In the late 1980s, due to market demand, many manufacturers made comprehensive use of washing oil, and successively produced industrial methyl naphthalene fractions. The sum of the content of β-methylnaphthalene and α-methylnaphthalene in this fraction is about 70%. Because it also contains impurities such as naphthalene, quinoline, biphenyl and indole. Therefore, the usage is greatly restricted. The single-component β-methylnaphthalene and α-methylnaphthalene have a much wider range of uses than the mixture.
