Ethyl vinyl ether (EVE) can be prepared by reacting acetylene with absolute ethanol in the presence of an alkali catalyst. The most commonly used catalyst for vinylation is an alkali metal hydroxide or an alkali metal alkoxide.
In China, three processes for the manufacture of EVE using the acetylene route were used:
A continuous process with a homogeneous catalyst under high pressure. The advantages of this process are fast reaction rate and high conversion, but the disadvantages include the requirement of high standard equipment, large energy consumption, and easy safety issues.
A process with a solid catalyst (heterogeneous catalyst) under atmospheric pressure is relatively simple in product separation and refining compared with a process with a homogeneous catalyst under high pressure. However, it has the disadvantages of low output, the short service life of catalyst (about 110 h), and a high requirement on the specification of carrier lime.
A process with a homogeneous catalyst under atmospheric pressure has the advantages of high output and good safety but disadvantages of low conversion.
In the process with solid catalyst under atmospheric pressure, acetylene, and ethanol vapor were introduced into a fixed-bed reactor, and the vinylation reaction was carried out at a temperature as high as about 180 °C. EVE was produced with a concentration of about 70% in the outlet gas stream from the reactor. The fixed-bed reactor was charged with 4–5 mesh catalyst particles of potassium hydroxide supported on lime.
