Oils

An oil is a substance that is in a viscous liquid state ("oily") at ambient temperatures or slightly warmer, and is both hydrophobic, (immiscible with water, lit. water fearing) and lipophilic (miscible with other oils, literally "fat loving"). more...

This general definition includes compound classes with otherwise unrelated chemical structures, properties, and uses, including vegetable oils, petrochemical oils, and volatile essential oils. Oil is a nonpolar substance.

Etymology

Oil is a non-scientific term used to refer to certain diverse and unrelated compounds sharing the same physical properties (such as viscosity and a hydrophobic nature), while ignoring related compounds. The compounds found in cooking oil are chemically very similar, almost identical, to those found in butter and very different from those found in diesel fuel, but while diesel is an oil, butter is not. Indeed diesel is once again very similar to natural gas, but gas is certainly not oil. This disparity stems partly from the fact that oils must be liquid at room temperature, and thus only certain liquid chemicals in many unrelated families are recognised, collectively, as 'oil'. Scientists, instead of using the term 'oil', adopt the terms lipids and other terms to denote them instead.

Types of oils

Mineral oil

All oils, with their high carbon and hydrogen content, can be traced back to organic sources or space. Mineral oils, found in porous rocks underground, are no exception, as they were originally the organic material, such as dead plankton, accumulated on the seafloor in geologically ancient times. Through various geochemical processes this material was converted to mineral oil, or petroleum, and its components, such as kerosene, paraffin waxes, gasoline, diesel and such. These are classified as mineral oils as they do not have an organic origin on human timescales, and are instead derived from underground geologic locations, ranging from rocks, to underground traps, to sands.

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