1-Methylnaphthalene is an aromatic hydrocarbon. It has a cetane number of zero, and was previously used as the lower reference for cetane number. However, due to the expense and handling difficulty of 1-Methylnaphthalene, it was replaced in this capacity by isocetane, with a CN of 15.
Naphthalene, also known as naphthalin, or antimite and not to be confused with naphtha, is a crystalline, aromatic, white, solid hydrocarbon with formula c10h8 and the structure of two fused benzene rings. It is best known as the traditional, primary ingredient of mothballs.