Naphthenic oil is a type of mineral oil

Mineral oil

A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....

. In contrast with paraffin

Paraffin

In chemistry, paraffin is a term that can be used synonymously with "alkane", indicating hydrocarbons with the general formula CnH2n+2. Paraffin wax refers to a mixture of alkanes that falls within the 20 ≤ n ≤ 40 range; they are found in the solid state at room temperature and begin to enter the...

ic oils, naphthenic oils contain only low to no proportion of n-alkane

Alkane

Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...

s, being based on cycloalkane

Cycloalkane

Cycloalkanes are types of alkanes that have one or more rings of carbon atoms in the chemical structure of their molecules. Alkanes are types of organic hydrocarbon compounds that have only single chemical bonds in their chemical structure...

s (naphthenes) instead. The low-temperature behavior of naphthenic oils is better than of paraffinic oils, making them suitable for applications that require low pour point

Pour point

The pour point of a liquid is the lowest temperature at which it will pour or flow under prescribed conditions. It is a rough indication of the lowest temperature at which oil is readily pumpable. In crude oil a high pour point is generally assosiated with a high paraffin content. And typically...

. The degradation products of naphthenic oils are soluble in the oils, leading to fewer problems with formations of sludge

Sludge

Sludge refers to the residual, semi-solid material left from industrial wastewater, or sewage treatment processes. It can also refer to the settled suspension obtained from conventional drinking water treatment, and numerous other industrial processes...

s and deposits. Naphthenic oils have different solvent properties than paraffinic oils.

Naphthenic oils are characterized by high proportion of cyclic hydrocarbon fraction. The convention is that when the paraffinic carbon content is less than 55-60%, the oil is labeled as naphthenic.http://www.imakenews.com/lng/e_article000501390.cfm?x=b9WGFMC,bd1Rfpn,w

The principal uses of naphthenic oils are as transformer oil

Transformer oil

Transformer oil or insulating oil is usually a highly-refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled transformers, some types of high voltage capacitors, fluorescent lamp ballasts, and some types of high voltage...

s, coolant

Coolant

A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor...

s, solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

s, cutting fluid

Cutting fluid

Cutting fluid is a type of coolant and lubricant designed specifically for metalworking and machining processes. There are various kinds of cutting fluids, which include oils, oil-water emulsions, pastes, gels, aerosols , and air or other gases. They may be made from petroleum distillates, animal...

s, and some lubricant

Lubricant

A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...

s.