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John R. Lindsay Smith, Moray S. Stark, Julian J. Wilkinson

The Degradation of Lubricants in Gasoline Engines. STLE Annual Meeting : Toronto 17 th - 20 th May 2004. 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

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John R. Lindsay Smith, Moray S. Stark, Julian J. Wilkinson

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  1. The Degradation of Lubricants in Gasoline Engines STLE Annual Meeting : Toronto 17th- 20th May 2004 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

  2. The Degradation of Lubricants in Gasoline Engines Part 3: Chemical Mechanisms for the Oxidation of Branched Alkanes 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 Julian Wilkinson jjw102@york.ac.uk www.york.ac.uk/res/gkg

  3. Aims • Identify products from micro-reactor oxidation. • Compare results to engine. • Use identified products to propose reaction mechanisms. • Ultimately, understand and predict viscosity increase

  4. Aims

  5. Chemical Mechanisms for the Oxidation of Branched Alkanes • Previous Work • Branched Alkanes as Base Fluid Models • Chemical Analyses • Reaction Mechanisms

  6. Summary of oxidation ? Viscosity Increase

  7. Traditional Model of Hydrocarbon Oxidation Alkyl radical Alkane

  8. Traditional Model of Hydrocarbon Oxidation Alkane Alkyl radical Hydroperoxy radical

  9. Traditional Model of Hydrocarbon Oxidation Alkane Alkyl radical Hydroperoxy radical Hydroperoxide

  10. Traditional Model of Hydrocarbon Oxidation Hydroperoxide Alkoxy radical

  11. Traditional Model of Hydrocarbon Oxidation Alcohol Alkoxy radical

  12. Traditional Model of Hydrocarbon Oxidation Hydroperoxide Ketone

  13. Ease of abstraction of H atom

  14. Ease of abstraction of H atom

  15. Ease of abstraction of H atom Primary: Difficult

  16. Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult

  17. Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult Tertiary: Easy

  18. Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult Allylic: Very easy Tertiary: Easy

  19. Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 (random example)

  20. Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 (random example)

  21. Trimethylheptane Oxidation : 100 – 120 °C D. E. Van Sickle, J. Org. Chem., 37, 755 1972

  22. Trimethylheptane Oxidation : 100 – 120 °C D. E. Van Sickle, J. Org. Chem., 37, 755 1972

  23. Trimethylheptane Oxidation : 100 – 120 °C D. E. Van Sickle, J. Org. Chem., 37, 755 1972

  24. Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 Hexadecane 16 (random example)

  25. Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, 1742 1981 and 101, 7574 1979

  26. Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, 1742 1981 and 101, 7574 1979

  27. Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, 1742 1981 and 101, 7574 1979

  28. Hexadecane Oxidation : 120 – 180 °C Jensen et al, J. Am. Chem. Soc., 103, 1742 1981 and 101, 7574 1979

  29. Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 Hexadecane 16 Tetramethylpentadecane 19 (random example) (TMPD)

  30. Models of Hydrocarbon Base-Fluids No. of Carbons XHVI™ 8.2 (average) 39 Trimethylheptane 10 Hexadecane 16 TMPD 19 Squalane 30 (random example)

  31. Amount of Tertiary Carbons in a Range of Base Fluids McKenna et al. STLE Annual Meeting, Houston, 2002

  32. Amount of Tertiary Carbons in a Range of Base Fluids McKenna et al. STLE Annual Meeting, Houston, 2002

  33. Oxidation of TMPD Micro-reactor conditions: 1000 mbar O2, 200 ºC, 1 minute GC-MS conditions: ZB-5 column, 50-300 ºC, 6 ºC min-1 time (min) impurity

  34. Oxidation of TMPD: Ketones Ketone (m/e = +14) time (min) impurity

  35. Oxidation of TMPD: Ketones (m/e = +14) time (min)

  36. Oxidation of TMPD: Alkanes Alkane time (min)

  37. Oxidation of TMPD: Fragmentation + RH time (min)

  38. Oxidation of TMPD: Fragmentation + time (min)

  39. Oxidation of TMPD: Fragmentation + time (min)

  40. Oxidation of TMPD: Alkenes time (min)

  41. Possible Mechanisms of Alkene Formation

  42. Possible Mechanisms of Alkene Formation Alcohol Acid Ester

  43. Possible Mechanisms of Alkene Formation Alkene Acid Ester

  44. Alkenes and viscosity increase

  45. Alkenes and viscosity increase Dimer (sludge precursor) • Alkenes could cause large viscosity increase.

  46. Oxidation of TMPD: Alcohols Solvent (MeOH) time (min) Conditions: Carbowax column, 50-250 ºC, 4 ºC min-1

  47. Alcohols and viscosity increase Weak interactions Alkanes

  48. Alcohols and viscosity increase Strong interactions (Hydrogen bonding) • Alcohols may cause modest viscosity increase

  49. Oxidation of Squalane Micro-reactor conditions: 1000 mbar O2, 200 ºC, 2 mins GC conditions: ZB-5 column, 50-300 ºC, 6 ºC min-1 Time (mins)

  50. Products of Squalane Oxidation in Micro-Reactor: Ketones Time (mins)

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