Moray S. Stark,* Max Smethurst and Alexandra Neal Department of Chemistry, University of York, York...
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Moray S. Stark,* Max Smethurst and Alexandra Neal Department of Chemistry, University of York, York YO10 5DD, UK STLE 2006: Calgary 7 th - 11 th May 2006 Degradation of Methyl Ester Analogues of Vegetable Oils at Elevated Temperatures Department of Chemistry
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Transcript of Moray S. Stark,* Max Smethurst and Alexandra Neal Department of Chemistry, University of York, York...
Moray S. Stark,* Max Smethurst and Alexandra Neal
Department of Chemistry, University of York, York YO10 5DD, UK
STLE 2006: Calgary 7th- 11th May 2006
Degradation of Methyl Ester Analogues of
Vegetable Oils at Elevated Temperatures
Department of Chemistry
[email protected] www.york.ac.uk/res/gkg
Moray S. Stark,* Max Smethurst and Alexandra Neal
Department of Chemistry, University of York, York YO10 5DD, UK
STLE 2006: Calgary 7th- 11th May 2006
Degradation of Methyl Ester Analogues of
Vegetable Oils at Elevated Temperatures
Degradation of Diesel Biofuels In the Sump In Fuel Lines During Storage
Models of Degradation of Vegetable Oil Based Lubricants
As Analogues for the Oxidation of Alkenes Formed by Aldol Condensation of Aldehydes
Department of Chemistry
Degradation of Methyl Ester Analogues of
Vegetable Oils at Elevated Temperatures
Oxidation of Methyl Esters
Department of Chemistry
O
O
O
O
O
O
O
O
Methyl Palmate (e.g. Palm Oil)(Methyl Hexadecanoate)
Methyl Stearate (Methyl Octadecanoate)
Methyl Oleate (e.g. Olive Oil)(methyl cis-9-octadecanoate)
Methyl Linoleate (e.g. Soya Oil)(Methyl cis,cis-9,12-Octadecadienoate)
Derived From Common Commercial Crop Oils
Oxidation of Methyl Esters
Department of Chemistry
O
O
Derived From Common Commercial Crop Oils
Methyl Palmate (e.g. Palm Oil)(Methyl Hexadecanoate)
Methyl Stearate (Methyl Octadecanoate)
Methyl Oleate (e.g. Olive Oil)(methyl cis-9-octadecanoate)
Methyl Linoleate (e.g. Soya Oil)(Methyl cis,cis-9,12-Octadecadienoate)
Bench-Top Reactors
Department of Chemistry
Oxidation Conditions
Sealed Reactor
Initial pressure: 1000 mbar O2
Temperature: 130 ºC – 190 ºC
Sampling: Throughout the reaction
10 sec – 10 hours
+ ROO. .
+ ROOH
Department of Chemistry
Traditional Alkane Oxidation Mechanism
+ ROO. .
+ ROOH
.+ O2
OO
Department of Chemistry
Traditional Alkane Oxidation Mechanism
+ ROO. .
+ ROOH
.+ O2
OO
OO
+ RH
OO
H
+ R.
Department of Chemistry
Traditional Alkane Oxidation Mechanism
+ ROO. .
+ ROOH
.+ O2
OO
OO
+ RH
OO
H
+ R.
OO
H
O
O + H
Department of Chemistry
Traditional Alkane Oxidation Mechanism
H H
+ ROO.
Department of Chemistry
Traditional Alkane Oxidation Mechanism
H H
+ ROO.
Department of Chemistry
Traditional Alkane Oxidation Mechanism
H (C-H) 1 345 5 411 2 kJ mol-1
1: Handbook of Chemistry and Physics, pp9.64 – 9.72, Vol 86, CRC, 2005
H H
+ ROO. .
+ ROOH
Department of Chemistry
Traditional Alkane Oxidation Mechanism
H (C-H) 1 345 5 411 2 kJ mol-1
1: Handbook of Chemistry and Physics, pp9.64 – 9.72, Vol 86, CRC, 2005
H H
+ ROO. .
+ ROOH
.+ O2
OO
OO
+ RH
OO
H
+ R.
OO
H
O
O + H
Department of Chemistry
Traditional Alkane Oxidation Mechanism
1: Handbook of Chemistry and Physics, pp9.64 – 9.72, Vol 86, CRC, 2005
H (C-H) 1 345 5 411 2 kJ mol-1
Oxidation of Methyl Oleate : GC Analysis
Department of Chemistry
Oxidation Conditions: 170 ºC, 20 minutes
GC conditions: ZB-5 column, 50-340 ºC, 6 ºC min-1
Product Identification: EI-MS and CI-MS
Time (min)
Oxidation of Methyl Oleate : GC Analysis
Department of Chemistry
Oxidation Conditions: 170 ºC, 20 minutes
GC conditions: ZB-5 column, 50-340 ºC, 6 ºC min-1
Product Identification: EI-MS and CI-MS
O
O
Time (min)
Oxidation of Methyl Oleate : GC Analysis
Department of Chemistry
Oxidation Conditions: 170 ºC, 20 minutes
GC conditions: ZB-5 column, 50-340 ºC, 6 ºC min-1
Product Identification: EI-MS and CI-MS
O
O
Time (min)
x 6
Oxidation of Methyl Oleate : Epoxides
Department of Chemistry
Time (min)
O
OO
O
OO
Oxidation of Methyl Oleate : Epoxides
Department of Chemistry
0
20
40
60
80
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
trans epoxidecis epoxide
O
OO
O
OO
Oxidation Conditions: 170 ºC
Department of Chemistry
Epoxide Formation Mechanism
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586 M. S. Stark, J. Am. Chem. Soc. 2000, 122, 4162-4170G. Lercker, et al., J. Chromatography A. 2003, 985, 333-342
O
O
+RO2.
Department of Chemistry
Epoxide Formation Mechanism
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586 M. S. Stark, J. Am. Chem. Soc. 2000, 122, 4162-4170G. Lercker, et al., J. Chromatography A. 2003, 985, 333-342
O
O
+RO2. O
OOO
R
.
Department of Chemistry
Epoxide Formation Mechanism
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586 M. S. Stark, J. Am. Chem. Soc. 2000, 122, 4162-4170G. Lercker, et al., J. Chromatography A. 2003, 985, 333-342
O
O
+RO2. O
OOO
R
.
O
OOO
R
.
Department of Chemistry
Epoxide Formation Mechanism
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586 M. S. Stark, J. Am. Chem. Soc. 2000, 122, 4162-4170G. Lercker, et al., J. Chromatography A. 2003, 985, 333-342
O
O
+RO2. O
OOO
R
.
O
OOO
R
.
Department of Chemistry
Epoxide Formation Mechanism
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586 M. S. Stark, J. Am. Chem. Soc. 2000, 122, 4162-4170G. Lercker, et al., J. Chromatography A. 2003, 985, 333-342
O
O
+RO2. O
OOO
R
.
O
OOO
R
.O
O
OO
R
.
Department of Chemistry
Epoxide Formation Mechanism
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586 M. S. Stark, J. Am. Chem. Soc. 2000, 122, 4162-4170G. Lercker, et al., J. Chromatography A. 2003, 985, 333-342
O
O
+RO2. O
OOO
R
.
O
OOO
R
.O
O
OO
R
.
O
OO
+ RO. O
O
O+ RO.
Department of Chemistry
Reactions of Alkoxyl Radicals (e.g. 11-alkoxyl)
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586
O
O
O.O
O
O
.+ O2 + HO2
Department of Chemistry
Reactions of Alkoxyl Radicals (e.g. 11-alkoxyl)
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586
O
O
O.
O
O
O.
O
O
O
.+ O2 + HO2
O
O
OH
.+ RH + R
Oxidation of Methyl Oleate : Ketones and Alcohols
Department of Chemistry
Time (min)
O
O
O
O
O
OH
e.g.
e.g.
Oxidation of Methyl Oleate : Alcohols and Ketones
Department of Chemistry
Oxidation Conditions: 170 ºC
0
20
40
60
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
ketomethyl oleateshydroxymethyl oleates
O
O
OH
O
O
O
e.g.
e.g.
Department of Chemistry
Reactions of Alkoxyl Radicals (e.g. 11-alkoxyl)
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586
O
O
O.
O
O
O.
O
O
O
.+ O2 + HO2
O
O
OH
.+ RH + R
O
O
O.O
O
O+.
Methyl-11-oxoundec-9-enoateHeptyl radical
Department of Chemistry
Reactions of Alkoxyl Radicals (e.g. 11-alkoxyl)
C. B. Whitlock, J. Am. Oil Chem. Soc., 1976, 53, 586
O
O
O.
O
O
O.
O
O
O
.+ O2 + HO2
O
O
OH
.+ RH + R
O
O
O.O
O
O+.
+ RH
O
+ O2
Heptanal
Methyl-11-oxoundec-9-enoate
Heptane
Oxidation of Methyl Oleate : Alkoxyl Fragmentation
Department of Chemistry
Time (min)
O
O
O
OHeptanal
Methyl-11-oxoundec-9-enoate
Heptane
0
2
4
6
8
10
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
Methyl-11-oxoundec-9-enoateHeptaneHeptanal
Oxidation of Methyl Oleate : Volatile Products
Department of Chemistry
Oxidation Conditions: 170 ºC
O
O
O
O
Department of Chemistry
Formation of Alkoxyl Radicals
E. N. Frankel, W. E. Neff, W. K. Rohwedder, Lipids, 1977, 12, 901-907 E. N. Frankel, et al., J. C. S. Perkin Trans. I, 1984, 2233
O
O
.11
Department of Chemistry
Formation of Alkoxyl Radicals
E. N. Frankel, W. E. Neff, W. K. Rohwedder, Lipids, 1977, 12, 901-907 E. N. Frankel, et al., J. C. S. Perkin Trans. I, 1984, 2233
O
O.9O
O
.11
Department of Chemistry
Formation of Alkoxyl Radicals
E. N. Frankel, W. E. Neff, W. K. Rohwedder, Lipids, 1977, 12, 901-907 E. N. Frankel, et al., J. C. S. Perkin Trans. I, 1984, 2233
O
O.9
O
OOO
+ O2 .
9
OO
O
O
+ O2
.
11
O
O
.11
Department of Chemistry
Formation of Alkoxyl Radicals
E. N. Frankel, W. E. Neff, W. K. Rohwedder, Lipids, 1977, 12, 901-907 E. N. Frankel, et al., J. C. S. Perkin Trans. I, 1984, 2233
O
O.9
O
OOO
+ O2 .
9
O
O
O.
11
O
OO
9
.
OO
O
O
+ O2
.
11
O
O
.11
Department of Chemistry
Formation of Alkoxyl Radicals
E. N. Frankel, W. E. Neff, W. K. Rohwedder, Lipids, 1977, 12, 901-907 E. N. Frankel, et al., J. C. S. Perkin Trans. I, 1984, 2233
O
O
O
O
OO
O
O
O
O
OO
O
O
O
O
O
O
.8
+ O2 + O2
.
8
.10
.
10
.
8
.
10
Department of Chemistry
Formation of Alkoxyl Radicals
E. N. Frankel, W. E. Neff, W. K. Rohwedder, Lipids, 1977, 12, 901-907 E. N. Frankel, et al., J. C. S. Perkin Trans. I, 1984, 2233
O
O
O
O
O
O
O
O
O
O
OO
.
8
.
10
.
11
.
9
Oxidation of Methyl Oleate : Alkoxyl Fragmentation
Department of Chemistry
Time (min)
O
O
O.
8O
O
O.
10
O
O
O.
11O
OO.
9
Oxidation of Methyl Oleate : Dehydrodimers
Department of Chemistry
Time (min)
e.g. O
O
O
O
Oxidation of Methyl Oleate : Dehydrodimers
Department of Chemistry
Time (min)
O
O
O
OO
O
O
O
.+ .
Oxidation of Methyl Oleate : Polymeric Products
Department of Chemistry
Oxidation Conditions: 170 ºC
0
2
4
6
8
10
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
dehydrodimers
O
O
O
O
e.g.
Simulation of Methyl Oleate Oxidation
Department of Chemistry
Chemical Mechanism Based on 2-Butene Oxidation
Simulation of Methyl Oleate Oxidation
Department of Chemistry
MeO + O2 => allyl + HO2
allyl + O2 => allylO2
allylO2 + MeO => allylO2H + allyl
allylO2H => allylO + OH
allylO2 + MeO => tepox + allylO
allylO2 + MeO => cepox + allylO
allylO + O2 => allylket + HO2
allylO + MeO => allylOH + allyl
allyl + allyl => dimer
allylO2 + allylO2 => allylO + allylO + O2
allylO2 + allylO2 => allylket + allylOH + O2
HO2 + MeO => tepox + OH
HO2 + MeO => cepox + OH
HO2 + MeO => allyl + H2O2
OH + MeO => H2O + allyl
allylO => ald1 + alkyl
alkyl + MeO => alkane + allyl
alkyl + O2 => alkylO2
alkylO2 + MeO => tepox + alkylO
alkylO2 + MeO => cepox + alkylO
alkylO + O2 => ald2 + HO2
Chemical Mechanism Based on 2-Butene Oxidation
24 reactions 22 species (7 products)
Simulation of Methyl Oleate Oxidation : Epoxides
Department of Chemistry
0
20
40
60
80
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
trans epoxidecis epoxide
O
OO
O
OO
Oxidation Conditions: 170 ºC
Simulation of Methyl Oleate Oxidation : Epoxides
Department of Chemistry
O
OO
O
OO
Oxidation Conditions: 170 ºC
0
20
40
60
80
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
trans epoxidecis epoxide
0
20
40
60
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
ketomethyl oleateshydroxymethyl oleates
Simulation of Oxidation : Alcohols and Ketones
Department of Chemistry
Oxidation Conditions: 170 ºC
O
O
OH
e.g.
O
O
O
e.g.
0
20
40
60
0 10 20 30 40
Time (min)
Co
nc
en
tra
tio
n (
10-3
mo
l dm
-3)
ketomethyl oleateshydroxymethyl oleates
Simulation of Oxidation : Alcohols and Ketones
Department of Chemistry
Oxidation Conditions: 170 ºC
O
O
OH
O
O
O
e.g.
e.g.
Conclusions
Time Development of Oxidation Products Measured
Epoxides of Dominant Products
Epoxidation Dominant Fate of Peroxyl Radicals
Fragmentation of Alkoxyl Radicals Also Significant
Many Alkane Products Formed, Even in Presence of O2
Chemical Kinetics Model of Oxidation Developed
Department of Chemistry
Future Work
Link Viscosity Change to Product Formation Study Polymeric Products by HPLC-GPC Complete Computer Simulation of Oxidation
Acknowledgements Trevor Dransfield (University of York) for GC-MS
Moray Stark [email protected] www.york.ac.uk/res/gkg
