An oil is any nonpolar chemical substance that is a viscous liquid at
ambient temperatures and is both hydrophobic (immiscible with water,
literally "water fearing") and lipophilic (miscible with other oils,
literally "fat loving"). Oils have a high carbon and hydrogen content
and are usually flammable and surface active.
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. 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.
2.1 Organic oils
2.2 Mineral oils
3.8 Chemical feedstock
4 See also
6 External links
First attested in English 1176, the word oil comes from Old French
Latin oleum, which in turn comes from the Greek
ἔλαιον (elaion), "olive oil, oil" and that from ἐλαία
(elaia), "olive tree", "olive fruit". 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.
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.
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. 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.
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 the olive, maize, sunflower and
many other species.
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
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 and Christianity.
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.
See also: Transformer oil
Oils are used as coolants in oil cooling, for instance in electric
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.
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 USA in 1980.
It is a long-running myth that spermaceti from whales has still been
used in NASA projects such as the
Hubble Telescope and the Voyager
probe because of its extremely low freezing temperature.
not actually an oil, but a mixture mostly of wax esters, and there is
no evidence that NASA has used whale oil.
Synthetic motor 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. 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-gallon barrel (U.S.) of crude oil
produces approximately 10 gallons of diesel, 4 gallons of jet fuel, 19
gallons of gasoline, 7 gallons of other products, 3 gallons split
between heavy fuel oil and liquified petroleum gases, and 2
gallons of heating oil. The total production of a barrel of crude into
various products results in an increase to 45 gallons. Not all
oils used as fuels are mineral oils, see biodiesel and vegetable oil
In the 18th and 19th centuries, whale oil was commonly used for lamps,
which was replaced with natural gas and then electricity.
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Crude oil can be refined into a wide variety of component
Petrochemicals are the refined components of crude
oil 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
Emulsifier, a chemical which allows oil and water to mix
Oxford English Dictionary
Oxford English Dictionary (3rd ed.). Oxford University Press.
September 2005. (Subscription or UK public library
^ oleum. Charlton T. Lewis and Charles Short. A
Latin Dictionary on
^ ἔλαιον. Liddell, Henry George; Scott, Robert; A
Greek–English Lexicon at the Perseus Project.
^ ἐλαία in Liddell and Scott.
^ Harper, Douglas. "oil". Online Etymology Dictionary.
Linear B word e-ra-wo". Palaeolexicon. Word study tool of
ancient languages. "e-ra3-wo". Raymoure, K.A. "e-ra-wo".
Minoan Linear A & Mycenaean Linear B. Deaditerranean.
^ 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.
^ Kvenvolden, Keith A. (2006). "Organic geochemistry – A
retrospective of its first 70 years". Organic Geochemistry. 37: 1.
Oil Paintings Found in Afghanistan", Rosella Lorenzi,
Discovery News. Feb. 19, 2008. Archived June 3, 2011, at the Wayback
^ "Bavarian Clock Haus and Frankenmuth Clock Company". Frankenmuth
Clock Company & Bavarian Clock Haus.
^ "Troubled waters: Who Would Believe NASA Used Whale
Oil on Voyager
and Hubble?". Knight Science Journalism at MIT.
^ a b U.S. Energy Information Administration (EIA) — Retrieved
^ "Whale Oil". petroleumhistory.org.
^ Kostianoy, Andrey G.; Lavrova, Olga Yu (2014-07-08).
in the Baltic Sea. Springer. ISBN 9783642384769.
Look up oil in Wiktionary, the free dictionary.
Media related to
Oil at Wikimedia Commons
Petroleum Online e-Learning resource from IHRDC