Stearic acid, or octadecanoic acid, has a molecular formula of C18H36O2, which is produced by the hydrolysis of fats and oils, and is mainly used to produce stearates. Each gram is dissolved in 21ml ethanol, 5ml benzene, 2ml chloroform or 6ml carbon tetrachloride. Industrial production is mainly carried out by the oil hydrolysis method.

Grease hydrolysis is divided into three types according to pressure conditions:

1. Hydrolysis with catalyst under normal pressure, the hydrolysis cycle is long, it takes tens of hours, the conversion rate of fatty acid is low, and the later separation effect is poor.

2. Medium-pressure hydrolysis: No catalyst is required, the hydrolysis cycle is about ten hours, and the conversion rate basically reaches 90%. It is an intermittent reaction and is gradually being eliminated in China.

3. High-pressure hydrolysis: no catalyst is needed, the hydrolysis cycle is about 5 hours, the conversion rate is basically 98-99%, and continuous production. The prepared stearic acid has good color, high content and few impurities.