Environment-friendly synthesis method for cyclically preparing benzoin

Abstract

The invention discloses an environment-friendly synthesis method for cyclically preparing benzoin. The method comprises the steps that polyethylene glycol-400, vitamin B1 and anhydrous potassium carbonate are sequentially added into a reactor; after magnetic stirring is carried out for 5 min at room temperature, benzaldehyde is added; after a thin-layer chromatography monitoring reaction is carried out for 3 h, the colourless solution becomes faint yellow; along with the reaction, white solids in a flask are increased, the reaction is finished after 5 h, the solution stands for 10 min and then is filtered, a filter cake is recrystallized with 95% ethyl alcohol to obtain white powdery solids, and the yield is 93%; the filtrate is added into a reaction bottle, anhydrous potassium carbonate and benzaldehyde are added again, a primary circulation reaction is started, the reaction is finished after 5 h, standing and filtering are carried out, a filter cake is recrystallized with 95% ethyl alcohol to obtain white powdery solids, and the yield is 95%; after the circular reaction is totally carried out 15 times, the reaction yield and reaction time are basically not changed. The synthesis method is simple, the reaction cost is low, the catalytic efficiency is high, the yield is high, and environment friendliness is achieved.

Description

technical field [0001] The invention relates to the technical field of chemical product preparation, in particular to a green synthesis method for cyclically preparing benzoin. Background technique [0002] Benzoin (diphenoxyethanone) is a very meaningful intermediate for the synthesis of some important natural products. Since A.J.Lapworth proposed the benzoin condensation reaction mechanism in 1903, this reaction has been considered to be the most effective for the synthesis of a-hydroxy ketones. One of the methods, however, because the catalyst used in this reaction is often highly toxic potassium cyanide or sodium cyanide, it is very harmful to the environment and the human body, which brings great inconvenience to its wide application. Based on this , looking for and exploring better catalysts and other reaction conditions that are conducive to the condensation reaction of benzoin has attracted the attention of organic synthesis workers. [0003] After cyanide as a cata...

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Problems solved by technology

[0002] Benzoin (diphenoxyethanone) is a very meaningful intermediate for the synthesis of some important natural products. Since A.J.Lapworth proposed the benzoin condensation reaction mechanism in 1903, this reaction has been considered to be the most effective for the synthesis of a-hydroxy ketones. One of the methods, however, because the catalyst used in this reaction is often highly toxic potassium cyanide or sodium cyanide, it is very harmful to the environment and the human body, which brings great inconvenience to its wide application. Based on this , looking for and exploring better catalysts and other reaction conditions that are conducive to the condensation reaction of benzoin has attracted the attention of organic synthesis workers