Manufacturing method of vinyl acetate
Vinyl acetate (VA) is an important organic chemical raw material, widely used in the production of polyvinyl alcohol, adhesives, coatings, fibers and other chemical products. The following are the manufacturing methods of vinyl acetate:
I. Acetylene Method
Acetylene method is based on acetylene and acetic acid as raw materials, in the presence of zinc acetate catalyst, the reaction is carried out at 170-250 ℃ to generate vinyl acetate. The reaction liquid is separated by distillation to obtain vinyl acetate products. The method has the advantages of easy to obtain raw materials, low production costs, but the reaction process requires high temperature and high pressure conditions, equipment investment.
II, ethylene method
ethylene method is based on ethylene, acetic acid and oxygen as raw materials, through the oxidation reaction to generate vinyl acetate. The reaction is carried out in a fixed-bed reactor, using a palladium catalyst, the reaction temperature is controlled at 140-180 ℃, the pressure is 0.2-0.4 MPa. The reaction product is condensed, separated, distilled and other processes to obtain vinyl acetate products. Ethylene method has the advantages of easy availability of raw materials, mild reaction conditions, easy operation, etc. It is the main production method at home and abroad.
Third, ethanol method
Ethanol method is based on ethanol and acetic acid as raw materials, in the presence of sulfuric acid catalyst, esterification reaction to generate ethyl acetate, and then ethyl acetate in the presence of zinc powder, in 200-300 ℃ for thermal decomposition to generate vinyl acetate. This method is easy to obtain raw materials, but the reaction process requires high temperature conditions, high energy consumption.
Four, acetaldehyde method
Acetaldehyde method is based on acetaldehyde and acetic acid as raw materials, in the presence of zinc acetate catalyst, the addition reaction to generate vinyl acetate. The raw material of this method is more expensive and the production cost is higher.
In short, ethylene method is the main production method at home and abroad, with the advantages of easy availability of raw materials, mild reaction conditions, easy operation and so on. In the production process, the reaction conditions need to be strictly controlled to ensure product quality and production safety. At the same time, strengthen the maintenance and overhaul of equipment, improve the operation rate and life of equipment, reduce production costs, and improve the economic and social benefits of enterprises.
