Oleic acid, monoester with decaglycerol
[CAS 79665-93-3]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: Oleic acid, monoester with decaglycerol
• Synonyms: 3-[3-[3-[3-[3-[3-[3-[3-[3-(2,3-dihydroxypropoxy)-2-hydroxypropoxy]-2-hydroxypropoxy]-2-hydroxypropoxy]-2-hydroxypropoxy]-2-hydroxypropoxy]-2-hydroxypropoxy]-2-hydroxypropoxy]-2-hydroxypropoxy]propane-1,2-diol;(Z)-octadec-9-enoic acid
• Molecular Formula: C₄₈H₉₆O₂₃
• Molecular Weight: 1041.26
• CAS Registry Number: 79665-93-3
• EC Number: 279-230-0
• SMILES: CCCCCCCC/C=CCCCCCCCC(=O)O.C(C(COCC(COCC(COCC(COCC(COCC(COCC(COCC(COCC(COCC(CO)O)O)O)O)O)O)O)O)O)O)O

chemBlink Chemical Story

Oil and water do not need to become chemically identical to stay together. They need a mediator that is comfortable with both. Oleic acid, monoester with decaglycerol, commonly known as polyglyceryl-10 oleate, is a nonionic surfactant built for exactly that task.

Its architecture can be read almost like a diagram of an emulsion. Oleic acid contributes a long unsaturated C18 hydrocarbon chain that prefers oils. The decaglycerol portion contributes many hydroxyl groups and ether linkages that interact strongly with water. Joining the two produces an amphiphile: one end is lipophilic, the other strongly hydrophilic. At an oil-water boundary, the oleate chain can point into the oil while the polyglycerol head remains in the aqueous phase, lowering interfacial tension and helping small droplets resist merging back together.

Polyglycerol fatty acid esters are interesting because chemists can tune them without relying on a single fixed molecular design. Changing the average length of the polyglycerol head, the fatty acid tail, or the degree of esterification changes hydrophilic-lipophilic balance, self-assembly, and emulsion type. Reviews of this family describe uses ranging from food emulsification and fat crystallization control to cosmetics, cleansing systems, and pharmaceutical formulations. Their extensive hydrogen bonding with water also makes their behavior less sensitive than some nonionic surfactants to salts, polyols, and temperature.

Polyglyceryl-10 oleate occupies the relatively hydrophilic side of this design space. It is used in cosmetic and personal-care formulations where oils, fragrances, or oily soils need to be dispersed in water. In cleansing oils and related systems, the same amphiphilic logic works in reverse during rinsing: the formulation can begin oil-rich enough to dissolve makeup and sebum, then emulsify when water is added so the oily phase can be washed away.

The name sounds as if every commercial molecule must contain exactly ten glycerol units and exactly one oleate group. In practice, polyglycerol raw materials are distributions of oligomers and esterification produces a related mixture. The number in the INCI-style name therefore describes an average structural family rather than a single perfectly monodisperse molecule. That distinction matters when interpreting formulas, molecular weights, and structure drawings.

What makes polyglyceryl-10 oleate memorable is therefore not merely that it is an emulsifier. It shows how formulators design the boundary between oil and water. A flexible, highly hydrated polyglycerol head is paired with an oil-loving fatty chain, creating a molecular translator that allows two normally separating liquids to coexist in a useful product.

References:
1. Higuchi T. Emulsification and solubilization characteristics of polyglycerol fatty acid esters. Oleoscience. 2019, 19, 405-410. DOI: 10.5650/oleoscience.19.405.
2. Recent Advances in the Properties and Applications of Polyglycerol Fatty Acid Esters. Polymers. 2025, 17, 879.
3. Matsushita K., Shioyama Y. Polyglycerol Fatty Acid Esters and Their Uses. Journal of Japan Oil Chemists' Society. 1986, 35, 71-79. DOI: 10.5650/jos1956.35.71.
4. FDA/Cosmetic ingredient identity resources for Polyglyceryl-10 Oleate, CAS 79665-93-3.

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