An oil is any neutral, 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 slippery.
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, fuel, lubrication, and the manufacture of paints, plastics, and other materials. Specially prepared oils are used in some religious ceremonies as purifying agents.
- Etymology 1
- Organic oils 2.1
- Mineral oils 2.2
- Cooking 3.1
- Cosmetics 3.2
- Religion 3.3
- Painting 3.4
- Heat transfer 3.5
- Lubrication 3.6
- Fuel 3.7
- Chemical feedstock 3.8
- See also 4
- References 5
- External links 6
First attested in English 1176, the word oil comes from Old French oile, from 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 , e-rai-wo, written in the Linear B syllabic script.
Lipids can be classified by the way that they are made by an organism, their chemical structure and their limited nonpolar molecules, but may include both polar and nonpolar regions as in the case of phospholipids and steroids.
Crude oil, or Mineral oil also refers to several specific distillates of crude 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).
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.
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.
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.
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 1980. As no suitable substitute is available, whale oil is still used in space (in small quantities).
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 fuel.
In the 18th and 19th centuries, whale oil was commonly used for lamps, which was replaced with natural gas and then electricity.
Crude oil can be refined into a wide variety of component hydrocarbons. 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 green chemistry.
- Emulsifier, a chemical which allows oil and water to mix
- Wax, a class of compounds with oil-like properties that are solid at common temperatures
- oleum. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
- . Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
- in Liddell and Scott.
- "The 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.
- Basil (Ocimum basilicum)
- Best Oil for Hair Growth
- "Oldest Oil Paintings Found in Afghanistan", Rosella Lorenzi, Discovery News. Feb. 19, 2008.
- Cuckoo Clock Questions
- Troubled waters: Did we really save the whale?
- U.S. Energy Information Administration (EIA) — Retrieved 2011-10-02.
- Whale Oil