How does acetylene become acetaldehyde?

The main method of producing acetaldehyde from acetylene is liquid phase hydration of acetylene under catalysis.

Liquid-phase hydration of acetylene has been industrialized for more than 60 years and is still in industrial use. This method takes acetylene as raw material, which is obtained by hydrolyzing acetylene with calcium carbide. It consumes a lot of electricity and needs toxic mercury salt as catalyst, which pollutes the environment, so its development is limited.

Extended data:

It's just that acetylene is hydrated in liquid phase under catalysis to produce acetaldehyde. There are three main methods for industrial production of acetaldehyde:

1, oxidative dehydrogenation of ethanol or ethanol dehydrogenation.

Although the technology of oxidative dehydrogenation of ethanol is mature and the yield of acetaldehyde is high, this method depends on the source of ethanol to a certain extent.

If ethanol comes from grain processing, its price is very high, especially if the grain is not abundant.

If it comes from agricultural and sideline products, such as rice bran and bagasse, the price of such raw materials is relatively low, and another source of ethanol is ethylene synthesis. If so, it is better to synthesize acetaldehyde directly from ethylene.

2, propane-butane gas phase direct oxidation method.

On the one hand, the method of producing acetaldehyde by gas phase oxidation of propane and butane is limited by the source of raw materials, and at the same time, the oxide is complex, the separation is difficult and the yield of acetaldehyde is not high. ?

3. Homogeneous oxidation of ethylene. ?

Direct oxidation of ethylene is a one-step synthesis with petroleum pyrolysis ethylene as raw material, which is rich in raw materials, simple in technological process, mild in reaction conditions, high in selectivity and easy to realize industrialization. This is the most economical method to produce acetaldehyde.