a monobasic carboxylic acid with two isolated double bonds, CH3(CH2)3 (CH2CH=CH)2(CH2)7COOH; a colorless oily liquid. Melting point, — 11°C; boiling point, 182°C (at 532 newtons per sq m, or 4 mm of mercury); density, 0.903 g/cm3 at 20°C.
Together with arachidonic acid and linolenic acid, linoleic acid is an irreplaceable fatty acid, necessary for normal vital activity. These acids are ingested by humans and animals with food, mainly in the form of complex lipids (triglycerides and phosphatides). A substantial quantity of linoleic acid in triglyceride form (up to 40–60 percent) is known to occur in many vegetable oils and animal fats, such as soy, cottonseed, sunflower, linseed, and hemp oils and whale blubber.