Sebacic acid is made from natural castor oil or adipic acid monoester. Sebacic acid can also be obtained by polymerization reaction with ethylene and carbon tetrachloride, but at present, almost all sebacic acid produced in industry in the world uses castor oil as raw material. 1. Castor oil cracking method Castor oil is heated and hydrolyzed under the action of alkali to generate sodium ricinoleate soap, and then acidified with sulfuric acid to generate ricinoleic acid; in the presence of the diluent cresol, heat to 260-280℃ with alkali for cracking , Produces sebacic acid disodium salt, secondary octanol and hydrogen. After the lysate is diluted with water, it is heated and neutralized by adding acid to turn the disodium salt into monosodium salt; then the neutralized liquid after decolorization with activated carbon is boiled and acid is added. The monosodium sebacic acid is transformed into sebacic acid to crystallize out, and then separated and dried to obtain the finished product.