Keggin type vacancy polyacid and application thereof in catalytic synthesis of benzoxazole derivative

Abstract

The invention belongs to the technical field of application of inorganic functional materials, and discloses Keggin type vacancy polyacid and application thereof in a reaction for catalytic synthesis of a benzoxazole derivative. The chemical formula of the Keggin type trivacancy polyacid is Na8H [A-PW9O34]*7H2O, wherein A represents a structure type of the Keggin type trivacancy polyacid. The Keggin type trivacancy polyacid is taken as an environment-friendly catalyst and applied to a reaction in which aldehydes and 2-aminophenol are taken as raw materials for catalytic synthesis of the benzoxazole derivative in a liquid phase, catalysis for oximation reaction of most aldehyde or ketone under a mild condition is achieved, high catalytic activity and principal product selectivity are provided, and various problems in the conventional synthesis of the benzoxazole derivative are solved.

Description

technical field [0001] The invention belongs to the technical field of preparation of inorganic functional materials, and in particular relates to the catalytic application of a Keggin type three-vacancy polyacid in liquid phase to the synthesis of benzoxazole derivatives by using aldehydes and 2-aminophenol as raw materials. Background technique [0002] Polyacid compounds are a class of multimetal oxides containing metals such as V, Mo, W, and Nb, and these atoms are generally in their highest oxidation state. The condensation of the same oxoacid ions is called isopolyanion, and the corresponding acid is called isopolyacid. The condensation of different types of oxyacid anions is called heteropolyanion, and the corresponding acid is called heteropolyacid. They have better thermal and redox stability than common organic ligands. The redox ability, electron transfer characteristics, acidity and solubility of polyacids can be adjusted to a large extent by changing the metal...

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Problems solved by technology

Based on the above-mentioned rich applications of benzoxazole derivatives in the synthesis of chemical intermediates and drugs, a series of catalytic systems have been developed for the synthesis of benzoxazole derivatives, but the reported catalytic systems often have the following three Disadvantages: 1) In homogeneous reactions, catalysts are difficult to recycle and reuse; 2) In most heterogeneous reactions, catalyst efficiency and product yields are unsatisfactory; 3) Reaction needs to be carried out at the reflux temperature of the solvent, and Most solvents such as CH 2 Cl 2 , CHCl 3 ,CH 2 CH 2 Cl 2 , DMF or toluene are toxic or even highly toxic solvents

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