Department of Chemistry John R. Lindsay Smith, Moray S. Stark, Julian J. Wilkinson Department of Chemistry, University of York, York YO10 5DD, UK Peter M. Lee, Martin Priest School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK R. Ian Taylor Shell Global Solutions, Shell Research Ltd., Chester, CH1 3SH, UK Simon Chung Infineum UK Ltd., Milton Hill, Abingdon, Oxfordshire, OX13 6BB, UK The Degradation of Lubricants in Gasoline Engines STLE Annual Meeting : Toronto 17 th - 20 th May 2004
Department of Chemistry John R. Lindsay Smith, Moray S. Stark, Julian J. Wilkinson* Department of Chemistry, University of York, York YO10 5DD, UK Peter M. Lee, Martin Priest School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK R. Ian Taylor Shell Global Solutions, Chester, CH1 3SH, UK Simon Chung Infineum UK Ltd., Milton Hill, Abingdon, Oxfordshire, OX13 6BB, UK The Degradation of Lubricants in Gasoline Engines Julian Wilkinson Part 3: Chemical Mechanisms for the Oxidation of Branched Alkanes
Department of Chemistry Aims Identify products from micro-reactor oxidation. Compare results to engine. Use identified products to propose reaction mechanisms. Ultimately, understand and predict viscosity increase
Department of Chemistry Aims
Department of Chemistry Chemical Mechanisms for the Oxidation of Branched Alkanes Previous Work Branched Alkanes as Base Fluid Models Chemical Analyses Reaction Mechanisms
Department of Chemistry Summary of oxidation ? Viscosity Increase
Department of Chemistry Traditional Model of Hydrocarbon Oxidation Alkane Alkyl radical
Department of Chemistry Traditional Model of Hydrocarbon Oxidation AlkaneAlkyl radical Hydroperoxy radical
Department of Chemistry Traditional Model of Hydrocarbon Oxidation AlkaneAlkyl radical Hydroperoxy radical Hydroperoxide
Department of Chemistry Traditional Model of Hydrocarbon Oxidation Hydroperoxide Alkoxy radical
Department of Chemistry Traditional Model of Hydrocarbon Oxidation Alkoxy radical Alcohol
Department of Chemistry Traditional Model of Hydrocarbon Oxidation HydroperoxideKetone
Department of Chemistry Ease of Abstraction of Hydrogen Atom Vinylic: Very difficult Allylic: Very easy Tertiary: Easy Primary: Difficult Secondary: Moderately difficult Benzylic: Very easy Aromatic: Very difficult
Department of Chemistry Ease of abstraction of H atom
Department of Chemistry Ease of abstraction of H atom
Department of Chemistry Ease of abstraction of H atom Primary: Difficult
Department of Chemistry Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult
Department of Chemistry Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult Tertiary: Easy
Department of Chemistry Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult Allylic: Very easy Tertiary: Easy
Department of Chemistry Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 (random example)
Department of Chemistry Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 (random example)
Department of Chemistry Trimethylheptane Oxidation : 100 – 120 °C D. E. Van Sickle, J. Org. Chem., 37,
Department of Chemistry Trimethylheptane Oxidation : 100 – 120 °C D. E. Van Sickle, J. Org. Chem., 37,
Department of Chemistry Trimethylheptane Oxidation : 100 – 120 °C D. E. Van Sickle, J. Org. Chem., 37,
Department of Chemistry Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 Hexadecane 16 (random example)
Department of Chemistry Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, and 101,
Department of Chemistry Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, and 101,
Department of Chemistry Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, and 101,
Department of Chemistry Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, and 101,
Department of Chemistry Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 Hexadecane 16 Tetramethylpentadecane 19 (random example) (TMPD)
Department of Chemistry Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 Hexadecane 16 TMPD 19 Squalane 30 (random example)
Department of Chemistry Amount of Tertiary Carbons in a Range of Base Fluids McKenna et al. STLE Annual Meeting, Houston, 2002
Department of Chemistry Amount of Tertiary Carbons in a Range of Base Fluids McKenna et al. STLE Annual Meeting, Houston, 2002
Department of Chemistry Oxidation of TMPD time (min) Micro-reactor conditions: 1000 mbar O 2, 200 ºC, 1 minute GC-MS conditions: ZB-5 column, ºC, 6 ºC min -1 impurity
Department of Chemistry Oxidation of TMPD: Ketones time (min) (m/e = +14) Ketone impurity
Department of Chemistry Oxidation of TMPD: Ketones time (min) (m/e = +14)
Department of Chemistry Oxidation of TMPD: Alkanes time (min) Alkane
Department of Chemistry Oxidation of TMPD: Fragmentation time (min) + RH
Department of Chemistry Oxidation of TMPD: Fragmentation time (min) +
Department of Chemistry Oxidation of TMPD : Fragmentation time (min) +
Department of Chemistry Oxidation of TMPD : Alkenes time (min)
Department of Chemistry Possible Mechanisms of Alkene Formation
Department of Chemistry Possible Mechanisms of Alkene Formation
Department of Chemistry Possible Mechanisms of Alkene Formation
Department of Chemistry Possible Mechanisms of Alkene Formation Alcohol Acid
Department of Chemistry Possible Mechanisms of Alkene Formation Alcohol Acid Ester
Department of Chemistry Possible Mechanisms of Alkene Formation Acid Ester Alkene
Department of Chemistry Alkenes and viscosity increase
Department of Chemistry Alkenes and viscosity increase Alkenes could cause large viscosity increase. Dimer (sludge precursor)
Department of Chemistry Oxidation of TMPD : Alcohols time (min) Solvent (MeOH) Conditions: Carbowax column, ºC, 4 ºC min -1
Department of Chemistry Alcohols and viscosity increase Alkanes Weak interactions
Department of Chemistry Alcohols and viscosity increase Alcohols may cause modest viscosity increase Strong interactions (Hydrogen bonding)
Department of Chemistry Oxidation of Squalane Micro-reactor conditions: 1000 mbar O 2, 200 ºC, 2 mins GC conditions: ZB-5 column, ºC, 6 ºC min -1 Time (mins)
Department of Chemistry Products of Squalane Oxidation in Micro-Reactor: Ketones Time (mins)
Department of Chemistry Products of Squalane Oxidation in the Micro-Reactor + Isomers Time (mins) Alkane Alkene
Department of Chemistry Products of Squalane Oxidation in Micro-Reactor: Minor Products
Department of Chemistry Oxidation of TMPD : Fragmentation time (min) + RH O2O2
Department of Chemistry Oxidation of TMPD : Carboxylic acids GC Conditions: FFAP column, ºC 4 ºC min -1 Time (mins)
Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids
Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids
Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids
Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids
Department of Chemistry Oxidation of Squalane: Carboxylic acid detection by GC-MS Carboxylic acids are difficult to detect directly by GC-MS. Have been converted to esters. Carboxylic acid Ester
Department of Chemistry Products of Squalane Oxidation in Engine…..
Department of Chemistry Oxidation of Squalane: Carboxylic acid detection by GC-MS Detected by GC-MS methylated
Department of Chemistry Oxidation of Squalane : Formation of Carboxylic Acids and Ketones (Infra-red spectroscopy) Ketone peak Acid peak
Department of Chemistry Oxidation of Squalane : Formation of Carboxylic Acids and Ketones (Infra-red spectroscopy) Ketone peak After washing with KOH (aq )
Department of Chemistry XHVI™ 8.2 Oxidation in Engine Conditions : Sump Oil Samples, 2000 rpm, 50 % throttle Lubricant : XHVI TM 8.2, 2 % (w/w) sulfonate detergent
Department of Chemistry Oxidation in Engine : Carbonyl vs. Acid Conditions : Sump Oil Samples, 2000 rpm, 50 % load Lubricant : XHVI TM 8.2, 2 % (w/w) sulfonate detergent
Department of Chemistry Carboxylic Acid : Total Carbonyl Ratio Conditions : Sump Oil Samples, 2000 rpm, 50 % throttle Lubricant : XHVI TM 8.2, 2 % w/w sulfonate detergent
Department of Chemistry Comparison of Products in Ring Pack and Micro-Reactor Ring pack sample Micro-reactor, 200 ºC, O 2, 2 minutes
Department of Chemistry Squalane oxidation: Engine Test Squalane + detergent was used as the lubricant in Ricardo-Hydra engine. Samples collected from the sump and ring-pack.
Department of Chemistry Squalane oxidation: Engine Test
Department of Chemistry Conclusions Radical abstraction mainly occurs at tertiary sites. Alkenes very significant, possible sludge precursors. Alcohols could give modest viscosity increase. Not predicted by previous work on model base fluids
Department of Chemistry Conclusions Radical abstraction mainly occurs at tertiary sites. Alkenes very significant, possible sludge precursors. Alcohols could give modest viscosity increase. Not predicted by previous work on model base fluids Acknowledgements Shell Global Solutions