CN108503853A - A kind of covalent organic frame material and its preparation method and application based on secondary amine bonding - Google Patents

Abstract

The present invention discloses a kind of covalent organic frame material and its preparation method and application being bonded based on secondary amine with high chemical stability, belongs to porous crystalline material preparation field.First conventional method is used to synthesize the COF materials based on imine bound, three-dimensional frame structure COF 300 and 366 M of two-dimensional framework structure C OF are realized by solid-state to solid conversion by the method for sodium borohydride reduction, the COF materials by being bonded based on secondary amine have been synthesized for the first time, on the one hand the material remains the original orderly crystalline state pore structure of COF materials based on imine bound, on the other hand its chemical stability has obtained great reinforcement compared to the COF based on imine bound, also orderly NH is introduced in the frame, for the broader application prospect of the materials open.

Description

A covalent organic framework material based on secondary amino group bonding and its preparation method and application

technical field

The invention belongs to the field of preparation of porous crystalline materials, and in particular relates to a covalent organic framework material with high chemical stability based on secondary amino group bonding and its preparation method and application.

Background technique

Covalent Organic Framework (COF) is a new type of porous crystalline material [Wiki.Covalent Organic Frameworks] formed by covalent bonds between small organic molecules, because of its relatively high specific surface area and Due to the controllability of the pore environment, COF has broad application prospects in gas storage and separation, catalysis, drug loading and delivery [Science, 2015, 310, 1166-1170; Chem.Soc.Rev., 2012, 41, 6010 -6022; Chem. Soc. Rev., 2013, 42, 548-568].

However, due to the large correlation between the formation of the crystalline state and the reversibility of the reaction during the synthesis of COF, there are only a few bonding methods for traditional COF materials, such as boronate bonds, imine bonds, and hydrazide bonds. , phenazine bonds and amide bonds, etc., and their chemical stability is correspondingly limited.

Contents of the invention

Aiming at the limitations of the existing COF synthesis system, the present invention proposes a method of post-modification, first using the traditional method to synthesize COF materials based on imine (-CN-) bonding, and realizing the three-dimensional framework through the reduction method of sodium borohydride The transformation of the structure COF-300 and the two-dimensional framework structure COF-366-M (M=Co, Cu, Zn) "from solid to solid", synthesized for the first time a COF material based on secondary amino (-NH-) bonding , on the one hand, the material retains the original ordered crystalline pore structure of the imine-bonded COF material, and on the other hand, its chemical stability has been greatly enhanced compared with the imine-bonded COF, The ordered -NH- is also introduced into the framework, opening up a wider application prospect for this material.

Compared with traditional amine polymers, this kind of COF material based on secondary amine group has improved crystal order from scratch, and has a relatively fixed pore structure; on the other hand, it is compatible with end groups containing Compared with -NH ₂ COF materials, the chemical stability of this material is much better, and the secondary amino groups (-NH-) arranged in the skeleton are more abundant than the terminal amino groups (-NH ₂ ) and Ordered, it can also cooperate with the ordered pore structure of the material, creating favorable conditions for broadening its application prospects.

Technical scheme of the present invention is specifically as follows:

A method for preparing a covalent organic framework material based on secondary amino group bonding, comprising the following steps: adding 1 equivalent of terephthalic acid and powder A containing 1 equivalent of imine bond to methanol, and mixing uniformly; Slowly add not less than 38 equivalents of sodium borohydride powder under stirring conditions at ~-5°C, continue stirring at -25~-5°C for 0.5 to 2 hours, and then stir at room temperature until the reaction is complete; after the reaction is completed, the reaction system Suction filtration, wash the solid crude product with methanol and hot water successively, remove by-products and catalyst, and obtain a light yellow powder; activate the light yellow powder with ethanol in a Soxhlet extractor, and then degas at room temperature to obtain radically bonded covalent organic framework materials;

The powder A is activated COF-300 powder or activated COF-366-M powder;

In the COF-366-M, M=Co, Cu or Zn.

The activated COF-300 powder is prepared in the following manner: tetraaminophenylmethane and terephthalaldehyde with a mass ratio of 25:16 are dissolved in 1,4-dioxane and added to a glass tube; Exchange the atmosphere in the glass tube with argon, seal the tube after freezing in liquid nitrogen; place the glass tube in an oven at 120°C for 3 days, and filter the solid; , The mixed solvent of 4-dioxane and acetone is activated by reflux, and then activated by supercritical carbon dioxide to obtain activated COF-300 powder.

The activated COF-366-M powder is prepared in the following manner: dissolving tetraaminophenyl metalloporphyrin and terephthalaldehyde in a mass ratio of 9:5 in 1,4-dioxane, adding into the glass tube; exchange the atmosphere in the glass tube with argon, and seal the tube after freezing in liquid nitrogen; place the glass tube in an oven at 120°C for 3 days and filter the solid; extract the solid in Soxhlet reflux activation with a mixed solvent of 1,4-dioxane and acetone in a device, and then activate with supercritical carbon dioxide to obtain activated COF-366-M powder; the tetraaminophenyl metalloporphyrin is Cobalt tetraaminophenylporphyrin, copper tetraaminophenylporphyrin, or zinc tetraaminophenylporphyrin.

Stirring was continued at -15°C for 1 hour after addition of sodium borohydride powder.

The stirring time at room temperature was 12 hours.

A covalent organic framework material based on secondary amino bonding, prepared by the above preparation method.

The application of the above-mentioned covalent organic framework materials based on secondary amino group bonding in the fields of gas storage and separation, catalysis, drug loading and delivery.

The COF in the present invention is synthesized by a solvothermal method, and solvent molecules in the channels of the COF are removed by solvent exchange cleaning to form activated COF powder.

The present invention has the following advantages and beneficial effects:

(1) The present invention provides a covalent organic framework material based on secondary amino group bonding, which can not only maintain the original crystalline pore structure of COF based on imine bonding, but also greatly improve the chemical stability of the COF material, making its application The scope has been broadened.

(2) The -NH- group was introduced into the COF framework through the reduction reaction, which provided potential application prospects for COF in the direction of gas selective adsorption, energy and environment.

(3) The preparation process of the present invention is simple and easy to adjust, and is an effective method for synthesizing a new type of bonded COF material.

Description of drawings

Figure 1 is a schematic diagram of the synthetic route of converting COF-300 into COF-300-AR.

Fig. 2 is a schematic diagram of the synthetic route of converting COF-366-M into COF-366-M-AR.

Figure 3 is the powder X-ray diffraction (PXRD) characterization of COF-300 series; among them, Figure 3(A) represents the PXRD diffraction of COF-300 and the pawley refinement applied to it, and Figure 3(B) represents COF-300 -AR PXRD diffraction and pawley refinement applied to it, Figure 3(C) shows the PXRD spectrum of COF-300-AR after soaking in strong acid or alkali Series comparison.

Detailed ways

The sodium borohydride and methanol used in the following examples are all analytically pure, and the hydrochloric acid and sodium hydroxide solutions used are respectively prepared from analytically pure hydrochloric acid solution or solid sodium hydroxide and deionized water through a volumetric flask.

Example 1

1. Synthesis and activation of a three-dimensional covalent organic framework (COF-300) based on imine bonding

Following the method in the literature [J.Am.Chem.Soc.,2009,131,4570-4571], dissolve 100mg tetraaminophenylmethane and 64mg terephthalaldehyde in 2mL 1,4-dioxane, Then add it into the glass tube, and exchange the atmosphere in the glass tube with argon, and seal the tube after freezing in liquid nitrogen; put the glass tube in an oven at 120°C for 3 days, then filter the solid, and the obtained solid Refluxing activation with a mixed solvent of 1,4-dioxane and acetone in a Soxhlet extractor followed by activation with supercritical carbon dioxide gave a yellow covalent organic framework material based on imine bonding, namely activated COF-300 powder.

2. Preparation of COF-300-AR based on secondary amino group bonding

Add 57.6 mg (1 equivalent) of terephthalic acid and 50 mg (1 equivalent, based on the number of imine bonds) of activated COF-300 powder into 25 mL of methanol, stir at -15°C for 5 minutes; then divide within 10 minutes Slowly add 0.5 g (38 equivalents) of sodium borohydride powder in small amounts for several times, and continue to stir at -15°C for 1 hour, and then stir at room temperature for 12 hours to allow the reaction to fully proceed; Wash with methanol and hot water to remove by-products and catalysts to obtain a light yellow powder; activate the light yellow powder with ethanol in a Soxhlet extractor, and then degas at room temperature to obtain an activated COF-300-AR powder sample. That is, covalent organic framework materials based on secondary amine group bonding.

The COF-300 and COF-300-AR before and after reduction were tested by Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance carbon and nitrogen spectroscopy, and X-ray photoelectron spectroscopy to qualitatively and quantitatively analyze the reduction reaction "by solid-state The feasibility and degree of completion of the process to the solid state” found that the conversion of COF-300 into COF-300-AR from imine to secondary amine can be carried out, and the conversion rate is almost 100% verified by spectroscopic methods. After reduction The COF material based on secondary amine bonding can maintain the crystal structure and order of the original COF material based on imine bonding, and the results are shown in Figure 3(A) and Figure 3(B).

The thermal stability of COF-300 and COF-300-AR before and after reduction was determined by thermogravimetric analysis (heating rate: 10°C per minute), and it was found that both COF-300-AR and COF-300 were stable until 490°C exist.

Example 2

1. Synthesis and activation of a two-dimensional covalent organic framework (COF-366-M) based on imine bonding

Following the method in the literature [Science, 2015, 349, 1208-1213], 18 mg of tetraaminophenyl metal (cobalt, copper or zinc) porphyrin and 10 mg of terephthalaldehyde were dissolved in 1 mL of o-dichlorobenzene and 1 mL of n-butyl Alcohol was added to the glass tube, and the atmosphere was exchanged for argon. After freezing in liquid nitrogen, the tube was sealed, and the tube was placed in a 120°C oven to react for 3 days, and then the insoluble matter was collected by suction filtration. Using a Soxhlet extractor, 1,4-dioxane and acetone were used as solvents for reflux activation; then supercritical carbon dioxide was used for final activation to obtain a deep purple color to obtain a covalent organic framework material based on imine bonding, namely Activated COF-366-M powder.

2. Preparation of COF-366-M-AR based on secondary amino linkage

Add 57.6 mg (1 equivalent) of terephthalic acid, 50 mg (0.16 equivalent, based on the number of imine bonds) of activated COF-366-M powder into 25 mL of methanol, stir at -15°C for 5 minutes, then in 10 minutes Slowly add 0.5g (38 equivalents) of sodium borohydride powder in a small amount and several times, and continue to stir at -15°C for 1 hour, and then stir at room temperature for 12 hours to allow the reaction to fully proceed; after the reaction is completed, the reaction solution is suction filtered , followed by washing with methanol and hot water to remove by-products and catalysts to obtain purple-red powder; activate the purple-red powder with ethanol in a Soxhlet extractor, and then degas at room temperature to obtain activated COF-366-M- AR powder sample, a covalent organic framework material based on secondary amine bonding.

Embodiment 3: Stability test experiment

Add 50mg of COF-300-AR powder to 1mL 6M hydrochloric acid solution and 1mL 6M sodium hydroxide solution, stir at room temperature for 12 hours, centrifuge and remove the supernatant to collect the insoluble matter in the lower layer, wash 5 times with deionized water, acetone Wash 5 times and degas at room temperature. PXRD tests were carried out on COF-300, COF-300-AR and COF-300-AR soaked in acid-base solution, and the same characterization method was used for COF-366-M system. It was found that COF-300-AR, COF-366-M-AR based on secondary amine bonds and COF-300-AR, COF-366-M-AR soaked in acid-base solution can maintain the original imine bond The crystal structure and order of COF confirmed that COF-300-AR and COF-366-M-AR have good chemical stability.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (7)

1. a kind of preparation method of the covalent organic frame material based on secondary amine bonding, which is characterized in that include the following steps： 1 equivalent terephthalic acid (TPA), the powders A containing 1 equivalent imine linkage are added in methanol, are uniformly mixed；Then in -25~-5 DEG C of stirrings Under the conditions of be slowly added to the sodium borohydride powder of no less than 38 equivalents, continue stirring at -25~-5 DEG C 0.5~2 hour, then It is stirred at room temperature abundant to reaction；Reaction system is filtered after the completion of reaction, washs solids crude production with methanol and hot water successively Object removes by-product and catalyst, obtains pale yellow powder；By pale yellow powder Ethanol activation in Soxhlet extractor, so It deaerates at room temperature afterwards, obtains the covalent organic frame material being bonded based on secondary amine；

The powders A is the COF-300 powder of activation or the COF-366-M powder of activation；

In the COF-366-M, M=Co, Cu or Zn.

2. preparation method according to claim 1, it is characterised in that：The COF-300 powder of the activation passes through following Mode is prepared：It is 25 by mass ratio:16 tetrakisaminophenyl methane is dissolved in terephthalaldehyde in Isosorbide-5-Nitrae-dioxane, is added Enter into glass tube；Atmosphere in glass tube is exchanged for argon gas, after liquid nitrogen frozen, carries out tube sealing processing；Glass tube is set It is reacted 3 days in 120 DEG C of baking ovens, leaching solid；By obtained solid with 1,4- dioxane and acetone in Soxhlet extractor Mixed solvent carries out reflux activation, is then activated with the supercritical carbon dioxide, the COF-300 powder activated.

3. preparation method according to claim 1, it is characterised in that：The COF-366-M powder of the activation by with Under type is prepared：It is 9 by mass ratio:5 tetrakisaminophenyl metalloporphyrin is dissolved in 1,4- dioxane with terephthalaldehyde In, it is added in glass tube；Atmosphere in glass tube is exchanged for argon gas, after liquid nitrogen frozen, carries out tube sealing processing；By glass Pipe, which is placed in 120 DEG C of baking ovens, to react 3 days, leaching solid；Obtained solid is used into 1,4- dioxane and third in Soxhlet extractor The mixed solvent of ketone carries out reflux activation, is then activated with the supercritical carbon dioxide, the COF-366-M powder activated End；The tetrakisaminophenyl metalloporphyrin is tetrakisaminophenyl Cobalt Porphyrin, tetrakisaminophenyl porphyrin copper or tetrakisaminophenyl porphin Quinoline zinc.

4. preparation method according to claim 1, it is characterised in that：Continue at -15 DEG C after sodium borohydride powder is added Stirring 1 hour.

5. preparation method according to claim 1, it is characterised in that：The time being stirred at room temperature is 12 hours.

6. a kind of covalent organic frame material based on secondary amine bonding, it is characterised in that：Described in claim any one of 1-5 Preparation method be prepared.

7. the covalent organic frame material based on secondary amine bonding described in claim 6 stores in gas and detaches, is catalyzed, medicine Object loads the application with transportation art.