Castor oil
[4] Castor oil and its derivatives are used in the manufacturing of soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold-resistant plastics, waxes and polishes, nylon, and perfumes.
[9] Midwifery manuals from the 19th century recommended castor oil and 10 drops of laudanum for relieving "false pains.
[12] The laxative effect of castor oil is attributed to ricinoleic acid, which is produced by hydrolysis in the small intestine.
[16][17] Castor oil is used as a vehicle for serums administering steroid hormones such as estradiol valerate via intramuscular or subcutaneous injection.
There is no high-quality research proving that ingestion of castor oil results in cervical ripening or induction of labor; there is, however, evidence that taking it causes nausea and diarrhea.
[21][22] A systematic review of "three trials, involving 233 women, found there has not been enough research done to show the effects of castor oil on ripening the cervix or inducing labour or compare it to other methods of induction.
"[21][22] Castor oil is still used for labor induction in environments where modern drugs are not available; a review of pharmacologic, mechanical, and "complementary" methods of labor induction published in 2024 by the American Journal of Obstetrics and Gynecology stated that castor oil's physiological effect is poorly understood but "given gastrointestinal symptomatology, a prostaglandin mediation has been suggested but not confirmed.
"[23] According to Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk (2008), castor oil should not be ingested or used topically by pre-term pregnant women.
[29] Castor oil was also a tool of punishment favored by the Falangist and later Francoist Spain during and following the Spanish Civil War.
[30][31] This began during the war where Nationalist forces would specifically target Republican-aligned women, both troops and civilians, who lived in Republican-controlled areas.
[30] The forced drinking of castor oil occurred alongside sexual assault, rape, torture and murder of these women.
[32][33][34] Political dissidents were force-fed large quantities of castor oil by fascist squads so as to induce bouts of extreme diarrhea in the victims.
The average functionality (number of hydroxyl groups per triglyceride molecule) of castor oil is 2.7, so it is widely used as a rigid polyol and in coatings.
[1] One particular use is in a polyurethane concrete where a castor-oil emulsion is reacted with an isocyanate (usually polymeric methylene diphenyl diisocyanate) and a cement and construction aggregate.
[1] In this process, the OH group on the ricinoleic acid along with a hydrogen from the next carbon atom are removed, forming a double bond which then has oxidative cross-linking properties and yields the drying oil.
[39][40][41][42] Transesterification followed by steam cracking gives undecylenic acid, a precursor to specialized polymer nylon 11, and heptanal, a component in fragrances.
[53] Initiatives to grow more castor for energy production, in preference to other oil crops, are motivated by social considerations.
It was used almost universally in rotary-engined Allied aircraft in World War I. Germany had to make do with inferior ersatz oil for its rotary engines, which resulted in poor reliability.
One British manufacturer of sleeve valved four-cycle model engines has stated the "varnish" created[citation needed] by using castor oil in small percentages can improve the pneumatic seal of the sleeve valve, improving such an engine's performance over time.
