A Synthetic Lubricant is a Product That is Made From a Chemical Reaction

A synthetic lubricant is a product that is made from a chemical reaction (synthesis) of two or more simpler chemical compounds and also containing the necessary performance additives. The base stocks that form a synthetic lubricant are tailored through molecular restr ucturing in order to meet specific physical and chemical characteristics. Some of the most common synthetic lubricants are listed below

1. Polyglycol fluids- Polyalkylene Glycol, Polyglycol Ethers, Polyalkalylene Glycol Ethers 2. Silicones 3. Esters: Diesters (Dibasic Acid Esters) 4. Esters: Polyolesters (Neopentyl Poly Esters) 5. Polymerized alpha olefin: Polyalphaolefin, Polyalphaolefin, Olefin Polymers, Olefin OligomersOligomers- synthetic hydrocarbons 6. Alkylated Aromatics- Dialkylbenzenes- a synthetic hydrocarbon 7. Phosphate Esters There are many hundreds more types of synthetic lubricants and chemical variations variations of these synthetic lubricants. There is also no one specific synthetic lubricant that is superior in all respects, although a particular synthetic lubricant may possess certain specific advantages for a specific application. The

synthetic lubricants listed in this book account for the majority of the volume of synthetic lubricant base stocks now used.

Synthetic motor oil is thinner than regular motor o il but withstands high and low temperatures slightly better than regular motor oil and therefore recommended for high performance racing engines or for use in very extreme hot and/or very extreme cold climates. Synthetic oil takes slightly longer to breakdown before losing its lubricating properties which translates into longer time periods betwee n oil changes but it still requires periodic oil changes. Full-synthetic oil is recommended for extreme cold climate start-ups because its thinness makes it less sticky and less tacky betwee n the moving metal parts of a cold engine which makes it easier for cold engines to turn-over compared to using regular motor o il which is a thicker oil but then it's the same reason why 5W(Winter)/40 or higher multi -weight motor oil is recommended for extreme temperature temper ature climates rather than choosing 10W/30. But synthetic oil is warned against using during a new engine's break-in per iod and also warned against using in engines prone to leakage because the thinness of the synthetic oil increases leakage particularly in older engines.

Semi-synthetic motor oil is said to offer many same exact advantages as full-synthetic but at around half  the price or so.

Read more: http://wiki.answers.com/Q/Why_use_synthetic_or_semisynthetic_motor_oil#ixzz1uIb1mgxi emi-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 w ithout matching the cost of pure synthetic oil. Motul introduced the first semi-synthetic motor oil in 1966.[14]

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. Advantages

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

Measurably better low- and high-temperature viscosity performance at service temperature extreme s 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 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 r aw materials. Synthetic oil is used as a substitute for lubricant refined from petroleum when operating in ex tremes 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.