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Oil

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This article is about the chemical substance. For crude oil, see Petroleum. For other uses, see Oil (disambiguation).
A bottle of olive oil used in food
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An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated lipids that are liquid at room temperature.

The general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure, properties, and uses. Oils may be animal, vegetable, or petrochemical in origin, and may be volatile or non-volatile.[1] They are used for food (e.g., olive oil), fuel (e.g., heating oil), medical purposes (e.g., mineral oil), lubrication (e.g. motor oil), and the manufacture of many types of paints, plastics, and other materials. Specially prepared oils are used in some religious ceremonies and rituals as purifying agents.

Etymology

First attested in English 1176, the word oil comes from Old French oile, from Latin oleum,[2] which in turn comes from the Greek ἔλαιον (elaion), "olive oil, oil"[3] and that from ἐλαία (elaia), "olive tree", "olive fruit".[4][5] The earliest attested forms of the word are the Mycenaean Greek 𐀁𐀨𐀺, e-ra-wo and 𐀁𐁉𐀺, e-rai-wo, written in the Linear B syllabic script.[6]

Types

Organic oils

Organic oils are produced in remarkable diversity by plants, animals, and other organisms through natural metabolic processes. Lipid is the scientific term for the fatty acids, steroids and similar chemicals often found in the oils produced by living things, while oil refers to an overall mixture of chemicals. Organic oils may also contain chemicals other than lipids, including proteins, waxes (class of compounds with oil-like properties that are solid at common temperatures) and alkaloids.

Lipids can be classified by the way that they are made by an organism, their chemical structure and their limited solubility in water compared to oils. They have a high carbon and hydrogen content and are considerably lacking in oxygen compared to other organic compounds and minerals; they tend to be relatively nonpolar molecules, but may include both polar and nonpolar regions as in the case of phospholipids and steroids.[7]

Mineral oils

Main article: Mineral oil

Crude oil, or petroleum, and its refined components, collectively termed petrochemicals, are crucial resources in the modern economy. Crude oil originates from ancient fossilized organic materials, such as zooplankton and algae, which geochemical processes convert into oil.[8] The name "mineral oil" is a misnomer, in that minerals are not the source of the oil—ancient plants and animals are. Mineral oil is organic. However, it is classified as "mineral oil" instead of as "organic oil" because its organic origin is remote (and was unknown at the time of its discovery), and because it is obtained in the vicinity of rocks, underground traps, and sands. Mineral oil also refers to several specific distillates of crude oil.[citation needed]

Applications

Cooking

Main article: Cooking oil

Several edible vegetable and animal oils, and also fats, are used for various purposes in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water. Oils are also used for flavoring and for modifying the texture of foods (e.g. stir fry). Cooking oils are derived either from animal fat, as butter, lard and other types, or plant oils from olive, maize, sunflower and many other species.[9]

Cosmetics

Oils are applied to hair to give it a lustrous look, to prevent tangles and roughness and to stabilize the hair to promote growth. See hair conditioner.[citation needed]

Religion

Oil has been used throughout history as a religious medium. It is often considered a spiritually purifying agent and is used for anointing purposes. As a particular example, holy anointing oil has been an important ritual liquid for Judaism[10] and Christianity.[11]

Health

Oils have been consumed since ancient times. Oils hold lots of fats and medical properties. A good example is olive oil. Olive oil holds a lot of fats within it which is why it was also used in lighting in ancient Greece and Rome. So people would use it to bulk out food so they would have more energy to burn through the day. Olive oil was also used to clean the body in this time as it would trap the moisture in the skin while pulling the grime to the surface. It was used as an ancient form of unsophisticated soap. It was applied on the skin then scrubbed off with a wooden stick pulling off the excess grime and creating a layer where new grime could form but be easily washed off in the water as oil is hydrophobic.[12] Fish oils hold the omega-3 fatty acid. This fatty acid helps with inflammation and reduces fat in the bloodstream.[citation needed]  

Painting

Main article: Oil painting

Color pigments are easily suspended in oil, making it suitable as a supporting medium for paints. The oldest known extant oil paintings date from 650 AD.[13]

Heat transfer

See also: Transformer oil

Oils are used as coolants in oil cooling, for instance in electric transformers. Heat transfer oils are used both as coolants (see oil cooling), for heating (e.g. in oil heaters) and in other applications of heat transfer.[citation needed]

Lubrication

Synthetic motor oil

Given that they are non-polar, oils do not easily adhere to other substances. This makes them useful as lubricants for various engineering purposes. Mineral oils are more commonly used as machine lubricants than biological oils are. Whale oil is preferred for lubricating clocks, because it does not evaporate, leaving dust, although its use was banned in the US in 1980.[14]

It is a long-running myth that spermaceti from whales has still been used in NASA projects such as the Hubble Space Telescope and the Voyager probe because of its extremely low freezing temperature. Spermaceti is not actually an oil, but a mixture mostly of wax esters, and there is no evidence that NASA has used whale oil.[15]

Fuel

Main article: Fuel oil

Some oils burn in liquid or aerosol form, generating light, and heat which can be used directly or converted into other forms of energy such as electricity or mechanical work. In order to obtain many fuel oils, crude oil is pumped from the ground and is shipped via oil tanker or a pipeline to an oil refinery. There, it is converted from crude oil to diesel fuel (petrodiesel), ethane (and other short-chain alkanes), fuel oils (heaviest of commercial fuels, used in ships/furnaces), gasoline (petrol), jet fuel, kerosene, benzene (historically), and liquefied petroleum gas. A 42-US-gallon (35 imp gal; 160 L) barrel of crude oil produces approximately 10 US gallons (8.3 imp gal; 38 L) of diesel, 4 US gallons (3.3 imp gal; 15 L) of jet fuel, 19 US gallons (16 imp gal; 72 L) of gasoline, 7 US gallons (5.8 imp gal; 26 L) of other products, 3 US gallons (2.5 imp gal; 11 L) split between heavy fuel oil and liquified petroleum gases,[16] and 2 US gallons (1.7 imp gal; 7.6 L) of heating oil. The total production of a barrel of crude into various products results in an increase to 45 US gallons (37 imp gal; 170 L).[16]

In the 18th and 19th centuries, whale oil was commonly used for lamps, which was replaced with natural gas and then electricity.[17]

Chemical feedstock

Crude oil can be refined into a wide variety of component hydrocarbons. Petrochemicals are the refined components of crude oil[18] and the chemical products made from them. They are used as detergents, fertilizers, medicines, paints, plastics, synthetic fibers, and synthetic rubber.

Organic oils are another important chemical feedstock, especially in green chemistry.

See also

  • Emulsifier, a chemical which allows oil and water to mix

References

  1. ^ "oil". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  2. ^ oleum. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
  3. ^ ἔλαιον. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
  4. ^ ἐλαία in Liddell and Scott.
  5. ^ Harper, Douglas. "oil". Online Etymology Dictionary.
  6. ^ "The Linear B word e-ra-wo". Palaeolexicon. Word study tool of ancient languages. "e-ra3-wo". Archived from the original on 2016-03-21. Retrieved 2014-03-22. Raymoure, K.A. "e-ra-wo". Minoan Linear A & Mycenaean Linear B. Deaditerranean. Archived from the original on 2016-03-20. Retrieved 2014-03-22.
  7. ^ Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter. Molecular Biology of the Cell. New York: Garland Science, 2002, pp. 62, 118-119.
  8. ^ Kvenvolden, Keith A. (2006). "Organic geochemistry – A retrospective of its first 70 years". Organic Geochemistry. 37 (1): 1. Bibcode:2006OrGeo..37....1K. doi:10.1016/j.orggeochem.2005.09.001. S2CID 95305299.
  9. ^ Brown, Jessica. "Which cooking oil is the healthiest?". www.bbc.com. BBC. Retrieved 18 May 2021.
  10. ^ Chesnutt, Randall D. (January 2005). "Perceptions of Oil in Early Judaism and the Meal Formula in Joseph and Aseneth". Journal for the Study of the Pseudepigrapha. 14 (2): 113–132. doi:10.1177/0951820705051955. ISSN 0951-8207. S2CID 161240989.
  11. ^ Sahagun, Louis (2008-10-11). "Armenian priests journey for jars of holy oil". Los Angeles Times.
  12. ^ Ilak Peršurić, Anita Silvana; Težak Damijanić, Ana (January 2021). "Connections between Healthy Behaviour, Perception of Olive Oil Health Benefits, and Olive Oil Consumption Motives". Sustainability. 13 (14): 7630. doi:10.3390/su13147630. ISSN 2071-1050.
  13. ^ "Oldest Oil Paintings Found in Afghanistan", Rosella Lorenzi, Discovery News. February 19, 2008. Archived June 3, 2011, at the Wayback Machine
  14. ^ "Bavarian Clock Haus and Frankenmuth Clock Company". Frankenmuth Clock Company & Bavarian Clock Haus.
  15. ^ "Troubled waters: Who Would Believe NASA Used Whale Oil on Voyager and Hubble?". Knight Science Journalism at MIT. Archived from the original on 2015-02-15. Retrieved 2015-02-15.
  16. ^ a b U.S. Energy Information Administration (EIA) Archived 2018-05-02 at the Wayback Machine — Retrieved 2011-10-02.
  17. ^ "Whale Oil". petroleumhistory.org.
  18. ^ Kostianoy, Andrey G.; Lavrova, Olga Yu (2014-07-08). Oil Pollution in the Baltic Sea. Springer. ISBN 9783642384769.
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