Synthetic oil is a

lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, ...

consisting of chemical compounds that are artificially modified or synthesised. Synthetic oil is used as a substitute for petroleum-refined oils when operating in extreme temperature, in metal stamping to provide environmental and other benefits, and to lubricate

pendulum clock A pendulum clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. The advantage of a pendulum for timekeeping is that it is an approximate harmonic oscillator: It swings back and forth in a precise time interval dep ...

s. There are various types of synthetic oils. Advantages of using synthetic motor oils include better low-and high-temperature

viscosity Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for e ...

performance, better (higher)

viscosity index The viscosity index (VI) is an arbitrary, unit-less measure of a fluid's change in viscosity relative to temperature change. It is mostly used to characterize the viscosity-temperature behavior of lubricating oils. The lower the VI, the more the ...

(VI), and

chemical A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

and shear stability, while disadvantages are that synthetics are substantially more expensive (per volume) than

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, ...

s and have potential decomposition problems.

Description

Synthetic oil

comprises chemical compounds that are artificially modified or synthesised. Synthetic lubricants can be manufactured using chemically modified

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

components rather than whole

crude oil Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring u ...

, but can also be synthesized from other raw materials. The base material, however, is still overwhelmingly crude oil that is distilled and then modified physically and chemically. The actual synthesis process and composition of additives is generally a commercial trade secret and will vary among producers.

Use

* Synthetic oil is used as a substitute for petroleum-refined oils when operating in extreme temperature. Aircraft

jet engine A jet engine is a type of reaction engine, discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition may include Rocket engine, rocket, Pump-jet, water jet, and ...

s, for example, require the use of synthetic oils, whereas aircraft

piston engines A reciprocating engine, more often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common features of all ...

do not. * Synthetic oils are also used in metal stamping to provide environmental and other benefits when compared to conventional petroleum and animal-fat based products. These products are also referred to as "non-oil" or "oil free". * A polyalcanoate synthetic oil is widely used to lubricate

Types

Full

Some synthetic oils are made from Group III base stock, some from Group IV while other synthetic oils may be a blend of the two.

Mobil Mobil Oil Corporation, now known as just Mobil, is a petroleum brand owned and operated by American oil and gas corporation ExxonMobil, formerly known as Exxon, which took its current name after history of ExxonMobil#merger, it and Mobil merge ...

sued

Castrol Castrol Limited is a British oil company that markets industrial and automotive lubricants, offering a wide range of oil, greases and similar products for most lubrication applications. The company was originally named CC Wakefield; the nam ...

and Castrol prevailed in showing that their Group III base stock oil was changed enough that it qualified as full synthetic. Since then

American Petroleum Institute The American Petroleum Institute (API) is the largest U.S. trade association for the oil and natural gas industry. It claims to represent nearly 600 corporations involved in extraction of petroleum, production, oil refinery, refinement, pipeline ...

(API) has removed all references to synthetic in their documentation regarding standards. "Full synthetic" is a marketing term and is not a measurable quality.

Group IV: PAO

Poly-alpha-olefin (poly-α-olefin, PAO) is a

non-polar In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain one or more polar ...

polymer made by polymerizing an alpha-olefin. They are designated at API Group IV and are a 100% synthetic chemical compound. It is a specific type of

olefin In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as α-olefins. The International Union of Pu ...

(organic) that is used as a base stock in the production of most synthetic lubricants. An alpha-olefin (or α-olefin) is an

alkene In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins. The Internationa ...

where the carbon-carbon double bond starts at the α-carbon atom, i.e. the double bond is between the #1 and #2 carbons in the molecule.SynLube Incorporated

All About Synthetic Oil

Group V: Other synthetics

Group V base oils are defined by API as any other type of oil other than

s or PAO lubricants.

Ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

s are the most famous synthetics in Group V, which are 100% synthetic chemical compounds consisting of a

carbonyl In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double bond, double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such a ...

adjacent to an

ether In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R� ...

linkage. They are derived by reacting an

oxoacid An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce ...

with a

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

compound such as an

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

phenol Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () ...

. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (

alkoxy In chemistry, the alkoxy group is an alkyl group which is Single bond, singularly bonded to oxygen; thus . Denoted usually with apostrophe('). The range of alkoxy groups is vast, the simplest being methoxy (). An ethoxy group () is found in the ...

) group, most commonly from

carboxylic In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl group (e. ...

acids and alcohols. That is to say, esters are formed by condensing an acid with an alcohol. Many chemically different "esters"—due to their polarity and usually excellent lubricity—are used for various reasons as either "additives" or "base stocks" for lubricants.

=Polyalkylene glycol (PAG) synthetic oil

Industrial PAG

* The terms polyalkylene glycol and polyglycol are used interchangeably. * Synthetic lubricants are about 4% of the lubricants market. PAGs are about 24% of the synthetic lubricants market. * Ethylene is the basic raw material used to make the synthetic lubricant polyglycols oils. When

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon–carbon bond, carbon–carbon doub ...

and

propylene Propylene, also known as propene, is an unsaturated organic compound with the chemical formula . It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petroleum-like o ...

react with oxygen we obtain

ethylene oxide Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless ...

(EO) and

propylene oxide Propylene oxide is an epoxide with the molecular formula C3H6O. This colourless volatile liquid with an odour similar to ether, is produced on a large scale industrially. Its major application is its use for the production of polyether polyols f ...

(PO), from which the polyalkylene glycols are produced by means of polymerization. Polyalkylene glycols are usually made by combining ethylene oxide and/or propylene oxide with an alcohol or water. * The mixing ratio between EO and PO, plus the oxygen bonded in the chemical structure, crucially affect the behavior of polyglycols. The gear industry predominantly uses polyglycols with an EO/PO ratio of 50:50 to 60:40, which exhibit very similar behavior. The polyglycols featuring this composition are also generally referred to as water soluble polyglycols. * Polyalkylene glycol base oils are formed by reacting an alcohol with one or more alkylene oxides: Propylene oxide provides water insolubility, Ethylene oxide provides water solubility.

PAG properties

PAGs offer properties that include: high lubricity, polarity, low traction properties, high viscosity index, controlled quenching speeds, good temperature stability and low wear. They are available in both water soluble and insoluble forms.Croda Lubricants , Polyalkylene glycol base oils
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PAG uses

PAGs are commonly used in quenching fluids, metalworking fluids, gear oils, chain oils, food-grade lubricants and as lubricants in HFC type hydraulics and gas compressor equipment. PAG lubricants are used by the two largest U.S. air compressor OEMs in rotary screw air compressors. PAG oils of different viscosity grades (usually either ISO VG 46 or ISO VG 100) are often used as compressor lubricants for automotive air conditioning systems employing low

global warming potential Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide (). It is expressed as a multiple of warming caused by the same mass of carbon dioxide ( ...

refrigerants.

PAG advantages

* PAGs are available in a wide range of viscosity grades and additive packages for a variety of uses. Some PAGs properties such as water solubility are not commonly provided by other synthetic lubricants, such as polyalphaolefins (PAO). * PAGs prevent sludge and varnish from developing at high temperatures. PAGs have viscosity indexes that are higher than PAOs. * In large gears, PAG lubricant yielded lower friction than PAO lubricant. * PAG oils are polar, which means that an oil film easily develops upon all moving metal parts, reducing startup wear. * PAGs can be highly biodegradable, particularly the water-soluble PAGs. * PAGs perform better than in extreme weather condition.

PAG disadvantages

* PAGs are not compatible with

s, most seals,

paint Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...

varnish Varnish is a clear Transparency (optics), transparent hard protective coating or film. It is not to be confused with wood stain. It usually has a yellowish shade due to the manufacturing process and materials used, but it may also be pigmente ...

es. * Synthetic oil is more expensive than mineral oils.

PAG seal compatibility

* PAG is usually compatible with

fluorocarbon Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often have distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Several fluorocarbons and their derivatives are ...

-based

fluoroelastomer A fluoroelastomer is a fluorocarbon-based synthetic rubber. Fluoroelastomers generally have wide chemical resistance. Composition Several compositions of fluoroelastomers exist including FKM (by ASTM D1418 standard, equivalent to FPM by ISO/DIN ...

materials and vinyl methyl silicone (VMQ)

silicone rubber Silicone rubber is an elastomer composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers ar ...

. * PAG acts as a solvent and dissolves and removes the mineral grease which causes slower motions, air leaks, and can stop 4-way valves from operating. * Natural rubber, Buna-N, and most regular seals are incompatible with PAG oils, especially seals coated in mineral grease. PAG oils can cause seals to shrink or swell, thus causing severe leakage or seizure of the seal. Pneumatic air cylinders and 4-ways valves commonly use Buna-N rubber seals that are coated in mineral grease.

Semi-synthetic oil

Semi-synthetic oils (also called "synthetic blends") are a mixture of mineral oil and synthetic oil, which are engineered to have many of the benefits of full synthetic oil without the cost. Motul introduced the first semi-synthetic

motor oil Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, deterge ...

in 1966. Lubricants that have synthetic base stocks even lower than 30% but with high-performance additives consisting of esters can also be considered synthetic lubricants. In general, the ratio of the synthetic base stock is used to define commodity codes among the customs declarations for tax purposes.

Other base stocks help semi-synthetic lubricants

API Group II- and API Group III-type base stocks help to formulate more economic-type semi-synthetic lubricants. API Group I-, II-, II+-, and III-type mineral-base oil stocks are widely used in combination with additive packages, performance packages, and ester and/or API Group IV poly-alpha-olefins in order to formulate semi-synthetic-based lubricants. API Group III base oils are sometimes considered fully synthetic, but they are still classified as highest-top-level mineral-base stocks. A synthetic or synthesized material is one that is produced by combining or building individual units into a unified entity. Synthetic base stocks as described above are man-made and tailored to have a controlled molecular structure with predictable properties, unlike mineral base oils, which are complex mixtures of naturally occurring hydrocarbons and paraffins.

Performance of synthetic oil

The advantages of using synthetic motor oils include better low-and high-temperature viscosity performance at service temperature extremes, better (higher)

Viscosity Index The viscosity index (VI) is an arbitrary, unit-less measure of a fluid's change in viscosity relative to temperature change. It is mostly used to characterize the viscosity-temperature behavior of lubricating oils. The lower the VI, the more the ...

(VI), and

and shear stability. This also helps in decreasing the loss due to evaporation. It is resistant to oxidation, thermal breakdown,

oil sludge Oil sludge or black sludge is a gel-like or semi-solid deposit inside an internal combustion engine, that can create a catastrophic buildup. It is often the result of contaminated engine oil Motor oil, engine oil, or engine lubricant is an ...

problems and provides extended drain intervals, with the environmental benefit of less used oil waste generated. It provides better lubrication in extreme cold conditions. The use of synthetic oils promises a longer engine life with superior protection against "ash" and other deposit formation in engine hot spots (in particular in turbochargers and superchargers) for less oil burn-off and reduced chances of damaging oil passageway clogging. The performance of automobiles is improved as net increase in horsepower and torque due to less internal drag on engine. Moreover, it can improve

fuel efficiency Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical energy, chemical potential energy contained in a carrier (fuel) into kinetic energy or Mechanical work, w ...

- 1.8% to 5% as has been documented in fleet tests. However, synthetic motor oils are substantially more expensive (per volume) than

s and have potential decomposition problems in certain chemical environments (predominantly in industrial use).

References

{{DEFAULTSORT:Synthetic Oil Motor oils Non-petroleum based lubricants Tribology