Preparation of Ethyl Vinyl Ether

1.1 Acetylene method

Acetylene process is a traditional process,which is prepared by reacting acetylene gas and alcohol under high temperature and high pressure environment to generate a series of products.In order to improve the production efficiency of acetylene process,it is necessary to solve the problems of low yield of acetylene gas explosion risk and operation of high-temperature and high-pressure equipment,so as to meet the requirements of industrial production at this stage.With the continuous improvement of the industrial production process system,the theoretical research technology of acetylene method has also made continuous progress.In the process of industrial development,the structure of the raw alcohol will affect the yield and purity of the product.The longer the purity of the carbon chain,the smaller the yield, the greater the steric hindrance,and the smaller the yield. With the continuous development of catalyst technology,process conditions and technologies have been continuously optimized,and catalyst technologies such as Zn,Cd,Ag salts and their oxides have been continuously matured. However,such technologies lack good activity and need to be supported by certain pressure.In the process of acetylene preparation,the explosion limit range of acetylene is wide,and explosion problems may occur in the operation process. 

Therefore, CaC2 is gradually used as a catalyst in the industry,instead of directly using acetylene gas to generate vinyl ether compounds.During the catalytic process,vinyl ether compounds are collected by distillation,and the by-products have good stability,so the purity of the products will not be affected.With the continuous improvement of reaction equipment and the development of new processes, the application effect of alkoxylation has been continuously improved. In this process, tetravinylidene glycol is placed in a flask,fully heated in the oil bath, and protected by nitrogen. When the temperature rises to 120 ℃,the potassium metal is cut into small pieces, slowly put into the flask, heated to about 180 ℃, closed nitrogen,and then introduced acetylene gas.After the reaction, Close the acetylene gas, inject nitrogen,cool the finished product to room temperature, remove the solvent, and then obtain the bifunctional vinyl ether compound.

1.2 Dehalogenation hydrogen method

With the continuous development of acetylene method,dehydrohalogenation technology has emerged as the times require.The reaction conditions of this technology are relatively mild,but this method has certain requirements for the raw material structure of the reaction.In this process,vinyl ether compounds cannot be prepared by general ether synthesis methods,and their synthesis target products are limited to a certain extent.The difference between these methods is that they use different catalysts,The initial catalysts were metal compounds.With the continuous development of catalyst technology,phase transfer catalysts have been continuously applied,and their reaction conditions have eased.