Preparation method of nanometer-to-micrometer scale zeolitic imidazolate frameworks (ZIFs)

Abstract

The invention which belongs to the technical field of new materials relates to a synthetic method of ZIFs, and concretely discloses a method for synthesizing nanometer / micrometer scale ZIFs based on imidazole and its derivatives at room temperature in a concise, efficient and green manner. The method comprises the following steps: dissolving a single imidazole ligand or a mixture of two imidazole ligands in water or an organic liquid to form a solution, adding an alkaline substance to adjust the pH value of the solution, adding a metal salt to form a reaction system, and reacting to obtain the nanometer or micrometer scale ZIFs. The method which allows routine reactants to be utilized and the alkaline substance to be added to adjust the pH value of the system has the advantages of ligand application amount reduction, controllable product size, and high purity of the nanometer / micrometer scale ZIFs. The synthetic method has the characteristics of cheap and easily available raw materials and solvent, and no pollution, and has important meanings to the production and the application of the ZIFs.

Description

technical field [0001] The invention belongs to the technical field of new materials, and relates to a method for synthesizing zeolite imidazole framework materials (ZIFs). Background technique [0002] Zeolitic imidazole frameworks (ZIFs) are a class of nitrogen-containing heterocyclic metal-organic frameworks (MOFs) with organic imidazolates as linking ligands, which are similar in structure to traditional zeolite molecular sieves, with transition metal ions such as Zn or Co substituted The Si element and Al element in the traditional zeolite molecular sieve, imidazole or imidazole derivatives replace the bridging oxygen in the traditional zeolite molecular sieve, and form a coordination polymer through the assembly of the N atom on the imidazole ring and the transition metal. In addition to the large specific surface area and porous properties of conventional MOFs, ZIFs also have high thermal stability (>673K), chemical stability and moisture resistance due to the stro...

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Problems solved by technology

[0003] So far, most of the reported ZIFs have been synthesized using traditional solvothermal synthesis methods. For example, US Patent Publication US 2007 / 0202038A discloses a production method of a functional zeolite structure, using N,N-dimethylformamide or butanol as Solvent, heated to 120-150°C, and reacted for 24-72 hours to prepare ZIFs. The reaction conditions of this method are harsh, the reaction time is long, and the preparation process is complicated

Some other methods for preparing zeolite imidazole structures reported in the literature are such as ball milling (references Patrick J.Beldon, LászlóFábián, Robin S.Stein, A.Thirumurugan, Anthony K.Cheetham, Tomislav Angewandte Chemie International Edition, 2010,49,9640-9643), preparation method is simple but preparation kind is limited; Water vapor assisted synthesis method (reference literature Qi Shi, Zhaofeng Chen, Zhengwei Song, Jinping Li, Jinxiang Dong, Angewandte Chemie International Edition , 2011,50,672-675), need steam to participate in the reaction, and the preparation process is complicated; the aqueous phase rapid synthesis method (references Yichang Pan, Yunyang Liu, Gaofeng Zeng, Lan Zhao, Zhiping Lai, Chemical Communications, 2011,47,2071 -2073), although ZIFs can be rapidly synthesized in aqueous solution, the required organic ligands are excessive, and the ZIFs type can be prepared limited; The zeolite imidazole structure material is synthesized in the solution with a lower amount of ligand, but the yield is low, the product types are limited and it is difficult to control the crystal size

The shortcomings and deficiencies of the above-mentioned preparation or treatment methods limit the large-scale industrial production of zeolitic imidazole framework materials

At room temperature, by adding alkaline substances to adjust the pH value of the reaction system, a simple, efficient and green method for synthesizing nano / micro-sized ZIFs has not been reported yet.

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