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Synonyms:cis-9-Octadecenoic acid | |||||||||
112-80-1
bosschem
112-80-1
Oleic acid, also known as oleic acid (chemical name cis-9-octadecenoic acid), is a monounsaturated Omega-9 fatty acid and one of the most widely found fatty acids in nature. It is widely present in various animal and vegetable oils. Its chemical formula is usually written as:
C18H34O2 (CAS No.: 112-80-1, molecular weight approximately 282.46)
Oleic acid is a colorless to pale yellow oily liquid at room temperature with a lard-like odor. Its color gradually darkens upon prolonged exposure to air. It has a density of approximately 0.89–0.90 g/cm³, a melting point of approximately 13–14°C, a boiling point of approximately 286°C (13.3 kPa), a flash point of approximately 189°C (closed cup), and a refractive index of approximately 1.46. Oleic acid is sparingly soluble in water but miscible with organic solvents such as ethanol, ether, chloroform, and light gasoline. It is an excellent solvent for oils, fatty acids, and oil-soluble substances. The English name "oleic" originates from the Latin word "oleum" (oil), which is related to "olive." Edible oils such as olive oil and tea oil are rich in oleic acid.
From a molecular structure perspective, oleic acid consists of a long chain of 18 carbon atoms and a cis double bond at position 9 (CH3(CH2)7CH=CH(CH2)7COOH), classifying it as a monounsaturated fatty acid. The carboxyl group imparts its chemical activity, including saponification and esterification, while the cis double bond provides good fluidity and chemical reactivity—this combination of "carboxyl group activity + double bond activity" allows it to be saponified into soap, esterified into ester, and oxidized into a diacid (used in engineering plastics). This forms the structural basis for the widespread application of oleic acid in the daily chemical, lubricant, and coating industries. Industrial-grade oleic acid typically contains 7%–12% saturated fatty acids (palmitic acid, stearic acid) and a small amount of linoleic acid.
Chemically, oleic acid is easily oxidized and rancid in air, darkening in color, and must be stored in a sealed container away from light. It possesses the general properties of carboxylic acids, can be neutralized with alkalis to form soap, can be esterified with alcohols, and its double bonds can be hydrogenated, oxidized, or halogenated. It should be stored in a sealed container away from light, fire, and oxidizing agents.
Industrial-grade oleic acid refers to products primarily intended for industrial production, and is generally graded based on indicators such as acid value, iodine value, and saponification value. Compared to reagent-grade and other specifications, industrial-grade products place greater emphasis on the following indicators:
acid value
Acid value (generally 190~210) reflects the content and purity of free fatty acids and is a core indicator for measuring product quality.
iodine value
Iodine value (generally 80~100) reflects the degree of unsaturation and directly affects the downstream reaction activity and application, and must meet specifications.
Saponification value
The saponification value reflects the fatty acid composition and average molecular weight, and is an important indicator for quality control.
Freezing point
Freezing point reflects the content of saturated fatty acids and affects low-temperature fluidity; therefore, it must meet specifications.
Moisture
Excessive moisture content can affect saponification, esterification, and other reactions, as well as storage stability, and must be kept at a low level.
1. Soap and surfactant raw materials (core application)
Oleic acid is an important raw material for manufacturing soap, high-grade soap and synthetic detergents. Sodium oleate has good detergency and emulsifying abilities and is used as a surfactant and emulsifier, serving the daily chemical industry extensively.
2. Lubricants and metalworking fluids
Oleic acid and its derivatives are used as lubricating components in lubricating oils, cutting oils, and metalworking fluids to help improve lubrication and cooling performance. They are also used as thickeners for lubricating oils and raw materials for rust inhibitors, and are applied in machining and equipment lubrication.
3. Paint drying agents and coatings
Lead, manganese, and cobalt salts of oleic acid are important components of paint drying agents, which can accelerate the drying and film formation of paint. Oleic acid is also used in the formulation of alkyd resins and inks, serving the coatings and printing industries.
4. Textile auxiliaries
Oleic acid is used as a softening and lining agent in the textile industry. Aluminum oleate can be used as a waterproofing agent for fabrics, helping to improve the softness and processing properties of fibers, and is applied in the textile printing and dyeing industry.
5. Mineral processing flotation collectors
Oleic acid is a commonly used oil collector in metal beneficiation, which helps mineral particles separate and enrich from the slurry and is applied in the flotation process of non-ferrous metal ores.
6. Printed materials and ink (indirect contact)
Oleic acid is used in the formulation of printing inks and as a paint drier (lead, manganese, and cobalt salts of oleic acid). The production chain of printed materials and paints may indirectly involve it.
7. Plasticizers and Plastic Additives
Oleic acid is used as a plasticizer and lubricant for plastics. Oleic acid ester derivatives are important components of environmentally friendly plasticizers and are also used as processing aids for plastics such as PVC.
8. Other Applications
The application areas, including engineering plastics (nylon 8, nylon 9) and raw materials for synthetic fibers, as well as fishing net preservatives (copper salts), are still expanding.
Oleic acid (cis-9-octadecenoic acid) is a colorless to pale yellow monounsaturated Omega-9 fatty acid. It is one of the most widely found fatty acids in nature, and is abundant in animal and vegetable oils such as olive oil and tea oil. In daily life, we come into contact with it through the supply chain of edible oils, soaps and detergents, cosmetics, plastic products, printing inks, and textile fabrics. In the industrial sector, industrial-grade oleic acid is widely used as a raw material (core) for soaps and surfactants, a component of lubricants and metalworking fluids, a paint drier and coating raw material, a textile softener and softener, a flotation collector in mineral processing, a plasticizer, and a raw material for engineering plastics. It is an important fatty acid that connects "daily use" with "daily chemicals, lubricants, coatings, and mineral processing."
