Synthetic oil

A sample of synthetic motor oil

Synthetic oil is a lubricant consisting of chemical compounds that are artificially made (synthesized). Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials. Synthetic oil is used as a substitute for lubricant refined from petroleum when operating in extremes of temperature, because, in general, it provides superior mechanical and chemical properties than those found in traditional mineral oils. Aircraft jet engines, for example, require the use of synthetic oils, whereas aircraft piston engines do not.

History

Dr. Hermann Zorn^[1] of I.G. Farben Industries in Germany began^[when?] 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, polyolesters, and banana oil. During the same time period in the United States, Dr. William Albert Zismann^[4] working at the U.S. 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 concurrently in Germany and in the United States. The motivation in Germany may be related primarily 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. Because synthetic oils made engine starting in winter easier and significantly decreased soot deposits in oil radiators, the United States Army Air Forces adopted polyglycols (polypropylene glycol monobutylethers) beginning in March 1944.^[6][7]

Synthetic engine oil

In the early 1960s, Chevron U.S.A integrated the first commercial utilization of hydrocracking technology at its Richmond California refinery.^[8] By 1993 the company introduced lubricant Isodewaxing ^[9] technology making Chevron one of the world's 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, Chevron Corp. combined efforts with Phillips Petroleum Co., now ConocoPhillips, to become Chevron Phillips Chemical Company, LLC. The Chevron Phillips venture is one of the top producers of polyalphaolefin (PAO) Group IV base stocks, some of which are used for automotive synthetic motor oils.^{[citation needed]}

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 Corp.^[10] (AMSOIL) in 1972.

Other early synthetic motor oils marketed included "The Original Syn!" by SynLube in 1969, NEO Oil Company (formally EON) in 1970; they were dibasic acide esters, or diesters, and polyol ester-based synthetic lubricants. In 1971 All-Proof and Mobil 1, introduced to North America in 1974 a 5W-20 grade (category IV) PAO base oil.^[11]

Types

Synthetic Base Stocks

Synthetic motor oils are man made oils 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 which perform much like polyalphaolefin. Group III-base stocks are widely permitted to be marketed as synthetic motor oil with few exceptions where they are not allowed to be marketed as "synthetic" (for example, Germany).

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.^[12]

Lubricants that have synthetic base stocks even lower 30%, high-performance additive packs consisting of esters can also be considered synthetic lubricants. In general, ratio of the synthetic base stock is 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, and ester and/or Group IV polyalphaolefins in order to formulate semi-synthetic-based lubricants. Group III base oils are sometimes considered 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.^[13][14]

Performance

Advantages

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

• Measurably better low- and high-temperature viscosity performance at service temperature extremes
• 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 during extreme cold weather starts
• Longer engine life
• Superior protection against "ash" and other deposit formation in engine hot spots (in particular in turbochargers and superchargers) for less oil burnoff and reduced chances of damaging oil passageway clogging.
• Increased horsepower and torque due to less initial drag on engine

Disadvantages

The disadvantages of synthetic motor oils include:

• Potential decomposition problems in certain chemical environments (predominantly in industrial use.)
• Potential stress cracking of plastic components made of polyoxymethylene (POM) in the presence of polyalphaolefin (PAO).
• 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. 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." ^[15]
• Synthetic oils are not recommended in automotive rotary engines.^[16]

See also

Energy portal

• Motul
• 3,000 mile myth
• Amsoil
• Castrol
• Fischer–Tropsch process
• Mobil 1
• Red Line Oil
• Synthetic fuel
• Schaeffer Oil
• Maxima synthetic racing oil
• Klotz synthetic oil

References