21Manufacture of Lubricating Oil
viscosity index improvers are known: (1) olen copolymers, (2) hydrogenated diene
copolymers, and (3) acrylic acid–based copolymers.
1.6 SYNTHETIC LUBRICATING OIL
Synthetic lubricating oil is a lubricant consisting of chemical compounds that are
articially synthesized, rather than occurring naturally as petroleum constituents
(Rudnick and Shubkin 1999). Synthetic oils may cover a wide range of chemicals
but are generally found within the following categories: (1) synthetic hydrocarbons,
(2)hydrocarbon esters, (3) phosphate esters, (4) glycols, (5) chlorinated hydrocar-
bons, and (6) silicone oils. Synthetic hydrocarbons are similar in composition to
those found in petroleum base oils, but they are synthesized ...