What Is the Molecular Formula of Caprylic Acid?

Caprylic acid has the molecular formula C8H16O2. It is an eight-carbon, saturated fatty acid commonly found in humans, especially human breast milk.

Name

The systematic name for caprylic acid is "octanoic acid." The "octo-" prefix refers to the eight carbon atoms. "Octo-" becomes "octane-" because the carbon chain is saturated. In organic chemistry, saturated hydrocarbons are called "alkanes" and it is standard naming convention to append the prefix with "-ane" to reflect this.
"Octane-" becomes "octanol-" because there is a hydroxyl (-OH) or "alcohol" group on the end of the chain. Finally, "octanol-" becomes "octanoic acid" because the hydroxyl group is part of a larger carboxyl group.

Structure

The compound features eight carbon atoms connected in tandem by covalent single bonds and flanked by covalently bonded hydrogen atoms. In organic chemistry, such chains of single-bonded carbons are known as "saturated" hydrocarbons. However, in caprylic acid, one of the terminal carbon atoms is double bonded to an oxygen atom and single-bonded to a hydroxl (-OH) group. This carbon-oxygen-hydroxl configuration is known collectively as a "carboxyl group." The special way in which the atomic orbitals of the two oxygen atoms and the carbon atom align allows the hydrogen to readily dissociate from the carboxyl group, in effect making the compound a weak acid.

Function

While the hydrocarbon end of caprylic acid makes the molecule largely non-polar and minimally soluble in water, it allows the compound to be soluble in fats, oils and lipids. This non-repulsion to lipids allows the molecule to pass through the lipid-based cell membrane of various protozoa as well as the lipid-based membranes of fungi and bacteria intra-cellular structures. In the case of Staphylococcus aureus, the bacteria that causes 80% of serious Staph infections in humans, caprylic acid seems to be able to enter crucial structures within the cell, which the carboxyl group then destroys, thus killing the entire single-celled organism.

Medical Applications

Many natural medicine advocates (who consider caprylic acid "natural" because it is found in coconuts and human breast milk) believe that the compound is effective at fighting the dangerous Candida genus of yeast. However, the efficacy of this application has yet to be corroborated by scientific study.

Industrial Applications

The long saturated hydrocarbon chain in caprylic acid minimizes attractive forces between molecules, making it relatively volatile (for example, it easily turns from liquid to gas). That, combined with its distinct, slightly rancid smell, has made it a fairly common ingredient in perfumes. Caprylic acid is also used in very small concentrations in food manufacturing, although this is more for its anti-microbial properties. The terminal carboxyl group, in the presence of the carboxyl group of another molecule, can undergo dehydration to form a ester-type compounds. In this sense, caprylic acid can potentially be useful in the production of certain polymers.