Oleic acid

Oleic acid About

Oleic acid is an unsaturated fatty acid containing a single carbon-carbon double bond in its molecular structure; it is a constituent fatty acid of triglycerides and is the most widely distributed unsaturated fatty acid in nature. It can be obtained through the hydrolysis of fats and oils, and its chemical formula is CH3(CH2)7CH=CH(CH2)7COOH. Its glycerides are major components of olive oil, palm oil, lard, and other animal and vegetable fats. Industrial-grade oleic acid typically contains 712% saturated fatty acids (such as palmitic and stearic acids) and small amounts of other unsaturated fatty acids (such as linoleic acid). It is a colorless oily liquid with a specific gravity of 0.895 (25/25C), a freezing point of 4C, a boiling point of 286C (13,332 Pa), and a refractive index of 1.463 (18C). Its iodine value is 89.9, and its acid value is 198.6. It is insoluble in water but soluble in alcohol, benzene, chloroform, diethyl ether, and other volatile or non-volatile oils. Upon exposure to airespecially in the presence of impuritiesit oxidizes easily, turning yellow or brown and developing a rancid odor. It decomposes when heated to 80100C at atmospheric pressure. It is produced from animal and vegetable fats through saponification and acidification. Oleic acid is an essential nutrient in animal diets. Its lead, manganese, and cobalt salts serve as paint driers; its copper salt acts as a preservative for fishing nets; and its aluminum salt is used as a waterproofing agent for fabrics and a thickening agent for certain lubricating oils. Epoxidation of oleic acid yields epoxy oleate esters (plasticizers), while oxidative cleavage produces azelaic acid (a raw material for polyamide resins). It should be stored in a sealed container away from light. Oleic acid exists abundantly in animal and vegetable fats, primarily in the form of glycerides. Certain simple oleic acid esters are used in the textile, leather, cosmetic, and pharmaceutical industries. Alkali metal salts of oleic acid are water-soluble and constitute a major ingredient in soap. Salts of oleic acid with metals such as lead, copper, calcium, mercury, and zinc are water-insoluble and serve as dry lubricants, paint driers, and waterproofing agents. Oleic acid is primarily derived from natural sources; it is obtained by subjecting oils and fats with high oleic acid content to processes involving saponification, acidification, and separation. Oleic acid exists in *cis* and *trans* isomeric forms; naturally occurring oleic acid possesses the *cis* configuration (whereas the *trans* form cannot be absorbed by the human body). It helps soften blood vessels and plays a vital role in the metabolism of humans and animals. However, since the body cannot synthesize sufficient amounts of oleic acid to meet its needs, it must be obtained through diet; consequently, consuming edible oils rich in oleic acid is beneficial to health.