Method for preparing high-dispersion solid-carrying Keggin type polyoxometallate crystalline-state catalyst

Abstract

The invention belongs to a chemical synthesis method, and relates to a method for utilizing a hydrothermal synthesis technique to prepare a highly-dispersed solid-supported Keggin-type polymetallic acid oxide salt crystalline catalyst. The method mixes certain amount of Keggin-type heteropoly acid or heteropolyacid salt, trimesic acid, copper salt and various methyl ammonium salts in water, and then obtains a crystal of the solid-supported catalyst under the condition of hydrothermal authigenic pressure. Polyacid catalysts are dispersed in a microporous metal-organic frame in a unimolecular form. The method can accurately determine the composition, structure and supported amount of the catalyst, and the supported amount of the catalyst is up to over 45 percent. The catalyst of the invention has the advantages that the catalyst can not drain away, is high in thermal stability, resistant to acid and alkali, stable and insoluble in water and common organic solvents, such as various solvents such as alcohol, cyanide, ketone, chloroform, and is an ideal catalyst for realizing heterogeneous catalytic reaction.

Description

technical field [0001] The invention belongs to a chemical synthesis method, and relates to a method for preparing a highly dispersed and immobilized Keggin type polyoxometalate crystalline catalyst by utilizing a hydrothermal synthesis technology. Background technique [0002] Designing and synthesizing heterogeneous catalysts with high activity, selectivity, environmental friendliness and recyclability is of great significance in the fields of scientific research or catalytic industry. Polyoxometalates have strong Acidic, with rich redox properties, non-toxic and non-corrosive, it is used as an acidic or redox catalyst in many organic reactions, such as olefin hydration, esterification and hydrolysis, alkylation, olefin epoxidation, etc. Pure polyoxometalates have a small specific surface area (<10m 2 g -1 ), which shields the accessible active sites and limits its applications. Therefore, various high surface area supports, such as porous silicon, activated carbon...

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Problems solved by technology

However, these systems are usually considered as a class of materials with "undefined" composition and structure, and have many limitations, including low loading capacity, easy loss, easy aggregation, non-uniform active sites, easy passivation, etc.

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