CN113265057A

CN113265057A - Covalent-organic framework material and preparation method thereof

Info

Publication number: CN113265057A
Application number: CN202010092364.2A
Authority: CN
Inventors: 任世斌; 吴建波; 胡黛玉; 鲁赛峰; 韩得满
Original assignee: Taizhou University
Current assignee: Taizhou University
Priority date: 2020-02-14
Filing date: 2020-02-14
Publication date: 2021-08-17

Abstract

The invention belongs to the technical field of porous polymers, and particularly relates to a covalent-organic framework material and a preparation method thereof. The covalent-organic framework material is prepared by reacting tetraphenyl ethylene serving as a raw material with bromine to generate an intermediate product tetrabromophyrene, reacting the tetrabromophyrene with tetraacylphenylboronic acid under the catalysis of tetrakis (triphenylphosphine) palladium to generate an intermediate product tetraphenylethenal, and finally condensing the tetraphenylethenal with phloroglucinol strong aldehyde. The material has strong absorption to light with the wavelength of 300-600 nm, is stable in the temperature range of less than 300 ℃ and 600-1000 ℃, has an amorphous structure with spherical accumulation, cluster-shaped skeleton, compact arrangement and porosity, and provides a new reference for the preparation and performance research of organic frame materials.

Description

Covalent-organic framework material and preparation method thereof

Technical Field

The invention relates to the technical field of porous polymers, in particular to a covalent-organic framework material and a preparation method thereof.

Background

The porous polymer is a spherical polymer material with a pore structure, has the characteristics of high porosity, low density, light weight, large surface area and the like, and can adsorb CO in biomedicine₂Purifying environment, catalyzing degradation and the likeThe field is very widely applied. This has led to a great enthusiasm for the researchers in recent years.

The porous organic framework materials developed to date can be divided into metal-organic framework Materials (MOFs) and covalent-organic framework materials (COFs), and are zeolite-like nano-porous materials with excellent performances such as high specific surface area, high porosity and functional adjustability. The greatest advantage of MOFs, in addition to its diversified framework structure, large specific surface area and small density, is its framework structure design and controllability. Surface covalent organic networks (surface COFs), also known as two-dimensional polymers, are a class of two-dimensional materials with graphene-like structures. The preparation conditions of the material are simple, and the structure of the material can be designed by an organic chemical method. Currently, the preparation of surface COFs with monoatomic layer thickness, high order and large area coverage remains a very important challenge in the field of nanotechnology.

Disclosure of Invention

The invention aims to provide a covalent-organic framework material and a preparation method thereof, the prepared covalent-organic framework material has a novel structure, and provides a new reference for the preparation and performance research of the organic framework material.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of a covalent-organic framework material, which comprises the following steps:

mixing tetraphenyl ethylene with liquid bromine, and carrying out bromination reaction to obtain tetrabromo styrene;

mixing the tetrabromostyrene, the tetraacylphenylboronic acid, the potassium carbonate, the tetrakis (triphenylphosphine) palladium and the dioxane, and carrying out Suzuki coupling reaction to obtain tetraphenylethylenealdehyde;

and mixing the tetraphenylethylenealdehyde, the phloroglucinol and the 1, 4-dioxane, and carrying out strong aldehyde condensation reaction to obtain the covalent-organic framework material.

Preferably, the dosage ratio of the tetraphenylethylene to the liquid bromine is 5.0738g (0.2-0.5) mL.

Preferably, the bromination reaction is carried out at room temperature for a period of 7 days.

Preferably, the potassium carbonate is anhydrous potassium carbonate, and the using ratio of the tetrabromostyrene, the tetraacylphenylboronic acid, the potassium carbonate, the tetrakis (triphenylphosphine) palladium and the dioxane is 1.0607g, 1.6027g, 2.1384g, 0.2g and 80 mL.

Preferably, the Suzuki coupling reaction is carried out under the condition of oil bath, and the temperature of the Suzuki coupling reaction is 110 ℃ and the time is 3 d.

Preferably, the usage ratio of the tetraphenylethenal, the phloroglucinol and the 1, 4-dioxane is 0.2994g, 0.1493g and 8 mL.

Preferably, the condensation reaction of the strong aldehyde is carried out in a reaction kettle, and the lining material of the reaction kettle is PTFE.

Preferably, nitrogen is introduced into the reaction kettle for 5min before the strong aldehyde condensation reaction is carried out.

Preferably, the temperature of the condensation reaction of the strong aldehyde is 220 ℃ and the time is 4 d.

The invention provides a covalent-organic framework material prepared by the preparation method in the technical scheme.

The invention provides a preparation method of a covalent-organic framework material, which comprises the following steps: mixing tetraphenyl ethylene with liquid bromine, and carrying out bromination reaction to obtain tetrabromo styrene; mixing the tetrabromostyrene, the tetraacylphenylboronic acid, the potassium carbonate, the tetrakis (triphenylphosphine) palladium and the dioxane, and carrying out Suzuki coupling reaction to obtain tetraphenylethylenealdehyde; and mixing the tetraphenylethylenealdehyde, the phloroglucinol and the 1, 4-dioxane, and carrying out strong aldehyde condensation reaction to obtain the covalent-organic framework material. The invention takes tetraphenyl ethylene as raw material, which reacts with bromine to generate intermediate tetrabromo styrene, then the tetrabromo styrene reacts with tetraacylphenylboronic acid under the catalysis of tetra (triphenylphosphine) palladium to generate intermediate tetraphenyl ethylene aldehyde, and finally the tetraphenyl ethylene aldehyde is polymerized with phloroglucinol to prepare the covalent-organic framework material. The material has strong absorption to light with the wavelength of 300-600 nm, is stable in the temperature range of less than 300 ℃ and 600-1000 ℃, has an amorphous structure with spherical accumulation, cluster-shaped skeleton, compact arrangement and porosity, and provides a new reference for the preparation and performance research of organic frame materials.

Drawings

FIG. 1 is an IR spectrum of tetrabromostyrene prepared in example 1;

FIG. 2 is an infrared spectrum of tetraphenylvinylaldehyde prepared in example 1;

FIG. 3 is a nuclear magnetic spectrum of tetraphenylethylenealdehyde prepared in example 1;

FIG. 4 is a solid UV spectrum of LSF-COF prepared in example 1;

FIG. 5 is an IR spectrum of LSF-COF prepared in example 1;

FIG. 6 is a thermogravimetric and differential thermal profile of the LSF-COF prepared in example 1;

FIG. 7 is an XRD diffractogram of LSF-COF prepared in example 1;

FIG. 8 is an SEM image of LSF-COF prepared in example 1 at different magnifications.

Detailed Description

In the present invention, unless otherwise specified, all the starting materials required for the preparation are commercially available products well known to those skilled in the art.

In the invention, tetraphenylethylene and liquid bromine are mixed for bromination reaction to obtain tetrabromostyrene. In the invention, the dosage ratio of the tetraphenylethylene to the liquid bromine is preferably 5.0738g (0.2-0.5) mL. In the present invention, the mixing process is preferably carried out by placing tetraphenylethylene on a watch glass, placing the watch glass in a dryer, and dripping liquid bromine into the dryer. In the present invention, the temperature of the bromination reaction is preferably room temperature, and the time is preferably 7 d. After the bromination reaction is finished, the obtained light yellow solid is added into a mixed solution of dichloromethane and methanol (the volume ratio of the dichloromethane to the methanol is 2:1) (the polarity of the solvent is regulated and controlled so that the crude product can be just completely dissolved to form a state close to saturation), the mixture is heated to 60 ℃ until the solid is just dissolved, and the tetrabromostyrene is obtained by cooling, crystallizing and filtering under reduced pressure. The crystallization and reduced pressure filtration process is not particularly limited in the present invention, and a process well known in the art may be selected.

In the present invention, the process of the bromination reaction is as follows:

after tetrabromostyrene is obtained, the tetrabromostyrene, the tetraacylphenylboronic acid, the potassium carbonate, the tetrakis (triphenylphosphine) palladium and the dioxane are mixed for Suzuki coupling reaction to obtain the tetraphenylethylenealdehyde. In the present invention, the tetrakis (triphenylphosphine) palladium is preferably commercially available or prepared by methods well known in the art. In the embodiment of the present invention, the preparation process of the tetrakis (triphenylphosphine) palladium is preferably as follows: adding 0.6522g of triphenylphosphine, 0.0914g of palladium chloride and 10.0mL of dimethyl sulfoxide solution into a 50mL round-bottom flask, controlling the temperature of an oil bath at 130 ℃ under the protection of nitrogen, reacting for 1h until all solids are dissolved, adding 1mL of hydrazine hydrate (reducing bivalent palladium into zero-valent palladium) into the obtained solution, precipitating yellow insoluble substances in the solution to enable the solution to become a suspension, carrying out suction filtration by using a Buchner funnel while the solution is hot, washing the obtained solid by using absolute ethyl alcohol, and drying under vacuum conditions to obtain tetrakis (triphenylphosphine) palladium (named as palladium IV); the tetrakis (triphenylphosphine) palladium needs to be used immediately after the preparation is completed.

In the present invention, the potassium carbonate is preferably anhydrous potassium carbonate, and the amount ratio of tetrabromostyrene, tetraacylphenylboronic acid, potassium carbonate, tetrakis (triphenylphosphine) palladium and dioxane is preferably 1.0607g:1.6027g:2.1384g:0.2g:80 mL. The method takes potassium carbonate as alkali to participate in the reaction, takes tetrakis (triphenylphosphine) palladium as a catalyst, and takes dioxane as a solvent. The mixing process is not particularly limited in the present invention, and the raw materials can be uniformly mixed by selecting a process known to those skilled in the art.

In the invention, the Suzuki coupling reaction is preferably carried out under the protection of oil bath and nitrogen, and the temperature of the Suzuki coupling reaction is preferably 110 ℃ and the time is preferably 3 d.

After the Suzuki coupling reaction is completed, the solution obtained is preferably poured into a dilute hydrochloric acid solution (10%) to be washed (neutralization K)₂CO₃Stopping Suzuki reaction), generating yellow-green solid precipitate, carrying out suction filtration, washing the obtained solid with the dilute hydrochloric acid solution and distilled water in sequence, drying the obtained solid on filter paper to obtain a filter cake, wrapping the filter cake, putting the filter cake into a Soxhlet extractor, extracting and refluxing with dichloromethane for 48h, evaporating the solvent of the obtained extracting solution with a reduced-pressure rotary evaporator, and drying the obtained solid to obtain the tetraphenylaldehyde. The process of suction filtration, washing, drying extraction and evaporation is not particularly limited in the invention, and the process known by the skilled person in the art can be selected.

In the present invention, the process of the Suzuki coupling reaction is as follows:

after the tetraphenyl vinyl aldehyde is obtained, the tetraphenyl vinyl aldehyde, the phloroglucinol and the 1, 4-dioxane are mixed to carry out strong aldehyde condensation reaction, so that the covalent-organic framework material is obtained. In the present invention, the amount ratio of the tetraphenylethylenealdehyde, phloroglucinol, and 1, 4-dioxane is preferably 0.2994g, 0.1493g, and 8 mL. The mixing process is not particularly limited in the invention, and the raw materials can be uniformly mixed by selecting the process well known in the field.

In the present invention, the condensation reaction of the strong aldehyde is preferably carried out in a reaction vessel, and the material of the inner liner of the reaction vessel is preferably PTFE. Before the strong aldehyde condensation reaction is carried out, the methodPreferably, nitrogen is introduced into the reaction kettle for 5min, redundant oxygen and air are removed, and then the reaction kettle is sealed to carry out strong aldehyde condensation reaction. In the present invention, the temperature of the condensation reaction of the strong aldehyde is preferably 220 ℃ and the time is preferably 4 d. In the process of strong aldehyde condensation reaction, a hydroxyl group ortho-position C-H bond is opened to react with aldehyde group C ═ O, and a molecule of H is removed₂O。

After the strong aldehyde condensation reaction is completed, preferably, the obtained suspension is subjected to suction filtration, the obtained solid is soaked and washed for one day by using acetone, is subjected to suction filtration again, is soaked and washed for one day by using dichloromethane again, is subjected to suction filtration again, and is dried to obtain the covalent-organic framework material, namely the LSF-COF.

In the present invention, the synthesis mechanism of the strong aldehyde condensation reaction is as follows:

the invention provides a covalent-organic framework material prepared by the preparation method in the technical scheme. The invention takes tetraphenyl ethylene and liquid bromine as raw materials, firstly synthesizes intermediate product tetrabromo styrene, then under the catalysis of tetra (triphenylphosphine) palladium, the tetrabromo styrene and tetraacylphenylboronic acid are mixed and reacted to generate another intermediate product tetraphenyl ethylene aldehyde, and finally, the tetraphenyl ethylene aldehyde and phloroglucinol are polymerized to obtain the covalent-organic framework material, the material has stronger absorption to light with the wavelength of 300-600 nm, is relatively stable in the range of less than 300 ℃ and 600-1000 ℃, and has an amorphous structure which is spherically stacked, cluster-shaped in framework, tightly arranged and porous.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

5.0738g of tetraphenylethylene is weighed on a watch glass, the watch glass is placed in a dryer, 5 drops (0.25mL) of liquid bromine are dripped into the dryer, after 7 days, the liquid bromine is completely volatilized, the obtained light yellow solid is added into a mixed solution of dichloromethane and methanol (the volume ratio is 2:1), the mixture is heated to 60 ℃ to be just dissolved, the mixture is cooled, crystallized, decompressed and filtered to obtain tetrabromostyrene, and the tetrabromostyrene 3.1060g is obtained after drying.

0.6522g of triphenylphosphine, 0.0914g of palladium chloride and 10.0mL of dimethyl sulfoxide are added into a 50mL round-bottom flask, the oil bath temperature is controlled at 130 ℃ under the protection of nitrogen, the reaction is carried out for 1h until all the solid is dissolved, 1mL of hydrazine hydrate is immediately added into the obtained light yellow transparent solution, yellow insoluble substances in the solution are separated out to enable the solution to become a suspension, the suspension is filtered by a Buchner funnel while the solution is hot, the obtained bright yellow solid is washed by absolute ethyl alcohol, and the solid is dried under the vacuum condition, so that the tetrakis (triphenylphosphine) palladium is obtained.

1.0607g of tetrabromostyrene, 1.6027g of tetraacylphenylboronic acid, 2.1384g of anhydrous potassium carbonate, 0.2g of tetrakis (triphenylphosphine) palladium and 80mL of dioxane are added into a 250mL three-neck flask, the mixed solution is yellow, the mixed solution is kept in an oil bath at 110 ℃ for 3 days under the protection of nitrogen to obtain a dark yellow green solution, after the reaction is finished, the reaction solution is immediately poured into 200mL of dilute hydrochloric acid solution (the mass fraction is 10%) to be cleaned to generate yellow green solid precipitate, the yellow green solid precipitate is subjected to suction filtration and is sequentially washed by the dilute hydrochloric acid solution and distilled water, the obtained solid is dried on filter paper to obtain a filter cake, the filter cake is wrapped and then put into the bottom of a Soxhlet extractor to be extracted and refluxed for 48 hours by dichloromethane to obtain a yellow green extracting solution, the solvent is evaporated by a reduced pressure rotary evaporator, and the obtained solid is dried in a drying oven to obtain yellow powder, namely, 0.7371g of tetraphenylvinylaldehyde.

Adding 0.2994g of tetraphenylvinylaldehyde, 0.1493g of phloroglucinol and 8mL of 1, 4-dioxane into a polytetrafluoroethylene lining of a reaction kettle, dividing the materials into two reaction kettles, introducing nitrogen into the reaction kettles for 5min, covering the reaction kettles with a cover, sealing the reaction kettles, reacting for 4 days in a 220 ℃ oven, carrying out suction filtration on the obtained red brown suspension to obtain brick red solid, soaking and washing the brick red solid for one day by using acetone, carrying out suction filtration again, soaking and washing the brick red solid for one day by using dichloromethane, carrying out suction filtration, and drying to obtain brick red powder, namely a covalent-organic framework material, which is marked as LSF-COF.

Performance testing

1) Infrared characterization of the tetrabromostyrene prepared in example 1 is shown in FIG. 1.

From the graph analysis, it can be known that: 1450 and 1600cm^-1The peak is a C ═ C (skeleton C of benzene ring) characteristic peak at 650-950 cm^-1The presence of a benzene ring was judged by identifying the presence of a C-H stretching vibration on the benzene ring as a C-H characteristic peak. At 500-600 cm^-1Characteristic absorption peak of C-Br at 1685.79cm^-1The compound was judged to contain a group due to tetrabromostyrene by identifying a characteristic peak as a C ═ C absorption peak.

2) Infrared characterization of the tetraphenylethylenealdehyde prepared in example 1 is shown in FIG. 2.

From the graph analysis, it can be known that: at 1600-1850 cm^-1Has a-C-O stretching vibration and 1620-1680 cm^-1Has a C ═ C (skeleton of benzene ring) vibration absorption peak at 650-950 cm^-1The compound has a C-H stretching vibration ═ C-H characteristic peak on a benzene ring, and the compound is obtained to have the proper group of tetraphenyl vinyl aldehyde.

3) The tetraphenylvinylaldehyde prepared in example 1 was subjected to nuclear magnetic characterization, and the nuclear magnetic hydrogen spectrum obtained is shown in FIG. 3.

From the graph analysis, it can be known that: the absorption peak at delta 7.04ppm is the proton peak on the first benzene ring of the product, the absorption peak at delta 7.09ppm is the proton peak on the second benzene ring of the product, the absorption peak at delta 7.87ppm is the proton peak on the benzene ring of the product (adjacent to the aldehyde group), and the absorption peak at delta 10.04ppm is the proton peak on the aldehyde group of the compound; the other peaks are impurity peaks, indicating that the compound is tetraphenylaldehyde.

4) The LSF-COF prepared in example 1 was subjected to solid UV characterization and the results are shown in FIG. 4.

As can be seen from FIG. 4, the polymer LSF-COF has a distinct absorption peak in the wavelength range of 300-600 nm.

5) The LSF-COF prepared in example 1 was characterized by infrared and the results are shown in FIG. 5.

From the graph analysis, it can be known that: at 1450-1600cm^-1The absorption peak is the absorption peak of C ═ C on the benzene ring skeleton, and the absorption peak is 3016.67cm^-1The C-H stretching vibration on the benzene ring is the characteristic peak of C-H. In addition, according to 3620.39cm^-1The existence of-OH can be judged by the absorption peak. At 800.46cm^-1The absorption peak is C-H, and two symmetric and antisymmetric stretching vibrations representing aldehydes are very weak and are weaker and weaker, so that the aldehyde group disappears gradually in the reaction. The reaction proceeds in the expected direction according to the preliminary analysis described above.

6) The LSF-COF prepared in example 1 was subjected to thermogravimetric characterization and the results are shown in FIG. 6.

From the graph analysis, it can be known that: when the temperature is increased from 20 ℃ to 450 ℃, the Y axis represents the loss of the mass of the LSF-COF in the temperature increasing process, the final weight loss rate of the LSF-COF is 45.88%, and the weight loss speed is slow between 20 ℃ and 300 ℃, which is mainly because a certain amount of moisture is adsorbed on the surface of the polymer, dehydration is caused in the temperature increasing process, and the mass loss is caused. The weight loss speed is accelerated between 300 and 600 ℃, the TGA curve slides down rapidly, the compound collapses structurally at the moment, the quality is reduced, the weight loss speed is slowed down between 600 and 1000 ℃, and the collapse degree is proved to be maximum. From this, it can be judged that the compound is more stable before 300 ℃ and then becomes less stable until it is stabilized again. In conclusion, the thermal stability of LSF-COF is relatively stable under high temperature conditions.

7) XRD characterization of the LSF-COF prepared in example 1 was performed and the results are shown in FIG. 7.

From the graph analysis, it is understood that the XRD curve is relatively mild, the peak shape is not sharp and narrow or is obviously prominent, and the compound (LSF-COF) does not show a certain crystal structure.

8) SEM characterization was performed on the LSF-COF prepared in example 1, and the results are shown in FIG. 8.

In FIG. 8, the left side shows a scanning electron micrograph at 5 μm and the right side shows a scanning electron micrograph at 20 μm, from which it can be seen that LSF-COF has a spherical packing structure and clusters are close to each other, and at the same time, the polymers have gaps therebetween and are disordered in arrangement.

From the above examples, it can be seen that the present invention provides a covalent-organic framework material and a method for preparing the same. The invention takes tetraphenyl ethylene as raw material, which reacts with bromine to generate intermediate tetrabromo styrene, then tetrabromo styrene reacts with tetraacylphenylboronic acid under the catalysis of tetrakis (triphenylphosphine) palladium to generate intermediate tetraphenyl ethylene aldehyde, and finally tetraphenyl ethylene aldehyde is polymerized with phloroglucinol to prepare the polymer, covalent-organic framework material. The material has strong absorption to light with the wavelength of 300-600 nm, is stable in the temperature range of less than 300 ℃ and 600-1000 ℃, has an amorphous structure with spherical accumulation, cluster-shaped skeleton, compact arrangement and porosity, and provides a new reference for the preparation and performance research of organic frame materials.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a covalent-organic framework material, comprising the steps of:

2. The preparation method of claim 1, wherein the amount ratio of the tetraphenylethylene to the liquid bromine is 5.0738g (0.20-0.50) mL.

3. The method of claim 1, wherein the bromination reaction is carried out at room temperature for a period of 7 days.

4. The method according to claim 1, wherein the potassium carbonate is anhydrous potassium carbonate, and the ratio of the tetrabromostyrene, the tetraacylphenylboronic acid, the potassium carbonate, the tetrakis (triphenylphosphine) palladium and the dioxane is 1.0607g, 1.6027g, 2.1384g, 0.2g, and 80 mL.

5. The preparation method according to claim 1, wherein the Suzuki coupling reaction is carried out under oil bath conditions, and the temperature of the Suzuki coupling reaction is 110 ℃ and the time is 3 d.

6. The preparation method of claim 1, wherein the amount ratio of the tetraphenylethylenealdehyde, the phloroglucinol and the 1, 4-dioxane is 0.2994g, 0.1493g, and 8 mL.

7. The production method according to claim 1, wherein the strong aldehyde condensation reaction is carried out in a reaction tank, and a lining material of the reaction tank is PTFE.

8. The method according to claim 7, wherein nitrogen gas is introduced into the reaction vessel for 5min before the strong aldehyde condensation reaction is carried out.

9. The method according to claim 1 or 8, wherein the temperature of the condensation reaction of the strong aldehyde is 220 ℃ and the time is 4 days.

10. A covalent-organic framework material prepared by the preparation method of any one of claims 1 to 9.