oleic acid

Oleic acid
IUPAC name	(9Z)-Octadec-9-enoic acid
Other names	(9Z)-Octadecenoic acid (Z)-Octadec-9-enoic acid cis-9-Octadecenoic acid cis-Δ9-Octadecenoic acid Oleic acid 18:1 cis-9
Identifiers
CAS number	112-80-1 Y
SMILES	CCCCCCCC\C=C/CCCCCCCC(O)=O
Properties
Molecular formula	C18H34O2
Molar mass	282.4614 g/mol
Appearance	Pale yellow or brownish yellow oily liquid with lard-like odor
Density	0.895 g/mL
Melting point	13-14 °C (286 K)
Boiling point	360 °C (633 K) (760mm Hg)[1]
Solubility in water	Insoluble
Solubility in methanol	Soluble
Hazards
MSDS	ScienceLab.com
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Oleic acid is a mono-unsaturated omega-9 fatty acid found in various animal and vegetable sources. It has the formula CH₃(CH₂)₇CH=CH(CH₂)₇COOH).^[2] The trans-isomer of oleic acid is called elaidic acid.

The term Oleic means related to, or derived from, oil or olive.

Occurrence

Triglyceride esters of oleic acid comprise the majority of olive oil, though there may be less than 2.0% as actual free acid in the virgin olive oil, while higher concentrations make the olive oil inedible. It also makes up 15-20% of grape seed oil and sea buckthorn oil.^[3]

Oleic acid is the most abundant fatty acid in human adipose tissue.^[4]

Smell of death

Oleic acid is emitted by the decaying corpses of a number of insects, including bees and Pogonomyrmex ants and triggers the instincts of living workers to remove the dead bodies from the hive. If a live bee^[5] or ant^[6][7] is daubed with oleic acid, it is dragged off as if it were dead. This is why oleic acid is also sometimes referred as "smell of death". The repellent smell indicates to living insects how to avoid others that have succumbed to disease or places where predators lurk. This "death recognition system" based on a simple fatty acid likely evolved over 400 million years ago.^[8]

Chemistry

Oleic acid exhibits the reactions of carboxylic acids and alkenes. It is soluble in aqueous base to give Salts called oleates. Iodine adds across the double bond. Hydrogenation of the double bond give the saturated derivative called stearic acid. Oxidation at the double bond occurs slowly in air and is known as rancidification in foodstuffs and drying in coatings. Reduction of the carboxylic acid group yields oleyl alcohol.

Uses

As an excipient in pharmaceuticals, oleic acid is used as an emulsifying or solubilizing agent in aerosol products.^[9]

Health effects

Oleic acid may hinder the progression of ALD, or Adrenoleukodystrophy, a fatal disease that affects the brain and adrenal glands.^[10]

Oleic acid may help boost memory.^[11]

Oleic and monounsaturated fatty acid levels in the membranes of red blood cells have been associated with increased risk of breast cancer.^[12] Oleic acid may be responsible for the hypotensive (blood pressure reducing) effects of olive oil.^[13]

See also

• Fatty acids
• Linoleic acid
• Pheromone

References

External links

• NIST Chemistry Webbook