Naphthenic acid by a general formula CH O, where "n" indicates the carbon number and "z" specifies a homologous series. The "z" is equal to 0 for saturated, acyclic acids and increases to 2 in monocyclic naphthenic acids, to 4 in bicyclic naphthenic acids, to 6 in tricyclic acids, and to 8 in tetracyclic acids. Salts of naphthenic acids, called naphthenates, are widely used as hydrophobic sources of metal ions in diverse applications.Aluminium salts of naphthenic acid and palmitic acid were combined during World War II to produce napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.
Naphthenic acid to oil refinery equipment; the phenomenon of "naphthenic acid corrosion" (NAC) has therefore been well researched. Crude oils with a high content of naphthenic acids are often referred to as high total acid number (TAN) crude oils or high acid crude oil (HAC). Naphthenic acids are the major contaminant in water produced from the extraction of oil from Athabasca oil sands (AOS). Naphthenic acids have both acute and chronic toxicity to fish and other organisms. In their oft-cited article published in "Toxicological Sciences" Rogers et al. stated that "naphthenic acids are the most significant environmental contaminants resulting from petroleum extraction