What is a fatty acid?
Fatty acid
Fatty acids are mainly used in the production of soap, both for cosmetic purposes and, in the case of metallic soaps, as lubricants.  Fatty acids are also converted, via their methyl esters, to fatty alcohols and fatty amines, which are precursors to surfactants, detergents, and lubricants.[26] Other applications include their use as  emulsifiers, texturizing agents, wetting agents, anti-foam agents, or stabilizing agents.[31]