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Antioxidants and their purpose
• A molecule that inhibits the oxidation of other molecules
• They are used as fuel additives when creating fuel blends
Use antioxidants! Dummy!
• Oxidation reactions can produce free radicals leading to chain reactions
• Antioxidants terminate the chain reactions by disrupting radical intermediates
• Antioxidants prevent gumming in gasoline (IC Engines)
• Antioxidants deactivate metals (that cause oxidation) present in fuels
• Antioxidants prevent decomposition of lubricant base stocks
Substituted phenols and derivatives of phenylenediamine – Common antioxidants used to
inhibit gum formation in gasoline
Oxidation of lubricating oils
• Lubricating oils, when poured into engines, go under oxidation in air due to
numerous factors including
• Heat
• High Pressure
• Presence of metals (oxidizing agents)
How antioxidants work ?
• Oxidation takes place in three steps
• Initiation
• Propagation
• Termination
• The antioxidant part
Some common fuel antioxidant additives
• N,N′-Disalicylidene-1,2-propanediamine
• A metal deactivating compound in motor oils
• 2,4-Dimethyl-6-tert-butylphenol
• An anti-gumming agent
References
• Dr. Neil Canter (ed.), Use of antioxidants in automotive lubricants, Tribology and
Lubrication Technology, September 2008. – www.stle.org
• http://www.howstuffworks.com/5-symptoms-of-oil-deposits.htm#page=0
• http://en.wikipedia.org/wiki/Category:Fuel_antioxidants