阅读说明：本技术 一类温控离子液体功能化的温度响应共价有机框架材料及其制备方法 (Temperature-controlled ionic liquid functionalized temperature response covalent organic framework material and preparation method thereof ) 是由 姚文惠 陈永魁 于 2020-12-02 设计创作，主要内容包括：本发明公开了一类温控离子液体功能化的温度响应共价有机框架材料及其制备方法,属于热敏材料和共价有机框架材料技术领域。本发明的技术方案要点为：一类温控离子液体功能化的温度响应共价有机框架材料,其化学结构如下：其中,n＝8、12、16或22。本发明还具体公开了该温控离子液体功能化的温度响应共价有机框架材料的制备方法。本发明具有合成过程简单、晶型好、比表面积大、稳定性好、易操作等优点,所合成的温控离子液体功能化的温度响应共价有机框架材料COF-XXU温控特性较好,是一种较具实际应用潜力的热敏材料,可应用于储能、温控分子开关和智能电极材料等领域。(The invention discloses a temperature-controlled ionic liquid functionalized temperature response covalent organic framework material and a preparation method thereof, belonging to the technical field of thermosensitive materials and covalent organic framework materials. The technical scheme provided by the invention has the key points that: a temperature-controlled ionic liquid functionalized temperature response covalent organic framework material has the following chemical structure: wherein n is 8, 12, 16 or 22. The invention also specifically discloses a preparation method of the temperature-controlled ionic liquid functionalized temperature response covalent organic framework material. The invention has the advantages of simple synthesis process, good crystal form, large specific surface area, good stability, easy operation and the like, and the synthesized temperature-control ionic liquid functionalized temperature-response covalent organic framework material COF-XXU has better temperature control characteristic and is more practical applicationThe potential thermosensitive material can be applied to the fields of energy storage, temperature control molecular switches, intelligent electrode materials and the like.)

1. A temperature-control ionic liquid functionalized temperature-response covalent organic framework material is characterized in that the chemical structure of the temperature-response covalent organic framework material is as follows:

wherein n is 8, 12, 16 or 22.

2. A preparation method of the temperature-controlled ionic liquid functionalized temperature-responsive covalent organic framework material of claim 1, which is characterized by comprising the following specific steps:

step S1: adding 2-hydroxy terephthalaldehyde and 4,4' - (1,3, 5-triazine-2, 4, 6-triyl) triphenylamine into a pressure-resistant glass tube, adding an organic solvent, carrying out ultrasonic treatment on a mixed system for 10-20 minutes, adding an acetic acid solution, carrying out three freezing-vacuum-unfreezing circulation treatments, sealing the pressure-resistant glass tube, reacting at 120 ℃ for 48-96 hours to obtain solids, washing the solids with dimethylacetamide, water and ethanol respectively, and carrying out vacuum drying on the obtained solids at 80 ℃ for 24 hours to obtain a yellow covalent organic framework material COF-1;

step S2: dispersing the covalent organic framework material COF-1 obtained in the step S1 in an organic solvent, adding a catalyst, carrying out ultrasonic treatment for 20min, adding dibromo polyethylene glycol, stirring at room temperature for 2 hours, carrying out reflux reaction at 70-90 ℃ for 2-4 hours, washing the obtained solid with ethanol, and carrying out vacuum drying at 80 ℃ overnight to obtain a yellow covalent organic framework material COF-2, wherein the catalyst is anhydrous potassium carbonate, diethylamine, triethylamine or pyridine;

step S3: dispersing the covalent organic framework material COF-2 obtained in the step S2 into an organic solvent, adding methylimidazole, carrying out reflux reaction at the temperature of 60-80 ℃ for 24-48 hours, cooling the mixed solution to room temperature, carrying out suction filtration, washing with ethanol, and carrying out vacuum drying at the temperature of 80 ℃ for 12 hours to obtain a yellow covalent organic framework material COF-3;

step S4: and (3) dispersing the covalent organic framework material COF-3 obtained in the step S3 into water at room temperature, adding an aqueous solution of lithium trifluoromethanesulfonimide, reacting at room temperature for 2-4 hours, filtering the product, washing the product with ethanol, and drying in vacuum at 80 ℃ for 12 hours to obtain a yellow target product, namely the temperature-responsive covalent organic framework material COF-XXU.

3. The preparation method of the temperature-controlled ionic liquid functionalized temperature-responsive covalent organic framework material according to claim 2, characterized in that: in the step S1, the organic solvent is a mixed solvent of 1, 4-dioxane and mesitylene with a volume ratio of 1:1 or a mixed solvent of 1, 4-dioxane and ortho-dichlorobenzene with a volume ratio of 2:1, the molar concentration of the acetic acid solution is 6mol/L, and the feeding molar ratio of the 2-hydroxy terephthalaldehyde to the 4,4' - (1,3, 5-triazine-2, 4, 6-triyl) triphenylamine is 3: 0.5.

4. The preparation method of the temperature-controlled ionic liquid functionalized temperature-responsive covalent organic framework material according to claim 2, characterized in that: in the step S2, the organic solvent is N, N-dimethylformamide or tetrahydrofuran, and the feeding molar ratio of the covalent organic framework material COF-1, the catalyst and the dibromo polyethylene glycol is 1:2: 1.5-2.

5. The preparation method of the temperature-controlled ionic liquid functionalized temperature-responsive covalent organic framework material according to claim 2, characterized in that: in the step S3, the organic solvent is ethyl acetate, tetrahydrofuran or acetonitrile, and the feeding molar ratio of the covalent organic framework material COF-2 to the methylimidazole is 1: 1.5-2.

6. The preparation method of the temperature-controlled ionic liquid functionalized temperature-responsive covalent organic framework material according to claim 2, characterized in that: the feeding molar ratio of the covalent organic framework material COF-3 to the lithium trifluoromethanesulfonimide in the step S4 is 1: 1.2-2.

7. The use of the temperature-controlled ionic liquid functionalized temperature-responsive covalent organic framework material of claim 1 in the fields of energy storage, temperature-controlled molecular switches and intelligent electrode materials.

Technical Field

The invention belongs to the technical field of thermosensitive materials and covalent organic framework materials, is mainly applied to the field of intelligent temperature control molecular switches, and particularly relates to a temperature response covalent organic framework material functionalized by temperature control ionic liquid and a preparation method thereof.

Background

Covalent Organic Frameworks (COFs) are a new porous ordered crystal material, have the characteristics of high crystallinity, designable structure, large specific surface area, small density, high thermal stability and chemical stability and the like, are developed rapidly in recent years, and are a research hotspot in the field of polymer disciplines. Has wide application prospect in the fields of electric conduction, molecule capture and release, gas separation, catalysis, energy storage and conversion and the like.

In recent years, the environmental response type polymer has important application in drug carriers, biological detectors, intelligent materials and the like, and is an important component of future novel materials. Functional COFs materials that can sense and respond to environmental changes are receiving a great deal of attention due to their wide application in different fields, and are capable of undergoing structural and property changes under external stimuli such as light, pH, chemicals, and heat. Despite the significant advances that have been made, there are more and higher demands placed on the development and application of novel environmentally responsive COFs materials in the areas of basic research and application research. Compared with other functional COFs materials with environmental response, the research on heat-sensitive COFs, especially on temperature-response COFs with small front-back temperature difference, is still blank. It is worth noting that the thermosensitive COFs do not destroy the essential structure of the COFs before and after the temperature change, but only the physical properties are changed and are reversible. The COFs property change caused by the temperature stimulation can obviously change the properties of molecular adsorption, electric conduction and the like of the material.

The PEG functionalized ionic liquid is a novel organic temperature-controlled molecular switch, and when the temperature of a system is raised to a certain degree (lower critical temperature), reversible transformation can be realized between one phase and two phases. Unlike other environmental response molecular switches found previously, the structure of the ionic liquid is not changed substantially before and after the temperature rise, only the physical property is changed, and the ionic liquid has high fatigue resistance. Given that these important geometric changes and property changes will impart their particular functionality, the incorporation of PEG functionalized ionic liquids into porous materials is a very promising way to modulate and control their properties in response to external stimuli.

Therefore, the invention synthesizes a series of COF-XXU covalent organic framework materials by introducing a temperature-responsive PEG ionic liquid structural unit into the pore structure of the COFs for the first time through a post-synthesis strategy. Before and after temperature change, the water absorption capacity of the COF-XXU covalent organic framework material changes by more than 100 times, and the COF-XXU covalent organic framework material becomes a promising mode for functional modification of COFs.

At present, no report is found on a domestic method for preparing temperature-sensitive materials by using COFs. The conventional method generally uses polypropylene as a substrate, and one or two layers of temperature sensitive material coatings are coated on the surface of the polypropylene material. In contrast, the PEG-functionalized ionic liquid-modified thermosensitive COFs have more excellent performance.

Disclosure of Invention

The invention solves the technical problem of providing a temperature-control ionic liquid functionalized temperature-response covalent organic framework material and a preparation method thereof, the preparation method has the advantages of simple synthesis process, good crystal form, large specific surface area, good stability, easy operation and the like, and the synthesized temperature-control ionic liquid functionalized temperature-response covalent organic framework material COF-XXU has better temperature control characteristic, is a thermosensitive material with better practical application potential, and can be applied to the fields of energy storage, temperature-control molecular switches, intelligent electrode materials and the like.

The invention adopts the following technical scheme for solving the technical problems, and the temperature-control ionic liquid functionalized temperature-response covalent organic framework material is characterized in that the chemical structure of the temperature-response covalent organic framework material is as follows:

wherein n is 8, 12, 16 or 22.

The invention relates to a preparation method of a temperature-controlled ionic liquid functionalized temperature response covalent organic framework material, which is characterized by comprising the following specific steps:

step S1: adding 2-hydroxy terephthalaldehyde and 4,4' - (1,3, 5-triazine-2, 4, 6-triyl) triphenylamine into a pressure-resistant glass tube, adding an organic solvent, carrying out ultrasonic treatment on a mixed system for 10-20 minutes, adding an acetic acid solution, carrying out three freezing-vacuum-unfreezing circulation treatments, sealing the pressure-resistant glass tube, reacting at 120 ℃ for 48-96 hours to obtain solids, washing the solids with dimethylacetamide, water and ethanol respectively, and carrying out vacuum drying on the obtained solids at 80 ℃ for 24 hours to obtain a yellow covalent organic framework material COF-1;

step S2: dispersing the covalent organic framework material COF-1 obtained in the step S1 in an organic solvent, adding a catalyst, carrying out ultrasonic treatment for 20min, adding dibromo polyethylene glycol, stirring at room temperature for 2 hours, carrying out reflux reaction at 70-90 ℃ for 2-4 hours, washing the obtained solid with ethanol, and carrying out vacuum drying at 80 ℃ overnight to obtain a yellow covalent organic framework material COF-2, wherein the catalyst is anhydrous potassium carbonate, diethylamine, triethylamine or pyridine;

step S3: dispersing the covalent organic framework material COF-2 obtained in the step S2 into an organic solvent, adding methylimidazole, carrying out reflux reaction at the temperature of 60-80 ℃ for 24-48 hours, cooling the mixed solution to room temperature, carrying out suction filtration, washing with ethanol, and carrying out vacuum drying at the temperature of 80 ℃ for 12 hours to obtain a yellow covalent organic framework material COF-3;

step S4: and (3) dispersing the covalent organic framework material COF-3 obtained in the step S3 into water at room temperature, adding an aqueous solution of lithium trifluoromethanesulfonimide, reacting at room temperature for 2-4 hours, filtering the product, washing the product with ethanol, and drying in vacuum at 80 ℃ for 12 hours to obtain a yellow target product, namely the temperature-responsive covalent organic framework material COF-XXU.

Preferably, the organic solvent in step S1 is a mixed solvent of 1, 4-dioxane and mesitylene in a volume ratio of 1:1 or a mixed solvent of 1, 4-dioxane and ortho-dichlorobenzene in a volume ratio of 2:1, the molar concentration of the acetic acid solution is 6mol/L, and the feeding molar ratio of the 2-hydroxy terephthalaldehyde to 4,4' - (1,3, 5-triazine-2, 4, 6-triyl) triphenylamine is 3: 0.5.

Preferably, the organic solvent in the step S2 is N, N-dimethylformamide or tetrahydrofuran, and the feeding molar ratio of the covalent organic framework material COF-1, the catalyst and the dibromo polyethylene glycol is 1:2: 1.5-2.

Preferably, the organic solvent in step S3 is ethyl acetate, tetrahydrofuran or acetonitrile, and the feeding molar ratio of the covalent organic framework material COF-2 to methylimidazole is 1: 1.5-2.

Preferably, the feeding molar ratio of the covalent organic framework material COF-3 to the lithium trifluoromethanesulfonimide in step S4 is 1: 1.2-2.

The temperature-control ionic liquid functionalized temperature response covalent organic framework material is applied to the fields of energy storage, temperature-control molecular switches and intelligent electrode materials.

The temperature-sensitive ionic liquid is introduced into the temperature-responsive covalent organic framework material with functionalized temperature-controlled ionic liquid by a post-modification method on COFs materials, and belongs to the technical field of thermosensitive materials and covalent organic framework materials. The ionic liquid is as follows: polyethylene glycol (PEG) functionalized imidazolium salt, and the anion is trifluoromethyl sulfimide ([ NTf)₂]^-). Because the PEG functionalized ionic liquid has the phase property of Lower Critical Solution Temperature (LCST), the functionalized COFs material has good temperature control property: the random coil conformation of the PEG chain of the ionic liquid molecule post-modified on the COFs material is gradually reduced along with the increase of the temperature, and the hydrophobic group (CH) of the PEG chain is heated₂CH₂) Gradually loses water molecules with ordered structures around the COFs, thereby causing the clustering of ionic liquid and water and the phase separation of a system, realizing reversible transformation, further realizing the reversible transformation of physical properties such as water absorption capacity and the like of the COFs, and having better fatigue resistance.

Compared with the prior art, the invention has the following advantages:

1. the temperature control ionic liquid functionalized novel temperature response COFs material synthesized by the invention has good temperature control characteristics: before and after the temperature change, the water absorption performance of the COFs material is greatly changed and is more than 100 times, so that the COFs material becomes a promising mode for functional modification of the COFs.

2. The invention has simple preparation process and low cost, does not use p-toluenesulfonic acid and volatile organic solvents such as acetone in the synthesis process, and has less environmental pollution.

3. The yield of each step of reaction in the synthetic process of the invention is over 90 percent.

4. The covalent organic framework material synthesized by the invention has good crystal form and large specific surface area (>1000m²g^-1) The pore size distribution is uniform.

5. The covalent organic framework material synthesized by the method has good thermal stability and chemical stability and better fatigue resistance.

Drawings

FIG. 1 is a polycrystalline powder diffraction Pattern (PXRD) of the prepared covalent organic framework materials COF-1 and COF-XXU;

FIG. 2 is an infrared absorption spectrum (IR) of the prepared covalent organic framework materials COF-1 and COF-XXU;

FIG. 3 is an X-ray photoelectron spectroscopy (XPS) of the prepared covalent organic framework materials COF-1 and COF-XXU.

Detailed Description

The present invention is described in further detail below with reference to examples, but it should not be construed that the scope of the above subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the above subject matter of the present invention belong to the scope of the present invention.

The synthesis route of the temperature-controlled ionic liquid functionalized novel temperature response COFs material is different from the prior art, and the specific synthesis route is as follows:

example 1

The covalent organic framework material COF-1 is synthesized by a solvothermal method and comprises the following steps:

45mg of 2-hydroxy terephthalaldehyde and 159mg of 4,4' - (1,3, 5-triazine-2, 4, 6-triyl) triphenylamine were put into a 10mL pressure-resistant glass tube, a mixed solution of 1, 4-dioxane/mesitylene/6M acetic acid (1.5mL/1.5mL/0.5mL) was added thereto, the mixed system was sonicated for 20 minutes, the pressure-resistant glass tube was sealed after three freeze-vacuum-thaw cycles, and then the resultant solid was reacted at 120 ℃ for 72 hours, washed with dimethylacetamide, water and ethanol, respectively, and the resultant solid was vacuum-dried at 80 ℃ for 24 hours to obtain a yellow covalent organic framework material COF-1.

Example 2

The synthesis of covalent organic framework material COF-2 comprises the following steps:

44mg of covalent organic framework material COF-1 were dispersed in 10mL of DMF, and 21mg of catalyst anhydrous K was added₂CO₃And (3) carrying out ultrasonic treatment for 20min, then adding 184mg of dibromo polyethylene glycol 800, stirring for 2 hours at room temperature, carrying out reflux reaction for 3 hours at 80 ℃, washing the obtained solid with ethanol, and carrying out vacuum drying at 80 ℃ overnight to obtain a yellow covalent organic framework material COF-2.

Example 3

The synthesis of covalent organic framework material COF-3 comprises the following steps:

dispersing 26mg of covalent organic framework material COF-2 into 10mL of acetonitrile, adding 4mg of methylimidazole, carrying out reflux reaction at 80 ℃ for 48 hours, cooling the mixed solution to room temperature, carrying out suction filtration, washing with ethanol, and carrying out vacuum drying at 80 ℃ for 12 hours to obtain yellow covalent organic framework material COF-3.

Example 4

The synthesis of covalent organic framework material COF-XXU, comprising the following steps:

dispersing 28mg of covalent organic framework material COF-3 into 10mL of water at room temperature, adding 10mL of 3mmol/L aqueous solution of lithium trifluoromethanesulfonimide, reacting at room temperature for 2 hours, filtering the product, washing the product with ethanol, and drying the product at 80 ℃ in vacuum for 12 hours to obtain a yellow target product, namely the covalent organic framework material COF-XXU.

The foregoing embodiments illustrate the principles, principal features and advantages of the invention, and it will be understood by those skilled in the art that the invention is not limited to the foregoing embodiments, which are merely illustrative of the principles of the invention, and that various changes and modifications may be made therein without departing from the scope of the principles of the invention.