BASE OIL Is the name given to lubrication grade oils initially produced from refining crude oil (mineral base oil) or through chemical synthesis (synthetic base oil). Base oil is typically defined as oil with a boiling point range between 550 and 1050 F, consisting of hydrocarbons with 18 to 40 carbon atoms. They are typically high flash point and heavy in nature as compared to other crude oil distillates and mainly used for lubrication of machinery as well as for cosmetic applications . they are classified into several groups mainly depending on the process of manufacture and purity.
GROUP 1
The least refined type which produced by Solvent Refining. It usually consists of conventional petroleum base oils.
GROUP 2
Better grade of petroleum base oil, which may be partially produced by Hyrocracking.
GROUP 3
It is also known as synthetic base oils and is the best grade of petroleum base oil, since they are fully produced by Hyrocracking, which make these oils purer.
GROUP 4
Consists of synthetic oils made of Poly-alpha-olfiens PAO. Poly-alpha-olfiens PAO oils are much more stable in extreme temperatures, which make much more suitable for use in very cold weather (as found in northern Europe) as well as very hot weather (as in Middle East).
GROUP 5
Any type of base oil other than mentioned in the previously defined groups. They include, among others, naphthenic oils[6] and esters.