naphtha, any of various volatile, highly flammable liquidhydrocarbon mixtures used chiefly as solvents and diluents and as raw materials for conversion togasoline. Naphtha was the name originally applied to the more volatile kinds ofpetroleum issuing from the ground in the Baku district of Azerbaijan and Iran. As early as the 1st centuryad, naphtha was mentioned by the Greek writer Dioscorides and the Roman writerPliny the Elder. Alchemists used the word principally to distinguish various mobile liquids of lowboiling point, including certainethers and esters.

In modern usage the word naphtha is usually accompanied by a distinctive prefix. Coal-tar naphtha is a volatile commercial product obtained by the distillation ofcoal tar.Shale naphtha is obtained by the distillation of oil produced frombituminous shale by destructive distillation.Petroleum naphtha is a name used primarily in theUnited States for petroleum distillate containing principally aliphatic hydrocarbons and boiling higher than gasoline and lower thankerosene.