Base oils are important basic raw materials for any lubes,viz., engine oils, gear oils, industrial oils, metal working fluids,hydraulic oils & greases. All lubricants consist of a base oil. Normally, lubricants consist of 90% base oil and 10% additives. As per API classification Base oils can be grouped majorly into five groups, i.e., Group-I/II/III/IV/V.

The most common one is a type of paraffinic crude oil, although there are also naphthenic crude oils that create products with better solubility and very good properties at low temperatures. By using hydrogenation technology, in which sulfur and aromatics are removed using hydrogen under high pressure, you can obtain extremely pure base oils, which are suitable when quality requirements are particularly stringent.