At present, the main preparation methods of industrial ethyl acetate in the world include acetate esterification method, acetaldehyde condensation method, ethylene addition method and alcohol dehydrogenation method. The traditional acetate esterification process has been gradually eliminated abroad, and large-scale production equipment is mainly acetaldehyde condensation method and alcohol dehydrogenation method. In areas with abundant acetaldehyde raw materials, acetaldehyde condensation method units with a capacity of more than 10,000 tons have been obtained. a wide range of applications. The ethanol dehydrogenation method is a new process developed in recent years and has been promoted in areas where ethanol is abundant and low-cost. The latest ethyl acetate production method is the ethylene addition method. In 1998, a 50 kt/a production unit was built in the Mailaku area of ??Indonesia using the patented technology of Japan's Showa Denko.
(1) Acetate esterification method
The acetate esterification method is a traditional ethyl acetate production method. It is produced by the esterification reaction of acetic acid and ethanol in the presence of a catalyst. have to.
CH3CH2OH+CH3COOH=CH3COOCH2CH3+H2O
Ethanol Acetic acid Ethyl acetate Water
High yield can be obtained by removing the water produced by the reaction. The main disadvantages of this method for producing ethyl acetate are high cost and highly corrosive equipment. It is a process route that has been eliminated internationally.
(2) Acetaldehyde condensation method
In the presence of the catalyst aluminum ethoxide, two molecules of acetaldehyde are automatically oxidized and condensed, and rearranged to form one molecule of ethyl acetate.
2CH3CHO→CH3COOCH2CH3
Aldehyde ethyl acetate
This method has formed large-scale production equipment in Europe, America, Japan and other places in the 1970s. It has obvious advantages in terms of production cost and environmental protection.
(3) Alcohol dehydrogenation method
Use a copper-based catalyst to dehydrogenate ethanol to produce crude ethyl acetate, and remove the boiling matter through high and low pressure distillation to obtain a purity of 99.8 % or more of ethyl acetate.
2C2H5OH→CH3COOCH2CH3+H2
Ethanol ethyl acetate hydrogen
(4) Ethylene addition method
As attached in 2 In the presence of a heteropolyacid metal salt or a heteropoly acid on a carrier such as silicon oxide as a catalyst, ethylene is hydrated in the gas phase and directly esterified with vaporized acetic acid to generate ethyl acetate.
CH2CH2+CH3COOH=CH3COOCH2CH3
Ethylene acetic acid ethyl acetate
The single-pass conversion rate of acetic acid in this reaction is 66%, and the choice of ethyl acetate is based on ethylene. Safety is 94%. Multinational companies such as Rhone-Poulenc, Showa Denko and BP have developed this production process.