Castor oil is a vegetable oil obtained by pressing the seeds of the castor oil plant (Ricinus communis). The common name "castor oil", from which the plant gets its name, probably comes from its use as a replacement for castoreum, a perfume base made from the dried perineal glands of the beaver (castor in Latin).
Castor oil is a colorless to very pale yellow liquid with a distinct taste and odor once first ingested. Its boiling point is 313 °C (595 °F) and its density is 961 kg/m3. It is a triglyceride in which approximately 90 percent of fatty acid chains are ricinoleate. Oleate and linoleates are the other significant components.
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, pharmaceuticals and perfumes.
Annually 270,000–360,000 tonnes (600–800 million pounds) of castor oil are produced for a variety of uses.
Castor oil is used as bio-based polyol in the polyurethane industry. The average functionality (number of hydroxyl groups per triglyceride molecule) of castor oil is 2.7, so it is widely used as rigid polyol and coating.
Castor oil is not a drying oil, meaning that it has a low reactivity toward air compared to other oils such as linseed oil and tung oil. Dehydration of castor oil gives linoleic acids, which do have drying properties.
Precursor to industrial chemicals
Castor oil can be broken down into other chemical compounds that have numerous applications. Transesterification followed by steam cracking gives undecylenic acid, a precursor to specialized polymer nylon 11, and heptanal, a component in fragrances. Breakdown of castor oil in strong base gives 2-octanol, both a fragrance component and a specialized solvent, and the dicarboxylic acid sebacic acid. Hydrogenation of castor oil saturates the alkenes, giving a waxy lubricant.
The production of lithium grease consumes a significant amount of castor oil. Hydrogenation and saponification of castor oil yields 12-hydroxystearic acid which is then reacted with lithium hydroxide or lithium carbonate to give high performance lubricant grease.
Since it has a relatively high dielectric constant (4.7), highly refined and dried castor oil is sometimes used as a dielectric fluid within high performance high voltage capacitors.
Vegetable oils like castor oil are typically unattractive alternatives to petroleum-derived lubricants because of their poor oxidative stability. Castor oil has better low-temperature viscosity properties and high-temperature lubrication than most vegetable oils, making it useful as a lubricant in jet, diesel, and racing engines. The viscosity of castor oil at 10 °C is 2,420 centipoise. However, castor oil tends to form gums
in a short time, and therefore its usefulness is limited to engines
that are regularly rebuilt, such as racing engines. The lubricants
company Castrol took its name from castor oil.
Castor oil has been suggested as a lubricant for bicycle pumps because it does not degrade natural rubber seals.
Early aviation and aeromodelling
Castor oil was the preferred lubricant for rotary engines, such as the Gnome engine
after that engine's widespread adoption for aviation in Europe in 1909.
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.
The methanol-fueled two-cycle glow plug engines used for aeromodelling, since their adoption by model airplane
hobbyists in 1948, have used varying percentages of castor oil as a
lubricant. It is highly resistant to degradation when the engine has its
fuel-air mixture leaned for maximum engine speed. Gummy residues can
still be a problem for aeromodelling powerplants lubricated with castor
oil, however, usually requiring eventual replacement of ball bearings when the residue accumulates within the engine's bearing races. One British manufacturer of sleeve valved
four-cycle model engines has stated the "varnish" created by using
castor oil in small percentages can improve the pneumatic seal of the
sleeve valve, improving such an engine's performance over time.
Turkey red oil
red oil, also called sulphonated (or sulfated) castor oil, is made by
adding sulfuric acid to vegetable oils, most notably castor oil. It was the first synthetic detergent after ordinary soap. It is used in formulating lubricants, softeners, and dyeing assistants.
Castor oil, like currently less expensive vegetable oils, can be used as feedstock in the production of biodiesel. The resulting fuel is superior for cold winters, because of its exceptionally low cloud and pour points.
Initiatives to grow more castor for energy production, in preference
to other oil crops, are motivated by social considerations. Tropical
subsistence farmers would gain a cash crop.
Parents often punished children with a dose of castor oil. Physicians recommended against the practice because they did not want medicines associated with punishment.
A heavy dose of castor oil could be used as a humiliating punishment
for adults, especially political dissenters. Colonial officials used it
in the British Raj (India) to deal with recalcitrant servants.
The most famous use as punishment came in Fascist Italy under Benito Mussolini. It was a favorite tool used by the Blackshirts to humiliate their opponents. Political dissidents were force-fed large quantities of castor oil by Fascist squads. This technique was said to have been originated by Gabriele D'Annunzio.
Victims of this treatment did sometimes die, as the dehydrating effects
of the oil-induced diarrhea often complicated the recovery from the
nightstick beating they also received along with the castor oil;
however, even those victims who survived had to bear the humiliation of
the laxative effects resulting from excessive consumption of the oil.
It is said that Mussolini's power was backed by "the bludgeon
and castor oil". In lesser quantities, castor oil was also used as an
instrument of intimidation, for example, to discourage civilians or
soldiers who would call in sick either in the factory or in the military.
It took decades after Mussolini's death before the myth of castor oil
as a panacea for a wide range of diseases and medical conditions was
totally demystified, as it was also widely administered to pregnant
women, and elderly or mentally ill patients in hospitals in the false
belief it had no negative side effects.
Today, the Italian terms manganello and olio di ricino,
even used separately, still carry strong political connotations
(especially the latter). These words are still used to satirize
patronizing politicians, or the authors of disliked legislation. They
should be used with caution in common conversation. The terms Usare l'olio di ricino, ("to use castor oil") and usare il manganello ("to use the bludgeon") mean "to coerce or abuse", and can be misunderstood in the absence of proper context.
As a means of punishment or torture, force-feeding castor oil still lives on in animated cartoons such as Tom and Jerry.
The castor seed contains ricin,
a toxic protein. Heating during the oil extraction process denatures
and deactivates the protein. However, harvesting castor beans may not be
without risk. Allergenic
compounds found on the plant surface can cause permanent nerve damage,
making the harvest of castor beans a human health risk. India, Brazil,
and China are the major crop producers, and the workers suffer harmful
side effects from working with these plants.
These health issues, in addition to concerns about the toxic byproduct
(ricin) from castor oil production, have encouraged the quest for
alternative sources for hydroxy fatty acids. Alternatively, some researchers are trying to genetically modify the castor plant to prevent the synthesis of ricin.
While castor oil is sometimes used to induce labor in full-term
pregnancies (scientific evidence of its effectiveness is lacking),
consuming castor oil to treat constipation is not considered safe in
pregnancies that are not at full term yet, since it may cause
contractions of the womb.
The above statements have not been evaluated by the FDA
This information is for educational purposes only, it is not intended to treat, cure, prevent or, diagnose any disease or condition. Nor is it intended to prescribe in any way. This information is for educational purposes only and may not be complete, nor may its data be accurate.
All products are for manufacturing use only.