Mineral Oils - Nature’s Synthesis
Paraffinic
Cyclic/Aromatic
Low cost
Big mixture
Mineral Oil
Mineral oil refining removes many of the least desirable
components (e.g. aromatics, waxes) and modifies the rest
(e.g. hyrofinishing, hydrodewaxing and/or hydroprocessing)
Base Stock Component Properties
Paraffins Iso-Paraffins Naphthenes Aromatics
VI
very high
high
medium/low
lowest
high
low
lower
lowest
Traction
lowest
low
Volatility
low
low
higher
highest
Solvency
poor
fair
good
excellent
Oxidation
Resistance
good
good
lower
resistance
easily
oxidized
Pour point
medium/high medium/high
Synthetic Base stocks
• Synthesized hydrocarbons
• Synthesized non-hydrocarbons (typically containing
oxygen atoms)
Synthesized hydrocarbons
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•
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Polyalphaolefins
Polybutenes
Alkylated aromatics
Cycloaliphatics
Polyalphaolefins (PAO)
• Chain molecular structures synthesized from ethylene
polymerization
• High VI and high oxidation stability
• Low pour point, low traction and volatility
• Best as engine oil basestock. Most popular PAO is
polydecenes, which is the basestock of Mobil 1
Polymerization of ethylene
PAO Manufacture
R - CH = CH2
Polymerization
Hydrogenation
3
Hydrogenated trimers,
tetramers, etc.
Alpha-olefins
1-Decene
R - CH CH2 - CH H
CH
R x
Polydecene
“Ideal”
Actual
Synthetic Polyalphaolefin (PAO)
Hydrogenated Polydecene
From Crude Oil to Synthetic Lubricants
Synthetics are usually sourced from crude oil
Many manufacturing steps result in high cost
Crude Oil
Atmospheric
1-Decene
Distillation
Catalytic
Polymerization
Distillation
Distillation
Synthetic
Lubricants
Sales &
Marketing
Cracker Feed
Alphaolefins
Catalytic
Catalytic
Cracking
Polymerization
Hydrogenation
Blending
Polydecene
Formulation
Light Olefins
Separation
Ethylene
Additives
On sale at Walmart for $5.00
Polybutenes
• Synthezied through controlled polymerization of butenes and
isobutenes
• High dielectrics constant – electrical insulating oils
• Low thermal stability – metal working and compressor lubes
to decompose to gases
• High molecular weight polybutenes or polyisobutenes are
used as VI improvers
Alkylated aromatics
• Synthesized from alkylation of benzenes
• Very low pour point and low viscosity – subzero
temperature applications
Cycloaliphatics
• Synthesized naphthenes, multi-ring-structured molecules
• Develop a glasslike structure under high stresses to yield high
traction
• Used as traction-drive fluids, also used in rolling bearings to
reduce roller skidding
Synthesized non-hydrocarbons
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Organic esters
Polyglycols
Phosphate esters
Silicate esters
Polyphenyl esters
Organic esters
• Dibasic acid esters:
• Polyol esters:
Wide temperature range and good thermal stability
Used as base stocks for essentially all jet engine lubes
Polyglycols
• The largest single class of synthetic lubricant bases
• High VI and low pour point
• Used mainly as brake fluids and hydraulic fluids
Phosphate esters
• High fire resistance
• Used mainly as hydraulic fluids and compressor lubes
• Also used as antiwear additives by its formation of
phosphide films on metal surfaces
Silicate ester
• Extremely high VI > 300
• Used mainly as heat exchanger fluids
Polyphenyl esters
• Most thermally and oxidatively stable
• Used mainly as heat transfer fluids
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