A shortened name for a group chemicals that act as synthetic tanning agents. Syntans were first made in 1912. By 1930s, they replaced vegetable tannins as the predominate tanning agents, although they are often used now in conjunction with vegetable tannins. Examples of simple synthetic tannins are Formaldehyde, Glutaraldehyde, and glycolic acid. More complex syntans are made by treating aromatic compounds, such as cresols, phenols, naphthalenes, with formaldehyde and Sulfuric acid.