Palmitic acid, or hexadecanoic acid in IUPAC nomenclature, is the most common fatty acid (saturated) found in animals, plants and microorganisms. Its chemical formula is CH3(CH2)14COOH. As its name indicates, it is a major component of the oil from palm trees (palm oil), but can also be found in meats, cheeses, butter, and dairy products. Palmitate is a term for the salts and esters of palmitic acid. The palmitate anion is the observed form of palmitic acid at physiologic pH (7.4). Aluminium salts of palmitic acid and naphthenic acid were combined during World War II to produce napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.
Palmitic acid was discovered by Edmond Frémy in 1840, in saponified palm oil. This remains the primary industrial route for its production, with the triglycerides (fats) in palm oil being hydrolysed by high temperature water (above 200 °C or 390 °F) and the resulting mixture fractionally distilled to give the pure product.
Palmitic acid is naturally produced by a wide range of other plants and organisms, typically at low levels. It is naturally present in butter, cheese, milk and meat also as well as cocoa butter, soybean oil and sunflower oil. The cetyl ester of palmitic acid (cetyl palmitate) occurs in spermaceti.
Palmitic acid is used to produce soaps, cosmetics, and release agents. These applications utilize sodium palmitate, which is commonly obtained by saponification of palm oil. To this end, palm oil, rendered from palm tree (species Elaeis Guineensis), is treated with sodium hydroxide (in the form of caustic soda or lye), which causes hydrolysis of the ester groups. This procedure affords glycerol and sodium palmitate.
Because it is inexpensive and adds texture to processed foods (convenience food), palmitic acid and its sodium salt find wide use including foodstuffs. Sodium palmitate is permitted as a natural additive in organic products.The aluminium salt is used as a thickening agent of napalm used in military actions. Hydrogenation of palmitic acid yields cetyl alcohol, which is used to produce detergents and cosmetics.
Recently, a long-acting antipsychotic medication, paliperidone palmitate, used in the treatment of schizophrenia, has been synthesized using the oily palmitate ester as a long-acting release carrier medium when injected intramuscularly. The underlying method of drug delivery is similar to that used with decanoic acid to deliver long-acting depot medication, in particular, neuroleptics such as haloperidol decanoate.