Oleic anhydride
[CAS 24909-72-6]

Identification

• Classification: Chemical reagent >> Organic reagent >> Carboxylic anhydride
• Name: Oleic anhydride
• Synonyms: [(Z)-octadec-9-enoyl] (Z)-octadec-9-enoate
• Molecular Formula: C₃₆H₆₆O₃
• Molecular Weight: 546.91
• CAS Registry Number: 24909-72-6
• EC Number: 246-522-4
• SMILES: CCCCCCCC/C=CCCCCCCCC(=O)OC(=O)CCCCCCC/C=CCCCCCCCC

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*
• Melting point: 22 - 24 °C (Expl.)
• Boiling point: 609.4±44.0 °C 760 mmHg (Calc.)^*, 384 - 404.3 °C (Expl.)
• Flash point: 275.4±25.6 °C (Calc.)^*, 109 °C (Expl.)
• Index of refraction: 1.471 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

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

Discovery and Applications

Oleic anhydride is a long-chain fatty acid anhydride derived from oleic acid, a monounsaturated C18 fatty acid widely distributed in natural fats and oils. The compound belongs to the broader class of carboxylic acid anhydrides, which are characterized by the presence of two acyl groups linked through an oxygen atom. In the case of oleic anhydride, the acyl groups are derived from oleic acid, resulting in a highly hydrophobic, lipid-like structure.

The development and use of fatty acid derivatives such as oleic anhydride are closely connected to the evolution of lipid chemistry and industrial organic synthesis. Carboxylic acid anhydrides have long been recognized as reactive acylating agents, and the preparation of symmetrical anhydrides from fatty acids provided a route to more reactive intermediates for further chemical transformation. Oleic acid, being one of the most abundant unsaturated fatty acids in nature, has served as a key starting material for a wide range of oleochemical products, including esters, amides, and polymer precursors.

Oleic anhydride is typically formed through dehydration of two molecules of oleic acid under conditions that promote condensation and removal of water. This transformation produces a dimeric structure in which two oleoyl groups are linked by an oxygen bridge. The resulting anhydride retains the long hydrophobic hydrocarbon chains and the cis-double bond characteristic of oleic acid, while introducing a highly reactive acylating functional group.

One of the primary applications of oleic anhydride is as an acylating agent in organic synthesis. Carboxylic acid anhydrides are more reactive than their corresponding acids and can readily react with nucleophiles such as alcohols and amines. In this context, oleic anhydride can be used to introduce oleoyl groups into target molecules, forming esters and amides. These reactions are important in the preparation of surfactants, emulsifiers, and other surface-active materials derived from fatty acids.

In polymer and materials chemistry, fatty acid anhydrides such as oleic anhydride have been used as intermediates for modifying polymer surfaces and introducing hydrophobic functionality. The long alkyl chains impart flexibility and water repellency, making them useful in coatings, plasticizers, and surface treatment applications. The unsaturation present in oleic-derived structures can also provide sites for further chemical modification or crosslinking.

Oleic anhydride is also relevant in the field of oleochemistry, which focuses on the industrial utilization of natural fats and oils. Fatty acid derivatives are widely used as renewable feedstocks for the production of chemicals traditionally derived from petrochemical sources. The conversion of oleic acid into more reactive derivatives such as anhydrides expands its utility in synthetic pathways, enabling the production of higher-value specialty chemicals.

Another area of application involves the preparation of amphiphilic molecules. Because oleic anhydride contains long hydrophobic chains, its reaction with hydrophilic nucleophiles can produce compounds with both polar and nonpolar regions. Such amphiphilic products are important in the formulation of emulsifiers, detergents, and dispersing agents used in industrial and consumer applications.

From a physicochemical perspective, oleic anhydride is expected to exhibit strong hydrophobicity and low polarity due to its long hydrocarbon chains. The anhydride functional group is reactive toward hydrolysis, particularly in the presence of water, regenerating oleic acid under mild conditions. This reactivity is characteristic of carboxylic acid anhydrides and is a key factor in their use as transient acylating agents.

Overall, oleic anhydride is a fatty acid-derived carboxylic anhydride that serves as a reactive intermediate in organic synthesis and oleochemical processing. Its importance lies in its ability to transfer oleoyl groups to nucleophilic substrates and to serve as a building block for surfactants, coatings, and other lipid-derived materials. Through its role in fatty acid chemistry, it contributes to the broader utilization of renewable lipid resources in chemical manufacturing.

References

2025. Functionalization of Lignin by Esterification. Handbook of Lignin.
DOI: 10.1007/978-981-96-7633-0_26

2024. Remission of iron overload in adipose tissue of obese mice by fatty acid-modified polyoxovanadates. Rare Metals.
DOI: 10.1007/s12598-024-02925-0

2024. Sub-nanosized vanadate hybrid clusters maintain glucose homeostasis and restore treatment response in inflammatory disease in obese mice. Nano Research.
DOI: 10.1007/s12274-023-6366-7