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CN-121991375-A - Method for rapidly synthesizing metal-organic framework material under mild condition

CN121991375ACN 121991375 ACN121991375 ACN 121991375ACN-121991375-A

Abstract

The invention discloses a method for rapidly synthesizing a metal-organic framework material under mild conditions, which comprises the following steps of adding at least one metal source and at least one organic ligand into a polar organic solvent, mixing to form a liquid reaction medium, adding a high molecular auxiliary agent into the liquid reaction medium to form and maintain a dynamic chemical environment for guiding the orderly assembly of the metal source and the organic ligand in the liquid reaction, and reacting and crystallizing the metal source and the organic ligand under the dynamic chemical environment to obtain the metal-organic framework material. The invention provides a brand new path for green and efficient preparation of the metal-organic framework material, and realizes the synthesis of the tetravalent metal-organic framework under the conditions of room temperature and normal pressure, wherein the synthesis time is in the order of minutes.

Inventors

  • ZHOU XIN
  • LIN DONGPING
  • Liu Shuen

Assignees

  • 华南理工大学

Dates

Publication Date
20260508
Application Date
20260210

Claims (10)

  1. 1. A method for rapid synthesis of metal-organic framework materials under mild conditions, comprising the steps of: adding at least one metal source and at least one organic ligand into a polar organic solvent, and mixing to form a liquid reaction medium; Adding a polymer auxiliary agent into a liquid reaction medium to form and maintain a dynamic chemical environment for guiding ordered assembly of the metal source and the organic ligand in the liquid reaction, so that the metal source and the organic ligand react and crystallize to obtain a metal-organic framework material, wherein the dynamic chemical environment is formed in such a way that the polymer auxiliary agent induces a transient ordered micro-region in a polar organic solvent to form a local entropy increasing effect and a space limiting environment, and the metal source and the organic ligand perform directional collaborative self-assembly.
  2. 2. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein said polymeric auxiliary agent is a polymeric compound containing proton or hydrogen bond acceptors.
  3. 3. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein the polymeric auxiliary agent is a polymeric compound containing hydroxyl groups and ether linkages.
  4. 4. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein the polymeric auxiliary agent is polyethylene glycol polymer with a number average molecular weight controlled to be 400-2000 Da.
  5. 5. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein the metal source comprises at least one of a divalent metal source, a trivalent metal source, a tetravalent metal source.
  6. 6. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein the organic ligand is one of phthalic acid BDC, 5-aminoisophthalic acid AMBA.
  7. 7. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein said liquid reaction medium further comprises a small molecular compound having biological activity, wherein the small molecular compound is trapped inside the framework during the crystal growth phase, achieving stable encapsulation and controlled release in situ.
  8. 8. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein a high-speed centrifugal field with a rotation speed of 5000-12000 rpm is applied in the reaction for a time of 1-3 min, so that crystals of the metal-organic framework materials are oriented under the action of centrifugal force to exhibit macroscopic transparency.
  9. 9. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein the mild conditions are in particular a reaction temperature between-5 ℃ and 65 ℃ and a reaction pressure of normal pressure.
  10. 10. The method for rapid synthesis of metal-organic framework materials under mild conditions according to claim 1, wherein the reaction time is 15 to 30 minutes.

Description

Method for rapidly synthesizing metal-organic framework material under mild condition Technical Field The invention relates to a method for synthesizing a metal-organic framework material, in particular to a method for rapidly synthesizing the metal-organic framework material under mild conditions. Background The preparation of metal-organic frameworks (MOFs) has been almost monopolized by solvothermal/hydrothermal processes in the past two decades, by placing metal salts with polycarboxylic acid ligands in autoclaves, reacting at 80-220 ℃ for 6-72 h, crystallizing, filtering, solvent exchange and high temperature vacuum activation to obtain the product. The process is simple and easy in a laboratory level, but the process has the following essential defects of high reaction temperature, long time, single kettle batch production period of more than or equal to 24 h, potential safety hazard of high pressure and polar solvents (DMF, DEF) decomposition at high temperature to generate CO, dimethylamine, formic acid and the like, thereby corroding equipment and limiting solvent recovery. Meanwhile, a product-competing phase exists, namely polyvalent metal (especially Ti 4+、Zr4+、Ce4+) is easy to generate compact amorphous precipitate or various topology competing phases due to kinetic inertia, mineralizer (HF, HCl) or regulator (monocarboxylic acid) is needed to be added for crystallization, and the cost of three wastes and equipment is further increased. To circumvent the high temperature and pressure, two new routes have emerged in the last two years to prepare crystalline divalent and trivalent metal-organic frameworks in a minute-scale, room temperature environment: a) "dissolution-crystallization" transient precipitation method Acetate M (OAc) 2 (m=cu 2+、Zn2+、Co2+) was used as a precursor, which was first completely dissolved in room temperature water and filtered, then rapidly mixed with 4,4' -oxybenzoic acid (H2 oba) dissolved in small amounts of DMF, a liquid-solid transition occurred within 0-60 s, PXRD within 1 min showed a high crystallinity product, BET area comparable to that of the solvothermal sample. Compared with the method, the method has the advantages that the tetravalent metal-organic framework is difficult to synthesize, and as the concentration of the fed materials increases, the system can generate strong competitive reaction and phase change, so that a large amount of impurity phases can be formed, the synthesis efficiency is low, and industrial production is difficult to realize. B) Electrochemical oxidation deposition process Under the constant potential of +0.75V (vs Ag/Ag+), fe 2+ dissolved in DMF/2, 6-lutidine is oxidized into Fe 3+,Fe3+ to coordinate with terephthalic acid at the electrode interface, and a compact Fe-MIL-101 film (BET approximately 2300 m 2 g-1) can be generated on the carboxyl modified ITO surface within 30 min, and the Faraday efficiency is as high as 96%. Different topologies such as Fe-MIL-88B-NH2, fe-MIL-100 and the like can be directionally obtained by adjusting the potential or the ligand, so that the 'potential-phase' selectivity is realized. Compared with the method, the method needs to strictly control the potential and electric power input, does not belong to a narrow normal-temperature rapid synthesis method, and as the concentration of the fed materials increases, nucleation and growth unbalance can lead to poor crystallinity of the product, easy agglomeration, and polarization and passivation of the electrode surface can occur, so that the reaction is terminated in advance, and resources are wasted. Although the divalent and trivalent systems can be crystallized within a few minutes at room temperature, the room-temperature high-speed synthesis of tetravalent MOFs such as Ti 4+、Zr4+、Hf4+、Ce4+ and the like is not reported so far, and the technical barriers are mainly as follows: The kinetics of metal-ligand bond formation is extremely slow, the high charge density makes M-O bond strength high, ligand exchange rate 2-4 orders of magnitude lower than Fe 3+, resulting in long nucleation induction period (UiO-66 requires 12-24 h,180 ℃); The low-cluster precursor is difficult to generate at room temperature, zr 4+ needs to be hydrolyzed into [ Zr 6(μ3-O)4(μ3-OH)4 ] dodecanoic acid Secondary Building Unit (SBU), the equilibrium constant of the process is extremely small at 25 ℃, and a detectable amount of hexanuclear clusters can be observed usually at 100-150 ℃; The competitive phase and compact precipitation, namely, when alkali is quickly dripped or the concentration is increased, monoclinic ZrO 2 or amorphous zirconium-carboxylic acid gel is preferentially separated out from the system instead of an open framework; the modifier depends on that a large amount of benzoic acid/acetic acid is needed to be added as a modifier in the conventional method for inhibiting the excessively fast precipitation and crystallization, the concentration of the modifier is