CN108610504B

CN108610504B - Preparation method of monolithic material with hierarchical pore structure

Info

Publication number: CN108610504B
Application number: CN201611127503.0A
Authority: CN
Inventors: 欧俊杰; 刘忠山; 叶明亮
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2016-12-09
Filing date: 2016-12-09
Publication date: 2020-12-22
Anticipated expiration: 2036-12-09
Also published as: CN108610504A

Abstract

The invention relates to a preparation method of a hierarchical pore monolithic material containing a Covalent Organic Framework (COF). Specifically, a covalent organic framework polymer, a compound (functional monomer) containing an epoxy functional group, a compound (functional monomer) containing an amino functional group, a pore-forming agent and the like are mixed, oscillated and dispersed, and then subjected to ring-opening polymerization reaction of epoxy at a certain temperature, so that the integral material with a hierarchical pore structure (micropore-mesopore-macropore) can be prepared in one step. The preparation method has the advantages of mild conditions, high efficiency, controllability and the like. In addition, different covalent organic framework polymers can be selected according to different application requirements, or the doping amount of the covalent organic framework polymers can be adjusted, so that a series of hierarchical pore integrated materials with different physical and chemical properties can be prepared.

Description

Preparation method of monolithic material with hierarchical pore structure

Technical Field

The invention relates to a preparation method of a hierarchical pore monolithic material containing a Covalent Organic Framework (COF). Specifically, a covalent organic framework polymer, a compound (functional monomer) containing an epoxy functional group, a compound (functional monomer) containing an amino functional group, a pore-forming agent and the like are mixed, oscillated and dispersed, and then subjected to ring-opening polymerization reaction of epoxy at a certain temperature, so that the integral material with a hierarchical pore structure (micropore-mesopore-macropore) can be prepared in one step.

Background

Typically, a hierarchical pore monolith has more than two pore sizes (microporous, pore size less than 2 nm; mesoporous, pore size greater than 2nm and less than 50 nm; macroporous, pore size greater than 50 nm). The multilevel pore structure not only increases the specific surface area of the integral material, but also improves the mass transfer process of substances in the integral material. Currently, hierarchical pore monolithic materials, including polymer matrices, silica gel matrices, carbon matrices, metal organic framework polymer matrices, and the like, have been widely used in the fields of catalysis, adsorption, separation media, storage carriers, and the like. However, according to the reported preparation method, when the pore structure of one scale is adjusted, the pore structure of another scale is affected. Thus, effectively tuning the hierarchical pore structure of the bulk material remains a significant challenge.

Covalent organic framework polymers (COFs) are a lightweight porous material emerging in recent years, having a large specific surface area and a rich microporous or mesoporous structure. However, the covalent organic polymer obtained is often in the form of powder and the material has no heavy plasticity, which severely restricts the practical application of the material. To solve these problems, the present inventors have developed a process based on the ring-opening polymerization of epoxy, which efficiently converts COF in powder form into monolithic materials. The monolithic material prepared by the method not only retains the inherent pore structure of COF, but also has a continuous macroporous structure. In addition, the method also has the following characteristics: 1. the preparation steps are simpler; 2. the universality is strong, and the method can be applied to covalent organic polymers; 3. the reaction condition is mild, easy to control and good in reproducibility.

Disclosure of Invention

The object of the present invention is to simply and efficiently prepare a series of monolithic materials having a hierarchical pore structure.

In order to achieve the purpose, the invention adopts the technical scheme that:

a series of multi-level pore monolithic materials with different physical and chemical properties are prepared by adjusting the content of COF and selecting different COF by ring-opening polymerization reaction (ring-opening polymerization). The hierarchical porous integral material prepared by the method better keeps the inherent microporous structure of COF, generates a continuous macroporous structure, and is expected to improve the adsorption capacity of the integral material to substances and improve the mass transfer performance of the substances in the integral material.

Preparation of a COF-containing hierarchical pore monolith in conjunction with ring-opening polymerization: specifically, COF, an epoxy functional group-containing compound (functional monomer), an amino functional group-containing compound (functional monomer) and a pore-forming solvent are mixed and oscillated uniformly, and then heated to perform an epoxy ring-opening polymerization reaction to prepare the integral material with a hierarchical pore structure in one step.

The specific process is as follows:

1) adding 30-70mg of compound containing epoxy functional group into a reaction vessel;

2) adding 30-70mg of an amino-functional compound to a reaction vessel;

3) adding 10-35mg of polyethylene glycol (PEG, Mn ═ 10,000), 100-500. mu.L of n-propanol (1-propanol) and 80-400. mu.L of 1,4-butanediol (1,4-butane diol) into a reaction vessel;

4) adding 1-100mg of COF to a reaction vessel;

5) oscillating the mixed system at normal temperature for more than 1min to disperse the mixed system to form uniform suspension;

6) placing the container containing the mixed solution obtained in the step 5) in a heating device for reacting for more than 1 minute until a solid is formed;

7) and washing the monolithic material by using methanol to remove the pore-forming agent and unreacted or unbound substances, thereby obtaining the monolithic material with the hierarchical pore structure.

The process of the present invention for the preparation of a hierarchical pore entity containing a covalent organic backbone polymer based on an epoxy ring opening polymerization is shown in figure 1.

The reaction containers used in the steps 1), 2), 3) and 4) are centrifuge tubes; the compound containing epoxy functional group adopted in the step 1) is octaglycidyl dimethylsilane POSS (POSS-epoxy); the compound containing amino functional group adopted in the step 2) is Polyethyleneimine (PEI), Mn is 1200,50 wt% in H₂O)) or 1, 8-octanediamine (1,8-diaminooctane) or 1, 10-decamethylenediamine (1, 10-diaminodecacan); the COF adopted in the step 4) is an azine-linked COF prepared from trimesic aldehyde and hydrazine hydrate; the container used in the step 6) is a plastic centrifuge tube, the heating device is a water bath kettle or a thermostat, the heating temperature is 0-100 ℃, and the reaction time is more than 1 hour; the pore-foaming agent in the step 7) is polyethylene glycol (PEG, Mn ═ 10,000), n-propanol (1-propanol) and 1,4-butanediol (1,4-butane diol).

The monolithic material prepared by the invention has a hierarchical pore structure. Wherein the microporous or mesoporous structure is determined by the type of COF, and the macroporous structure is determined by the ring-opening polymerization. Therefore, the size of the hierarchical pore of the monolithic material prepared by the invention is easy to adjust. Furthermore, the preparation of the covalent organic framework polymers in powder form as monolithic materials will facilitate the industrial application of the covalent organic framework polymers.

Drawings

FIG. 1 is a schematic representation of the preparation of a hierarchical pore monolith comprising a covalent organic backbone polymer based on an epoxy ring opening polymerization.

FIG. 2 is a graph of the adsorption kinetics of azine-linked COF doped hierarchical pore monoliths (example 1) on bisphenol A in aqueous solution.

FIG. 3 is a graph of the adsorption kinetics of azine-linked COF doped hierarchical pore monoliths (example 2) on bisphenol A in aqueous solution.

Detailed Description

Example 1

1. 50.0mg of POSS-epoxy reagent was added to the centrifuge tubes.

2. 54.0mg of an aqueous PEI solution was added to the centrifuge tube.

3. To the tube was added 25mg PEG, 280. mu.L n-propanol and 40. mu.L 1, 4-butanediol.

4. 20mg of azine-linked COF was added to the tube and the tube was shaken for 5min to mix the components well.

5. And (4) reacting the centrifuge tube in the step 4 in a water bath kettle at 50 ℃ for 10 hours, wherein the mixed liquid in the centrifuge tube forms a yellow solid.

6. And repeatedly soaking and washing the material in the centrifuge tube by using methanol to obtain the azine-linked COF doped hierarchical pore integral material.

Example 2

1. 50.0mg of POSS-epoxy reagent was added to the centrifuge tubes.

2. 54.0mg of an aqueous PEI solution was added to the centrifuge tube.

4. 40mg of toluene pre-saturated azine-linked COF was added to the tube and the tube was shaken for 5min to mix the components.

FIG. 2 is a graph of the adsorption kinetics of azine-linked COF doped hierarchical pore monoliths (example 1) on bisphenol A in aqueous solution. The experimental conditions are as follows: bisphenol A aqueous solution (22.8 mg/L); UV-vis detection wavelength, 276 nm. The multistage pore monolithic material prepared by the invention has rapid and efficient adsorption action on bisphenol A.

FIG. 3 is a graph showing the adsorption kinetics of Azine-linked COF doped hierarchical pore monoliths (example 2) on bisphenol A in aqueous solution. The experimental conditions are as follows: bisphenol A aqueous solution (22.8 mg/L); UV-vis detection wavelength, 276 nm. The multistage pore monolithic material prepared by the invention has rapid and efficient adsorption action on bisphenol A.

Claims

1. A method for preparing a monolithic material with a hierarchical pore structure is characterized by comprising the following steps: the process is as follows,

1) adding 30-70mg of octaepoxypropyldimethylsilane-substituted POSS into a reaction vessel;

2) adding 30-70mg of one or more of polyethyleneimine, 1, 8-octanediamine or 1, 10-decamethylenediamine into a reaction container;

3) adding 10-35mg of polyethylene glycol, 100-500 mu L of n-propanol and 80-400 mu L of 1,4-butanediol into a reaction vessel;

4) adding 1-100mg of covalent organic framework polymer prepared from trimesic aldehyde and hydrazine hydrate into a reaction vessel;

2. The method of claim 1, wherein: the reaction vessels used in the steps 1), 2), 3) and 4) are centrifuge tubes.

3. The method of claim 1, wherein: the container used in the step 6) is a centrifuge tube; the heating device is a water bath or a thermostat; the heating temperature is 0-100 ℃; the reaction time is 1 hour or more.

4. The method of claim 3, wherein: the container used in the step 6) is a centrifuge tube; the heating device is a water bath or a thermostat; the heating temperature is 50 ℃; the reaction time was 10 hours.

5. The method of claim 1, wherein: the pore-foaming agent in the step 7) is polyethylene glycol, n-propanol and 1, 4-butanediol.