Stearyl caprylate is a chemical compound, the ester resulting from the reaction of stearyl alcohol with caprylyl acid. It belongs to the general class of chemicals called stearyl alkanoates. Soluble in ethanol, mineral oil and other organic solvents but not soluble in water.

The name describes the structure of the molecule.

 "Stearyl" refers to the stearil group, which is a long-chain alkyl group derived from stearic acid. "Caprylate" refers to the caprylate group, which is derived from caprylic acid, a type of medium-chain fatty acid.

The synthesis process takes place in several stages:

• Step 1: Preparation of raw materials: stearilic alcohol and caprylic acid.
• Step 2: Esterification. Stearyl alcohol and caprylic acid react together in the presence of an acid catalyst to form the ester, Stearyl caprylate. This reaction is known as esterification.
• Step 3: Purification. The resulting Stearyl caprylate is purified to remove unreacted stearyl alcohol and caprylic acid by various techniques, such as distillation and filtration.
• Step 4: Drying. Purified stearyl caprylate is then dried to remove any residual solvent.

What it is used for and where it is used

Cosmetics

• 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.
• 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.

Typical optimal commercial product characteristics Octadecyl octanoate

• Molecular Formula  C₂₆H₅₂O₂
• Molecular Weight     396.7
• Exact Mass   396.39700
• CAS  18312-31-7
• UNII    06TS6O9194
• EC Number   242-200-2
• DSSTox Substance ID  DTXSID5051816
• IUPAC  octadecyl octanoate
• InChI=1S/C26H52O2/c1-3-5-7-9-10-11-12-13-14-15-16-17-18-19-21-23-25-28-26(27)24-22-20-8-6-4-2/h3-25H2,1-2H3
• InChl Key      VNLRTFSQCPNNIM-UHFFFAOYSA-N
• SMILES   CCCCCCCCCCCCCCCCCCOC(=O)CCCCCCC
• MDL number  
• PubChem Substance ID    
• SCHEMBL  180243

Synonyms:

• Octanoic acid, octadecyl ester
• Octadecyl octanoate