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The manufacturing method
of vinyl acetate
vinyl acetate (Acetate, referred to as VA) is an important organic chemical raw material, widely used in the production of polymers, coatings, adhesives and other chemicals. There are various methods for producing vinyl acetate, among which the methods commonly used in industry are acetylene method, ethylene method and ethanol method. This article will detail these three manufacturing methods.
1. acetylene method
acetylene method is a classic method for the production of vinyl acetate, which mainly uses acetylene and acetic acid as raw materials, and under the action of zinc acetate catalyst, the addition reaction is carried out to obtain vinyl acetate.
1. Raw material preparation: mix acetylene and acetic acid in a certain proportion, and add zinc acetate catalyst.
2. Addition reaction: At appropriate temperature and pressure, acetylene and acetic acid in the role of zinc acetate catalyst under the addition reaction to generate vinyl acetate.
3. Separation and purification: After completion of the reaction, vinyl acetate is separated from the reaction mixture by distillation and purified.
the
acetylene method has mature production process and relatively simple operation, the production cost of raw material acetylene is high, and a large amount of wastewater is produced in the production process, which puts great pressure on environmental protection.
2. ethylene method
ethylene method is based on ethylene, acetic acid and oxygen as raw materials, through the oxidation reaction to produce vinyl acetate.
1. Raw material preparation: ethylene, acetic acid and oxygen are mixed in a certain proportion.
2. oxidation reaction: under the action of catalyst, ethylene and acetic acid and oxygen oxidation reaction, generating vinyl acetate.
3. Separation and purification: Vinyl acetate is separated from the reaction mixture by distillation or the like and purified.
ethylene method has the advantages of easy access to raw materials and low production cost, which is a common production method in industry. However, this method requires the use of noble metal catalysts and is highly corrosive to equipment.
3. ethanol method
ethanol method is based on ethanol and acetic acid as raw materials, through the esterification reaction to produce ethyl acetate, and then ethyl acetate and ethylene for addition reaction to produce vinyl acetate.
1. Esterification reaction: Ethanol and acetic acid are esterified under the action of acidic catalyst to generate ethyl acetate.
2. addition reaction: ethyl acetate and ethylene are added under the action of a catalyst to generate vinyl acetate.
3. Separation and purification: Vinyl acetate is separated from the reaction mixture by distillation or the like and purified.
ethanol method has the advantages of easy access to raw materials and mild reaction conditions, but the production process needs to consume a lot of energy and produces more wastewater.
In summary, the acetylene method, ethylene method and ethanol method are commonly used methods for the production of vinyl acetate, and each method has its advantages and disadvantages. In the actual production process, the appropriate production method should be selected according to the source of raw materials, production costs, environmental protection requirements and other factors. In addition, with the continuous progress of science and technology, new production methods and technologies are also emerging, such as ionic liquid catalytic method, biological method, etc., these new methods have higher selectivity and environmental protection, and are expected to become the mainstream technology for the production of vinyl acetate in the future.