How to make acetic acid industrially

At present, the main preparation methods of industrial ethyl acetate in the world include acetic acid esterification, acetaldehyde condensation, ethylene addition and ethanol dehydrogenation. The traditional acetic acid esterification process has been phased out in foreign countries, and large-scale production units are mainly acetaldehyde condensation and ethanol dehydrogenation method, in the acetaldehyde raw material is more abundant in the region of more than 10,000 tons of acetaldehyde condensation method device has been widely used. Ethanol dehydrogenation method is a new process developed in recent years, which has been popularized in regions with abundant and low-cost ethanol. The latest method of ethyl acetate production is ethylene addition method, and a 50

kt/a production unit was built in 1998 in Myrakou area of Indonesia using the patented technology of Showa Denko of Japan.

(1) Acetic acid esterification method

Acetic acid esterification method is the traditional method of ethyl acetate production, in the presence of a catalyst, by the esterification reaction of acetic acid and ethanol.

CH3CH2OH + CH3COOH = CH3COOCH2CH3 + H2O

Ethanol

Acetic acid

Ethyl acetate

Water

The reaction removes the resulting water, which gives a high yield. The main disadvantages of this method of producing ethyl acetate are high cost and corrosive equipment, and it is among the process routes that have been eliminated internationally.

(2)

Acetal Condensation Method

In the presence of the catalyst aluminum ethanol, two molecules of acetaldehyde are automatically oxidized and condensed, rearranging to form one molecule of ethyl acetate.

2CH3CHO→CH3COOCH2CH3

Acetaldehyde

Ethyl acetate

This method has formed large-scale production units in Europe, America and Japan in the 1970s, and it has obvious advantages in terms of production cost and environmental protection.

(3) ethanol dehydrogenation method

Copper-based catalyst is used to dehydrogenate ethanol to produce crude ethyl acetate, which is distilled at high and low pressures to remove ****-boiling material, and ethyl acetate with a purity of more than 99.8% is obtained.

2C2H5OH→CH3COOCH2CH3+H2

Ethanol

Ethyl acetate

Hydrogen

(4)

Ethylene Addition

In the presence of heteropolyacid metal salts or heteropolyacids attached to carriers such as silica as catalysts, the gas-phase hydration of ethylene is carried out with the vaporized acetic acid to produce ethyl acetate by direct esterification.

CH2CH2+CH3COOH=CH3COOCH2CH3

Ethylene

Ethanoic acid

Ethyl acetate

Ethyl acetate

This reaction has a one-way conversion of acetic acid of 66%, and a selectivity of ethyl acetate to ethylene of 94%. BP are among the multinational companies that have developed this production process.