An oil bath is a type of

heated bath A heated bath is used in the laboratory to allow a chemical reaction to occur at an elevated temperature. The heated bath is a fluid placed in an open (metal) pot. Water and silicone oil are the most commonly used fluids. A water bath is used f ...

used in a

laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physi ...

, most commonly used to heat up chemical reactions. It's essentially a container of

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

that is heated by a

hot plate A hot plate is a portable self-contained tabletop small appliance cooktop that features one or more electric heating elements or gas burners. A hot plate can be used as a stand-alone appliance, but is often used as a substitute for one of t ...

or (in rare cases) a

Bunsen burner A Bunsen burner, named after Robert Bunsen, is a kind of ambient air gas burner used as laboratory equipment; it produces a single open gas flame, and is used for heating, sterilization, and combustion. The gas can be natural gas (which is ma ...

Use

These baths are commonly used to heat

reaction Reaction may refer to a process or to a response to an action, event, or exposure: Physics and chemistry *Chemical reaction *Nuclear reaction * Reaction (physics), as defined by Newton's third law *Chain reaction (disambiguation). Biology and m ...

mixtures more evenly than would be possible with a hot plate alone, as the entire outside of the reaction flask is heated. Generally,

silicone oil A silicone oil is any liquid polymerized siloxane with organic side chains. The most important member is polydimethylsiloxane. These polymers are of commercial interest because of their relatively high thermal stability, lubricating, and dielect ...

is used in modern oil baths, although

mineral oil Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils. The name 'mineral oil' by itself is imprecise ...

cottonseed oil Cottonseed oil is cooking oil from the seeds of cotton plants of various species, mainly '' Gossypium hirsutum'' and ''Gossypium herbaceum'', that are grown for cotton fiber, animal feed, and oil. Cotton seed has a similar structure to other oi ...

and even

phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...

have been used in the past.

Hazards

Overheating the oil bath can result in a fire hazard, especially if mineral oil is being used. Generally, the maximum safe operating temperature of a mineral oil bath is approximately , the oil's flash point. Mineral oil can't be used above due to the compound's boiling point. If higher temperatures are needed, a silicone oil or a sand bath may be used instead. Silicone oil baths are effective in the 25 °C (77 °F) - 230 °C (446 °F) range. Sand baths are effective from 25 °C (77 °F) to above 500 °C (932 °F).

In mechanics

Another use of an oil bath is to filter

particulate Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The te ...

s out of air, by leading the air stream through an unheated oil bath. This type of

air filter A particulate air filter is a device composed of fibrous, or porous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may a ...

was used in car and tractor engines, but has been replaced by modern paper air filters; some

small engine A small engine is the general term for a wide range of small-displacement, low-powered internal combustion engines used to power lawn mowers, generators, concrete mixers and many other machines that require independent power sources. These eng ...

s continue to use this system. In some cases oil baths are used to heat bearings so they expand before installing them on shafts of aircraft engines and tractors.

References

Laboratory equipment Filters Particulate control {{chemistry-stub

Use

Hazards

In mechanics

See also

References