What Is the Main Use of Adipic Acid?

1. The chemical properties of adipic acid

Adipic acid is a white crystalline powder with a melting point of 153°C, a density of 1.360g/cm³, mp153°C, and a normal boiling point of 337.5°C. It starts to decompose at 330.5°C and has a flash point of 210°C and 191°C (closed-mouth). It is one of the types of compounds in organic chemistry.

2. The functions of adipic acid

Adipic acid is mainly used as a raw material for nylon 66 and engineering plastics, as well as for the production of various ester products, and as the raw material for polyurethane elastomers. Adipic acid is also a raw material for medicine, yeast purification, pesticides, adhesives, synthetic leather, synthetic dyes and perfumes.

3. The adipic acid uses

Adipic acid is used as a raw material for the synthetic high polymers, and also used to make plasticizers and lubricants. Adipic acid is a white crystalline solid, which is easily soluble in alcohol and ether, soluble in acetone, slightly soluble in cyclohexane and benzene. When the mass content of oxygen in the adipic acid is higher than 14%, it is easy to generate static electricity and cause fire. The mass content of adi pic acid dust which may explode in the air ranges from 3.9% to 7.9%. Adipic acid is the most valuable dibasic acid among the aliphatic dibasic acids. It can produce salt forming reaction, esterification reaction, amidation, etc., and can be polycondensed with diamines or dihydric alcohols to form high-molecular polymers, etc.

It is a white crystal with a melting point of 153.0 to 153.1℃. It is an industrially important dicarboxylic acid, and its output ranks second among all dicarboxylic acids. It is mainly used in the production of adiponitrile so as to produce hexamethylene diamine, and then together with hexamethylene diamine to produce nylon 66. In addition, it is also used to produce unsaturated polyester, hexanediol and adipic acid esters.

In 1937, the American DuPont Company used nitric acid to oxidize cyclohexanol (prepared by the hydrogenation of phenol), and first realized the industrial production of the adipic acid.

In the 1960s, the industry gradually changed to adopt the cyclohexane oxidation method, that is, the intermediate product cyclohexanone and cyclohexanol mixture (that is, ketol oil, also known as ka oil) is prepared from cyclohexane, and then the ka oil is oxidized with the nitric acid or air. The catalyst used in the reaction is copper-vanadium series (copper of 0.1% to 0.5%, vanadium of 0.1% to 0.2%), with a temperature of 60 to 80℃and pressure of 0.1 to 0.4mpa. The yield is 92% to 96% of the theoretical value. After nitric acid is distilled from the oxidation product of ka oil, high-purity adipic acid can be obtained through two-stage crystallization and refining.