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Modelling ozonolysis in a multi-inlet flow reactor
Mixtli Campos-PinedaGroup Meeting 2
Fall 2016
1 2 3 4 5 76 8 109P
To pump
39.75”
22.75”
Purge N2 Purge N2
Orange: Ozone inlet
Green: Alkene inlet(+ Oxygen during oxygen experiments)
Blue: plugged port (ultratorr+cap)
Multi-inlet flow cell/CRDS cavity
Ozone flow manifold
FMFM
N2 in
Ozone adsorbed
in silica gel
To flow cell
Alkene + N2 + Scavenger flow manifold
FM
FM N2 in
FM
O2 in(oxygen experiments only)
Alkene inTo flow cell
Simulation of the reaction in a flow reactor.
The system of ODEs is solved using an approximation method by the kinetic simulator KINTECUS.
Multi-Inlet Flow Cell (reaction perpendicular to beam)
1 2 3 4 5 76 8 109P
Ozone in
Alkene/Nitrogen/Scavenger in
1 2 3 4 5 76 8 109P
To pump
Pros:• Every segment is independent• No carryover reaction• Simple modelling
Cons:• Turbulence
Multi-Inlet Flow Cell (reaction parallel to beam)
1 2 3 4 5 76 8 109P
To pump
Ozone + Alkene
Ozone
Pros:• Greatly reduced turbulence
Cons:• Measurement is the average of segment concentrations• Initial conditions change for each segments
1 2 3 4 5 76 8 109P
To pump
39.75”
22.75”
Purge N2 Purge N2
Orange: Ozone inlet
Green: Alkene inlet(+ Oxygen during oxygen experiments)
Blue: plugged port (ultratorr+cap)
Multi-inlet flow cell/CRDS cavity
Total flow changes due to ozone addition:
• Ozone “spike” concentration changes• Species concentrations change
We measure averages:
Nozone,average = [O30+(O3
1+(F1/F2)O30)+...+(O3
9+(F9/F10)O30)]/10
Nozone,segment = O3s-1+(Fs-1/Fs)O3
0
Nspecies,segment = (Fs-1/Fs) Nspecies,s-1
Nspecies,average = [∑110
Nspecies,s]/10
0 1E16 2E16 3E16 4E16 5E16 6E16 7E16 8E16 9E16
0.20
0.40
0.60
0.80
1.00
1.20
[CH
2CH
O]/[
CH
2CH
O] 0
Oxygen (molecules/cc)
11/4/16 5/5/16
Vinoxy data (with new experiments from Friday)
OO
+
O3
OCH2CO CH3OH
SOZ
OH
O O
H H
O
O++H2O
P
P
P
P
P
O O +
H H
O
+
P
H H
O
+ 2O2 P
SOZ
P
H H
O
OH
OH + CO
OH
O2
H2OO3
OH
wall
decomp
wall
O
O
CH2OHCH3OH2O
OH
O2
H H
O
+ HO2
OHOH
HO2 + O2P
0.5 OH + P
trans-2-butene ozonolysis mechanism used in KINTECUS (11/06/2016)
2 +H2O+H2C2
1.00 0.1 0.5 0.05 0.07
0.950.05
0.850.15
1.1E-12
2.6E-14
3.6E-15
1.7E-16
7.5E-13
1.9E-16
6.4E-11 1.6E-12
4E-18
370 s-1
1E-15
1E-12
6.12E-15
1.84E-14
3.67E-14
1E-11
9.1E-12
1E-11
10 s-1
10 s-1
1E-11 HCHO + OH HCO + H2O
7.5E-13
0 2 4 6 8 10
0.00E+000
2.00E+013
4.00E+013
6.00E+013
8.00E+013
F
A
CH2CHO
No oxygen
No oxygen
0 2 4 6 8 10
0.00E+000
2.00E+010
4.00E+010
6.00E+010
8.00E+010
1.00E+011
1.20E+011E
A
CH3CHOO
8.45E15 molecule/cc oxygen
0 2 4 6 8 10
0.00E+000
1.00E+012
2.00E+012
F
A
CH2CHO
8.45E15 molecule/cc oxygen
0 2 4 6 8 10-2.00E+010
0.00E+000
2.00E+010
4.00E+010
6.00E+010
8.00E+010
1.00E+011
1.20E+011
1.40E+011
1.60E+011
1.80E+011
E
A
CH3CHOO
8.45E15 molecule/cc oxygen
0 2 4 6 8 106.80E+015
7.00E+015
7.20E+015
7.40E+015
7.60E+015
7.80E+015
8.00E+015
8.20E+015
8.40E+015
8.60E+015
G
A
O2
0.00E+000 2.00E+015 4.00E+015 6.00E+015 8.00E+015 1.00E+0160.0
0.2
0.4
0.6
0.8
1.0
Simulation Exp 11/04/2016
Oxygen (molecule/cc)
[Vin
oxy]
/[Vin
oxy]
0
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
[Vin
oxy]
/[Vin
oxy]
0
Comparison experiment vs simulation
• Vinoxy concentration from modelling much higher:
Yield of vinoxy in model is overestimated Not enough vinoxy depletion channels, or rates underestimated
• Vinoxy depletion by oxygen much higher:
Vinoxy + Oxygen rates overestimated High vinoxy concentration in modelling driving reaction Not enough oxygen depletion channels, or rates underestimated
OO
+
O3
OCH2CO CH3OH
SOZ
OH
O O
H H
O
O++H2O
P
P
P
P
P
O O +
H H
O
+
P
H H
O
+ 2O2 P
SOZ
P
H H
O
OH
OH + CO
OH
O2
H2OO3
OH
wall
decomp
wall
O
O
CH2OHCH3OH2O
OH
O2
H H
O
+ HO2
OHOH
HO2 + O2P
0.5 OH + P
trans-2-butene ozonolysis mechanism used in KINTECUS (11/06/2016)
2 +H2O+H2C2
1.00 0.1 0.5 0.05 0.07
0.950.05
0.850.15
1.1E-12
2.6E-14
3.6E-15
1.7E-16
7.5E-13
1.9E-16
6.4E-11 1.6E-12
4E-18
370 s-1
1E-15
1E-12
6.12E-15
1.84E-14
3.67E-14
1E-11
9.1E-12
1E-11
10 s-1
10 s-1
1E-11 HCHO + OH HCO + H2O
7.5E-13
0 2 4 6 8 10
0.00E+000
2.00E+010
4.00E+010
6.00E+010
8.00E+010
1.00E+011
1.20E+011
E
A
CH3CHOO
Revisiting Criegee Intermediates
What about acetone oxide?
OO
O
+ O3+
0 2 4 6 8 10-1.00E+011
0.00E+000
1.00E+011
2.00E+011
3.00E+011
4.00E+011
5.00E+011
6.00E+011
7.00E+011
G
A
CH3CO2CH3
Parallel
0 5 10
8.60E+011
8.80E+011
9.00E+011
9.20E+011
9.40E+011
9.60E+011
9.80E+011
1.00E+012
1.02E+012
1.04E+012
F
A
CH3CO2CH3
Perpendicular
Summary
Mechanism for t2b need more work!
Time to revisit measurement of CIs