Linoleic acid

Not to be confused with linolenic acid, alpha-linolenic acid, lipoic acid, or linolelaidic acid.

Linoleic acid
Names
Preferred IUPAC name
(9Z,12Z)-Octadeca-9,12-dienoic acid
Other names
cis,cis-9,12-Octadecadienoic acid
C18:2 (Lipid numbers)
Identifiers
3D model (JSmol)
3DMet
1727101
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.428 Edit this at Wikidata
EC Number
  • 200-470-9
57557
KEGG
UNII
  • InChI=1S/C18H32O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h6-7,9-10H,2-5,8,11-17H2,1H3,(H,19,20)/b7-6-,10-9- checkY
    Key: OYHQOLUKZRVURQ-HZJYTTRNSA-N checkY
  • InChI=1/C18H32O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h6-7,9-10H,2-5,8,11-17H2,1H3,(H,19,20)/b7-6-,10-9-
    Key: OYHQOLUKZRVURQ-HZJYTTRNBX
  • CCCCC/C=C\C/C=C\CCCCCCCC(=O)O
Properties
C18H32O2
Molar mass 280.452 g·mol−1
Appearance Colorless oil
Density 0.9 g/cm3[1]
Melting point −12 °C (10 °F)[1]
−6.9 °C (19.6 °F)[2]
−5 °C (23 °F)[3]
Boiling point 229 °C (444 °F) at 16 mmHg[2]
230 °C (446 °F) at 21 mbar[3]
230 °C (446 °F) at 16 mmHg[1]
0.139 mg/L[3]
Vapor pressure 16 Torr at 229 °C[citation needed]
Acidity (pKa) 4.77 at 25°C[4]
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Flash point 112 °C (234 °F)[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Linoleic acid (LA) is an organic compound with the formula HOOC(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups (−CH=CH−) are cis. It is a fatty acid sometimes denoted 18:2 (n−6) or 18:2 cis-9,12. A linoleate is a salt or ester of this acid.[5]

Linoleic acid is a polyunsaturated, omega−6 fatty acid. It is a colorless liquid that is virtually insoluble in water but soluble in many organic solvents.[2] It typically occurs in nature as a triglyceride (ester of glycerin) rather than as a free fatty acid.[6] It is one of two essential fatty acids for humans, who must obtain it through their diet,[7] and the most essential, because the body uses it as a base to make the others.

The word "linoleic" derives from Latin linum 'flax' and oleum 'oil', reflecting the fact that it was first isolated from linseed oil.

  1. ^ a b c The Merck Index, 11th Edition, 5382
  2. ^ a b c William M. Haynes (2016). CRC Handbook of Chemistry and Physics (97th ed.). Boca Raton: CRC Press. pp. 3–338. ISBN 978-1-4987-5429-3.
  3. ^ a b c d Record of CAS RN 60-33-3 in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  4. ^ National Center for Biotechnology Information (2024). PubChem Compound Summary for CID 5280450, Linoleic Acid. Retrieved January 20, 2024 from https://pubchem.ncbi.nlm.nih.gov/compound/Linoleic-Acid.
  5. ^ "Fatty Acids". Cyber Lipid. Archived from the original on 28 October 2018. Retrieved 31 July 2017.
  6. ^ Mattes, Richard D. (2009). "Is there a fatty acid taste?". Annual Review of Nutrition. 29: 305–327. doi:10.1146/annurev-nutr-080508-141108. PMC 2843518. PMID 19400700.
  7. ^ Simopoulos, Artemis P. (2008). "The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases". Experimental Biology and Medicine. 233 (6): 674–688. doi:10.3181/0711-mr-311. PMID 18408140. S2CID 9044197.