Synthetic oil: Wikis


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A sample of synthetic motor oil

Synthetic oil is a lubricant consisting of chemical compounds which are artificially made (synthesized) from compounds other than crude oil (petroleum). Synthetic oil is used as a substitute for lubricant refined from petroleum when operating in extremes of temperature, because it generally provides superior mechanical and chemical properties than those found in traditional mineral oils. Aircraft turbines, for example, require the use of synthetic oils, whereas aircraft piston engines don't.



Dr. Hermann Zorn[1] of I.G. Farben Industrie in Germany actually began to search for lubricants with the properties of natural oils but without the tendencies to gel or gum when used in an engine environment. His work[2][3] led to the preparation of over 3500 esters in the late 1930s and early 1940s including diesters and polyolesters and banana oil. During the same time period in the United States, Dr. W.A. Zisman[4] working at the Naval Research Laboratory (NRL) was also synthesizing esters, especially diesters.

Comparison of the viscosimetric properties of ester- and polyglycol-based engine oils in WWII and in 1973 at Renault/ELF. SS stands for "Synthetischer Schmierstoff," synthetic oil.

The first real synthetic engine oils appeared for aircraft engines in World War II in Germany and in the United States of America (USA). The motivation in Germany may be primarily related to resource issues, but also to functional performance requirements. The base oils for aircraft engines in Germany were based on a blend of an adipic acid ester with a poly(ethylene) oil[5] e.g. polymerized olefins/ethylene. Easing engine starts in winter and avoiding soot deposits in the oil radiator were two of the drivers of the US Air Force.[6][7], to apply from March 1944 polyglycols (polypropylene glycol monobutylether).

Synthetic engine oil

In the early 1960s, Chevron U.S.A integrated the first commercial utilization of hydrocracking technology at its Richmond California refinery [2]. By 1993 the company introduced lubricant Isodewaxing [3] technology making Chevron one of the worlds largest manufacturers of API (category II and III) base oils. Today, API (category III) base oils are marketed to the general public as fully synthetic motor oil. On July 1, 2000 the Chevron Corporation combined efforts with Phillips Petroleum Company, now ConocoPhillips, to become Chevron Phillips Chemical Company, LLC. The Chevron Phillips venture is one of the top producers of polyolefin (PAO) Group IV base stocks, some of which are used for automotive synthetic motor oils. [4]

Although used in the aviation and aerospace industries beginning in the early 1950s, the first synthetic oil developed for automotive combustion engines and fully recognized by the American Petroleum Institute (API) was produced by the Hatco Corporation[5] in 1972 as per specific specification requirements by Albert J. Amatuzio, current President and CEO of Amsoil, Inc. This first API rated synthetic motor oil was distributed exclusively through Amsoil, Inc, meeting API (SE/CC) specifications and was based on a 10W-40 grade Diester API (category V) formulation. Today Amsoil, Inc markets a full line of API (category III) licensed synthetic motor oil [6] and many other API (category IV) PAO-base oil formulations that are claimed by Amsoil to meet or exceed current API requirements.

Other early synthetic motor oils marketed included "The Original Syn!" by SynLube in 1969, NEO Oil Company (formally EON) in 1970, which were dibasic acide esters, or diesters, and polyolesters based synthetic lubricants. In 1971 All-Proof now called Redline and Mobil 1, introduced in North America in 1974 with a 5W-20 grade(category IV) PAO-base oil [7].



Synthetic Base Stocks

Synthetic motor oils have been made from the following classes of lubricants:

  • Polyalphaolefin (PAO) = American Petroleum Institute (API) Group IV base oil
  • Synthetic esters, etc = API Group V base oils (non-PAO synthetics, including diesters, polyolesters, alklylated napthlenes, alkyklated benzenes, etc.)
  • Hydrocracked/Hydroisomerized = API Group III base oils. Chevron, Shell, and other petrochemical companies developed processes involving catalytic conversion of feed stocks under pressure in the presence of hydrogen into high quality mineral lubricating oil. In 2005 production of GTL (Gas-to-liquid) Group III base stocks began. The best of these perform much like polyalphaolefin[citation needed]. Group III base stocks are considered synthetic motor oil ONLY in the United States. [8]. Group III based lubricants are not allowed to be marketed as "synthetic" in any market outside of the USA.

Semi-synthetic oil

Semi-synthetic oils (also called 'synthetic blends') are blends of mineral oil with no more than 30% synthetic oil. Designed to have many of the benefits of synthetic oil without matching the cost of pure synthetic oil. Motul introduced the first semi-synthetic motor oil in 1966.[9]

Lubricants which have synthetic base stocks even lower 30%, high performance additive packs consisting of esters can also be considered as synthetic lubricants. Ratio of the synthetic base stock is generally used to define commodity codes among the customs declarations of tax purposes.

Other base stocks help semi-synthetic lubricants

Group II and Group III type base stocks help to formulate more economic type semi-synthetic lubricants. Group I, II, II+ and III type mineral base oil stocks are widely used in combination with additive packages, performance packages, ester and/or Group IV polyalphaolefins in order to formulate semi-synthetic based lubricants. Group III base oils are sometimes considered as 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 entry. 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.[10][11]

  • Hydrocracked/Hydroisomerized = API Group III base oils. Chevron, Shell, and other petrochemical companies developed processes involving catalytic conversion of feed stocks under pressure in the presence of hydrogen into high quality mineral lubricating oil. In 2005 production of GTL (Gas-to-liquid) Group III base stocks began. Even though they are considered a synthetic product they are still mineral base stocks and counted as the mineral part of all semi-synthetic lubricants. Group III base stocks [with certain amount of mixture of PAOs and esters and Group V] are considered synthetic motor oil ONLY in the United States.[citation needed] Group III based lubricants are not allowed to be marketed as "synthetic" in any market outside of the USA.



The technical advantages of synthetic motor oils include:[citation needed]

  • Measurably better low and high temperature viscosity performance
  • Better chemical & shear stability
  • Decreased evaporative loss
  • Resistance to oxidation, thermal breakdown and oil sludge problems
  • Extended drain intervals with the environmental benefit of less oil waste.
  • Improved fuel economy in certain engine configurations.
  • Better lubrication on cold starts
  • Longer engine life


The disadvantages of synthetic motor oils include

  • The lower friction may make them unsuitable for break-in (i.e. the initial run-in period of the vehicle) where friction is desirable to cause wear. Improved engine part machining has made break-in less critical than it once was, though. Many modern cars now come with synthetic oil as a factory fill.
  • Potential decomposition problems in certain chemical environments (industrial use dominantly)
  • Potential stress cracking of plastic components like POM (polyoxymethylene) in the presence of PAOs (polyalphaolefins).
  • Synthetics do not hold lead in suspension as well as mineral oil, thus caution is advised when the engine is run on leaded fuel.[citation needed] As an example, leaded fuel is still commonly used in aviation (avgas).[12]
  • In July 1996, Consumer Reports published the results of a two year motor oil test involving a fleet of 75 New York taxi cabs and found no noticeable advantage of synthetic oil over regular mineral oil.[13] In their article, they noted that "Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service — stop-and-go city driving." According to their study, synthetic oil is "worth considering for extreme driving conditions: high ambient temperatures and high engine load, or very cold temperatures." [14]
  • Synthetic oils are not recommended in automotive rotary engines.[15]

See also


  1. ^ Eilhard Jantzen: The Origins of Synthetic Lubricants: The Work of Hermann Zorn in Germany, Part 1, Basic Studies of Lubricants and the Polymerisation of Olefins, Journal of Synthetic Lubrication, 12. 1996, Nr. 4, S. 283-301.
  2. ^ H. Zorn, Chemischer Aufbau und physikalische Eigenschaften der Schmierstoffe VDI-Berichte Band 20, 1957, p. 47 ff.
  3. ^ Eilhard Jantzen, The Origins of Synthetic Lubricants: The Work of Hermann Zorn in Germany Part 2: esters and Additives for Synthetic Lubricants Journal of Synthetic Lubrication (JSL) 13-2 (1996),
  4. ^ W.A. Zismann, Historical Review, Lubricants and Lubrication, In:Synthetic Lubricants, eds.: R.C. Gunderson, A.W. Hart, 1962, chapter 2, p. 6-60
  5. ^ M.E. Spaght, German Aircraft Oils were made by Polymerization of Olefins Petroleum Processing, October 1946, p. 126-135
  6. ^ D.K. Wilson, Fleet tests of synthetic lubricants SAE Quarterly Transactions, April 1948, Vol. 2, No. 2, p. 242-250
  7. ^ C. Kratzer, D.H. Green and D.B. Williams, New synthetic lubricants SAE Journal (Transactions), Vol. 54, No. 5, May, 1946, p. 228-238
  8. ^ [1]
  9. ^ DELPHI history
  10. ^ ASTM Fuels & Lubricants Handbook, Hydrocarbon Chemistry, pg 169-184, section 7
  11. ^ [Ref: Lubrication Fundamentals, J. George Wills, Mobil Oil Corporation]
  12. ^ "avgas grades". Retrieved 2009-03-21. 
  13. ^ "Consumer Reports Oil Testing Results". Retrieved 2007-10-15. 
  14. ^ "The surprising truth about motor oils". Consumer Reports: 10–13. July 1996. 
  15. ^ "Mobil rotary engine statement". Retrieved 2009-03-21. 


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