MINOR PRODUCTS ANALYSIS DURING THE LOW-TEMPARATURE...

The 7th InternationalThe 7th International ConferenceConferenceThe 7th International The 7th International ConferenceConferenceon on ChemicalChemical kineticskinetics

July 10July 10--14, 201114, 2011MIT, Cambridge (USA)MIT, Cambridge (USA)MIT, Cambridge (USA)MIT, Cambridge (USA)

MINOR PRODUCTS ANALYSIS DURING THE MINOR PRODUCTS ANALYSIS DURING THE LOWLOW--TEMPARATURE OXIDATION OF ALKANESTEMPARATURE OXIDATION OF ALKANESLOWLOW TEMPARATURE OXIDATION OF ALKANESTEMPARATURE OXIDATION OF ALKANES

FF BattinBattin LeclercLeclerc OO HerbinetHerbinet B Husson P A Glaude RB Husson P A Glaude R FournetFournetF. F. BattinBattin--LeclercLeclerc, , O. O. HerbinetHerbinet, B. Husson, P.A. Glaude, R. , B. Husson, P.A. Glaude, R. FournetFournet, , Z.Z. Wang, Wang, MingfengMingfeng XieXie and F. Qiand F. Qi

Best possible understanding

of the chemistryyinvolved in

detailled kineticmodelsEXGAS

FUEL

EXGAS

Reaction base

Writechemical models

Alk• Alkanes• Alkanes

Radicals

Primary M h i

C2Molecules to help to design

cleaner engines• Alkanes• Alkenes

• Cyclanes• Aromatics

• Alkenes• Cyclanes• Aromatics

• Alkenes

• Aromatics

• EstersPrimaryproducts

MechanismGenerator

Molecules and

radicals

• Aromatics• Esters

• Esters•Alcohols Secondary MechanismGenerator

Thermodynamic data Kinetic data

THERGAS KINGASBuda et al., Combustion&Flame, 2005,Biet et al Energy&Fuel 2008THERGAS KINGAS

Thermodynamic data

Biet et al., Energy&Fuel, 2008,Glaude et al.,Combustion&Flame, 2010.

initiation stepsRH + O2 or • OH

H abstractions

Mechanismusualllyproposed

R• R’• + alkene(2) O2

(3)

proposed for the gas-phase oxidation

HO2 • + alkene ROOH + O2RHR’• + H2O2 ROO•

degenerate branching

O2(2)

(1)HO2•

O2oxidation of alkanes

•QOOH RO• + •OH

•OH + cyclic ethers, RH •OOQOOH

gsteps

O2

R’• + H2O aldehydes or ketones •OOQOOH

•U(OOH)2

R + H2O

degenerate keto-hydroperoxides + • OH

2

XO• + •OH

branching steps

E i t l id f th f ti fE i t l id f th f ti f h d idh d idExperimental evidences of the formation of Experimental evidences of the formation of hydroperoxideshydroperoxidesduring during autoignitionautoignition

Links between the concentration of hydroperoxides and the appearance of cool flame

h i i d i h dshown using iodometric method, but the structure of the involved species could not be determined by this way

(Burgess and Laughlin, 1967)

Ketohydroperoxides detectedafter trapping at the outlet of a CFR enginepp g g

(experiments never repeated)and of a flow reactor

(very low temperatures (498-518 K) and with very large excess in oxygen (oxygen/hydrocarbon ratio was 1176

while the stoichiometric ratio for a complete combustion is 18.5)(Sahetchian et al., 1991-2001)

A new method to detect hydroperoxidesA new method to detect hydroperoxidesd diti l t th b d i t i itid diti l t th b d i t i itiunder conditions close to those observed prior autoignition under conditions close to those observed prior autoignition

Hydroperoxidesare very reactive species:y p

need to minimize possible reactions

between their formation and their detection.

Use a molecular beam


Molecular beam


Molecular beam

Hydroperoxidesformed in very low amounts

amongst a large number g gof other oxidation products :

use of a high sensitivity mass spectrometermass spectrometer

with a very low ionization energyto avoid the fragmentation

Time-of-flight mass spectrometermass spectrometer

combined with tunable vacuumultraviolet synchrotron (SVUV)

photoionization


Molecular beam TOF-MS with SVUV photoionizationphotoionization


Molecular beamTOF-MS with SVUV

photoionization

Need of accumulatingseveral scans to obtain

photoionization

several scans to obtain a good sensitivity

Coupling withti t

.

a reacting system working

under steady conditions

Spherical quartz p qjet-stirred reactor


Molecular beam TOF-MS with SVUV photoionization

Spherical quartz jet stirred reactor (JSR) photoionizationjet-stirred reactor (JSR)

Recent applications of mass spectrometry with SVUV photoionisationphotoionisation

C.A.Taatjes, N. Hansen, A. McIlroy, J.A .Miller, J.P. Senosiain, S.J. Klippenstein, F. Qi, L. Sheng, Y. Zhang, T A Cool J Wang P R Westmoreland M E La T Kasper K Kohse Hoïngha sT.A. Cool, J. Wang, P.R. Westmoreland, M.E. Law, T. Kasper, K. Kohse-Hoïnghaus, Chemistry: Enols are common intermediates in hydrocarbon oxidationScience, 308, 1887 (2005).

Coupling of a mass spectrometer combined with tunable synchrotron vacuum ultraviolet photoionization to a JSR through a molecular-beam sampling system

Isotherm quartz

jet-stirred reactor

at atmospheric pressure (JSR)

The coupling through a molecular-beam sampling system between a JSR and a mass spectrometer combined with tunable synchrotron vacuum ultraviolet photoionization made in Hefei

The cone, with the reactor and its heating systemhas been connected to the MS chamberA cone, the tip of which is pierced with a

75 m hole has been inserted in the reactor(made in France)

has been connected to the MS chamber

Study of the lowStudy of the low--temperature temperature oxidation of oxidation of nn--butanebutane

i j ti j t ti d t dti d t din a jetin a jet--stirred reactor under stirred reactor under conditionsconditionsconditions conditions

close to that observed prior close to that observed prior ppignitionignition

Study of the low-temperature oxidation of n-butanein a jet-stirred reactor under conditionsin a jet stirred reactor under conditions close to that observed prior ignition

Conversion of Conversion of nn--butanebutaneP = 1 bar, = 1, = 6 s, , 4% n-butane

(3.1 % for a stoichiometric n-butane/air mixture)

5x10-2In Hefei:Quantification by assuming no reaction 4

3

frac

tio

n

In Nancy:

assuming no reaction below 580K

2

Mo

le f

Exp Hefei

In Nancy:on-line gas chromatographicanalysis of outlet gas

1

0

Exp. Hefei Exp. Nancy (GC analysis) simulation

analysis of outlet gas

Simulation:Using a model generated

800750700650600550Temperature (K)

Using a model generated using EXGAS software


Main combustion productsMain combustion productsppP = 1 bar, = 1, = 6 s, , 4% n-butane

0.4 CO M=280.3

0.2

0 1Mol

e fr

actio

n O2, M=32

Exp. Nancy

3.0x10-2

2.0

1 0e fr

actio

n

CO, M=28

0.1

0.0

M

800700600T/K

Exp. Hefei Simu.

1.0

0.0

Mol

e

800700600T/K

1.2x10-2

1.00.80 6fr

actio

n CO2, M=44 4x10-2

3

2actio

n

H2O, M=18Reference is argon (16.2 Reference is argon (16.2 eVeV))

0.60.40.20.0

Mol

e f

800700600

2

1

0

Mol

e fr

a

800700600800700600T/K

800700600T/KExp. Hefei Exp. Nancy Simu.


Main combustion productsMain combustion productsMain combustion productsMain combustion productsP = 1 bar, = 1, = 6 s, , 4% n-butane

1.0x10-3

0.8

0 6on

Propene, M=424.0x10-3

3.0

ctio

n

Ethylene, M=28

0.6

0.4

0.2Mol

e fr

actio2.0

1.0

0.0

Mol

e fr

ac

0.0

800700600T/K

800700600T/K

E H f i E N Si

For the measurements made in Hefei,For the measurements made in Hefei,

Exp. Hefei Exp. Nancy Simu.

reference is reference is ethylene (11 ethylene (11 eVeV) ) andand butenebutene (10 (10 eVeV))measured at 650 K in Nancymeasured at 650 K in Nancy

Study of the low-temperature oxidation of n-butanein a jet-stirred reactor under conditions Not usuallyin a jet stirred reactor under conditions close to that observed prior ignition

Light oxygenated productsLight oxygenated products

considered in models

g yg pg yg pP = 1 bar, = 1, = 6 s, , 4% n-butane

-335x10-3

432fr

actio

n

CH3OH, M=322.5x10-3

2.01.51.0e

frac

tion

Acetic acid, M=60,6x10-4

4

2frac

tion

Propanal, M=5810x10-3

864fr

actio

n

CH2O, M=30

2

10M

ole

800750700650600550T/K

3

0.50.0

Mol

e

800700600T/K

2

0Mol

e

800700600T/K

20M

ole

700600T/K

1.0x10-2

0.80.60.4fr

actio

n

Acetaldehyde, M=443.0x10-3

2.0

1 0e fr

actio

n

Acetone, M=58Simulated mole fractions x 1x105

1.0x10-3

0.80.60.4e

frac

tion Acrolein, M=563.0x10-4

2.0

1 0frac

tion

Ethanol, M=46

0.20.0Mol

e

700600T/K

1.0

0.0

Mol

e

800700600T/K

0.20.0

Mol

e

800700600T/K

1.0

0.0Mol

e

800700600T/KExp. Hefei Exp. Nancy Simu.

Reference is Reference is ethylene (11 ethylene (11 eVeV) ) andand butenebutene (10 (10 eVeV))

p p y S


Hydrogen peroxideHydrogen peroxidey g py g pP = 1 bar, = 1, = 6 s, , 4% n-butane

2.0x10-4

1.5

onH2O2, M=34Simulated mole fractions /50

1.0

Mol

e fr

actio

0.5

0.0

800750700650600550T/K

PIE (10.65 PIE (10.65 eVeV) in good agreement with literature) in good agreement with literatureReference is Reference is ethylene (11 ethylene (11 eVeV), ), is estimatedis estimated

Herbinet et al., PCCP, 2011.


Main CMain C productsproducts

ButenesButenes Oxygenated compoundsOxygenated compounds

Main CMain C44 productsproductsP = 1 bar, = 1, = 6 s, 4% n-butane

ute esute es Oxygenated compoundsOxygenated compounds5x10-3

4Mass 56 (Exp. Hefei)1 butene+2 butene (Exp Nancy)

2.5x10-3

2 0Mass 72 (exp. Hefei)Sum of C4H8O (exp. Nancy)4

3

2e fr

actio

n

1-butene+2-butene (Exp. Nancy)Simulation

2.0

1.5

1 0e fr

actio

n

4 8 ( p y)Simulation

2

1

0

Mol

e 1.0

0.5

0.0

Mol

e

0

800750700650600550Temperature (K)

0.0

800750700650600550Temperature (K)

Reference is Reference is butenebutene (10 (10 eVeV, 650 K),, 650 K),ii of oxygenated compounds taken equal to that of of oxygenated compounds taken equal to that of tetrahydrofuranetetrahydrofurane


DetailsDetails of Cof C44HH88O O productsproductsb b ( )

8x10-5

Butanal8x10

-4

Butanone

P = 1 bar, = 1, = 6 s, 4% n-butane (GC Nancy)

6420M

ole

fract

ion Butanal

5x10-4

6420M

ole

fract

ion Butanone

0M

800750700650600550T/K

5x104321e

fract

ion Tetrahydrofuran0M

800750700650600550T/K

-4

6x10-4

4

2actio

n

Oxiranes10M

ol

800750700650600550T/K

8x10-4

642e

fract

ion Methyloxetane

2

0

Mol

e fra

800750700650600550

T/K20M

ole

800750700650600550T/K T/K

Study of the low-temperature oxidation of n-butanein a jet-stirred reactor under conditions

Obtained mass spectrumObtained mass spectrum

in a jet stirred reactor under conditions close to that observed prior ignition

200

ppP = 1 bar, = 1, = 6 s, 4% n-butane, 590 K, 10 eV

200

15058: Butane

72: C4 oxygenated compounds

56: ButeneOO

OH

150

100gnal

56: Butene

C4H9OOH CH 3 O

C H 3

100

50

Sig

62

90CH3OOHC2H5OOH

OOH

50

0

1044862

0

110105100959085807570656055504540Mass

Study of the low-temperature oxidation of n-butanein a jet-stirred reactor under conditions close to that observed prior ignition

Ionization energy (IE) measurementsIonization energy (IE) measurementsP = 1 bar, = 1, = 6 s, 4% n-butane, 590 K

close to that observed prior ignition

, , , ,

IE of CH3OOH=

9.83 eV

IE of C2H5OOH=

9.61 eV

IE of C4H9OOH=

IE of ketohydroperoxides

9.33-9.36 eV =9.34-9.39 eV

Zero-point energy corrected adiabatic IEs have been calculated from the CBS-QB3 method using Gaussian03.


Evolution ofEvolution of hydroperoxideshydroperoxides signal with temperaturesignal with temperature


Evolution of Evolution of hydroperoxideshydroperoxides signal with temperature signal with temperature P = 1 bar, = 1, = 6 s, 4% n-butane, 10 eV

ExperimentalExperimental SimulationSimulation

20 400

pe e tape e ta

350

300800

SimulationSimulation

15

10pero

xide

s 300

200

Major C

4 prC4H9OOH/4

KetoH.

Cyclic ethers

250

200

150pero

xide

s 600

400

Major C

4

(MF/5)

5Hyd

rop

100

roducts

CH3OOH

C2H5OOH Butenes

y150

100

50H

ydro

p 400

200

products

(MF/5)

0

700650600550500Temperature (K)

0 0700650600550500

Temperature (K)

0

Battin-Leclerc et al., Angewante Chemie Int. Ed., 2010.


Quantification of CQuantification of C44 hydroperoxideshydroperoxides


P = 1 bar, = 1, = 6 s, 4% n-butane

C4H9OOH Ketohydroperoxides4 9

2.0x10-4

1 5

3.0x10-5

2.5 Simulated mole fractions /51.5

1.0

ole

frac

tion 2.0

1.5

1 0ole

frac

tion

0.5

0.0

Mo

8000006 06000

1.0

0.5

0.0

Mo

800750700650600550Temperature (K)

800750700650600550Temperature (K)


Reference is Reference is butenebutene (10 (10 eVeV, 650 K),, 650 K),ii taken equal to that of taken equal to that of tetrahydrofuranetetrahydrofurane


Other peaks on the obtained mass spectrumOther peaks on the obtained mass spectrum


p pp pP = 1 bar, = 1, = 6 s, 4% n-butane, 590 K, 10 eV

200

150 58: Butane

72: C4 oxygenated

O

HO

CH386

100

Sign

al

56: Butene

CH3CH3

O

OHO

50

S

90

CH OOHC2H5OOH

C4H9OOH

OC H OOH

CH3O

88CH3

CH

O

0

1044862CH3OOH OC4H7OOHCH3

O

110105100959085807570656055504540Mass

Battin-Leclerc et al., Proc. Combust. Inst., 2011.


Possible ways of formation of CPossible ways of formation of C44 dioxygenateddioxygenated compoundscompounds


O

O

O

O+ OH

OOHO

+ HO2

OO

+ HO

HOO+ O2

Mass = 86Mass = 88


Quantification of CQuantification of C44 dioxygenateddioxygenated compoundscompoundsP = 1 bar = 1 = 6 s 4% n butane


P = 1 bar, = 1, = 6 s, 4% n-butane

C4H6O2Hydroxybutanone

8x10-4

6ion

Not detected by GC1.2x10-4

n

4

2Mol

e fr

acti

0.8

0.4

Mol

e fr

actio

n

0

800750700650600T/K

0.0

M

800750700650600550T/K

Reference isReference is butenebutene (10(10 eVeV 650 K)650 K)

T/K


T/K

Reference is Reference is butenebutene (10 (10 eVeV, 650 K),, 650 K),ii taken equal to that of taken equal to that of tetrahydrofuranetetrahydrofurane


Minor peaks on the obtained mass spectrumMinor peaks on the obtained mass spectrumP 1 b 1 6 4% b t 630 K 10 V


P = 1 bar, = 1, = 6 s, 4% n-butane, 630 K, 10 eV

120

ry u

nits

)

5658

70 86 Not only butenone

80

40

0Sign

al (A

rbitr

ar

48

72

84

88

90

10210462

HO2 +M

0S

110100908070605040m/z

M 102 i i lO H-abstraction O+ O2

O2 Mass

= 70

M = 102 is mainly:

O O

+ HO2

H-abstraction

OO O O OHO

Mass = OH

+ OH + H Mass = 102

= 84

3rd addition on oxygen ?

Study of the low-temperature oxidation of n-butane

S l ti it f d tS l ti it f d t t 590 Kt 590 K (13% i )(13% i )

in a jet-stirred reactor under conditions close to that observed prior ignition

Selectivity of products Selectivity of products at 590 K at 590 K (13% conversion)(13% conversion)P = 1 bar, = 1, = 6 s, 4% n-butane

15% l ti it

10

2

%

selectivity

More than

1

2

4

ty in

C a

tom

/% More thanmajor C4H8O0.4%

selectivity

0.1

2

4

Sele

ctiv

it

Buta

nal

C2H

5OO

H

C3H

6

Prop

anal

Acro

lein

Bute

none

hylo

xeta

ne

rope

roxi

de

C2H

5OH

prop

anon

e

ylen

e ox

ide

ydro

fura

ne

xybu

tano

ne

Buta

none

rope

roxi

de

C4

oxira

nes

C2H

4

C4H

6O2

CO

2

CO

CH

3OH

Bute

nes

Acet

one

Acet

ic a

cid

CH

2O

CH

3CH

O

C

Met

Keto

hyd

Hyd

roxy

Ethy

Tetra

hy

Hyd

rox

Buty

lhyd C A

Study of the lowStudy of the low--temperature temperature oxidation of oxidation of nn--heptaneheptane



Study of the low-temperature oxidation of n-heptanein a jet-stirred reactor under conditionsin a jet stirred reactor under conditions close to that observed prior ignition

Conversion of Conversion of nn--heptaneheptaneppP = 1 bar, = 1, = 2 s, 0.5% n-heptane

In Hefei:Quantification by assuming no reaction

6x10-3

5

In Nancy:


5

4

3Frac

tion Exp. Hefei

Exp. Nancy Simulation


3

2

1

Mol

e F

analysis of outlet gas

Simulation:Using a model generated

1

01100900700500Using a model generated

using EXGAS software Temperature (K)

Study of the low-temperature oxidation of n-heptanein a jet-stirred reactor under conditionsin a jet stirred reactor under conditions close to that observed prior ignition

Light oxygenated productsLight oxygenated products

3

g yg pg yg pP = 1 bar, = 1, = 2 s, 0.5% n-heptane

-6 -61.6x10-3

1.2on

CH2O

600x10-6

500on

Acetic acid

500x10-6

400

n

Acid Propanoic

0.8

e Fr

actio 400

300

ole

Frac

ti

300

200Frac

tion

0.4Mol

e

200

100

Mo 200

100Mol

e

0.0800600

Temperature (K)

0700500

Temperature (K)

0700500

Temperature (K)Temperature (K)


Temperature (K) Temperature (K)

Study of the low-temperature oxidation of n-heptanein a jet-stirred reactor under conditions



1.0

ppP = 1 bar, = 1, = 2 s, 0.5% n-heptane, 530 K, 9.5 eV

0.8 100: Heptane(mostly hexanones)

114: C7 oxygenatedcompounds 128:

heptadiones0.6

0.4Sign

al

(mostly hexanones)

146:Ketohydro

heptadiones

0.298: Heptenes peroxides

0.01501301109070

m/zm/z

No No hydroperoxidehydroperoxide smaller than smaller than ketohydroperoxidesketohydroperoxides

Study of the low-temperature oxidation of n-heptanein a jet-stirred reactor

Analysis of Analysis of dionesdiones and and hydroperoxideshydroperoxidesP = 1 bar, = 1, = 2 s, 0.5% n-heptane

HEFEI NANCY (on-line GC)

6

2.0

1.5

M =

146

)

800x10-6

600

Com

put

100x10-6

80

60actio

n

2,4-heptadione100x10-6

80

60actio

n

50

40

30

Hefei signa

2,4-heptadione

1.0

0.5

0 0

Sign

al (M 400

200

0

ted Mole Fra

40

20

0

Mol

e Fr

a

40

20

0

Mol

e Fr

a 30

20

10

0

al (mass 1280.0


0 action

Ketohydroperoxides

0


40x10-6

0


0 8)

40x10

30

20 Fra

ctio

n

3,5-heptadione25

20

15= 12

8)

10

0

Mol

e

700600500

15

10

5

0

Sign

al (M

Diones (Mass = 128, good PIE)

700600500Temperature (K)700500

Temperature (K) Are diones seen in Nancy partly due to ketohydroperoxides decomposed in GC ?

Study of the lowStudy of the low--temperature temperature oxidation of oxidation of propanepropane



Study of the low-temperature oxidation of propanein a jet-stirred reactor under conditionsin a jet stirred reactor under conditions close to that observed prior ignition

Conversion of Conversion of propanepropanep pp pP = 1 bar, = 1, = 6 s, 12% propane

In Hefei:Quantification by assuming no reaction

0.16

0 12ion Propane

In Nancy:


0.12

0.08

0 04le F

ract


0.04

0.00

Mol

750700650600550analysis of outlet gas 750700650600550Temperature (K)

Study of the low-temperature oxidation of propanein a jet-stirred reactor under conditions



50 58 C t d

ppP = 1 bar, = 1, = 6 s, 12% propane, 635 K, 11 eV

50

40 44: Propane(mostly acetaldehyde)

58: C3 oxygenatedcompounds

76: Propylhydroperoxides

60: Aceticid +P l

30

20Sig

nal

42: Propene

hydroperoxides

74: Propan-2one-3-ol (seen by GC)

acid +Propanols

20

10

42: Propene 72:Propadione

08070605040

m/zm/z

No No hydroperoxidehydroperoxide other than other than propylhydroperoxidespropylhydroperoxides

Conclusion

Use of a new type of apparatus coupling through a molecular beama jet stirred reactor and a tunable synchrotron vacuum ultraviolet photoionization mass spectrometerphotoionization mass spectrometer

Evidence of the formation of hydroperoxides compounds, especially ketohydroperoxidesespecially ketohydroperoxides during the low-temperature oxidation of n-butane and n-heptane:mainly 2,4 and 3,5-ketohydroperoxides formed from n-heptane

N t k

Evidence of the formation of products deriving from ketohydroperoxides:diones

Next work

Study of the low-temperature oxidation of a series of branched alkanes to better understand the influence of the structure of the moleculeto better understand the influence of the structure of the molecule on the formation of hydroperoxide compounds

ThankThank youyou forfor youryour attentionattentionThankThank youyou for for youryour attentionattention

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