A covalent organic framework for highly efficient one-step purification of ethylene, a preparation method thereof, and applications thereof
By designing and synthesizing covalent organic frame materials and introducing them into crystalline porous materials using pyridine moieties, the problem of high energy consumption of ethylene purification in the prior art is solved, and one-step efficient purification of ethylene and stable reuse of the material is achieved.
Patent Information
- Application Number
- CN202310289984.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-21
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2043-03-21
AI Technical Summary
The prior art consumes a high energy consumption during the ethylene purification process, and it is difficult to achieve one-step efficient purification.
Using covalent organic frame materials, the pyridinyl moieties are introduced into the crystalline porous material by designing and synthesizing a stable new covalent organic frame, achieving one-step efficient purification of ethylene.
One-step efficient purification of ethylene is achieved, reducing separation energy consumption, and the material is highly stable and can be reused.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of the preparation of porous materials and the purification of ethylene, and particularly relates to a covalent organic framework capable of efficiently purifying ethylene in one step, a preparation method thereof, and an application thereof. Background Art
[0002] As an important chemical raw material, the global annual output of ethylene has exceeded 200 million tons. Industrially, low-temperature rectification is usually used to remove the by-product ethane to obtain high-purity ethylene, but this method has high energy consumption. The use of porous materials to selectively adsorb the impurity ethane can achieve the efficient purification of ethylene and reduce energy consumption. Covalent organic frameworks are crystalline organic porous materials formed by connecting molecular building blocks through covalent bonds, and have the characteristics of low density, high specific surface area, strong structural designability, etc. At present, they are widely used in the fields of gas adsorption, separation, catalysis, energy storage, and optoelectronics.
[0003] The use of covalent organic frameworks for the purification of ethylene mainly has the following advantages: First, since it is a pure organic material without the participation of metal components, it can avoid strong interactions with ethylene molecules, improve its selective adsorption ability for ethane, and is conducive to realizing the one-step purification of ethylene. Second, due to the controllability of its pore environment, a covalent organic framework with strong selective adsorption ability for ethane can be constructed, thereby realizing the efficient separation of ethane / ethylene. Finally, the formation method of covalent bond connection endows it with high stability, meeting the requirements of industrial recycling. Summary of the Invention
[0004] One of the purposes of the present invention is to provide a preparation method of a covalent organic framework capable of efficiently purifying ethylene in one step, which is easy to operate, environmentally friendly, low-cost, and easy to industrialize.
[0005] Another purpose of the present invention is to provide a covalent organic framework capable of efficiently purifying ethylene in one step; it has high stability, can achieve the one-step efficient purification of ethylene by selectively adsorbing ethane, can be reused, and reduces the separation energy consumption.
[0006] The third purpose of the present invention is to provide an application of a covalent organic framework capable of efficiently purifying ethylene in one step.
[0007] The solution adopted by the present invention to achieve the first purpose is: a preparation method of a covalent organic framework capable of efficiently purifying ethylene in one step, the steps are as follows: Disperse the tetraphenylmethane building block and the pyridine building block in a solvent, then add a catalyst, and react the obtained mixed system under vacuum or inert atmosphere at 100-130 °C. After the reaction is completed, a white solid powder is obtained, which is purified and then dried to obtain the covalent organic framework.
[0008] Preferably, the tetraphenylmethane building block is The pyridine building block is
[0009]
[0010] Preferably, the solvent is any one of chloroform, o-dichlorobenzene / dioxane mixed solvent, o-dichlorobenzene / mesitylene mixed solvent, and mesitylene / dioxane mixed solvent.
[0011] Preferably, the catalyst is acetic acid.
[0012] Preferably, the molar ratio of the tetraphenylmethane moiety, the pyridine moiety, and the catalyst is 1:1:30 - 120; the concentration of the tetraphenylmethane moiety in the mixed system is 0.01 - 0.1 mol / L.
[0013] Preferably, the purification process is as follows: after Soxhlet extraction of the solid with at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, and dimethyl sulfoxide, and finally Soxhlet extraction of the solid with dichloromethane.
[0014] Preferably, the preparation method of the pyridine moiety is as follows: dissolve the halogenated pyridine, phenylboronic acid reagent, catalyst, and base agent in a solvent to disperse them, then react under an inert atmosphere at 80 - 120 °C. After the reaction is completed, remove the solvent and then purify to obtain a white solid product, which is the pyridine moiety.
[0015] Preferably, the halogenated pyridine is 2,3,5,6-tetrabromopyridine or 2,3,5,6-tetraiodopyridine, the phenylboronic acid reagent is 4-formylphenylboronic acid or 4-formylphenylboronic acid pinacol ester, the catalyst is palladium acetate and an organic phosphorus ligand, the base agent is at least one of cesium carbonate, potassium carbonate, sodium carbonate, and potassium phosphate, the solvent is at least one of toluene, 1,4-dioxane, and N,N-dimethylformamide, and the molar ratio of the halogenated pyridine, phenylboronic acid reagent, palladium acetate, organic phosphorus ligand, and base agent is 50:200 - 500:5:1:200 - 500.
[0016] The solution adopted by the present invention to achieve the second object is: a covalent organic framework capable of efficiently purifying ethylene in one step, which is prepared by using the described preparation method.
[0017] The solution adopted by the present invention to achieve the third object is: an application of a covalent organic framework capable of efficiently purifying ethylene in one step, applying the covalent organic framework to purify ethylene in industrial production of ethylene.
[0018] Ethylene is generally prepared by steam cracking in industrial production, with ethane or naphtha as the raw material. The impurity gas in the prepared ethylene is generally ethane. The covalent organic framework material prepared by the present invention can selectively adsorb ethane and efficiently purify ethylene in one step.
[0019] The present invention has the following advantages and beneficial effects:
[0020] 1. The preparation method of the present invention is easy to operate, environmentally friendly, low in cost, and easy for industrial production.
[0021] 2. The preparation method of the present invention realizes the one-step high-efficiency purification of ethylene by designing and synthesizing a stable novel covalent organic framework and introducing pyridine moieties into the crystalline porous material.
[0022] 3. The covalent organic framework prepared by the present invention has high stability, can realize the one-step high-efficiency purification of ethylene by selectively adsorbing ethane, can be reused, and reduces the separation energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 are: Schematic diagram of the covalent organic framework prepared by the present invention, wherein Figure 1 a is a single-layer pts topological network structure, Figure 1 b is a five-fold interpenetrated pts framework, Figure 1 c is the one-dimensional pore structure of the framework;
[0024] Figure 2 are: X-ray powder diffraction pattern of the covalent organic framework prepared by the present invention;
[0025] Figure 3 are: Single-component gas adsorption curve of the covalent organic framework prepared by the present invention (under the condition of 293K);
[0026] Figure 4 are: Dynamic breakthrough curve of ethane / ethylene mixed gas of the covalent organic framework prepared by the present invention;
[0027] Figure 5 are: Dynamic breakthrough cycle stability test of the covalent organic framework prepared by the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0028] To better understand the present invention, the following examples are further descriptions of the present invention, but the content of the present invention is not limited to the following examples only.
[0029] The tetraphenylmethane moiety in the present invention is synthesized according to the literature (J. Am. Chem. Soc. 2005, 127, 14530-14531.).
[0030] Example 1
[0031] Disperse tetraphenylmethane moiety (22.8 mg, 0.06 mmol) and pyridine moiety (29.7 mg, 0.06 mmol) in chloroform (3.0 mL), and then add 0.3 mL of 12 mol L -1An acetic acid solution, and finally it is placed in an oven at 120 °C for reaction for 72 hours. After the reaction is completed, a white solid powder is obtained. The solid is successively Soxhlet extracted with tetrahydrofuran and dichloromethane, and finally the solid is heated and dried in a vacuum environment for use; the tetraphenylmethane moiety is The pyridyl moiety is Synthesis is as follows;
[0032]
[0033] In this example, the synthesis of the pyridyl moiety is as follows:
[0034]
[0035] Pyridyl moiety synthesis
[0036] Compound 1 (4.00 g, 10.1 mmol), 4-formylphenylboronic acid (12.0 g, 80.0 mmol), palladium acetate (0.20 g, 0.89 mmol), organic phosphorus ligand (Sphos, 0.80 g, 0.19 mmol) and tripotassium phosphate (12.0 g, 56.5 mmol) are placed in a round-bottom flask, and then toluene solvent (150 mL) is added to disperse it. Then, it is heated and reacted at 90 °C under nitrogen protection for 3 days. After the reaction is completed, the solvent is removed by rotary evaporation, and then purified by column chromatography to obtain a white solid product. The product is characterized by NMR 1 HNMR (400 MHz, CDCl3, ppm): δ = 10.04 (s, 2H), 10.02 (s, 2H), 7.90 (s, 1H), 7.87 (d, J = 8.0 Hz, 4H), 7.81 (d, J = 8.0 Hz, 4H), 7.65 (d, J = 8.0 Hz, 4H), 7.46 (d, J = 8.0 Hz, 4H).
[0037] The covalent organic framework prepared by the present invention is a three-dimensional structure, and the structural formula is as Figure 1 shown, where Figure 1 a is a single-layer pts topological network structure, Figure 1 b is a five-fold interpenetrated pts framework, Figure 1 c is a one-dimensional pore structure of the framework.
[0038] Figure 2 is the X-ray powder diffraction pattern of the covalent organic framework prepared by the present invention. It can be seen from the figure that: the covalent organic framework exhibits a series of diffraction peaks in the range of 2-40°, indicating that it has a long-range ordered crystalline structure.
[0039] Figure 3Single-component gas adsorption curve of the covalent organic framework prepared for the present invention (under the condition of 293K). It can be seen from the figure that in the pressure range of 0-1 bar, the adsorption amount of ethane by this covalent organic framework is higher than that of ethylene, indicating its ability to selectively adsorb ethane and can be used for the one-step purification of ethylene.
[0040] Example 2
[0041] Experiment on the one-step purification of ethylene from ethane / ethylene mixed gas:
[0042] Fill about 500 mg of covalent organic framework powder into a stainless steel tube (inner diameter 3.0 mm, length 120 mm) to make a separation column. Place the prepared separation column in an environment of 100 °C and purge it with helium (10 mL min -1 ) for 12 hours for activation to remove impurities such as air and moisture in the framework material. Subsequently, under the conditions of 293K and 1 bar, a mixture of ethane / ethylene / helium (volume ratio 1 / 1 / 8) is introduced into the separation column at a constant speed (2 mL min -1 ). (Helium is not required for gas drainage in later industrial production.) Use a mass spectrometer to record the gas components and contents at the outlet. The results are as Figure 4 shown. It can be seen from the figure that ethylene gas first passes through the separation column, while ethane gas takes a longer time to pass through the separation column, indicating that this material has the ability to directly produce high-purity ethylene from ethane / ethylene mixed gas.
[0043] After the test is completed, reactivate the separation column and test its ethylene purification performance again. Conduct four tests in a cycle. The results are as Figure 5 shown. It can be seen from the figure that this covalent organic framework has good stability and shows consistent separation ability in four cycle experiments.
[0044] The above is the preferred implementation manner of the present invention. Of course, the scope of the rights of the present invention cannot be limited by this. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and changes can be made, and these improvements and changes are also regarded as the protection scope of the present invention.
Claims
1. A preparation method of a covalent organic framework for one-step high-efficient purification of ethylene, characterized in that: The steps are as follows: Disperse the tetraphenylmethane unit and the pyridine unit in a solvent, then add a catalyst, and react the obtained mixed system under vacuum or an inert atmosphere at 100-130 °C. After the reaction is completed, a white solid powder is obtained. After purification and drying, the covalent organic framework is obtained. The tetraphenylmethane moiety is , and the pyridine moiety is .
2. The preparation method of the covalent organic framework capable of efficiently purifying ethylene in one step according to claim 1, characterized in that: The solvent is any one of chloroform, o-dichlorobenzene / dioxane mixed solvent, o-dichlorobenzene / mesitylene mixed solvent, and mesitylene / dioxane mixed solvent.
3. The preparation method of the covalent organic framework capable of efficiently purifying ethylene in one step according to claim 1, wherein: The catalyst is acetic acid.
4. The preparation method of the covalent organic framework capable of efficiently purifying ethylene in one step according to claim 1, characterized in that: The molar ratio of the tetraphenylmethane unit, the pyridine unit, and the catalyst is 1:1:30-120; the concentration of the tetraphenylmethane unit in the mixed system is 0.01-0.1 mol / L.
5. The preparation method of the covalent organic framework capable of efficiently purifying ethylene in one step according to claim 1, characterized in that: The purification process is as follows: Soxhlet extract the solid with at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, and dimethyl sulfoxide, and finally Soxhlet extract the solid with dichloromethane.
6. The preparation method of the covalent organic framework capable of efficiently purifying ethylene in one step according to claim 1, wherein: The preparation method of the pyridine unit is as follows: Dissolve the halogenated pyridine, the phenylboronic acid reagent, the catalyst, and the base agent in a solvent to disperse them, and then react at 80-120 °C under an inert atmosphere. After the reaction is completed, the solvent is removed and purified to obtain a white solid product, which is the pyridine unit.
7. The preparation method of the covalent organic framework capable of efficiently purifying ethylene in one step according to claim 6, characterized in that: The halogenated pyridine is 2,3,5,6-tetrabromopyridine or 2,3,5,6-tetraiodopyridine, the phenylboronic acid reagent is 4-formylphenylboronic acid or 4-formylphenylboronic acid pinacol ester, the catalyst is palladium acetate and an organic phosphorus ligand, the base agent is at least one of cesium carbonate, potassium carbonate, sodium carbonate, and potassium phosphate, the solvent is at least one of toluene, 1,4-dioxane, and N,N-dimethylformamide, and the molar ratio of the halogenated pyridine, the phenylboronic acid reagent, palladium acetate, the organic phosphorus ligand, and the base agent is 50:200-500:5:1:200-500.
8. A covalent organic framework for one-step efficient purification of ethylene, characterized in that: It is prepared by using the preparation method described in any one of claims 1-7.
9. Use of a covalent organic framework capable of efficiently purifying ethylene in one step prepared by the preparation method according to any one of claims 1-7, characterized in that: Apply the covalent organic framework to purify ethylene in industrial production of ethylene.