application;
[0031] Figure 2 A pore structure diagram of the covalent organic framework material provided in Example 1 of the present application;
[0032] Figure 3 This is a schematic structural diagram of the covalent organic framework material provided in Example 1 of the present application;
[0033] Figure 4 The N2 adsorption-desorption isotherm and pore size distribution diagram of the covalent organic framework material provided in Example 1 of the present application, wherein Figure 4 (a) is the N2 isotherm diagram of TABQ-TCPPy-COF-1, Figure 4 (b) is the pore size distribution diagram of TABQ-TCPPy-COF-1.
[0034] Figure 5 This is a graph showing the yield of cyclic carbonates in Examples 5 to 7 and Comparative Examples 1 to 3 of the present application. DETAILED DESCRIPTION
[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts also fall within the scope of protection of this application.
[0036] In a first aspect, the present application provides a benzimidazole-linked covalent organic framework material, which is obtained by solid-phase reaction of an organic carboxylic acid ligand and a tetraaminobenzene ligand compound; and comprises a structural unit shown in Formula 1 or Formula 2:
[0037]
[0038] Wherein, R includes any one of the carboxylic acid-containing organic ligands shown in Formula 3 to Formula 9:
[0039]
[0040] Specifically, the covalent organic framework material provided in the present application is obtained by solid-phase reaction of an organic carboxylic acid ligand and a tetraaminobenzene ligand compound. The covalent organic framework material has different topological structures such as hcb, sql, and hxl. The covalent organic framework material also has high crystallinity, high specific surface area, uniform pore structure, absorption in the visible light range, excellent thermal stability, and a uniform two-dimensional layered morphology.
[0041] In a second aspect, the present application provides a method for preparing a benzimidazole-linked covalent organic framework material, which is used to prepare the above-mentioned covalent organic framework material, and the method comprises the following steps:
[0042] An organic carboxylic acid ligand, a tetraaminobenzene ligand compound, and a reaction medium are taken in proportion, added to the polytetrafluoroethylene liner of a high-pressure reactor, mixed, and the high-pressure reactor is transferred to a constant temperature oven for heating and reaction. After the reaction is completed, the high-pressure reactor is naturally cooled to room temperature to obtain a crude covalent organic framework material;
[0043] The crude covalent organic framework material is filtered, the precipitate is collected, and the precipitate is washed with an organic solvent and dried to obtain the covalent organic framework material.
[0044] Specifically, the covalent organic framework material provided in the present application is synthesized by a solid-phase melting method, and a small amount of reaction medium is used in the synthesis process, which not only saves production costs and improves reaction efficiency, but also significantly reduces the generation of solvent waste liquid in the subsequent purification process of the product, and has good economic and environmental benefits.
[0045] The organic solvent includes at least one of methanol, DMF (NN dimethylformamide), and tetrahydrofuran, and the mass ratio of the organic solvent to the mass of the washed precipitate is 1.5-5.
[0046] At the same time, the covalent organic framework material prepared in this application has crystalline states with different topological structures including hcb, spl, kgm, hxl, etc.
[0047] The drying condition is to dry at 70-85 degrees Celsius to constant weight.
[0048] Optionally, the molar ratio of the organic carboxylic acid ligand to the tetraaminobenzene ligand compound is 1:2-5.
[0049] Specifically, controlling the added molar ratio of the reaction raw material organic carboxylic acid ligand to the tetraaminobenzene ligand compound helps to smoothly generate the covalent organic framework material linked by benzodiimidazole, is conducive to the efficient progress of the reaction, and ensures that the covalent organic framework material has high crystallinity, high specific surface area, uniform pore structure and uniform two-dimensional layered morphology.
[0050] Optionally, the reaction medium is benzoic anhydride, and the ratio of the amount of the reaction medium added to the sum of the amounts of the organic carboxylic acid ligand and the tetraaminobenzene ligand compound is 0.5-5:1.
[0051] Specifically, benzoic anhydride is in a molten state during the reaction process, and not only serves as a reaction medium to increase the contact area of the reaction raw materials and improve the reaction efficiency, but also serves as a catalyst to adjust the pH of the reaction system and further improve the reaction efficiency.
[0052] Optionally, the tetraaminobenzene ligand compound is 2,3,5,6-tetrakis(amino)-p-benzoquinone or 1,2,4,5-phenylenetetramine.
[0053] Optionally, during the heating reaction process, the reaction temperature is 60-400 degrees Celsius and the reaction time is 6-120 hours.
[0054] Furthermore, the reaction temperature is 90-300 degrees Celsius, and the reaction time is 12-72 hours;
[0055] Furthermore, the reaction temperature is 90-300 degrees Celsius, and the reaction time is 20-60 hours;
[0056] Furthermore, the reaction temperature is 90-300 degrees Celsius, and the reaction time is 24-48 hours.
[0057] In a third aspect, the present application provides an application of a benzimidazole-linked covalent organic framework material in catalyzing the reaction of carbon dioxide and epoxy compounds to prepare cyclocarbonates. The covalent organic framework material is the above-mentioned covalent organic framework material, or a covalent organic framework material obtained by the above-mentioned preparation method.
[0058] Optionally, a method for preparing cyclic carbonate comprises the following steps:
[0059] A covalent organic framework material connected by benzdiimidazole, an epoxy compound and tetrabutylammonium bromide are mixed in proportion to obtain a mixture; carbon dioxide gas is introduced into the mixture, and the mixture is stirred and reacted for 0.5-72 hours at a temperature of 0-100 degrees Celsius and a pressure of 0.1-6 MPa. After the reaction is completed, the crude cyclocarbonate product is purified by silica gel column rapid column chromatography to obtain cyclocarbonate with a purity greater than 98%.
[0060] Specifically, the benzodiimidazole-linked covalent organic framework material, as a catalyst, enables the catalytic conversion of carbon dioxide and epoxides, particularly epoxides with substituents at both ends, under mild conditions. The yield of carbon dioxide to cyclic carbonates catalyzed by this covalent organic framework material catalyst can reach over 98%, with a selectivity exceeding 99%.
[0061] The crude cyclocarbonate product is purified by silica gel rapid column chromatography. The purification method can be any common method used by those skilled in the art, and the specific operation will not be described in detail here.
[0062] Optionally, the molar ratio of the benzimidazole-linked covalent organic framework material to the epoxy compound is 1:1-25;
[0063] The molar ratio of tetrabutylammonium bromide to the epoxy compound is 1:5-1000.
[0064] Optionally, the epoxy compound includes: ethylene oxide, propylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,2-epoxyhexane, phenyl ethylene oxide, 1,2-epoxydodecane, 1,2,7,8-diepoxyoctane, 1,2-epoxy-2-methylpropane, trans-2,3-epoxybutane, trans-1,2-stilbene oxide, 1-allyloxy-2,3-epoxypropane, 1,2-epoxy-3-phenoxypropane, 3,3,3-trifluoropropylene oxide, butylene oxide and any one of their corresponding chlorinated or fluorinated epoxy compounds.
[0065] The technical solution of this application is described in detail below with reference to specific embodiments.
[0066] Example 1
[0067] A benzdiimidazole-linked covalent organic framework material and a preparation method thereof, the method comprising the following steps:
[0068] Synthesis of TABQ-TCPPy-COF-1
[0069] 2,3,5,6-tetrakis(amino)-p-benzoquinone (3 mol), 1,3,6,8-tetrakis(4-carboxyphenyl)perylene (1 mol) and benzoic anhydride (5 mol) were weighed and added to the polytetrafluoroethylene liner of the autoclave, and the mixture was shaken and mixed evenly. The autoclave was transferred to a constant temperature oven and kept at 160 degrees Celsius for 60 hours. After the heating reaction was completed, the reactor was cooled, the precipitate was collected by filtration, and the precipitate was washed with methanol and dried at 70 degrees Celsius to constant weight to obtain a brown solid, namely TABQ-TCPPy-COF-1, whose structural schematic is shown as follows: Figure 3 shown.
[0070] Example 2
[0071] A benzdiimidazole-linked covalent organic framework material and a preparation method thereof, the method comprising the following steps:
[0072] Synthesis of TAB-TCPPy-COF-1
[0073] 1,2,4,5-Tetraaminophenyl (5 mol), 1,3,6,8-tetrakis(4-carboxyphenyl)perylene (1 mmol) and benzoic anhydride (10 mol) were added to the polytetrafluoroethylene liner of an autoclave and mixed uniformly by oscillation. The autoclave was transferred to a constant temperature oven and kept at 200°C for 40 hours. After the heating reaction was completed, the autoclave was cooled, the precipitate was collected by filtration, washed with DMF, and dried at 75°C to constant weight to obtain a brown solid, namely TAB-TCPPy-COF-1.
[0074] Example 3
[0075] A benzdiimidazole-linked covalent organic framework material and a preparation method thereof, the method comprising the following steps:
[0076] Synthesis of TABQ-TCPPy-COF-2
[0077] 2,3,5,6-tetrakis(amino)-p-benzoquinone (5 mol), 1,3,6,8-tetrakis(4-carboxyphenyl)perylene (2 mol) and benzoic anhydride (6 mol) were weighed and added to the polytetrafluoroethylene liner of the autoclave. The mixture was shaken and mixed evenly. The autoclave was transferred to a constant temperature oven and kept at 160 degrees Celsius for 72 hours. After the heating reaction was completed, the reactor was cooled, the precipitate was collected by filtration, the precipitate was washed with tetrahydrofuran, and dried at 80 degrees Celsius to constant weight to obtain a brown solid, namely TABQ-TCPPy-COF-2.
[0078] Example 4
[0079] A benzdiimidazole-linked covalent organic framework material and a preparation method thereof, the method comprising the following steps:
[0080] Synthesis of TAB-TCPPy-COF-2
[0081] 1,2,4,5-Tetraaminophenyl (5 mol), 1,3,6,8-tetrakis(4-carboxyphenyl)perylene (3 mol) and benzoic anhydride (8 mol) were added to the polytetrafluoroethylene liner of an autoclave and mixed uniformly by oscillation. The autoclave was transferred to a constant temperature oven and kept at 120°C for 120 hours. After the heating reaction was completed, the autoclave was cooled, the precipitate was collected by filtration, the precipitate was washed with DMF, and dried at 85°C to constant weight to obtain a brown solid, namely TAB-TCPPy-COF-2.
[0082] Experimental Example 1
[0083] Taking the covalent organic framework material TABQ-TCPPy-COF-1 obtained in Example 1 as an example, the crystal structure of TABQ-TCPPy-COF-1 was determined by powder X-ray diffractometer, and the results were as follows: Figure 1X-ray powder diffraction pattern of .
[0084] Depend on Figure 1 It can be seen that the obtained covalent organic framework material TABQ-TCPPy-COF-1 is consistent with the results of theoretical simulation, indicating that the covalent organic framework material obtained in Example 1 belongs to the trigonal crystal system and is a two-dimensional structure with good crystallinity.
[0085] Experimental Example 2
[0086] The morphology of the covalent organic framework material TABQ-TCPPy-COF-1 was characterized by transmission electron microscopy, and the results were as follows: Figure 2 shown.
[0087] Depend on Figure 2 It can be seen that the prepared TABQ-TCPPy-COF-1 has a regular porous structure and a uniform two-dimensional layered morphology.
[0088] Experimental Example 3
[0089] A series of fully automatic physical and chemical adsorption instruments were used to characterize the porous structure of TABQ-TCPPy-COF-1 through nitrogen adsorption and desorption tests. The characterization results included nitrogen adsorption and desorption isotherms and pore size distribution. Figure 4 (a) is the N2 adsorption-desorption isotherm of TABQ-TCPPy-COF-1. Figure 4 (b) is the pore size distribution diagram of TABQ-TCPPy-COF-1.
[0090] Combine Figure 4 (a) and Figure 1 It can be seen that the covalent organic framework material TABQ-TCPPy-COF-1 has a uniform pore structure and a spl topological structure. Figure 4 (b) It was observed that the specific surface area of TABQ-TCPPy-COF-1 was about 1108 m 2 / g, and the pore size distribution is concentrated at 2.5nm.
[0091] Example 5
[0092] A method for preparing a cyclocarbonate by using a covalent organic framework material linked by benzdiimidazole comprises the following steps:
[0093] The covalent organic framework material TABQ-TCPPy-COF-1 obtained in Example 1, ethylene oxide, and tetrabutylammonium bromide were mixed in proportion to obtain a mixture; carbon dioxide gas was introduced into the mixture, and the mixture was stirred and reacted for 0.5 hours at a temperature of 0 degrees Celsius and a pressure of 0.1 MPa to obtain a cyclocarbonate.
[0094] The molar ratio of TABQ-TCPPy-COF-1 to ethylene oxide is 1:1; the molar ratio of tetrabutylammonium bromide to ethylene oxide is 1:5.
[0095] Example 6
[0096] A method for preparing a cyclocarbonate by using a covalent organic framework material linked by benzdiimidazole comprises the following steps:
[0097] The covalent organic framework material TABQ-TCPPy-COF-1 obtained in Example 1, ethylene oxide, and tetrabutylammonium bromide were mixed in proportion to obtain a mixture; carbon dioxide gas was introduced into the mixture, and the mixture was stirred and reacted at a temperature of 30 degrees Celsius and a pressure of 3 MPa for 48 hours to obtain cyclocarbonate.
[0098] The molar ratio of TABQ-TCPPy-COF-1 to ethylene oxide is 1:10; the molar ratio of tetrabutylammonium bromide to ethylene oxide is 1:20.
[0099] Example 7
[0100] A method for preparing a cyclocarbonate by using a covalent organic framework material linked by benzdiimidazole comprises the following steps:
[0101] The covalent organic framework material TABQ-TCPPy-COF-1 obtained in Example 1, ethylene oxide, and tetrabutylammonium bromide were mixed in proportion to obtain a mixture; carbon dioxide gas was introduced into the mixture, and the mixture was stirred and reacted at a temperature of 100 degrees Celsius and a pressure of 6 MPa for 48 hours to obtain a cyclocarbonate.
[0102] The molar ratio of TABQ-TCPPy-COF-1 to ethylene oxide is 1:25; the molar ratio of tetrabutylammonium bromide to ethylene oxide is 1:100.
[0103] Comparative Example 1
[0104] A method for preparing a cyclocarbonate by using a covalent organic framework material linked by benzdiimidazole comprises the following steps:
[0105] The difference from Example 6 is that:
[0106] The covalent organic framework material TABQ-TCPPy-COF-1 obtained in Example 1, ethylene oxide, and tetrabutylammonium bromide were mixed in proportion to obtain a mixture; carbon dioxide gas was introduced into the mixture, and the mixture was stirred and reacted for 73 hours at a temperature of 15 degrees Celsius and a pressure of 0.08 MPa to obtain a cyclocarbonate.
[0107] Comparative Example 2
[0108] A method for preparing a cyclocarbonate by using a covalent organic framework material linked by benzdiimidazole comprises the following steps:
[0109] The difference from Example 6 is that:
[0110] The covalent organic framework material TABQ-TCPPy-COF-1 obtained in Example 1, ethylene oxide, and tetrabutylammonium bromide were mixed in proportion to obtain a mixture; carbon dioxide gas was introduced into the mixture, and the mixture was stirred and reacted at a temperature of 5 degrees Celsius and a pressure of 6.1 MPa for 73 hours to obtain cyclocarbonate.
[0111] Comparative Example 3
[0112] An existing metal-containing covalent organic framework material (Zn-Salen COF) was used as a control example and was used as a catalyst for the preparation of cyclocarbonates. The catalytic activity of the Zn-Salen COF-1 for epoxides was compared with that of the TABQ-TCPPy-COF-1 provided in this application.
[0113] Preparation of Zn-Salen COF: 50 mg of TTHEPB (CAS No: 2489272-57-1) was dissolved in a mixture of 6.4 ml of THF (tetrahydrofuran) and 1.6 ml of ethanol. 30 μL of EDA (ethylenediamine) was then added, causing the mixed solution to rapidly turn green. 0.1 ml of 3 M HOAc was then added to the mixed solution, which was then transferred into a 10 mL pressure tube. After three freeze-pump-thaw cycles, the pressure tube was heated at 120 degrees Celsius for three days. The solid was collected by centrifugation and washed with dry THF and acetone. The yellow powder was then vacuum-dried at 80 degrees Celsius for 24 hours to yield Zn-Salen COF.
[0114] A mixture of Zn-Salen COF, tetrabutylammonium bromide, and ethylene oxide was placed in a vacuum tube, and the reaction system was refilled with CO2. After stirring at 25 degrees Celsius for 48 hours, cyclocarbonate was obtained.
[0115] The molar ratio of Zn-Salen COF to ethylene oxide is 1:1; the molar ratio of tetrabutylammonium bromide to ethylene oxide is 1:5.
[0116] Experimental Example 4
[0117] According to the amount of cyclic carbonate obtained, the yield of cyclic carbonate in Examples 5-7 and Comparative Examples 1-3 was calculated. Each experiment was conducted at least three times in parallel and the average value was taken to obtain the results as shown below. Figure 5 shown.
[0118] Depend on Figure 5It can be seen that the benzimidazole-linked covalent organic framework material catalyst provided in this application realizes the catalytic conversion of carbon dioxide and epoxy compounds under mild conditions. Among them, the yield of catalytic conversion of carbon dioxide to cyclic carbonate using this catalyst reaches more than 98%. In Comparative Example 3, the metal-containing covalent organic framework material (Zn-Salen COF) is used as a catalyst, and the yield of cyclic carbonate is 84%. This shows that the benzimidazole-linked covalent organic framework material provided in this application is used as a catalyst. The active functional groups in its structure have better catalytic activity than the metal active sites of Zn-Salen COF, and can further increase the yield of cyclic carbonate.
[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A covalent organic framework material linked by benzene diimidazole, characterized in that: The covalent organic framework material is obtained by solid-phase reaction of an organic carboxylic acid ligand and a tetraaminobenzene ligand compound; and includes a structural unit shown in Formula 1 or Formula 2: Wherein, R includes any one of the organic carboxylic acid ligands shown in Formula 3 to Formula 9:
2. The benzimidazole-linked covalent organic framework material according to claim 2, characterized in that: The tetraaminobenzene ligand compound is selected from 2,3,5,6-tetrakis(amino)-p-benzoquinone or 1,2,4,5-phenylenetetramine.
3. A method for preparing a covalent organic framework material linked by benzene diimidazole, characterized in that: The method is used to prepare the covalent organic framework material according to claim 1 or 2, and the method comprises the following steps: taking an organic carboxylic acid ligand, a tetraaminobenzene ligand compound, and a reaction medium in proportion, adding them to the polytetrafluoroethylene liner of a high-pressure reactor, mixing them, transferring the high-pressure reactor to a constant temperature oven for heating and reaction, and after the reaction is completed, naturally cooling the high-pressure reactor to room temperature to obtain a crude covalent organic framework material; The crude covalent organic framework material is filtered to collect the precipitate, and the precipitate is washed with an organic solvent and dried to obtain the covalent organic framework material.
4. The method for preparing a benzimidazole-linked covalent organic framework material according to claim 3, wherein: The added molar ratio of the organic carboxylic acid ligand to the tetraaminobenzene ligand compound is 1:2-5.
5. The method for preparing a benzimidazole-linked covalent organic framework material according to claim 3, wherein: The reaction medium is benzoic anhydride, and the ratio of the amount of the reaction medium added to the sum of the amounts of the organic carboxylic acid ligand and the tetraaminobenzene ligand compound is 0.5-5:
1.
6. The method for preparing a benzimidazole-linked covalent organic framework material according to claim 3, wherein: During the heating reaction process, the reaction temperature is 60-400 degrees Celsius and the reaction time is 6-120 hours.
7. Use of a benzimidazole-linked covalent organic framework material in catalyzing the reaction of carbon dioxide and epoxy compounds to prepare cyclic carbonates, characterized in that: The covalent organic framework material is the covalent organic framework material according to claim 1 or 2, or the covalent organic framework material obtained by the preparation method according to any one of claims 3 to 6.
8. Use of the benzimidazole-linked covalent organic framework material according to claim 7 in catalyzing the reaction of carbon dioxide and epoxy compounds to prepare cyclic carbonates, characterized in that: The method for preparing the cyclic carbonate comprises the following steps: The benzdiimidazole-linked covalent organic framework material, epoxy compound and tetrabutylammonium bromide are mixed in proportion to obtain a mixture; carbon dioxide gas is introduced into the mixture, and the mixture is stirred and reacted for 0.5-72 hours at a temperature of 0-100 degrees Celsius and a pressure of 0.1-6 MPa to obtain the cyclocarbonate.
9. Use of the benzimidazole-linked covalent organic framework material according to claim 8 in catalyzing the reaction of carbon dioxide and epoxy compounds to prepare cyclic carbonates, characterized in that: The molar ratio of the benzimidazole-linked covalent organic framework material to the epoxy compound is 1:1-25; The molar ratio of the tetrabutylammonium bromide to the epoxy compound is 1:5-1000.
10. Use of the benzimidazole-linked covalent organic framework material according to claim 1 in catalyzing the reaction of carbon dioxide and epoxy compounds to prepare cyclic carbonates, characterized in that: The epoxy compounds include: Any one of ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,2-propylene oxide, 1,2-hexylene oxide, phenylethylene oxide, 1,2-epoxydodecane, 1,2,7,8-diepoxyoctane, 1,2-epoxy-2-methylpropane, trans-2,3-butylene oxide, trans-1,2-stilbene oxide, 1-allyloxy-2,3-epoxypropane, 1,2-epoxy-3-phenoxypropane, 3,3,3-trifluoropropylene oxide, butylene oxide and their corresponding chlorinated or fluorinated epoxy compounds.