Oleic acid

Oleic acid is an unsaturated fatty acid that contains a carbon-carbon double bond. It is found in many natural sources, such as olive oil, palm oil, and lard. Oleic acid can also be produced through the hydrolysis of oil lipids. It is an important nutrient in animal food and has various industrial applications, including paint driers, fish net preservatives, and plasticizers. Oleic acid can also be used to produce epoxy oleate and azelaic acid. The alkali metal salt of oleic acid is a main component of soap. Most natural oleic acids have a cis-isomer structure, while trans-isomers are not absorbed by the human body. Consuming edible oil that is high in oleic acid content is considered healthy.

Oleic acid is a single unsaturated carboxylic acid widely found in animal and vegetable oils. It has two types: stable (α-type) and unstable (β-type). It appears as a colorless transparent oily liquid with a lard odor. It is insoluble in water, soluble in benzene and chloroform, and miscible with methanol, ethanol, ether, and carbon tetrachloride. It easily undergoes air oxidation, producing a bad smell with the color turning yellow. It can be converted to elaidic acid with nitrogen oxides, nitric acid, mercurous nitrate, and sulfurous acid, and into stearic acid upon hydrogenation. It can be obtained through the hydrolysis of olive oil and lard oil, followed by steam distillation and crystallization or extraction for separation. It is an excellent solvent for other oils, fatty acids, and oil-soluble substances, and can be used for the manufacture of soap, lubricants, and flotation agents, such as ointment and oleate.
 
Fig. 1 the vegetable oleic acid;

Oleic acid and linoleic acid are both unsaturated long-chain fatty acids that provide energy and are essential nutrients for animals, as they cannot be synthesized in the body. Linoleic acid can be produced by some animals from arachidonic acid. These fatty acids are mainly found in vegetable oil, and therefore, poultry and pigs who consume vegetable oil are not lacking them. However, recent poultry feeding standards require a certain amount of linoleic acid, as it generates EPA (eicosapentaenoic acid) during metabolism. EPA is an important component of phospholipids in cell membranes and has essential physiological functions in the body. EPA and DHA are mainly found in fish oil, which, when fed to egg-laying chickens, produce eggs that reduce cholesterol intake in humans.

Oleic acid, defined as a processing aid in GB 2760-96, has multiple uses. It can act as an antifoaming agent, fragrance, binder, and lubricant. It is useful for manufacturing soap, ointments, and flotation agents. It is an excellent solvent for fatty acids and oil-soluble substances. Additionally, oleic acid can be used to polish gold, silver, and other precious metals. It is also a key raw material for producing epoxidized oleic acid ester, plasticizers, and azelaic acid. Oleic acid is also used as a printing and dyeing auxiliary, industrial solvent, and in the sugar processing industry. It is a chemical reagent used for biochemical research and can activate protein kinase C in liver cells. Oleate products are important derivatives of oleic acid and it is widely used in various industries.

Oleic acid is a fatty acid found in animal and vegetable oils. Oleic acid is a mono-saturated fat generally believed to be good for one's health. Indeed, it is the chief fatty acid found in olive oil, comprising 55 to 85 percent of the important substance, which is commonly used in Mediterranean cuisine and has been hailed for its therapeutic characteristics since antiquity. Modern studies support the notion of the benefits of consuming olive oil, since evidence suggests that oleic acid helps lower levels of harmful low-density lipoproteins (LDLs) in the bloodstream, while leaving levels of beneficial high-density lipoproteins (HDLs) unchanged. Found also in significant quantities in canola, cod liver, coconut, soybean, and almond oils, oleic acid can be consumed from a variety of sources, some of which may soon contain even higher levels of the valuable fatty acid due to the efforts of genetic engineers.
Oleic acid occurs naturally in greater quantities than any other fatty acid. It is present as glycerides in most fats and oils. High concentrations of oleic acid can lower blood levels of cholesterol. It is used in the food industry to make synthetic butters and cheeses. It is also used to flavor baked goods, candy, ice cream, and sodas.
According to the American Diabetes Association, more than 25 million Americans have diabetes. In addition, 7 million have undiagnosed diabetes, and 79 million others have prediabetes. In a study published in February 2000 in the medical journal "QJM," researchers in Ireland found that diets rich in oleic acid improved the participants' fasting plasma glucose, insulin sensitivity and blood circulation. Lower fasting glucose and insulin levels, along with enhanced blood flow, suggest better diabetes control and less risk for other diseases. For millions of people with diagnosed diabetes and prediabetes, consuming foods rich in oleic acid may be beneficial in controlling the disease.

Oleic acid is available from seed oils such as pumpkin, grape, avocado, and mango. Its esterification with diols 1,3-propanediol, resorcinol and orcinol was used to form diesters and the naturally occurring norspermidine has been used to prepare a diamide, all under ambient conditions. These compounds were then epoxidized and polymerized. When the esterification was followed by an epoxidation and subsequent curing at elevated temperature with p-phenylenediamine or diethylenetriamine, hard insoluble resins were formed. When the sequence was changed, as the epoxidized oleic acid was first reacted with cis-1,2-cyclohexanedicarboxylic anhydride and then esterified with orcinol and resorcinol, insoluble crosslinked polymers were also obtained.

It is natural fatty acids, being non-toxic.
It can be safely used in food (FDA, §172.862, 2000).
LD50: 74 g/kg (rat, oral).

FEMA (mg/kg): soft drinks 0.25 to 0.40, cold drinks 30, candy 3.5, baked food 25, seasoning 0.02.

Oleic acid is a monounsaturated fatty acid and a major component of membrane phospholipids that has been found in human plasma, cell membranes, and adipose tissue. It contributes approximately 17% of the total fatty acids esterified to phosphatidylcholine, the major phospholipid class in porcine platelets. Oleic acid inhibits collagen-stimulated platelet aggregation by approximately 90% when used at a concentration of 10 μg/ml. It also inhibits fMLF-induced neutrophil aggregation and degranulation by 55 and 68%, respectively, when used at a concentration of 5 μM, similar to arachidonic acid ( | 90010.1 | 10006607). Oleic acid (60 μM) induces release of intracellular calcium in human platelets. In vivo, oleic acid increases TNF-α, IL-8, IL-6, and IL-1β production, neutrophil accumulation, and apoptotic and necrotic cell death in mouse lung and has been used to induce lung injury in a mouse model of acute respiratory distress syndrome (ARDS).

Oleic acid, C17H33COOH, also known as red oil, elaine oil, and octadecenoic acid, is a yellowish unsaturated fatty acid with an aroma similar to lard. Oleic acid consists chiefly of (Ζ)-9-octadecenoic acid together with varying amounts of saturated and other unsaturated acids.  It is insoluble in water, but soluble in most organic solvents. Oleic acid is the main component in cooking and olive oils.It is used for making aluminum oleate, which thickens lubricating oil, and in the preparation of soaps and cosmetics.

Reported found in apple, banana, cranberry, guava, grapes, melon, papaya, ginger, hop oil, ginger, beef fat, beer, rum, whiskies, cider, sherry, tea, goat milk, butterfat, celery, cheese, blue cheese, munster cheese, other cheeses, cognac, country cured ham, pork fat, potato, raspberry oil, tomato, peanut oil, coconut meat, avocado, mushroom, fenugreek, tamarind, kelp, cardamom, rice, dill seed, sake, buckwheat, malt, wort, roasted chicory root and cape gooseberry.

Oleic Acid is an unsaturated fatty acid that functions as a lubricant, binder, and defoamer.

oleic acid is also known as omega-9. oleic acid can improve the skinpenetration abilities of a preparation’s other components. An essential fatty acid, it is obtained from various animal and vegetable fats and oils, and may be mildly irritating to the skin.

Oleic acid is a monounsaturated omega-9 fatty acid. Oleic Acid is obtained by the hydrolysis of various animal and vegetable fats and oils. Oleic Acid is used as an emulsifying or solubilizing agent i n aerosol products.

Oleic acid is obtained by the hydrolysis of various animal and vegetable fats or oils, such as olive oil, followed by separation of the liquid acids. It consists chiefly of (Ζ)-9-octadecenoic acid. Oleic acid that is to be used systemically should be prepared from edible sources.

ChEBI: Oleic acid is an octadec-9-enoic acid in which the double bond at C-9 has Z (cis) stereochemistry. It has a role as an EC 3.1.1.1 (carboxylesterase) inhibitor, an Escherichia coli metabolite, a plant metabolite, a Daphnia galeata metabolite, a solvent, an antioxidant and a mouse metabolite. It is a conjugate acid of an oleate. It derives from a hydride of a cis-octadec-9-ene.

Colorless to pale yellow liquid with a mild odor. Floats on water.

Keep cis-9-Octadecenoic acid well closed; protect cis-9-Octadecenoic acid from air and light. . May form peroxides upon exposure to air. This is taken to account for an explosion that occurred, by the mixing of the acid with aluminum, [J. Chem. Educ., 1956, 36, 308]. Water Insoluble.

cis-9-Octadecenoic acid is a carboxylic acid. Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acid dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in cis-9-Octadecenoic acid to corrode or dissolve iron, steel, and aluminum parts and containers. Carboxylic acids, like other acids, react with cyanide salts to generate gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. Carboxylic acids, especially in aqueous solution, also react with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Their reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Like other organic compounds, carboxylic acids can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. A wide variety of products is possible. Like other acids, carboxylic acids may initiate polymerization reactions; like other acids, they often catalyze (increase the rate of) chemical reactions.

Industrial use of compound involves no known hazards. Ingestion causes mild irritation of mouth and stomach. Contact with eyes or skin causes mild irritation.

cis-9-Octadecenoic acid is combustible.

Oleic acid is used as an emulsifying agent in foods and topical pharmaceutical formulations. It has also been used as a penetration enhancer in transdermal formulations,to improve the bioavailability of poorly water-soluble drugs in tablet formulations, and as part of a vehicle in soft gelatin capsules, in topical microemulsion formulations,in oral self-emulsifying drug delivery systems,in oral mucoadhesive patches,and in a metered dose inhaler.Oleic acid was shown to be an important factor in the hypoglycemic effect produced by multiple emulsions containing insulin intended for intestinal delivery of insulin.
The phase behavior of sonicated dispersions of oleic acid has been described,and mechanisms for the topical penetrationenhancing actions of oleic acid have been presented.
Oleic acid has been reported to act as an ileal ‘brake’ that slows down the transit of luminal contents through the distal portion of the small bowel.
Oleic acid labeled with 131I and 3H is used in medical imaging.

Oleic acid is a colourless, odourless fatty acid that blocks the glucose production and food intake when administered intracerebroventricularly.

Poison by intravenous route. Mildly toxic by ingestion. Mutation data reported. A human skin and eye irritant. Questionable carcinogen with experimental tumorigenic data. Combustible when exposed to heat or flame. To fight fire, use CO2, dry chemical. The peroxidzed acid explodes on contact with aluminum. Potentially dangerous reaction with perchloric acid + heat. When heated to decomposition it emits acrid smoke and irritating fumes.

Oleic acid is used in oral and topical pharmaceutical formulations.
In vitro tests have shown that oleic acid causes rupture of red blood cells (hemolysis), and intravenous injection or ingestion of a large quantity of oleic acid can therefore be harmful. The effects of oleic acid on alveolar and buccal epithelial cells in vitro have also been studied; the in vitro and in vivo effects of oleic acid on rat skin have been reported. Oleic acid is a moderate skin irritant; it should not be used in eye preparations.
An acceptable daily intake for the calcium, sodium, and potassium salts of oleic acid was not specified by the WHO since the total daily intake of these materials in foods was such that they did not pose a hazard to health.
LD₅₀ (mouse, IV): 0.23 g/kg
LD₅₀ (rat, IV): 2.4 mg/kg
LD₅₀ (rat, oral): 74 g/kg

Some recent studies suggested that oleic acid may decrease the incidence of mammary gland tumors of some rodent species. In a reviewof several fatty acids, Ip concludes that there is little evidence for the protective effect of oleic acid on the development of cancer.

On exposure to air, oleic acid gradually absorbs oxygen, darkens in color, and develops a more pronounced odor. At atmospheric pressure, it decomposes when heated at 80–100°C.
Oleic acid should be stored in a well-filled, well-closed container, protected from light, in a cool, dry place.

Purify the acid by fractional crystallisation from its melt, followed by molecular distillation at 10 -3mm, or by conversion to its methyl ester, the free acid can be crystallised from acetone at -40o to -45o (12mL/g). For purification by the use of lead and lithium salts, see Keffler and McLean [J Soc Chem Ind (London) 54 176T 1935]. Purification based on direct crystallisation from acetone is described by Brown and Shinowara [J Am Chem Soc 59 6 1937, pK White J Am Chem Soc 72 1857 1950]. [Beilstein 2 H 463, 2 I 198, 2 II 429, 2 III 1387, 2 IV 1641.]

Incompatible with aluminum, calcium, heavy metals, iodine solutions, perchloric acid, and oxidizing agents. Oleic acid reacts with alkalis to form soaps.

GRAS listed. Included in the FDA Inactive Ingredients Database (inhalation and nasal aerosols, tablets, topical and transdermal preparations). Included in nonparenteral medicines (metered dose inhalers; oral capsules; oral prolonged release granules; topical creams and gels) licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.