Method for preparing 2-methyl-1-acetenyl-2-amylene-1-ol

Abstract

The invention provides a method for preparing 2-methyl-1-acetenyl-2-amylene-1-ol. The method comprises the following steps: firstly, stirring propionaldehyde in a mixture liquid of inorganic base and carbonate salt to perform condensation reaction at normal temperature, collecting an oil phase, and performing reduced pressure distillation to prepare a 2-methyl-2-amylene aldehyde intermediate product; secondly, adding sodium amide and methylbenzene at minus 34 DEG C to minus 45 DEG C of liquid ammonia, introducing an acetylene gas to react sufficiently, subsequently flowing into 2-methyl-2-amylene aldehyde for reaction, after the reaction is completed, volatilizing liquid ammonia, adding hydrochloric acid for hydrolysis, and performing reduced pressure distillation and rectification on an organic layer, thereby preparing 2-methyl-1-acetenyl-2-amylene-1-ol. 2-methyl-1-acetenyl-2-amylene-1-ol prepared by using the method has the advantages of simplicity and convenience to operate, low in energy consumption, high in purity, high in yield, low in production cost, beneficial for industrial on-scale production, and the like.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a preparation method of 2-methyl-1-ethynyl-2-penten-1-ol. Background technique [0002] 2-Methyl-1-ethynyl-2-penten-1-ol is a kind of "alkynyl alcohol", which is the synthesis of pentethrin (also known as fenthrin, code name S-2852) and pentynethrin One of the main intermediates of new pyrethroid insecticides with high efficiency and low toxicity such as permethrin (code S-2876). The main production process is that propionaldehyde undergoes self-condensation reaction under alkali catalysis to generate 2-methyl-2-pentenal, and then reacts with sodium acetylene in liquid ammonia to generate 2-methyl-1-ethynyl-2-pentene -1-ol. The reaction formula is as follows: [0003] first step: [0004] + H 2 o [0005] Step two: [0006] NaNH 2 + HC≡CH → 液氨 NaC≡CH [0007] [0008] About the preparation of 2-methyl-1-ethynyl-2-penten-1-alcohol, almost no ...

AI Technical Summary

Problems solved by technology

The first step in this article is to react with a high concentration of sodium hydroxide solution, and the reaction temperature is as high as 80-85°C. Atmospheric distillation is used, and the temperature reaches 137-140°C. The yield is low, resulting in high production costs and energy consumption.

There is a large amount of liquid ammonia used in the second step reaction, the reaction time is longer, it is difficult to feed solid ammonium chloride under the condition of liquid ammonia, the cost is still high due to the lack of reuse of liquid ammonia and toluene, etc., the operation is more difficult, and the yield is low. Insufficient high

Images