The document discusses the five categories of base oils used in lubricants as defined by the American Petroleum Institute. Group I-III oils are refined from petroleum, Group IV are full synthetic polyalphaolefin oils, and Group V includes other base oils. It provides details on the characteristics of Group I and II base oils, noting Group I oils are cheaper but have fewer saturated molecules, while Group II oils are more refined but also more common and competitively priced. The document also mentions paraffinic, naphthenic and aromatic base oil types as well as differences between synthetic and mineral base oils and monograde and multigrade oils.

1. BASIC BASE OILS
CHEMISTRY

2. • Almost every lubricant used in plants today started off as
just a base oil.
• The American Petroleum Institute (API) has categorized
base oils into five categories (API 1509, Appendix E).
• The first three groups are refined from petroleum crude oil.
• Group IV base oils are full synthetic (polyalphaolefin) oils.
• Group V is for all other base oils not included in Groups I
through IV.
• Before all the additives are added to the mixture,
lubricating oils begin as one or more of these five API
groups.

3. BASE OIL DIFFERENCES

4. GROUP 1 BASE OILS
• Group I base oils are classified as less than 90
percent saturates, greater than 0.03 percent
sulphur and with a viscosity-index range of 80
to 120.
• Group I base oils are solvent-refined, which is
a simpler refining process.
• This is why they are the cheapest base oils on
the market.

5. GROUP 2 BASE OILS
• Group 2 base oils are defined as being more than 90
percent saturates, less than 0.03 percent sulphur and with
a viscosity index of 80 to 120.
• They are often manufactured by hydrocracking, which is a
more complex process than what is used for Group 1 base
oils.
• Since all the hydrocarbon molecules of these oils are
saturated, Group 2 base oils have better anti-oxidation
properties.
• They also have a clearer colour and cost more in
comparison to Group I base oils.
• Still, Group 2 base oils are becoming very common on the
market today and are priced very close to Group 1 oils.

6. Paraffinic, Naphthenic and Aromatics

7. Synthetics Vs Mineral

8. Monograde Vs Multigrade Oils

9. Monograde Vs Multigrade