Ethyl octanoate, also known as ethyl caprylate, is a

fatty acid ester Fatty acid esters (FAEs) are a type of ester that result from the combination of a fatty acid with an alcohol. When the alcohol component is glycerol, the fatty acid esters produced can be monoglycerides, diglycerides, or triglycerides. Dietary fa ...

formed from

caprylic acid Caprylic acid (), also known under the systematic name octanoic acid or C8 Acid, is a saturated fatty acid, medium-chain fatty acid (MCFA). It has the structural formula , and is a colorless oily liquid that is minimally soluble in water with ...

and

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a h ...

. A colorless liquid at room temperature, it has the semi-developed formula of CH₃(CH₂)₆COOCH₂CH₃, and is used in food industries as a flavoring and in the perfume industry as a scent additive. It is present in many fruits and alcoholic beverages, and has a strong odor of fruit and flowers. It is used in the creation of synthetic fruity scents.

Synthesis

Ethyl octanoate can be synthesized from caprylic acid and ethanol via a classic

Fischer–Speier esterification Fischer esterification or Fischer–Speier esterification is a special type of esterification by refluxing a carboxylic acid and an alcohol in the presence of an acid catalyst. The reaction was first described by Emil Fischer and Arthur Speier in ...

. CH3(CH2)6COOH + CH3CH2OH <=> CH3(CH2)6COOCH2CH3 + H2O Equilibrium can be shifted towards the right side of the equation through removal of water.

Uses

Ethyl octanoate does not see widespread use due to the greater availability of reasonably similar esters such as

ethyl acetate Ethyl acetate ( systematically ethyl ethanoate, commonly abbreviated EtOAc, ETAC or EA) is the organic compound with the formula , simplified to . This colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues ...

. However, there are certain applications where it fills a niche. Ethyl octanoate has a strong odor of fruit and flowers and a taste of apricot, and as such it can be used as a flavoring or to create scents. It sees some use as a cleaning agent. Ethyl octanoate also sees incidental use. It is found in some

wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are ...

s, where overall ester concentration and composition is considered important to the flavor and aroma profile.Marais, J. et al. (2003) http://www.sawislibrary.co.za/dbtextimages/MaraisJ10.pdf "Effect of Different Wine-Making Techniques on the Composition and Quality of Pinotage Wine. I. Low-Temperature Skin Contact Prior to Fermentation"

Safety

Like many esters, ethyl octanoate is not considered to be toxic. LD50 in rats is 25.96 g/kg. Though it has a low

explosive limit Mixtures of dispersed combustible materials (such as gaseous or vaporised fuels, and some dusts) and oxygen in the air will burn only if the fuel concentration lies within well-defined lower and upper bounds determined experimentally, referred to a ...

of only 0.67 vol%, it is also weakly volatile, with a vapor pressure of only 0.2 mbar at room temperature. Ethyl octanoate is combustible.

References

{{Esters Octanoate esters Ethyl esters