Ricinoleic acid, formally called 12-hydroxy-9-cis-octadecenoic acid, is a fatty acid. It is an unsaturated omega-9 fatty acid and a hydroxy acid. It is a major component of the seed oil obtained from the seeds of castor plant (Ricinus communis L., Euphorbiaceae), the plant that produces ricin. It is also found in the sclerotium of ergot (Claviceps purpurea Tul., Clavicipitaceae). About 90% of the fatty acid content in castor oil is the ricinolein.

Production

Ricinoleic acid is manufactured for industries by saponification or fractional distillation of hydrolyzed castor oil. The first attempts to prepare ricinoleic acid were made by Friedrich Krafft in 1888.

Use

Sebacic acid ((CH2)8(CO2H)2), which is used in preparing certain nylons, is produced by cleavage of ricinoleic acid. The coproduct is 2-octanol. The mechanism of the base-induced cleavage is proposed to proceed by initial dehydrogenation of the secondary alcohol, affording the ketone. The resulting α,β-unsaturated ketone undergoes retroaldol reaction, resulting in lysis of the C-C bond. The zinc salt is used in personal care products such as deodorants.