Decyl Oleate is a chemical compound produced by the reaction of decanol and oleic acid.

The name describes the structure of the molecule:

• Decyl is a decyl functional group with chemical formula -C₁₀H₂₁. It is derived from decane by removal of a hydrogen atom.
• Oleate is an oleate ion, derived from oleic acid, a type of monounsaturated fatty acid. Oleic acid has the chemical formula C₁₈H₃₄O₂  and, when it loses a hydrogen ion (H+), it becomes an oleate ion (C₁₈H₃₃O^-2).

The synthesis process takes place in different steps:

• Production of decyl alcohol and oleic acid. The first step concerns the production of the two components that will make up the ester: decyl alcohol and oleic acid. Decyl alcohol can be produced by the hydrogenation of decyl aldehyde, which is derived from the hydroformylation of 1-nonene. Oleic acid can be obtained from natural sources such as vegetable oils, or it can be synthesised from stearic acid.
• Esterification. After production, decyl alcohol and oleic acid can be fed into a reaction process to form the ester. This is done by heating the two components in the presence of a catalyst such as sulphuric acid to accelerate the reaction. The reaction produces decyl oleate and water.
• Purification. The decyl oleate thus obtained is purified to remove unreacted decyl alcohol or oleic acid, the catalyst and any other impurities. This is generally done by a process such as distillation or filtration.

It appears as a yellow liquid.

What it is used for and where

Cosmetics

It is used by the cosmetic industry as an emollient in moisturizers, creams, sunscreens, lip balms, anti-aging serums and various makeup products and has become a typical component in beauty and body care products as it makes the skin smooth and pleasant to the touch.

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Skin conditioning agent - Emollient. Emollients have the characteristic of enhancing the skin barrier through a source of exogenous lipids that adhere to the skin, improving barrier properties by filling gaps in intercorneocyte clusters to improve hydration while protecting against inflammation. In practice, they have the ability to create a barrier that prevents transepidermal water loss.  Emollients are described as degreasing or refreshing additives that improve the lipid content of the upper layers of the skin by preventing degreasing and drying of the skin. The problem with emollients is that many have a strong lipophilic character and are identified as occlusive ingredients; they are oily and fatty materials that remain on the skin surface and reduce transepidermal water loss. In cosmetics, emollients and moisturisers are often considered synonymous with humectants and occlusives.

Regarding skin permeation, this study found that microemulsions prepared using the most lipophilic lipids (decyl oleate or cetyl stearyl isonononanoate) showed the lowest stability (1). 

Medical

Solid lipid nanoparticle (SLN) has been considered as a novel topical delivery system for pharmaceutical and cosmetic active ingredients, and this study developed delivery systems for organic and inorganic sunscreens based on a matrix composed of carnauba wax and decyl oleate (2).

Other uses

It is an excellent lubricant as it has a low viscosity.

The most relevant studies on this chemical compound have been selected with a summary of their contents:

Decyl Oleate studies

• Molecular Formula: C₂₈H₅₄O₂
• Molecular Weight: 422.7
• CAS: 3687-46-5
• UNII ZGR06DO97T
• EC Number: 222-981-6
• DSSTox Substance ID: DTXSID1029259

Synonyms: 

• Decyloleate
• SCHEMBL15078
• 9-Octadecenoic acid(9Z)-, decyl ester
• Oleic acid, decyl ester
• Tegosoft DO
• Ceraphyl 140

References________________________________________________________________________

(1) Montenegro L, Carbone C, Puglisi G. Vehicle effects on in vitro release and skin permeation of octylmethoxycinnamate from microemulsions. Int J Pharm. 2011 Feb 28;405(1-2):162-8. doi: 10.1016/j.ijpharm.2010.11.036.

(2) Nesseem D. Formulation of sunscreens with enhancement sun protection factor response based on solid lipid nanoparticles. Int J Cosmet Sci. 2011 Feb;33(1):70-9. doi: 10.1111/j.1468-2494.2010.00598.x.