Coal oil is a

shale oil Shale oil is an unconventional oil produced from oil shale rock fragments by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock (kerogen) into synthetic oil and gas. The resulting oil c ...

obtained from the

destructive distillation Destructive distillation is a chemical process in which decomposition of unprocessed material is achieved by heating it to a high temperature; the term generally applies to processing of organic material in the absence of air or in the presence o ...

cannel coal Cannel coal or candle coal is a type of bituminous coal, also classified as terrestrial type oil shale. Hutton(1987) Dyni (2006), pp. 3–4 Speight (2012), pp. 6–7 Due to its physical morphology and low mineral content cannel coal is considered ...

, mineral wax, or bituminous shale, once used widely for illumination. Chemically similar to the more refined,

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

-derived

kerosene Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...

, it consists mainly of several

hydrocarbons In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic; their odor is usually faint, and may b ...

of the

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whi ...

series, with 10 to 16

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

atoms Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other ...

in each

molecule A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemi ...

, with a

boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding envi ...

of , higher than

gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

or the

petroleum ether Petroleum ether is the petroleum fraction consisting of aliphatic hydrocarbons and boiling in the range 35–60 °C, and commonly used as a laboratory solvent. Despite the name, petroleum ether is not an ether; the term is used only figurativ ...

s, and lower than the oils. Because kerosene was first derived from cannel coal, classified as terrestrial type of

oil shale Oil shale is an organic-rich Granularity, fine-grained sedimentary rock containing kerogen (a solid mixture of Organic compound, organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general compos ...

, it continued to be popularly referred to as "coal oil" even after production shifted to petroleum as a

feedstock A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials/Intermediate goods that are feedstock for future finishe ...

. Refined hydrocarbons of the alkane series with 10 to 16 carbon atoms are the same thing whether taken from coal or petroleum.

History

The term was in use by the late 18th century for oil produced as a by-product of the production of coal gas and coal tar. In the early 19th century, it was discovered that coal oil distilled from cannel coal could be used in lamps as an illuminant, although the early coal oil burned with a smokey flame, so that it was used only for outdoor lamps; cleaner-burning whale oil was used in indoor lamps. Coal oil that burned cleanly enough to compete with whale oil as an indoor illuminant was first produced in 1850 on the Union Canal in Scotland by James Young, who patented the process. Production thrived in Scotland, making Young a very wealthy man. In Addiewell,

West Lothian West Lothian (; ) is one of the 32 council areas of Scotland, bordering (in a clockwise direction) the City of Edinburgh council area, Scottish Borders, South Lanarkshire, North Lanarkshire and Falkirk (council area), Falkirk. The modern counci ...

, Young built a substantial industrial complex for separating petroleum from various oil shales, including cannel coal. In its time it was one of the largest chemical works in Scotland. Construction began in 1866. Addiewell remained the centre of operations for Young's Paraffin Light and Mineral Oil Co. Ltd., but as local supplies of bituminous shale became exhausted, activities were increasingly focussed on other shale-fields. The refinery closed around 1921. In the United States, coal oil was widely manufactured in the 1850s under the trade name Kerosene, manufactured by a process invented by Canadian geologist

Abraham Gesner Abraham Pineo Gesner (May 2, 1797 – April 29, 1864) was a Nova Scotian and New Brunswickan physician and geologist who invented kerosene. Gesner was born in Cornwallis, Nova Scotia (now called Chipmans Corner) and lived much of his life i ...

. Young won his patent lawsuit against the Gesner process in the United States in 1860. But by that time, US coal oil distillers were switching over to refining cheaper petroleum, after the discovery of abundant petroleum in

western Pennsylvania Western Pennsylvania is a region in the Commonwealth of Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the Unite ...

in 1859, and oil from coal operations ceased in the US.

Uses

Lighting

Coal oil was used to provide lighting.

Medicinal use

Coal oil was once used as an internal and topical home remedy as a general cure-all for many ailments, including coughs, flu, cuts, abrasions, and wounds. Internal applications were administered by adding the toxic petroleum product to

sugar cube Sugar cubes are white sugar granules pressed into small cubes measuring approximately 1 teaspoon each. They are usually used for sweetening drinks such as tea and coffee. They were invented in the early 19th century in response to the difficulti ...

molasses Molasses () is a viscous byproduct, principally obtained from the refining of sugarcane or sugar beet juice into sugar. Molasses varies in the amount of sugar, the method of extraction, and the age of the plant. Sugarcane molasses is usuall ...

, honey or some other substance to mask the taste, while topical applications were applied by adding it to bandages or by pouring the coal oil directly on the affected area. "Pale sulfonated shale oil" (PSSO), a sulfonated and ammonia neutralized variant named "Ichthammol" (chemical: Ammonium bituminosulfonate) is still in application today.

Culinary use of the term

The term "coal oil" is sometimes used in the context of food; it is not mineral coal oil as discussed in this article, but edible vegetable oil infused with wood-derived

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ca ...

for flavour. Article describes how to make haroal oil,

References