Purification of the product is afterwards carried out by a process of fractional distillation.

This process is called " fractional distillation," and the various products are called "fractions."

The ethers are returned as ethyl acetate, but from fractional distillation amyl acetate was found to be present.

Toluene, which was discovered in 1837 by Pelletier, was recognised in the fractional distillation of crude naphtha by Mansfield in 1848.