阅读说明：本技术 一种羧酸类金属有机框架微球的制备方法 (Preparation method of carboxylic acid metal organic framework microspheres ) 是由 李健生 张雨婷 齐俊文 王超海 孙秀云 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种羧酸类金属有机框架微球的制备方法,将高分子树脂添加到金属有机框架材料的制备过程中,反应后再通过非溶剂致相分离法,利用注射泵挤出工艺可得到单一粒径分布的毫米级金属有机框架微球。本发明在高粘度体系下通过溶剂热法原位生长得到的成型微珠可自由实现不同的金属有机框架负载量,并规避了粘结剂对孔道的堵塞,制备简单,易于回收,在催化、分离、吸附等领域有广阔的应用前景。(The invention discloses a preparation method of carboxylic acid metal organic framework microspheres, which comprises the steps of adding high molecular resin into a metal organic framework material in the preparation process, reacting, then carrying out a non-solvent induced phase separation method, and utilizing an injection pump extrusion process to obtain millimeter-scale metal organic framework microspheres with single particle size distribution. The formed microspheres obtained by in-situ growth in a high-viscosity system through a solvothermal method can freely realize different metal organic framework loading amounts, avoids blockage of pore channels by a binder, is simple to prepare and easy to recover, and has wide application prospects in the fields of catalysis, separation, adsorption and the like.)

1. The preparation method of the carboxylic acid metal organic framework microspheres is characterized by comprising the following steps:

1) dissolving high polymer resin and a hole-making agent PVP in N, N-dimethylformamide at 50-90 ℃ to prepare a solution A;

2) adding an organic carboxylic acid ligand into the solution A, stirring and dissolving to obtain a solution B;

3) adding the solution B into a DMF solution of a metal precursor, and uniformly stirring to obtain a solution C;

4) putting the solution C into a polytetrafluoroethylene high-pressure reaction kettle, and carrying out thermal reaction to obtain a solution D:

5) and extruding the solution D into a gelling bath, carrying out phase-splitting gelling, and airing to obtain the metal organic framework microspheres.

2. The method for preparing carboxylic acid metal organic framework microspheres according to claim 1, wherein the mass fraction of the polymeric resin in the solution A is 10-24%, and the mass ratio of the polymeric resin to the PVP is 2: 1-8: 1.

3. The method for preparing carboxylic acid metal-organic framework microspheres according to claim 2, wherein the polymeric resin is selected from Polyacrylonitrile (PAN) or polyether sulfone (PES).

4. The method for preparing carboxylic acid metal organic framework microspheres according to claim 1, wherein the mass ratio of the organic carboxylic acid ligand to the polymer resin is 1: 1-1: 20.

5. The method for preparing carboxylic acid metal-organic framework microspheres according to claim 4, wherein the organic carboxylic acid ligand is selected from terephthalic acid or trimesic acid.

6. The method for preparing carboxylic acid metal-organic framework microspheres according to claim 1, wherein the mass ratio of the metal precursor to the polymer resin is 1: 10-3: 2.

7. The method for preparing carboxylic acid metal-organic framework microspheres according to claim 6, wherein the metal precursor is selected from zirconium tetrachloride, copper nitrate trihydrate, manganese acetate tetrahydrate, or ferric trichloride hexahydrate.

Technical Field

The invention belongs to the technical field of metal organic framework materials, and particularly relates to a preparation method of carboxylic acid metal organic framework microspheres.

Background

Metal Organic Frameworks (MOFs) are a class of crystalline materials with periodic three-dimensional network Frameworks formed by self-assembly of Organic ligands and Metal ions. Compared with the traditional porous material, the MOFs has the advantages of extremely developed pore channel structure, ordered micropore structure, various skeleton structures, adjustable pore diameter and surface property, unsaturated metal active sites and the like. The MOFs material as a novel functional molecular material has the characteristics of structure designability and easy functionalization which are incomparable with other materials, and therefore plays an important role in many fields such as catalysis, sensing, separation and the like.

Conventional synthesis methods typically result in MOF crystal powders with crystallite sizes from nanometers to hundreds of microns. Polycrystalline powder materials are generally undesirable in industry because of the many difficulties in handling, such as pressure drop, dust, plugging, attrition, loss of quality of the fluid as it flows through the packed bed, and challenges in transport and handling. MOFs have recently received considerable attention in the form of more useful particles, gels or films (Y.Chen, X.Huang, S.Zhang, et al.Shaping of Metal-Organic Frameworks: from Fluid to Shaped solids and Robust F oams, J.Am.chem.Soc.,2016,138, 10810-one 10813.). In practical application, especially in the field of gas phase transmission and separation, how to realize the formation of the MOFs is an urgent problem to be solved.

At present, the molding method of the MOFs material mainly comprises pressure molding, bonding molding, embedding molding and the like. Pressure forming, i.e. binding the MOFs powder into aggregates with higher bulk density by the action of high pressure, greatly reduces the volume space for storage and use, and solves the problem of difficult recovery (BardiyaValizadeh, TuN. Nguyen, Kyrakos C. Stylanon. shape engineering of metal-organic frames [ J ]. polyhedrons, 2018,145: 1-15.). However. Too high pressure can transform the originally unstable MOFs framework into an amorphous state, resulting in collapse of the pore structure and loss of the unique characteristics of MOFs. The bonding molding is to realize the molding of the MOFs particles under lower pressure by adding a certain high molecular organic solvent or a bonding agent on the basis of pressure molding. Compared with high-pressure shaping, the lower shaping pressure can effectively avoid collapse and transformation of the framework structure, and the shaped particles in different shapes can be obtained according to the use requirement. However, the blocking and covering of the pore structure and active metal sites of the MOFs by the binder are inevitable, and the service performance of the MOFs is seriously influenced. On the basis of this, the embedding and molding methods represented by spray drying and electrostatic spinning also cannot avoid the blockage of the pore structure by organic polymer chains (D.Lozano-Castell resin, D.Cazorla-Amor resin, A.lines-Solano, et al.activated Carbon monolithis for methane storage, Carbon,2002,40(15): 2817-2825.). And the complex forming process and the low utilization rate of the material efficiency establish barriers for the practical popularization and application of the material.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a simple preparation method of carboxylic acid metal organic framework microspheres, which can freely realize different metal organic framework loading amounts through formed microspheres obtained by in-situ growth in a high-viscosity system through a solvothermal method, avoids the blockage of pore channels by a binder, is simple to prepare and easy to recover, and has wide application prospects in the fields of catalysis, separation, adsorption and the like.

In order to achieve the technical purpose of the invention, the invention specifically adopts the following technical scheme:

the preparation method of the carboxylic acid metal organic framework microspheres adopts a one-step method to add the high molecular resin into the preparation process of the carboxylic acid metal organic framework material, and applies the non-solvent-phase separation method in the field of membrane separation to the molding of the carboxylic acid metal organic framework material after the reaction; millimeter-scale metal organic framework microspheres with single particle size distribution can be obtained by an injection pump extrusion process; the proportion of the carboxylic acid ligand and the corresponding metal precursor can be adjusted in the system to obtain the content-controllable MOFs microspheres.

A preparation method of carboxylic acid metal organic framework microspheres comprises the following steps:

1) dissolving polymer resin and a pore-forming agent PVP in N, N-Dimethylformamide (DMF) at 50-90 ℃ to prepare a solution A;

2) adding an organic carboxylic acid ligand into the solution A, stirring and dissolving to obtain a solution B;

3) adding the solution B into a DMF solution of a metal precursor, and uniformly stirring to obtain a solution C;

4) putting the solution C into a polytetrafluoroethylene high-pressure reaction kettle, and carrying out solvothermal reaction, wherein MOFs grows in the process to obtain a solution D;

5) and extruding the solution D into a gelling bath, carrying out phase-splitting gelling, and airing to obtain the metal organic framework microspheres.

Further, the mass fraction of the polymer resin in the solution A is 10-24%, and the mass ratio of the polymer resin to the PVP is 2: 1-8: 1.

Further, the polymer resin is selected from Polyacrylonitrile (PAN) or polyether sulfone (PES).

Further, the mass ratio of the organic carboxylic acid ligand to the polymer resin is 1: 1-1: 20, wherein the organic carboxylic acid ligand is selected from terephthalic acid or trimesic acid.

Further, the mass ratio of the metal precursor to the polymer resin is 1: 10-3: 2, and the metal precursor is selected from zirconium tetrachloride, copper nitrate trihydrate, manganese acetate tetrahydrate or ferric trichloride hexahydrate.

Further, the thermal reaction condition is 80-220 ℃.

Furthermore, the split-phase gelation extrusion speed is 0.5mL/min to 1.0 mL/min.

The invention has the beneficial effects that:

1) the macromolecular resin is added into the preparation of carboxylic acid MOFs, and the complex processes such as bonding forming and the like are replaced by one-step blending, so that the operation is simple, the cost is low, and the equipment requirement is simple and convenient;

2) after the reaction, the spherical polymer-based precursor extruded by the injection pump has extremely narrow particle size distribution, high sphericity, simple and controllable process and easy industrial expanded production;

3) the controllable preparation of the molding microspheres with different MOFs content can be realized by adjusting the proportion of the polymer resin, the carboxylic acid ligand and the metal precursor.

Drawings

FIG. 1 is a scanning electron microscope image of a cross section and a partial enlargement of a shaped metal organic framework material prepared in example 1;

FIG. 2 is an X-ray diffraction pattern of the shaped metal organic framework materials obtained in examples 1, 3, 4 and 5;

FIG. 3 is a thermal analysis graph of the formed metal organic framework material obtained in example 1.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to specific embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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

The embodiment specifically provides a preparation method of carboxylic acid metal organic framework microspheres, which comprises the following steps:

1) 2g PAN and 0.3g PVP were weighed accurately into an Erlenmeyer flask, and 13ml N, N-dimethylformamide was added and mechanically stirred at 60 ℃ until dissolved.

2) 1g of terephthalic acid was added and stirring was continued until the solution was uniformly dissolved.

3) 1.5g of manganese acetate tetrahydrate is weighed and dissolved in 5mL of DMF, and then the solution in the step 2) is added and stirred uniformly.

4) Transferring the mixed solution in the step 3) to a 50mL polytetrafluoroethylene reaction kettle, and placing the reaction kettle in an oven at 150 ℃ for reaction for 12 hours.

5) After the reaction kettle is cooled to room temperature, 5mL of the solution obtained after the reaction in the step 4) is taken by an injector and placed on an injection pump, the speed of the injection pump is adjusted to be 0.7 mL/min, and the solution is extruded and dropped into 500mL of deionized water right below the needle head of the injector to be separated and gelled.

6) And after 12 hours, taking out the millimeter-sized beads, and airing at room temperature to obtain the formed Mn-BDC microspheres.

Example 2

The embodiment specifically provides a preparation method of carboxylic acid metal organic framework microspheres, which comprises the following steps:

1) 2g PAN and 0.3g PVP were weighed accurately and placed in an Erlenmeyer flask, and 13ml LN, N-dimethylformamide was added and mechanically stirred at 60 ℃ until dissolved.

2) 1.5g of terephthalic acid was added and stirring was continued until the solution was uniformly dissolved.

3) 2.25g of manganese acetate tetrahydrate is weighed and dissolved in 5mL of DMF, and then the solution in the step 2) is added and stirred evenly.

4) Transferring the mixed solution in the step 3) to a 50mL polytetrafluoroethylene reaction kettle, and placing the reaction kettle in an oven at 150 ℃ for reaction for 12 hours.

5) After the reaction kettle is cooled to room temperature, 5mL of the solution obtained after the reaction in the step 4) is taken by an injector and placed on an injection pump, the speed of the injection pump is adjusted to be 0.7 mL/min, and the solution is extruded and dropped into 500mL of deionized water right below the needle head of the injector to be separated and gelled.

6) And after 12 hours, taking out the millimeter-sized beads, and airing at room temperature to obtain the formed Mn-BDC microspheres.

Example 3

The embodiment specifically provides a preparation method of carboxylic acid metal organic framework microspheres, which comprises the following steps:

1) 2g PES and 0.3g PVP were weighed accurately, placed in an Erlenmeyer flask, and 8ml LN, N-dimethylformamide was added and mechanically stirred at 60 ℃ until dissolved.

2) 0.4g of trimesic acid was added and stirred until dissolved uniformly.

3) 0.42g of copper nitrate trihydrate is weighed out and dissolved in 4mL of DMF, and then the solution obtained in step 2) is added and stirred uniformly.

4) Transferring the mixed solution obtained in the step 3) to a 50mL polytetrafluoroethylene reaction kettle, and placing the kettle in an oven at 80 ℃ for reaction for 24 hours.

5) After the reaction kettle is cooled to room temperature, 5mL of the solution obtained after the reaction in the step 4) is taken by an injector and placed on an injection pump, the speed of the injection pump is adjusted to be 0.7 mL/min, and the solution is extruded and dropped into 500mL of deionized water right below the needle head of the injector to be separated and gelled.

6) And after 12 hours, taking out the millimeter-sized ball, and airing at room temperature to obtain the formed Cu-BTC microsphere.

Example 4

The embodiment specifically provides a preparation method of carboxylic acid metal organic framework microspheres, which comprises the following steps:

1) 2g PES and 0.3g PVP were weighed accurately, placed in an Erlenmeyer flask, and 8ml LN, N-dimethylformamide was added and mechanically stirred at 60 ℃ until dissolved.

2) 0.52g of terephthalic acid was added and stirring was continued until the solution was uniformly dissolved.

3) After 0.73g of zirconium tetrachloride was dissolved in 4mL of DMF, the solution of step 2) was added and stirred well.

4) Transferring the mixed solution in the step 3) to a 50mL polytetrafluoroethylene reaction kettle, and placing the reaction kettle in an oven at 120 ℃ for reaction for 24 hours.

5) After the reaction kettle is cooled to room temperature, 5mL of the solution obtained after the reaction in the step 4) is taken by an injector and placed on an injection pump, the speed of the injection pump is adjusted to be 0.7 mL/min, and the solution is extruded and dropped into 500mL of deionized water right below the needle head of the injector to be separated and gelled.

6) After 12 hours, the millimeter-sized beads are taken out and dried at room temperature, and the formed UIO-66 microspheres are obtained.

Example 5

The embodiment specifically provides a preparation method of carboxylic acid metal organic framework microspheres, which comprises the following steps:

1) 2g PAN and 0.3g PVP were weighed accurately and placed in an Erlenmeyer flask, and 13ml LN, N-dimethylformamide was added and mechanically stirred at 60 ℃ until dissolved.

2) 0.6g of terephthalic acid was added and stirring was continued until the solution was uniformly dissolved.

3) 0.97g of ferric chloride hexahydrate is weighed and dissolved in 5mL of DMF, and then the solution in the step 2) is added and stirred uniformly.

4) Transferring the mixed solution in the step 3) to a 50mL polytetrafluoroethylene reaction kettle, and placing the reaction kettle in an oven at 100 ℃ for reaction for 12 hours.

5) After the reaction kettle is cooled to room temperature, 5mL of the solution obtained after the reaction in the step 4) is taken by an injector and placed on an injection pump, the speed of the injection pump is adjusted to be 0.7 mL/min, and the solution is extruded and dropped into 500mL of deionized water right below the needle head of the injector to be separated and gelled.

6) And after 12 hours, taking out the millimeter-sized beads, and airing at room temperature to obtain the formed MIL-88B microspheres.

As shown in fig. 1 to 3, fig. 1 shows that the formed metal-organic framework material prepared in example 1 has obvious finger-shaped holes under the cortical layer, and a large amount of MOFs particles are gathered in a local graph; FIG. 2 shows that the X-ray diffraction pattern of the resulting shaped metal organic framework material is consistent with the X-ray diffraction peak positions of Mn-BDC, Cu-BTC, HKUST-1 and MIL-88B, illustrating the successful preparation of the shaped metal organic framework material; fig. 3 shows a thermal analysis graph of a formed metal organic framework material.

Comparative example 1

This comparative example is essentially the same as example 1, except that: the polymer resin adopts PVDF (polyvinylidene fluoride), but the molecular chain of the PVDF is broken under high temperature and high pressure for a long time, and the obtained material cannot be pelletized.

Comparative example 2

This comparative example is essentially the same as example 5, except that: 2.5g of ferric chloride hexahydrate is added, and a metal precursor containing a large amount of crystal water is excessively added, so that the whole system is subjected to phase separation, and the obtained material cannot be pelletized.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.