When choosing engine oil, many car enthusiasts often wonder whether the “Full Synthetic” label on the bottle actually uses true PAO (Group IV), Esters (Group V), or highly hydrocracked VHVI (Group III) base oils. The most objective and direct way to uncover the mystery of an engine oil’s formulation is to check its Safety Data Sheet (SDS / MSDS).

In an SDS document, each chemical component is labeled with a unique CAS Number (Chemical Abstracts Service Registry Number), which acts as the “ID card” for chemical substances. To help you quickly decode these cryptic codes, this article compiles a reference table of CAS numbers for the most common base oils (Group I ~ V) and core additives (such as ZDDP, detergents, dispersants, etc.) found in engine oil formulations. Whether you want to verify the actual ingredients or are simply interested in the science of lubricants, this table will be a practical lookup tool.

Category CAS Number Description
Group IV
(PAO Synthetics)
68037-01-4 1-Decene, homopolymer, hydrogenated
  68649-12-7 1-decene Tetramer, Mixed With 1-decene Trimer, hydrogenated
  68649-11-6 1-Decene, Dimer, Hydrogenated
  163149-29-9
(and 8002-05-9)
1-Decene, Homopolymer, Hydrogenated; Polymer of Octene, Decene, 163149-29-9; (8002-05-9), and Dodecene, Hydrogenated; C8, C12 Olefin Polymer, Hydrogenated
  151006-63-2 1-Dodecene, Homopolymer, Hydrogenated
  151006-62-1 1-Dodecene, Trimer, Hydrogenated
  151006-60-9 1-DODECENE, POLYMER WITH 1-DECENE, HYDROGENATED
  163149-28-8 1-DECENE, POLYMER WITH 1-OCTENE AND 1-DODECENE, HYDROGENATED
Group III
(GTL Gas-to-Liquid)
848301-69-9 Distillates (Fischer-Tropsch), heavy, C18-50–branched, cyclicand linear
  1262661-88-0 Distillates (Fischer-Tropsch), heavy, C18-50-branched and linear
Group III
(VHVI Hydrocracked)
64741-89-5 HIGHLY HYDROTREATED PARAFFINIC BASE OILS
  64742-54-7 HIGHLY HYDROTREATED PARAFFINIC BASE OILS
  64742-55-8 HIGHLY HYDROTREATED PARAFFINIC BASE OILS
  64742-70-7 Paraffin oils (petroleum), catalytic dewaxed heavy
  72623-87-1 Severely Hydrotreated Paraffinic Hydrocarbons (Oil)
  72623-85-9 Lubricating oils (petroleum), C20-50, hydrotreated neutral oil-based, high-viscosity
  72623-86-0 Hydrotreated Neutral Oil-Based
  178603-64-0 Gas oils, petroleum, vacuum, hydrocracked, hydroisomerized, hydrogenated, C15-30, branched and cyclic, high viscosity index; Severely hydrotreated, hydorcracked, hydroisomerized, high viscosity synthetic iso-alkane
  178603-65-1 Gas oils, petroleum, vacuum, hydrocracked, hydroisomerized, hydrogenated, C20-40, branched and cyclic, high viscosity index
  178603-66-2 Gas oils, petroleum, vacuum, hydrocracked, hydroisomerized, hydrogenated, C25-55, branched and cyclic, high viscosity index
Group I / II
(Mineral Oils)
64741-50-0 Distillates, petroleum, light paraffinic
  64741-50-5 Distillates(Petroleum), Light Paraffinic
  64741-52-2 Distillates, petroleum, light naphthenic
  64742-65-0 Distillates (petroleum), solvent-dewaxed heavy paraffinic
  64742-55-8 HIGHLY HYDROTREATED PARAFFINIC BASE OILS
  64742-58-1 Lubricating oils (petroleum), hydrotreated spent
  64742-56-9 Distillates (petroleum), solvent-dewaxed light paraffinic
  64742-62-7 Residual oils (petroleum), solvent-dewaxed
Group V
(Esters / Others)
27178-16-1 DIISODECYL ADIPATE
  16958-92-2 ESTER SYNTHETIC BASE OILS
  28472-97-1 di-isodecyl azelate is a diester basestock
  9003-13-8 Polyalkylene glycol (PAG)
Anti-wear Additives
(ZDTP / ZDDP)
68649-42-3 ZINC DIALKYL DITHIOPHOSPHATE ZDTP
  84605-29-8 Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts
Friction Modifiers
(MoDTC / MoDTP)
68958-92-7 Moly Dithiophosphate
  68958-92-9 molybdenum di(2-ethylhexyl) phosphorodithioate
Antioxidants 36878-20-3 Bis(nonylphenyl)amine
  128-39-2 2,6-di-tert-butylphenol
Detergents 61789-86-4 Calcium petroleum sulfonate
  68783-96-0 Sulfonic acids, petroleum, calcium salts, overbased
  115733-09-0 Calcium long-chain alkyl phenate sulfide
Dispersants No CAS Polyolefin polyamine succinimide, polyol
  296-404-1
(EC Number)
PHOSPHORIC ACID ESTERS
  84605-20-9 Polyisobutylene succinimide (PIBSI)
Viscosity Modifiers
(VM)
25038-36-2 Olefin Copolymer
  127883-08-3 Aryl polyolefin, Ethylene/Propylene
Pour Point Depressants
(PPD)
No CAS POLY METHYL METHACRYLATE ESTER
Anti-foam 63148-62-9 Polydimethylsiloxane (Silicone oil)

References