Oleic acid
[CAS# 112-80-1]

Identification

• Classification: Biochemical >> Fatty drug
• Name: Oleic acid
• Synonyms: Octadecenoic acid; cis-9-Octadecenoic acid
• Molecular Formula: C₁₈H₃₄O₂
• Molecular Weight: 282.46
• CAS Registry Number: 112-80-1
• EC Number: 204-007-1
• FEMA: 2815
• SMILES: CCCCCCCC/C=CCCCCCCCC(=O)O

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*, 0.89 g/mL (Expl.)
• Melting point: 13 - 14 °C (Expl.)
• Boiling point: 360.0 °C 760 mmHg (Calc.)^*, 467.8 - 469.3 °C (Expl.)
• Flash point: 270.1±14.4 °C (Calc.)^*, 189 º°C (Expl.)
• Solubility: water: negligible (Expl.)
• Index of refraction: 1.467 (Calc.)^*, 1.459 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319
• Safety Statements: P264-P264+P265-P280-P302+P352-P305+P351+P338-P321-P332+P317-P337+P317-P362+P364

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Eye irritation	Eye Irrit.	2A	H319
Flammable liquids	Flam. Liq.	3	H226
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412

Discovery and Applications

Oleic acid is a monounsaturated fatty acid with the chemical formula C₁₈H₃₄O₂. It is one of the most abundant fatty acids in nature and is found in significant quantities in animal fats and vegetable oils, particularly olive oil, from which its name is derived. The structure of oleic acid is characterized by a single cis double bond located between the ninth and tenth carbon atoms from the methyl end of the carbon chain, making it a cis-9-octadecenoic acid. This double bond contributes to the fluidity and low melting point of fats that contain it.

The discovery and identification of oleic acid date back to the early developments in organic chemistry and lipid analysis in the 19th century. Chevreul, a French chemist, was among the first to isolate and characterize fatty acids from natural fats, including oleic acid, during his systematic study of saponification products. By analyzing the reaction of fats with alkali to form soap and glycerol, he laid the groundwork for distinguishing between saturated and unsaturated fatty acids. Oleic acid was recognized for its unique physical properties, including its liquid state at room temperature and its ability to undergo oxidation and addition reactions due to the presence of a double bond.

Oleic acid has extensive applications across various industrial and biomedical fields. In the food industry, it is a major component of edible oils, particularly olive oil, canola oil, and high-oleic sunflower oil. It contributes to the oxidative stability and shelf life of these oils and is associated with favorable health profiles. Dietary intake of oleic acid is linked to improved lipid profiles, including reduced low-density lipoprotein (LDL) cholesterol and increased high-density lipoprotein (HDL) cholesterol, which has led to its inclusion in dietary guidelines promoting monounsaturated fats.

In the chemical industry, oleic acid is used as a raw material for the production of a wide range of derivatives, including esters, amides, and soaps. These derivatives serve functions in lubricants, surfactants, emulsifiers, plasticizers, and cosmetics. Oleic acid is also used as an intermediate in the manufacture of biodegradable detergents and is a key ingredient in pharmaceutical formulations, where it serves as a penetration enhancer for transdermal drug delivery systems.

Oleic acid is also utilized in the production of metallic oleates, such as cobalt or manganese oleate, which function as catalysts or driers in paints and varnishes. In the rubber industry, oleic acid acts as a softening agent and plasticizer. In textile and leather processing, it is employed in emulsification processes and as a dispersing agent.

From a biomedical perspective, oleic acid has been the subject of numerous studies investigating its roles in cell signaling, membrane structure, and inflammation. It is a major component of phospholipids in cell membranes and affects membrane fluidity and function. Studies have indicated that oleic acid may have anti-inflammatory properties and may help modulate immune responses and metabolic pathways, although these effects depend on the context and concentration.

Oleic acid is biodegradable and exhibits low toxicity, which supports its use in eco-friendly formulations and sustainable industrial practices. Its widespread availability from renewable resources such as vegetable oils further contributes to its environmental and economic advantages. Continued research into oleic acid and its derivatives focuses on developing novel applications in materials science, biomedicine, and green chemistry.

References

Ruíz‑Gutiérrez V, Muriana FJ, Guerrero A, Cert AM, Villar J (1996) Plasma lipids, erythrocyte membrane lipids and blood pressure of hypertensive women after ingestion of dietary oleic acid from two different sources J Hypertens 14(12):1483–1490 DOI: 10.1097/00004872-199612000-00016

Ursin VM (2003) Modification of plant lipids for human health development of functional land‑based omega‑3 fatty acids J Nutr 133(12):4271–4274 DOI: 10.1093/jn/133.12.4271

Burnett CL, Bergfeld WF, Belsito DV et al. (2012) Final report of the Cosmetic Ingredient Review Expert Panel on the safety assessment of cocamidopropyl betaine (CAPB) Int J Toxicol 31:77S–111S DOI: 10.1177/1091581812447202