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Department of Chemistry John R. Lindsay Smith, Moray S. Stark, Julian J. Wilkinson Department of Chemistry, University of York, York YO10 5DD, UK Peter.

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Presentation on theme: "Department of Chemistry John R. Lindsay Smith, Moray S. Stark, Julian J. Wilkinson Department of Chemistry, University of York, York YO10 5DD, UK Peter."— Presentation transcript:

1 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

2 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 jjw102@york.ac.uk www.york.ac.uk/res/gkg Part 3: Chemical Mechanisms for the Oxidation of Branched Alkanes

3 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

4 Department of Chemistry Aims

5 Department of Chemistry Chemical Mechanisms for the Oxidation of Branched Alkanes  Previous Work  Branched Alkanes as Base Fluid Models  Chemical Analyses  Reaction Mechanisms

6 Department of Chemistry Summary of oxidation ? Viscosity Increase

7 Department of Chemistry Traditional Model of Hydrocarbon Oxidation Alkane Alkyl radical

8 Department of Chemistry Traditional Model of Hydrocarbon Oxidation AlkaneAlkyl radical Hydroperoxy radical

9 Department of Chemistry Traditional Model of Hydrocarbon Oxidation AlkaneAlkyl radical Hydroperoxy radical Hydroperoxide

10 Department of Chemistry Traditional Model of Hydrocarbon Oxidation Hydroperoxide Alkoxy radical

11 Department of Chemistry Traditional Model of Hydrocarbon Oxidation Alkoxy radical Alcohol

12 Department of Chemistry Traditional Model of Hydrocarbon Oxidation HydroperoxideKetone

13 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

14 Department of Chemistry Ease of abstraction of H atom

15 Department of Chemistry Ease of abstraction of H atom

16 Department of Chemistry Ease of abstraction of H atom Primary: Difficult

17 Department of Chemistry Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult

18 Department of Chemistry Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult Tertiary: Easy

19 Department of Chemistry Ease of abstraction of H atom Primary: Difficult Secondary: Moderately difficult Allylic: Very easy Tertiary: Easy

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

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

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

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

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

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

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

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

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

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

30 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)

31 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)

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

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

34 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, 50-300 ºC, 6 ºC min -1 impurity

35 Department of Chemistry Oxidation of TMPD: Ketones time (min) (m/e = +14) Ketone impurity

36 Department of Chemistry Oxidation of TMPD: Ketones time (min) (m/e = +14)

37 Department of Chemistry Oxidation of TMPD: Alkanes time (min) Alkane

38 Department of Chemistry Oxidation of TMPD: Fragmentation time (min) + RH

39 Department of Chemistry Oxidation of TMPD: Fragmentation time (min) +

40 Department of Chemistry Oxidation of TMPD : Fragmentation time (min) +

41 Department of Chemistry Oxidation of TMPD : Alkenes time (min)

42 Department of Chemistry Possible Mechanisms of Alkene Formation

43 Department of Chemistry Possible Mechanisms of Alkene Formation

44 Department of Chemistry Possible Mechanisms of Alkene Formation

45 Department of Chemistry Possible Mechanisms of Alkene Formation Alcohol Acid

46 Department of Chemistry Possible Mechanisms of Alkene Formation Alcohol Acid Ester

47 Department of Chemistry Possible Mechanisms of Alkene Formation Acid Ester Alkene

48 Department of Chemistry Alkenes and viscosity increase

49 Department of Chemistry Alkenes and viscosity increase Alkenes could cause large viscosity increase. Dimer (sludge precursor)

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

51 Department of Chemistry Alcohols and viscosity increase Alkanes Weak interactions

52 Department of Chemistry Alcohols and viscosity increase  Alcohols may cause modest viscosity increase Strong interactions (Hydrogen bonding)

53 Department of Chemistry Oxidation of Squalane Micro-reactor conditions: 1000 mbar O 2, 200 ºC, 2 mins GC conditions: ZB-5 column, 50-300 ºC, 6 ºC min -1 Time (mins)

54 Department of Chemistry Products of Squalane Oxidation in Micro-Reactor: Ketones Time (mins)

55 Department of Chemistry Products of Squalane Oxidation in the Micro-Reactor + Isomers Time (mins) Alkane Alkene

56 Department of Chemistry Products of Squalane Oxidation in Micro-Reactor: Minor Products

57 Department of Chemistry Oxidation of TMPD : Fragmentation time (min) + RH O2O2

58 Department of Chemistry Oxidation of TMPD : Carboxylic acids GC Conditions: FFAP column, 50-250 ºC 4 ºC min -1 Time (mins)

59 Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids

60 Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids

61 Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids

62 Department of Chemistry Reactions of Primary Alkyl Radicals : Formation of Carboxylic Acids

63 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

64 Department of Chemistry Products of Squalane Oxidation in Engine…..

65 Department of Chemistry Oxidation of Squalane: Carboxylic acid detection by GC-MS Detected by GC-MS methylated

66 Department of Chemistry Oxidation of Squalane : Formation of Carboxylic Acids and Ketones (Infra-red spectroscopy) Ketone peak Acid peak

67 Department of Chemistry Oxidation of Squalane : Formation of Carboxylic Acids and Ketones (Infra-red spectroscopy) Ketone peak After washing with KOH (aq )

68 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

69 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

70 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

71 Department of Chemistry Comparison of Products in Ring Pack and Micro-Reactor Ring pack sample Micro-reactor, 200 ºC, O 2, 2 minutes

72 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.

73 Department of Chemistry Squalane oxidation: Engine Test

74 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

75 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


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