Coal Oil

Coal oil is a term once used for a specific shale oil used for illuminating purposes. Coal oil is obtained from the destructive distillation of cannel coal, mineral wax, and bituminous shale, while kerosene is obtained by the distillation of petroleum. A special type of coal known as cannel coal (classified also as terrestrial type of oil shale) is required to produce it.

Coal oil was first produced in 1850 by James Young on the Union Canal in Scotland. He was the first to patent the process of distilling this cannel coal into coal oil. This industry thrived in Scotland, creating much wealth for Young.

It consists mainly of several hydrocarbons of the alkane series, having from 10 to 16 carbon atoms in each molecule, and having a higher boiling point (175–325°C) than gasoline or the petroleum ethers, and a lower boiling point than the oils. Early belief that kerosene was produced from coal led to kerosene being popularly referred to as "coal oil." This is a technicality, however, because hydrocarbons of the alkane series, with 10 to 16 carbon atoms, when refined, are the same thing whether taken from coal or petroleum.