Covalent organic framework materials for indoor humidity conditioning and methods of making the same
By designing a rhombic pore structure for a covalent organic framework material, the problems of instability and insufficient adsorption performance of existing materials in indoor humidity regulation are solved, achieving a highly efficient humidity control effect in indoor environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGNAN UNIV
- Filing Date
- 2023-08-02
- Publication Date
- 2026-04-14
AI Technical Summary
Existing silica gel and zeolite cannot desorb at room temperature, limiting their application in humidity control. Meanwhile, metal-organic framework materials are unstable and pose a risk of metal leakage in indoor humidity control. There is a lack of covalent organic framework materials suitable for indoor humidity control.
By introducing bipyridine dialdehyde isomers with hydrophilic sites and tetraamine derivatives as raw materials, rhomboid channels with a diagonal distance greater than 2.0 nm are constructed, and covalent organic framework materials with typical S-type water vapor adsorption/desorption isotherms are designed and synthesized to achieve indoor humidity regulation.
It achieves efficient humidity control within the 45-65% RH range, can absorb water molecules under high humidity and release them under low humidity, and has a suitable hysteresis loop to meet indoor humidity control needs.
Smart Images
Figure CN116854877B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of covalent organic framework materials, specifically relating to a method for preparing a covalent organic framework material for indoor humidity control. Background Technology
[0002] Indoor relative humidity (RH) is closely related to human life, and maintaining comfortable and healthy indoor humidity levels has always been a goal. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends an optimal relative humidity of 45-65% for habitable environments. Silica gel and zeolite have been widely used for moisture absorption in humid areas, but their inability to desorb at room temperature limits their application in humidity regulation. Metal-organic frameworks (MOFs), as a novel type of crystalline porous material, have shown great potential in indoor humidity regulation, but their less-than-ideal stability and the risk of metal leakage limit their development. Therefore, it is necessary to develop a new generation of more efficient and stable materials for automatic indoor humidity regulation.
[0003] Covalent organic frameworks (COFs) are a class of crystalline porous materials composed of light elements such as C, H, O, N, and B linked by covalent bonds. They have attracted widespread attention due to their tunable and diverse structures. The high porosity and stability of COFs have been proven to be beneficial for the adsorption of gases and vapors. Furthermore, COFs possess advantages such as high adsorption capacity, high cycling stability, and easy regeneration, making them promising for applications in water adsorption. However, no COFs have been reported for use in indoor humidity control. Summary of the Invention
[0004] As an ideal porous material for indoor humidity control, COFs should exhibit a typical S-shaped water vapor adsorption / desorption isotherm and possess a suitable hysteresis loop within the 45-65% RH range, allowing COFs to absorb water molecules above 65% RH and release them below 45% RH. To meet this standard, the hysteresis phenomenon of the water vapor adsorption / desorption isotherm and the strength of the water molecule adsorption sites must be considered simultaneously in the COF structural design. For the hysteresis phenomenon, mesoporous elements must be introduced into the COF channels to achieve capillary condensation, thereby leading to the formation of the hysteresis loop; the strength of the water molecule adsorption sites should be moderate, as too strong or too weak a strength will cause the inflection point of the water vapor adsorption curve to deviate from the required 65% RH.
[0005] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a method for preparing a covalent organic framework material for indoor humidity control. This method is based on constructing rhomboid channels with a diagonal distance greater than 2.0 nm by introducing a two-connected building block containing bipyridine N as a hydrophilic site and a planar four-connected building block to achieve a typical S-shaped water vapor adsorption-desorption curve with a hysteresis loop of appropriate size. Using bipyridine dialdehyde isomers with hydrophilic sites and a series of tetraamine derivatives as raw materials, a covalent organic framework material for indoor humidity control is obtained through a solvothermal reaction.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A covalent organic framework material for indoor humidity control, the material having the following structural formula:
[0008] , , or .
[0009] The second objective of this invention is to provide a method for preparing a covalent organic framework material for indoor humidity control. The preparation method includes the following steps: dissolving a bipyridine dialdehyde isomer with hydrophilic sites and a tetraamine derivative as raw materials in a reaction solvent and reacting them under a catalyst.
[0010] In one embodiment, the bipyridine dialdehyde isomer having hydrophilic sites comprises:
[0011] , , or .
[0012] In one embodiment, the tetraamine derivative includes:
[0013] , , ,
[0014] , , ,
[0015] , or .
[0016] In one embodiment, the molar ratio of the bipyridine dialdehyde isomer with hydrophilic sites to a series of tetraamine derivatives is 1:3 to 3:1; the catalyst is 10 to 20% of the volume of the reaction solvent.
[0017] In one embodiment, the reaction solvent is dioxane and mesitylene.
[0018] In one embodiment, the volume ratio of dioxane to mesitylene is 1:1 to 5:1.
[0019] In one embodiment, the catalyst comprises acetic acid.
[0020] In one embodiment, the concentration of acetic acid is 3-6 mol / L.
[0021] In one embodiment, the reaction is carried out at 110-150°C for 3-7 days.
[0022] In one embodiment, the reaction is carried out in a reaction vessel.
[0023] In one embodiment, after the reaction is completed, the mixture is cooled to room temperature and the solid is collected by filtration, followed by repeated washing, purification, and drying processes.
[0024] In one embodiment, the washing is performed using an organic solvent.
[0025] In one embodiment, the organic solvent includes one or two of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF).
[0026] In one embodiment, the drying conditions are vacuum and 70~120°C.
[0027] In one embodiment, the purification method includes Soxhlet extraction.
[0028] Beneficial effects
[0029] This invention rationally designs the structure of a covalent organic framework (COF) material for indoor humidity control. By introducing a moderate strength of water vapor adsorption sites and reacting bipyridine units with tetraamine derivatives, a COF material with rhombic channels having a diagonal distance greater than 2.0 nm was obtained. This achieves the water vapor adsorption / desorption isotherm with a suitable hysteresis loop required for indoor humidity control. This allows COFs to absorb water molecules at humidity levels above 65% and release water molecules at humidity levels below 45%, as demonstrated by laboratory and real-world experiments, thus realizing the first application of COF materials in indoor humidity control. Attached Figure Description
[0030] Figure 1This is a schematic diagram of the synthesis route of IHR-COF-1, a covalent organic framework material with indoor humidity control, provided in Embodiment 1 of the present invention. In this embodiment, IHR represents indoor humidity control, COF represents a covalent organic framework, and the covalent organic framework material is referred to as IHR-COF-1.
[0031] Figure 2 This is a schematic diagram of the synthesis route of IHR-COF-2, a covalent organic framework material with indoor humidity control, provided in Example 2 of the present invention. In this diagram, IHR represents indoor humidity control, COF represents a covalent organic framework, and the covalent organic framework material is referred to as IHR-COF-2.
[0032] Figure 3 This is a schematic diagram of the synthesis route of IHR-COF-3, a covalent organic framework material with indoor humidity control, provided in Example 3 of the present invention. In this diagram, IHR represents indoor humidity control, COF represents a covalent organic framework, and the covalent organic framework material is referred to as IHR-COF-3.
[0033] Figure 4 This is a schematic diagram of the synthesis route of the covalent organic framework material IHR-COF-4 with indoor humidity control provided in Example 4 of the present invention, wherein IHR represents indoor humidity control, COF represents covalent organic framework, and the covalent organic framework material is referred to as IHR-COF-4.
[0034] Figure 5 The infrared spectrum of the covalent organic framework material for indoor humidity control prepared in Example 1;
[0035] Figure 6 Powder X-ray diffraction pattern of the covalent organic framework material for indoor humidity control prepared in Example 1;
[0036] Figure 7 Nitrogen adsorption / desorption isotherms of the covalent organic framework material for indoor humidity control prepared in Example 1;
[0037] Figure 8 Water vapor adsorption / desorption isotherm of the covalent organic framework material for indoor humidity control prepared in Example 1;
[0038] Figure 9 The diagram shows the application of the covalent organic framework material for indoor humidity control prepared in Example 1; a is a schematic diagram of the device for indoor humidity control; b is a schematic diagram of the laboratory experiment; c is a schematic diagram of the real environment experiment; d is a graph showing the change of humidity over time in the laboratory experiment; e is a graph showing the change of humidity over time in the real environment experiment. Detailed Implementation
[0039] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.
[0040] Example 1
[0041] The preparation method of the covalent organic framework material used for indoor humidity control in this embodiment is as follows:
[0042] (1) 0.6 mmol of bipyridine dialdehyde bpy-1 and 0.3 mmol of pyrene tetramine Py (see schematic diagram of synthesis) Figure 1 Add it to a mixed reaction solvent of 0.5 mL dioxane and 1.5 mL mesitylene, and disperse it evenly by ultrasonication.
[0043] (2) Add 0.2 mL of 6 mol / L acetic acid to the uniformly dispersed solution as a catalyst, put it into the reaction vessel, and after ultrasonic dispersion, put it into the reaction vessel.
[0044] (3) Keep the reactor at 110°C for 5 days. After the reaction is completed, cool it to room temperature and filter to collect the solid.
[0045] (4) Wash the collected solids by centrifugation with DMF and THF for 10 mL × 5 times, and collect the solids again.
[0046] (5) After Soxhlet extraction of solid THF for 24 hours, vacuum drying at 120°C for 12 hours yields a yellow powder, which is the covalent organic framework material for indoor humidity control, labeled as IHR-COF-1.
[0047] Figure 5 The infrared spectrum of IHR-COF-1, a covalent organic framework material for indoor humidity control obtained in this embodiment, shows the formation of C=N, proving the successful synthesis of the material. Figure 6 The image shows the powder X-ray diffraction pattern of IHR-COF-1, a covalent organic framework material for indoor humidity control obtained in this embodiment. The comparison with the simulated value shows that it has good crystallinity. Figure 7 The nitrogen adsorption / desorption isotherm image of IHR-COF-1, a covalent organic framework material for indoor humidity control obtained in this embodiment, shows that it has a high specific surface area. Figure 8 The image shows the water vapor adsorption / desorption isotherm of the covalent organic framework material IHR-COF-1 for indoor humidity control obtained in this embodiment. It can be seen that it exhibits a typical S-shaped water vapor adsorption / desorption isotherm and has a suitable hysteresis loop in the range of 45-65% RH.
[0048] Indoor humidity control experiment
[0049] like Figure 9As shown in Figure a, the present invention designs a device to simulate an indoor environment. The device for simulating an indoor environment is 10cm*10cm*8cm in size and has a 10cm*0.5cm window. It is equipped with a temperature and humidity probe for real-time monitoring of the temperature and humidity inside the device. 200mg of IHR-COF-1 prepared in this embodiment is placed inside the device to regulate the humidity.
[0050] like Figure 9 As shown in b, laboratory experiments were conducted in this invention. A device containing IHR-COF-1 was used as the experimental group, while an empty device was used as the control group. The two devices were placed in a high humidity environment (25°C, 75%RH) and a low humidity environment (25°C, 20%RH), respectively. Figure 9 As shown in Figure c, the present invention conducted a real-world environmental experiment. The device equipped with IHR-COF-1 was set as the experimental group, while an empty device was set as the control group. The two devices were placed in an open outdoor environment.
[0051] like Figure 9 As shown in d, in laboratory experiments, when the humidity of the control group was 20-75%RH, the experimental group equipped with IHR-COF-1 effectively controlled the humidity at 45-60%RH; Figure 9 As shown in e, in real-world environmental experiments, when the external ambient humidity was 27-67%RH, the humidity inside the experimental group device was 41-58%RH. The results show that IHR-COF-1 can be used as a new, unique, and energy-saving indoor humidification / dehumidification dual-function humidity control material.
[0052] Example 2
[0053] The preparation method of the covalent organic framework material used for indoor humidity control in this embodiment is as follows:
[0054] (1) 0.6 mmol of bipyridine dialdehyde bpy-2 and 0.5 mmol of pyrene tetramine Py (see schematic diagram of synthesis) Figure 2 Add it to a mixed reaction solvent of 1 mL dioxane and 1 mL mesitylene, and disperse it evenly by ultrasonication.
[0055] (2) Add 0.2 mL of 6 mol / L acetic acid to the uniformly dispersed solution as a catalyst, put it into the reaction vessel, and after ultrasonic dispersion, put it into the reaction vessel.
[0056] (3) Keep the reactor at 120°C for 5 days. After the reaction is completed, cool it to room temperature and filter to collect the solid.
[0057] (4) Wash the collected solids by centrifugation with DMF and THF for 15 mL × 6 times, and collect the solids again.
[0058] (5) After Soxhlet extraction of solid THF for 24 hours, vacuum drying at 120°C for 15 hours yields a yellow powder, which is the covalent organic framework material used for indoor humidity control.
[0059] Tests showed that the covalent organic framework material prepared in this embodiment has the same indoor humidity regulation performance as the covalent organic framework material prepared in Example 1.
[0060] Example 3
[0061] The preparation method of the covalent organic framework material used for indoor humidity control in this embodiment is as follows:
[0062] (1) 0.6 mmol of bipyridine dialdehyde bpy-3 and 0.4 mmol of pyrene tetramine Py (see schematic diagram of synthesis) Figure 3 Add it to a mixed reaction solvent of 1.5 mL dioxane and 0.5 mL mesitylene, and disperse it evenly by ultrasonication.
[0063] (3) Add 0.4 mL of 5 mol / L acetic acid to the uniformly dispersed solution as a catalyst, put it into the reaction vessel, and after ultrasonic dispersion, put it into the reaction vessel.
[0064] (4) Keep the reactor at 110°C for 7 days. After the reaction is completed, cool it to room temperature and filter to collect the solid.
[0065] (5) Wash the collected solids by centrifugation with DMF and THF for 20 mL × 7 times, and collect the solids again.
[0066] (6) After Soxhlet extraction of solid THF for 24 hours, vacuum drying at 90°C for 24 hours yields orange powder, which is the covalent organic framework material used for indoor humidity control.
[0067] Tests showed that the covalent organic framework material prepared in this embodiment has the same indoor humidity regulation performance as the covalent organic framework material prepared in Example 1.
[0068] Example 4
[0069] The preparation method of the covalent organic framework material used for indoor humidity control in this embodiment is as follows:
[0070] (1) 0.5 mmol of bipyridine dialdehyde bpy-4 and 0.4 mmol of pyrene tetramine Py (see schematic diagram of synthesis) Figure 4 Add it to a mixed reaction solvent of 0.2 mL dioxane and 1.8 mL mesitylene, and disperse it evenly by ultrasonication.
[0071] (2) Add 0.2 mL of 9 mol / L acetic acid to the uniformly dispersed solution as a catalyst, put it into the reaction vessel, and after ultrasonic dispersion, put it into the reaction vessel.
[0072] (3) Keep the reactor at 120°C for 7 days. After the reaction is completed, cool it to room temperature and filter to collect the solid.
[0073] (4) Wash the collected solids by centrifugation with DMF and THF for 18 mL × 6 times, and collect the solids again.
[0074] (5) After Soxhlet extraction of solid THF for 24 hours, vacuum drying at 90°C for 24 hours yields a yellow powder, which is the covalent organic framework material used for indoor humidity control.
[0075] Tests showed that the covalent organic framework material prepared in this embodiment has the same indoor humidity regulation performance as the covalent organic framework material prepared in Example 1.
[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A covalent organic framework material for indoor humidity conditioning, characterized in that, The structural formula of the material is: 。 2. The method for preparing a covalent organic framework material for indoor humidity control according to claim 1, characterized in that, The preparation method includes the following steps: using bipyridine dialdehyde (bpy-2) with hydrophilic sites and pyrene tetramine (Py) as raw materials, dissolving them in a reaction solvent, and reacting them under a catalyst to obtain the product.
3. The method for preparing a covalent organic framework material for indoor humidity control according to claim 2, characterized in that, The molar ratio of bipyridine dialdehyde bpy-2 with hydrophilic sites to pyrene tetramine Py is 1:3 to 3:1; the catalyst is 10 to 20% of the volume of the reaction solvent.
4. The method for preparing a covalent organic framework material for indoor humidity control according to claim 2, characterized in that, The reaction solvent is dioxane and mesitylene, the volume ratio of dioxane to mesitylene is 1:1 to 5:1, and the reaction conditions are 110 to 150°C and standing for 3 to 7 days.
5. A method for preparing a covalent organic framework material for indoor humidity control according to claim 2 or 3, characterized in that, The catalyst includes acetic acid, and the concentration of the acetic acid is 3~6 mol / L.
6. The method for preparing a covalent organic framework material for indoor humidity control according to claim 2, characterized in that, After the reaction is completed, the mixture is cooled to room temperature and the solid is collected by filtration. The washing, purification and drying processes are repeated. The washing is performed with an organic solvent.
7. The method for preparing a covalent organic framework material for indoor humidity control according to claim 6, characterized in that, The organic solvent includes one or more of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF); the drying conditions are vacuum and 70-120°C; the purification method includes Soxhlet extraction.