阅读说明：本技术 一种三维共价有机骨架材料、开管毛细管电色谱柱及制备方法 (Three-dimensional covalent organic framework material, open-tube capillary electrochromatography column and preparation method ) 是由 叶能胜 宗蕊 于 2020-05-26 设计创作，主要内容包括：本发明涉及一种三维共价有机骨架材料、开管毛细管电色谱柱及制备方法,属于共价有机骨架材料技术领域,解决了现有三维共价有机骨架材料研究较少,毛细管电色谱柱的分离效果差的问题。三维共价有机骨架材料采用的配体包括1,3,5-三醛基间苯三酚和四(4-氨基苯基)甲烷。开管毛细管电色谱柱的固定相包括三维共价有机骨架材料。本发明的开管毛细管电色谱柱的分离效果和重现性好。(The invention relates to a three-dimensional covalent organic framework material, an open-tube capillary electrochromatography column and a preparation method, belonging to the technical field of covalent organic framework materials and solving the problems of less research on the existing three-dimensional covalent organic framework material and poor separation effect of the capillary electrochromatography column. The ligands used for the three-dimensional covalent organic framework material include 1,3, 5-trialdehyde phloroglucinol and tetrakis (4-aminophenyl) methane. The stationary phase of the open-tube capillary electrochromatography column comprises a three-dimensional covalent organic framework material. The open-tube capillary electrochromatography column has good separation effect and reproducibility.)

1. A three-dimensional covalent organic framework material, wherein ligands used in the three-dimensional covalent organic framework material comprise 1,3, 5-trialdehyde phloroglucinol and tetrakis (4-aminophenyl) methane.

2. The three-dimensional covalent organic framework material of claim 1, wherein the molar ratio of 1,3, 5-trialdehyde phloroglucinol to tetrakis (4-aminophenyl) methane is from 3:2 to 7: 2.

3. A method for the preparation of a three-dimensional covalent organic framework material according to claims 1 to 2, comprising the steps of:

step 1, dissolving 1,3, 5-trialdehyde phloroglucinol into a mixed solution of ethanol/tetrahydrofuran to obtain a first mixed solution; dissolving tetra (4-aminophenyl) methane in the ethanol/tetrahydrofuran mixed solution to obtain a second mixed solution;

step 2, after trifluoroacetic acid is added into the first mixed solution, ultrasonic dispersion is carried out to obtain a first mixture;

step 3, dropwise adding the second mixed solution into the first mixture, and then carrying out ultrasonic treatment to obtain a second mixture;

and 4, cleaning the second mixture with ethanol for 3-5 times, and drying to obtain the three-dimensional covalent organic framework material.

4. The method of claim 3, wherein in step 1, the mass-to-volume ratio of the mixed solution of tetrakis (4-aminophenyl) methane and ethanol/tetrahydrofuran is 8:3-8:1(mg: mL).

5. The method according to claim 4, wherein the volume ratio of the first mixture to the trifluoroacetic acid in step 2 is 50:1-110: 1.

6. The method according to claim 4, wherein the volume ratio of the first mixture to the second mixture in step 3 is 1:1 to 1.25: 1.

7. An open-capillary electrochromatography column, characterized in that it comprises a three-dimensional covalent organic framework material according to claim 1 or 2 or a three-dimensional covalent organic framework material prepared according to claims 3 to 6.

8. A method for preparing an open-tube capillary electrochromatography column according to claim 7, comprising the steps of:

s1, dissolving the three-dimensional covalent organic framework material in a mixed solution of ethanol/tetrahydrofuran and a mixed solution of trifluoroacetic acid, and performing ultrasonic dispersion to obtain a first suspension;

s2, adding 3-aminopropyl triethoxysilane (APTES) into the first suspension to obtain a third mixed solution;

s3, carrying out ultrasonic treatment on the third mixed solution, then centrifuging to remove supernatant to obtain a first solid, washing the first solid with ethanol, and drying;

s4, adding the dried first solid into acetonitrile to prepare acetonitrile suspension, and performing ultrasonic dispersion;

s5, introducing the acetonitrile suspension into the pretreated capillary column to obtain the open-tube capillary electrochromatography column with the inner wall modified with the three-dimensional covalent organic framework material.

9. The method of claim 8, wherein the mass to volume ratio of the three-dimensional covalent organic framework material to the mixed solution of ethanol/tetrahydrofuran and trifluoroacetic acid is 20-40:5-10:0.1(mg: mL: mL).

10. The method for preparing an open-tube capillary electrochromatography column according to claim 8 or 9, wherein the time of the ultrasonic treatment in S3 is 15-25 min.

Technical Field

The invention belongs to the technical field of covalent organic framework materials, and particularly relates to a three-dimensional covalent organic framework material, an open-tube capillary electrochromatographic column and a preparation method thereof.

Background

Covalent Organic Frameworks (COFs) are crystalline porous polymers connected by covalent bonds, and have attracted extensive attention since the Yaghi task group in 2005 brought forward for the first time due to the characteristics of large specific surface area, adjustable pore size, easiness in modification, good stability and the like. With the progress of research, COFs materials are primarily applied in various fields such as storage and separation of gases, adsorption of heavy metal ions, heterogeneous catalysis, optical materials and the like. Especially, it is a hot spot to research as the stationary phase of chromatographic technique.

Open-tube capillary electrochromatography (OT-CEC) is a separation mode of capillary electrophoresis technology. In short, the OT-CEC method is to fix the stationary phase on the inner wall of the capillary column, is easy to prepare and has good stability, but also has the disadvantages of low sample capacity, low phase ratio and the like. Among the stationary phases of various OT-CECs (carbon nanotubes, graphene oxide, metal organic framework materials, etc.), COFs materials with larger specific surface area and pore volume can better improve the above-mentioned problems.

Based on the difference in the dimensions of covalent bonds, COFs materials can be classified into two-dimensional (2D) layered structures (2D COFs) and three-dimensional (three-dimensional,3D) network structures (3D COFs). Compared with 2D COFs, 3D COFs have larger specific surface area, lower density and stronger interaction, and have very potential to be used as a stationary phase of a capillary electrochromatography technology by virtue of size selectivity and multiple actions such as hydrophobic interaction, electrostatic interaction and hydrogen bond which may exist with target compounds.

At present, compared with the research reports of richer and more systematic synthesis, modification and application fields of 2D COFs, the research on 3D COFs is relatively less.

The method for synthesizing COFs mainly comprises the following steps: solvothermal methods, surface growth methods, mechanical methods, and the like. Among them, the solvothermal method is the most commonly used method for preparing COFs with higher crystallinity and larger specific surface area. However, the method needs to be carried out in a closed condition at a higher temperature, the reaction time is longer (usually, the reaction needs to be carried out for 2 to 9 days at a high temperature of 80 to 120 ℃ in a sealed container), the reaction condition is harsh, the using amount of a solvent is large, and the large-scale production is difficult.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a three-dimensional covalent organic framework material, an open-tube capillary electrochromatography column and a preparation method. At least one of the following technical problems can be solved: (1) the existing three-dimensional covalent organic framework materials are less researched; (2) the existing preparation method of the three-dimensional covalent organic framework material has harsh conditions and low efficiency; (3) the existing capillary electrochromatography column has poor separation effect.

The purpose of the invention is mainly realized by the following technical scheme:

in one aspect, the present invention provides a three-dimensional covalent organic framework material employing ligands comprising 1,3, 5-trialdehyde phloroglucinol and tetrakis (4-aminophenyl) methane.

Further, the molar ratio of the 1,3, 5-trialdehyde phloroglucinol to the tetra (4-aminophenyl) methane is 3:2 to 7: 2.

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

step 1, dissolving 1,3, 5-trialdehyde phloroglucinol into a mixed solution of ethanol/tetrahydrofuran to obtain a first mixed solution; dissolving tetra (4-aminophenyl) methane in the ethanol/tetrahydrofuran mixed solution to obtain a second mixed solution;

step 2, after trifluoroacetic acid is added into the first mixed solution, ultrasonic dispersion is carried out to obtain a first mixture;

step 3, dropwise adding the second mixed solution into the first mixture, and then carrying out ultrasonic treatment to obtain a second mixture;

and 4, cleaning the second mixture with ethanol for 3-5 times, and drying to obtain the three-dimensional covalent organic framework material.

Further, in step 1, the mass-to-volume ratio of the mixed solution of tetrakis (4-aminophenyl) methane and ethanol/tetrahydrofuran is 8:3 to 8:1(mg: mL).

Further, in the step 2, the volume ratio of the first mixed solution to the trifluoroacetic acid is 50:1-110: 1.

Further, in step 3, the volume ratio of the first mixture to the second mixture is 1:1-1.25: 1.

In another aspect, the invention provides an open-tube capillary electrochromatography column comprising a three-dimensional covalent organic framework material.

The invention also provides a preparation method of the open-tube capillary electrochromatography column, which comprises the following steps:

s1, dissolving the three-dimensional covalent organic framework material in a mixed solution of ethanol/tetrahydrofuran and a mixed solution of trifluoroacetic acid, and performing ultrasonic dispersion to obtain a first suspension;

s2, adding 3-aminopropyl triethoxysilane (APTES) into the first suspension to obtain a third mixed solution;

s3, carrying out ultrasonic treatment on the third mixed solution, then centrifuging to remove supernatant to obtain a first solid, washing the first solid with ethanol, and drying;

s4, adding the dried first solid into acetonitrile to prepare acetonitrile suspension, and performing ultrasonic dispersion;

s5, introducing the acetonitrile suspension into the pretreated capillary column to obtain the open-tube capillary electrochromatography column with the inner wall modified with the three-dimensional covalent organic framework material.

Further, the mass-to-volume ratio of the three-dimensional covalent organic framework material to the mixed solution of ethanol/tetrahydrofuran and trifluoroacetic acid is 20-40:5-10:0.1(mg: mL: mL).

Further, in S3, the time of ultrasonic treatment is 15-25 min.

Compared with the prior art, the invention can at least realize one of the following technical effects:

1) the invention synthesizes the TpTAM three-dimensional covalent organic framework material by taking 1,3, 5-trialdehyde phloroglucinol (Tp) and tetra (4-aminophenyl) methane (TAM) as ligands for the first time, and the TpTAM three-dimensional covalent organic framework material has larger specific surface area (more than 6000 m)²Per gram), higher porosity, lower density (< 0.11 g/cm)³) Has wide application potential.

2) Compared with a traditional synthesis method by adopting a solvothermal method, the ultrasonic synthesis method for preparing the TpTAM three-dimensional covalent organic framework material greatly overcomes the defects of harsh reaction conditions, large solvent consumption and difficulty in large-scale production. On the basis of ensuring the perfect crystallinity, the preparation time of the material is greatly shortened (from the original 3 days and more to the current 2-3 hours), and the energy consumption is saved by more than 95 percent.

3) The open-tube capillary electrochromatography column is characterized in that a TpTAM three-dimensional covalent organic framework material is immobilized in a common capillary column, and the covalent organic framework material has better separation effect and reproducibility by virtue of the size selectivity brought by the porous structure and the hydrophobic interaction, pi-pi interaction, electrostatic interaction or hydrogen bond interaction between the covalent organic framework material and an analyte.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a flow chart of a process for preparing a three-dimensional covalent organic framework material of the present invention;

FIG. 2 is a flow chart of a process for preparing an open-tube capillary electrochromatography column of the present invention;

FIG. 3 is the electrochromatography separation chart of the open-tube capillary electrochromatography column of example 2 of the invention for quinolone drugs; wherein a is danofloxacin mesylate (DFM), b is ciprofloxacin hydrochloride (CIP), c is Enrofloxacin (ENR), and d is sarafloxacin hydrochloride (SF).

Detailed Description

A three-dimensional covalent organic framework material, an open-tube capillary electrochromatography column, and a method for making the same are described in further detail below with reference to specific examples, which are provided for purposes of comparison and explanation only and to which the present invention is not limited.

It is noted that relational terms such as first, second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily implying or requiring any such actual relationship or order between such entities or actions.

The invention provides a three-dimensional covalent organic framework material, which is a TpTAM three-dimensional covalent organic framework material; ligands used for three-dimensional covalent organic framework materials include 1,3, 5-trialdehyde phloroglucinol (Tp) and tetrakis (4-aminophenyl) methane (TAM).

Specifically, the three-dimensional covalent organic framework material is formed by connecting 1,3, 5-trialdehyde phloroglucinol (Tp) with a plane-like structure and tetra (4-aminophenyl) methane (TAM) with a structure similar to a methane space regular tetrahedron into basic structural units through covalent bonds.

Specifically, if the mass ratio of 1,3, 5-trialdehyde phloroglucinol (Tp) to tetrakis (4-aminophenyl) methane (TAM) is too high, the effective components are low, which causes waste; too low can result in insufficient free aldehyde groups, which cannot react well with the amino group of the coupling reagent 3-Aminopropyltriethoxysilane (APTES), thereby affecting subsequent immobilization of the material in the inner wall of the capillary column. Thus, the molar ratio of 1,3, 5-trialdehyde phloroglucinol (Tp) to tetrakis (4-aminophenyl) methane (TAM) was controlled to be 3:2 to 7: 2.

Specifically, the specific surface area of the three-dimensional covalent organic framework material is more than 6000m²G, density less than 0.11g/cm³。

Compared with the prior art, the invention synthesizes the TpTAM three-dimensional covalent organic framework material by taking 1,3, 5-trialdehyde phloroglucinol (Tp) and tetra (4-aminophenyl) methane (TAM) as ligands for the first time. The monomer Tp contains aldehyde group, and reacts with amino group in monomer TAM with stereo structure through Schiff base to form imine COFs material, and due to introduction of phenolic hydroxyl group in Tp monomer, enol and beta-position C ═ N double bond on benzene ring in COFs skeleton undergo irreversible tautomerization to become organic skeleton in enamine ketone form. Therefore, the TpTAM three-dimensional covalent organic framework material not only has the stability of the common imine COFs material, but also has larger specific surface area, larger porosity and smaller density of a three-dimensional network structure, and has wide application range.

The invention also provides a preparation method of the three-dimensional covalent organic framework material, as shown in figure 1, comprising the following steps:

step 1, dissolving 1,3, 5-trialdehyde phloroglucinol (Tp) in a mixed solution of ethanol/tetrahydrofuran to obtain a first mixed solution; dissolving tetra (4-aminophenyl) methane (TAM) in the mixed solution of ethanol/tetrahydrofuran to obtain a second mixed solution;

step 2, after trifluoroacetic acid is added into the first mixed solution, ultrasonic dispersion is carried out to obtain a first mixture;

step 3, dropwise adding the second mixed solution into the first mixture, and then carrying out ultrasonic treatment to obtain a second mixture;

and 4, washing the second mixture by using ethanol for 3-5 times, and drying to obtain a three-dimensional covalent organic framework material (TpTAM three-dimensional covalent organic framework material, namely 3D TpTAM).

It should be noted that, in the step 1, the volume content of ethanol in the ethanol/tetrahydrofuran mixed solution is 80% to 95%, because the ethanol/tetrahydrofuran mixed solution is used to provide a solution environment for the monomer reaction; too large or too small a volume ratio of ethanol and tetrahydrofuran affects the framework structure and the degree of crystallization of the crystal to some extent.

Specifically, in step 1, too large or too small a mass-to-volume ratio of the mixed solution of 1,3, 5-trialdehyde phloroglucinol (Tp) and ethanol/tetrahydrofuran affects the crystallization state of the subsequent material synthesis. Therefore, the mass-to-volume ratio of the mixed solution of 1,3, 5-trialdehyde phloroglucinol (Tp) and ethanol/tetrahydrofuran was controlled to 4:1 to 12:1(mg: mL).

Specifically, in step 1, too large or too small a mass-to-volume ratio of the mixed solution of tetrakis (4-aminophenyl) methane (TAM) and ethanol/tetrahydrofuran affects the crystallization state of the subsequent material synthesis. Therefore, the mass-to-volume ratio of the mixed solution of tetrakis (4-aminophenyl) methane (TAM) and ethanol/tetrahydrofuran was controlled to 8:3 to 8:1(mg: mL).

Specifically, in step 2, trifluoroacetic acid is present to provide an acidic environment for the schiff base reaction based on dehydration condensation of aldehyde groups and amino groups, thereby promoting the reaction rate and the formation of a crystal structure. However, the volume ratio of the first mixed solution to trifluoroacetic acid is too large or too small, which results in undesirable results. Therefore, the volume ratio of the first mixed solution to the trifluoroacetic acid is controlled to be 50:1-110: 1.

Specifically, in the step 2, the action of ultrasonic treatment is to enable trifluoroacetic acid to be uniformly dispersed in the solution, the temperature of ultrasonic dispersion is not too high, the room temperature is maintained, and the ultrasonic time is controlled to be 5-10 min.

Specifically, in step 3, in order to ensure that the first mixture and the second mixture can sufficiently react, the second mixture is dropwise added into the first mixture, and the dropwise addition condition is controlled to be 10mL of total dropwise addition completion time to be 5-7 min.

Specifically, in step 3, the structure of the COFs material is collapsed due to the long-time vibration of the external force caused by the overlong ultrasonic time; too short a time may result in incomplete contact between the two monomers, which may affect the synthesis of the material. Therefore, the ultrasonic dispersion time is controlled to be 30-50 min.

Specifically, in step 3, the volume ratio of the first mixture to the second mixture is too large, which results in the waste of the drug solvent; too small a level of free aldehyde groups is insufficient to effect subsequent bonding to 3-Aminopropyltriethoxysilane (APTES). Therefore, the volume ratio of the first mixture to the second mixture is controlled to be 1:1-1.25: 1.

Specifically, in step 4, if the drying temperature is too high, the structure of the material is damaged, and if the drying temperature is too low, the drying waiting time is prolonged. Therefore, the drying temperature is controlled to be 60-65 ℃. The drying time is 30-45 min.

The invention also provides an open-tube capillary electrochromatography column, wherein the stationary phase of the open-tube capillary electrochromatography column is the TpTAM three-dimensional covalent organic framework material.

The invention also provides a preparation method of the open-tube capillary electrochromatography column, as shown in figure 2, comprising the following steps:

s1, dissolving the TpTAM three-dimensional covalent organic framework material in a mixed solution of ethanol/tetrahydrofuran and a mixed solution of trifluoroacetic acid, and performing ultrasonic dispersion to obtain a first suspension;

s2, adding 3-aminopropyl triethoxysilane (APTES) into the first suspension to obtain a third mixed solution;

s3, carrying out ultrasonic treatment on the third mixed solution, then centrifuging to remove supernatant to obtain a first solid, washing the first solid with ethanol for 3 times, and drying;

s4, adding the dried first solid into acetonitrile to prepare acetonitrile suspension, and performing ultrasonic dispersion;

and S5, introducing acetonitrile suspension (5psi for 5min) into the pretreated capillary column at room temperature to obtain the open-tubular capillary electrochromatographic column with the inner wall modified with the TpTAM three-dimensional covalent organic framework material.

Specifically, in S1, the mass of the tpta three-dimensional covalent organic framework material is mg, the volume of the ethanol/tetrahydrofuran mixed solution and the trifluoroacetic acid is mL, and the mass-to-volume ratio of the tpta three-dimensional covalent organic framework material to the ethanol/tetrahydrofuran mixed solution and the trifluoroacetic acid is 20-40:5-10: 0.1.

Specifically, in the above S1, the action of the sonication is to dissolve the tptac sufficiently in the solution, and the sonication time is controlled to be 5 to 8 min.

Specifically, in the above S2, the 3-Aminopropyltriethoxysilane (APTES) is used to combine the amino group with the aldehyde group of the tpta three-dimensional covalent organic framework material, and to bond the end group at the other end with the silicon hydroxyl group on the inner wall surface of the capillary column, so as to realize the immobilization of the COFs material on the inner wall of the capillary column. Therefore, too large or too small volume ratio of the first suspension to 3-Aminopropyltriethoxysilane (APTES) can cause poor effect of material loading on the inner wall of the capillary, and waste of material can be caused. Therefore, the volume ratio of the first suspension to 3-Aminopropyltriethoxysilane (APTES) is controlled to be 50:1 to 100: 1.

Specifically, in S3, the time for the ultrasonic treatment is too long, so that the tptac three-dimensional covalent organic framework material gradually aggregates and is not enough to stably exist on the surface of APTES, and thus, the detachment occurs; if the time is too short, only part of TpTAM is synthesized on the surface of APTES. Therefore, the time of ultrasonic treatment is controlled to be 15-25 min.

Specifically, in S4, the dried first solid is added to acetonitrile to prepare an acetonitrile suspension, and an excessive or insufficient concentration of the first solid in the acetonitrile may affect the effect of immobilizing the APTES-modified COFs material on the inner wall of the capillary. Thus, the concentration of the first solid in acetonitrile was controlled in the range of 2-3 mg/mL.

Specifically, in S5, the capillary column pretreatment process includes: a31.0 cm quartz capillary (100. mu. mi.d.. times.375. mu. M. o.d.) was rinsed with 1M sodium hydroxide for 30min (20psi), 0.1M hydrochloric acid for 10min (20psi), ultra-pure water for 10min (20psi), and nitrogen blown dry.

Specifically, in the above S5, the acetonitrile suspension is introduced for a too long time, which is likely to damage the formed material coating and is not favorable for uniform coating; too short a transit time is detrimental to the complete coating of the material. Thus, the acetonitrile suspension was controlled to flow for 5-10min (5 psi).