UIC PYROLYTIC REACTIONS OF THE PHENYL RADICAL IN THE ...
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PYROLYTIC REACTIONS OF THE PHENYL RADICAL IN THE PRESENCE OF ACE PYROLYTIC REACTIONS OF THE PHENYL RADICAL IN THE PRESENCE OF ACE TYLENE TYLENE A. Comandini 1 , S. H. Duerrstein 2 , M. Olzmann 2* , K. Brezinsky 1* 1 University of Illinois at Chicago, USA; 2 University Karlsruhe (TH), Germany [email protected] ; [email protected] Institute of Physical Chemistry Chair of Molecular Physical Chemistry Kaiserstr.12, 76128 Karlsruhe, Germany 1000 1200 1400 1600 0,0 0,2 0,4 0,6 0,8 1,0 1,2 C 6 H 5 I Pyrolysis Reaction Time~1.5-2 ms [C 6 H 5 I] / [C 6 H 5 I] 0 Reflected Shock Temperature T 5 /K ■ [C 6 H 5 I] 0 = 50 ppm, 50 atm ▲ [C 6 H 5 I] 0 = 300 ppm, 50 atm ● [C 6 H 5 I] 0 = 850 ppm, 50 atm Δ [C 6 H 5 I] 0 = 200 ppm, 25 atm ○ [C 6 H 5 I] 0 = 300 ppm, 25 atm 1000 1200 1400 1600 1800 0,00 0,04 0,08 C 6 H 6 C 6 H 5 C 2 H C 10 H 8 C 6 H 5 I Pyrolysis, 300 ppm, 25 atm Reaction Time~1.5-2 ms Normalized Mole Fraction Reflected Shock Temperature T 5 /K 1000 1200 1400 1600 1800 0,00 0,04 0,08 0,12 0,16 0,20 0,24 0,28 C 2 H 2 C 4 H 2 C 6 H 5 I Pyrolysis, 300 ppm, 25 atm Reaction Time~1.5-2 ms Normalized Mole Fractions Reflected Shock Temperature T 5 /K Pyrolysis of Iodobenzene as Phenyl Radical Precursor Pyrolytic Reactions of Phenyl Radical in the Presence of Acetylene: Experimental Data • Negligible formation of phenylacetylene • BUT : considerable formation of naphthalene • Phenylacetylene profiles conform to phenyl + acetylene recombination • BUT : naphthalene profiles NOT conform to phenylacetylene + acetylene recombination • Similar trends observed at a nominal pressure of 25 atm 1000 1200 1400 1600 0 50 100 150 200 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~50atm; Reaction Time~1.5-2ms C 6 H 5 I mole fraction/ppm Reflected Shock Temperature T 5 /K C 2 H 2 =280ppm C 2 H 2 =60ppm 1000 1200 1400 1600 40 80 120 160 200 240 280 320 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~50atm; Reaction Time~1.5-2ms C 2 H 2 mole fraction/ppm Reflected Shock Temperature T 5 /K C 2 H 2 =280ppm C 2 H 2 =60ppm 1000 1200 1400 1600 0 10 20 30 40 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~50atm; Reaction Time~1.5-2ms C 4 H 2 mole fraction/ppm Reflected Shock Temperature T 5 /K C 2 H 2 =280ppm C 2 H 2 =60ppm 1000 1200 1400 1600 0 5 10 15 20 25 30 35 40 45 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~50atm; Reaction Time~1.5-2ms C 6 H 6 mole fraction/ppm Reflected Shock Temperature T 5 /K C 2 H 2 =280ppm C 2 H 2 =60ppm 1000 1200 1400 1600 0 10 20 30 40 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~50atm; Reaction Time~1.5-2ms C 6 H 5 C 2 H mole fraction/ppm Reflected Shock Temperature T 5 /K C 2 H 2 =280ppm C 2 H 2 =60ppm 1000 1200 1400 1600 1800 0 5 10 15 20 25 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~50atm; Reaction Time~1.5-2ms C 10 H 8 mole fraction/ppm Reflected Shock Temperature T 5 /K C 2 H 2 =280ppm C 2 H 2 =60ppm HPST Operating Conditions Temperatures: 600 - 2500 K Pressures: 5 - 1000 atm Reaction Times: 0.5 - 3.0 ms Experimental Technique: High-Pressure Shock Tube 100 +/- 2 °C over last 30 inches of tube Key Steps: Formation of the first aromatic ring (benzene) a Formation of the second aromatic ring (naphthalene) a Formation of polycyclic aromatics (PAH) and subsequent growth to PM a,b Benzene formation – Fairly well characterized c Naphthalene and multiple ring structures formation – Uncertain pathways c a. H. Bockhorn, Soot formation in combustion-Mechanisms and Models, Springer Series in Chemical Physics, Volume 59, 1994, 3-9. b. H. Richter, J. B. Howard, Prog. Ener. Combust. Sci., 26, 2000, 565-608. c. J. A. Miller, M. J. Pilling, J. Troe, Proc. Combust. Inst., 30, 2005, 43-88. Reaction Pathways to PM formation: Role of Aromatic Species UIC UNIVERSITY OF ILLINOIS AT CHICAGO Technical Objective : characterization of the pyrolytic reactions of the phenyl radical in the presence of acetylene over a wide range of pressures (1 - 50 atm) and temperatures (1000 - 1700 K) as possible pathway to the formation of naphthalene Summary Acknowledgments • Experiments on pyrolytic reactions of the phenyl radical in the presence of acetylene conducted over a wide range of pressures (1 - 50 atm) and temperatures (1000 - 1700 K) using two different experimental techniques. • The experiments conducted at University Karlsruhe indicate that at low pressure the recombination between phenyl and acetylene does not lead to naphthalene formation. • The experimental and theoretical work conducted at UIC shows that at high pressure acetylene is involved in the formation of the second-ring species, but the HACA mechanism is not the main pathway to naphthalene. • Possibly alternative pathways to naphthalene formation at high pressure exist. SERDP, financial sponsor through contract WP 1575. DFG, financial support through contract OL85/2-1. This work reflects the collaborative efforts of UIC and University Karlsruhe, and the authors would additionally like to thank the sponsors for encouraging this collaboration. Pyrolytic Reactions of the Phenyl Radical in the Presence of Acetylene: Modeling Main Naphthalene Formation Pathways a Richter, H. ; Mazyar, O. A. ; Sumathi, R. ; Green, W. H. ; Howard, J. B. ; Bozzelli, J. W. J. Phys. Chem. A 2001, 105, 1561-1573. b Frenklach, M.; Wang, H. Proc. Combust. Inst. 1991, 23, 1559. c Estimated. d Wang, H.; Frenklach, M. J. Phys. Chem. 1994, 98, 11465-11489. • Quite accurate simulations of phenyacetylene profiles • BUT : compared to the experiments, too small amounts of naphthalene predicted 1000 1200 1400 1600 0 50 100 150 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~25atm; Reaction Time~1.5-2ms C 6 H 5 I-C 2 H 2 mole fraction/ppm Reflected Shock Temperature T 5 /K C 6 H 5 I: ○ experiment; ● simulation C 2 H 2 : Δ experiment; ▲simulation C 4 H 2 : ○ experiment; ● simulation C 6 H 6 : □ experiment; ■ simulation C 6 H 5 C 2 H: Δ experiment; ▲simulation C 10 H 8 : □ experiment; ■ simulation 1000 1200 1400 1600 0 5 10 15 20 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~25atm; Reaction Time~1.5-2ms C 6 H 5 C 2 H-C 10 H 8 mole fraction/ppm Reflected Shock Temperature T 5 /K 1000 1200 1400 1600 0 10 20 30 Pyrolysis of C 6 H 5 I-C 2 H 2 Blends P~25atm; Reaction Time~1.5-2ms C 4 H 2 -C 6 H 6 mole fraction/ppm Reflected Shock Temperature T 5 /K Problem Statement • Environmental hazards - haze and poor air quality • Reduced combustor efficiency • Increased combustor wear and tear • Hinders tactical effectiveness • Deterrent - active recruitment and training of military personnel • Health hazard - asthma and cancer (10 mg/m3 increase in fine PM ~6% increase cardiopulmonary mortality and 8% increase in lung cancer mortality) a Particulate Matter (PM) Emissions a. Pope, III C. A.; Burnett, T. R.; Thurston, D. G.; Thun, J. M.; Calle, E.; Krewski, D.; Ito, K., Journal of the American Medical Association 2002, 287, 1132-1141. Supersonic jet Mass Spectrometer Pulsed Electron Impact Ionization 125 kHz 45 eV Reflectron mode Experimental Technique: Real-time TOF-Mass Spectrometry behind Shock Waves 1 mm Pinhole 30 – 140 μm Sampling unit TOF-MS ST Operating Conditions Temperatures: 800 - 2000 K Pressures: 0.1 - 2 atm Time Resolution: 15 μ μ μs Bath gas: Ne Pyrolysis of Iodobenzene as Phenyl Radical Precursor 0.0 0.5 1.0 1.5 0.0 0.2 0.4 1553 K; 1.14 bar [C 2 H 2 ]; [C 12 H 10 ] / a. u. t / ms biphenyl acetylene 150 175 200 225 -0.01 0.00 no 3 ring species 4 ring species 2 ring species I / V m / z 75 - 210 μs 1.5 - 1.65 ms • Iodobenzene and argon: 3400 ppm (each) • Products observed: C 2 H 2 , C 6 H 6 , C 8 H 6 , C 12 H 10 , C 18 H 12 • Diacetylene superimposed (fragment peaks) • Only PAH with even number of rings ! 0.0 0.5 1.0 1.5 0 1 [C 6 H 5 I] / [C 6 H 5 I] 0 t / ms 1247 K 1375 K 1492 K 1593 K 0.0 0.5 1.0 1.5 0.0 0.1 0.2 0.3 [C 8 H 6 ] / [C 6 H 5 I] 0 t / ms 1593 K 1440 K 1247 K 0.0 0.5 1.0 1.5 0.0 0.2 0.4 0.6 [C 6 H 6 ] / [C 6 H 5 I] 0 t / ms 1593 K 1375 K 1247 K 150 175 200 225 -0.05 0.00 1558 K; 1.04 bar t: 15 - 150 μs 4000 ppm C 6 H 5 I 1.23 % C 2 H 2 C 12 H 8 ? C 12 H 10 C 14 H 10 I / V m / z 0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 0.00 0.25 0.50 0.75 1.00 1.25 [C 6 H 6 ], [C 8 H 6 ] / 10 -8 mole / cm 3 t / ms benzene phenylacetylene benzene phenylacetylene 1553 K; 1.14 bar [C 6 H 5 I] / 10 -8 mole cm -3 t / ms • Iodobenzene: 3300 or 2000 ppm • C 2 D 2 : C 6 H 5 = 3 or 8.5 • C 2 D 2 to separate naphthalene and HI peaks • BUT : no naphthalene was observed • Products: C 6 H 6 , C 8 H 6 , C 12 H 10 , C 14 H 10 Pyrolytic Reactions of the Phenyl Radical in the Presence of Acetylene: Experimental Data + C 2 H 2 -H 2 ,+H +C 2 H 2 -H a, b c, b c c +C 2 H 2 a, b b, d -H a, b +C 2 H 2 b, d
Transcript of UIC PYROLYTIC REACTIONS OF THE PHENYL RADICAL IN THE ...
PYROLYTIC REACTIONS OF THE PHENYL RADICAL IN THE PR ESENCE OF ACEPYROLYTIC REACTIONS OF THE PHENYL RADICAL IN THE PR ESENCE OF ACETYLENETYLENEA. Comandini1, S. H. Duerrstein2, M. Olzmann2*, K. Brezinsky1*
1University of Illinois at Chicago, USA; 2University Karlsruhe (TH), [email protected]; [email protected]
Institute of Physical Chemistry
Chair of Molecular Physical Chemistry
Kaiserstr.12, 76128 Karlsruhe, Germany
1000 1200 1400 1600
0,0
0,2
0,4
0,6
0,8
1,0
1,2
C6H
5I Pyrolysis
Reaction Time~1.5-2 ms
[C6H
5I] / [
C6H
5I] 0
Reflected Shock Temperature T5/K
■ [C6H5I]0 = 50 ppm, 50 atm ▲ [C6H5I]0 = 300 ppm, 50 atm ● [C6H5I]0 = 850 ppm, 50 atm ∆ [C6H5I]0 = 200 ppm, 25 atm ○ [C6H5I]0 = 300 ppm, 25 atm
1000 1200 1400 1600 1800
0,00
0,04
0,08 C
6H
6
C6H
5C
2H
C10H8
C6H
5I Pyrolysis, 300 ppm, 25 atmReaction Time~1.5-2 ms
Nor
mal
ized
Mol
e F
ract
ion
Reflected Shock Temperature T5/K
1000 1200 1400 1600 1800
0,00
0,04
0,08
0,12
0,16
0,20
0,24
0,28
C2H
2
C4H
2
C6H
5I Pyrolysis, 300 ppm, 25 atm Reaction Time~1.5-2 ms
Nor
mal
ized
Mol
e F
ract
ions
Reflected Shock Temperature T5/K
Pyrolysis of Iodobenzene as Phenyl Radical Precursor
Pyrolytic Reactions of Phenyl Radical in the Presenc e of Acetylene: Experimental Data
• Negligible formation of phenylacetylene
• BUT: considerable formation of naphthalene
• Phenylacetylene profiles conform to phenyl + acetyle ne recombination
• BUT: naphthalene profiles NOT conform to phenylacetyle ne + acetylene recombination
• Similar trends observed at a nominal pressure of 25 atm
1000 1200 1400 1600
0
50
100
150
200
Pyrolysis of C6H
5I-C
2H
2 Blends
P~50atm; Reaction Time~1.5-2ms
C6H
5I m
ole
frac
tion/
ppm
Reflected Shock Temperature T5/K
C2H
2=280ppm
C2H
2=60ppm
1000 1200 1400 160040
80
120
160
200
240
280
320
Pyrolysis of C6H
5I-C
2H
2 Blends
P~50atm; Reaction Time~1.5-2ms
C2H
2 mol
e fr
actio
n/pp
m
Reflected Shock Temperature T5/K
C2H
2=280ppm
C2H
2=60ppm
1000 1200 1400 1600
0
10
20
30
40
Pyrolysis of C6H
5I-C
2H
2 Blends
P~50atm; Reaction Time~1.5-2ms
C4H
2 m
ole
frac
tion/
ppm
Reflected Shock Temperature T5/K
C2H
2=280ppm
C2H
2=60ppm
1000 1200 1400 1600
0
5
10
15
20
25
30
35
40
45
Pyrolysis of C6H
5I-C
2H
2 Blends
P~50atm; Reaction Time~1.5-2ms
C6H
6 mol
e fra
ctio
n/pp
m
Reflected Shock Temperature T5/K
C2H
2=280ppm
C2H
2=60ppm
1000 1200 1400 1600
0
10
20
30
40
Pyrolysis of C6H
5I-C
2H
2 Blends
P~50atm; Reaction Time~1.5-2ms
C6H
5C2H
mol
e fr
actio
n/pp
m
Reflected Shock Temperature T5/K
C2H
2=280ppm
C2H
2=60ppm
1000 1200 1400 1600 1800
0
5
10
15
20
25
Pyrolysis of C6H
5I-C
2H
2 Blends
P~50atm; Reaction Time~1.5-2ms
C10
H8 m
ole
frac
tion/
ppm
Reflected Shock Temperature T5/K
C2H
2=280ppm
C2H
2=60ppm
HPST Operating ConditionsTemperatures: 600 - 2500 K
Pressures: 5 - 1000 atmReaction Times: 0.5 - 3.0 ms
Experimental Technique: High-Pressure Shock Tube
100 +/- 2 °C over last 30 inches of tube
Key Steps: Formation of the first aromatic ring (be nzene) a
Formation of the second aromatic ring (naphthalene) a
Formation of polycyclic aromatics (PAH) and subsequ ent growth to PM a,b
Benzene formation – Fairly well characterized c
Naphthalene and multiple ring structures formation – Uncertain pathways c
a. H. Bockhorn, Soot formation in combustion-Mechanisms and Models, Springer Series in Chemical Physics, Volume 59, 1994, 3-9.b. H. Richter, J. B. Howard, Prog. Ener. Combust. Sci., 26, 2000, 565-608.c. J. A. Miller, M. J. Pilling, J. Troe, Proc. Combust. Inst., 30, 2005, 43-88.
Reaction Pathways to PM formation: Role of Aromatic Species
UICUNIVERSITYOF ILLINOISAT CHICAGO
Technical Objective : characterization of the pyrolytic reactions of the p henyl radical in the presence of acetylene over a wide ra nge of pressures (1 - 50 atm) and temperatures (1000 - 1700 K) as possible pathway to the formation of naphthalene
Summary Acknowledgments• Experiments on pyrolytic reactions of the phenyl rad ical in the presence of acetylene conducted over a wide range of pressures (1 - 50 atm) and temperature s (1000 - 1700 K) using two different experimental techniques.
• The experiments conducted at University Karlsruhe ind icate that at low pressure the recombination betwee n phenyl and acetylene does not lead to naphthalene formation.
• The experimental and theoretical work conducted at UIC shows that at high pressure acetylene is involv ed in the formation of the second-ring species, but the HACA mechanism is not the main pathway to naphthalene.
• Possibly alternative pathways to naphthalene format ion at high pressure exist.
SERDP, financial sponsor through contract WP 1575.
DFG, financial support through contract OL85/2-1.
This work reflects the collaborative efforts of UIC and University Karlsruhe, and the authors would additionally like to thank the sponso rs for encouraging this collaboration.
Pyrolytic Reactions of the Phenyl Radical in the Pre sence of Acetylene: ModelingMain Naphthalene Formation Pathways
a Richter, H. ; Mazyar, O. A. ; Sumathi, R. ; Green, W. H. ; Howard, J. B. ; Bozzelli, J. W. J. Phys. Chem. A 2001, 105, 1561-1573.b Frenklach, M.; Wang, H. Proc. Combust. Inst. 1991, 23, 1559.c Estimated.d Wang, H.; Frenklach, M. J. Phys. Chem. 1994, 98, 11465-11489.
• Quite accurate simulations of phenyacetylene profile s
• BUT: compared to the experiments, too small amounts of naphthalene predicted
1000 1200 1400 1600
0
50
100
150
Pyrolysis of C6H
5I-C
2H
2 Blends
P~25atm; Reaction Time~1.5-2ms
C6H
5I-C
2H
2 m
ole
frac
tion/
ppm
Reflected Shock Temperature T5/K
C6H5I: ○ experiment; ● simulationC2H2: ∆ experiment; ▲ simulation
C4H2: ○ experiment; ● simulationC6H6: □ experiment; ■ simulation
C6H5C2H: ∆ experiment; ▲ simulationC10H8: □ experiment; ■ simulation
1000 1200 1400 1600
0
5
10
15
20
Pyrolysis of C6H
5I-C
2H
2 Blends
P~25atm; Reaction Time~1.5-2ms
C6H
5C2H
-C10
H8
mol
e fr
actio
n/pp
m
Reflected Shock Temperature T5/K
1000 1200 1400 1600
0
10
20
30
Pyrolysis of C6H
5I-C
2H
2 Blends
P~25atm; Reaction Time~1.5-2ms
C4H
2-C
6H6 m
ole
frac
tion/
ppm
Reflected Shock Temperature T5/K
Problem Statement
• Environmental hazards - haze and poor air quality• Reduced combustor efficiency• Increased combustor wear and tear• Hinders tactical effectiveness• Deterrent - active recruitment and training of milit ary personnel• Health hazard - asthma and cancer (10 mg/m3 increase in fine PM ~6% increase cardiopulmonary mortality and 8% increase in lung c ancer mortality) a
Particulate Matter (PM) Emissions
a. Pope, III C. A.; Burnett, T. R.; Thurston, D. G.; Thun, J. M.; Calle, E.; Krewski, D.; Ito, K., Journal of the American Medical Association 2002, 287, 1132-1141.
Supersonic jet
Mass Spectrometer
Pulsed Electron Impact Ionization
125 kHz
45 eV
Reflectron mode
Experimental Technique: Real-time TOF-Mass Spectrom etry behind Shock Waves
1 mm
Pinhole 30 – 140 µm
Sampling unit
TOF-MS ST Operating ConditionsTemperatures: 800 - 2000 K
Pressures: 0.1 - 2 atmTime Resolution: 15 µµµµs
Bath gas: Ne
Pyrolysis of Iodobenzene as Phenyl Radical Precursor
0.0 0.5 1.0 1.50.0
0.2
0.41553 K; 1.14 bar
[C2H
2]; [
C12
H10
] / a
. u.
t / ms
biphenyl acetylene
150 175 200 225
-0.01
0.00
no 3 ring species 4 ring species
2 ring species
I / V
m / z
75 - 210 µs 1.5 - 1.65 ms
• Iodobenzene and argon: 3400 ppm (each)
• Products observed: C 2H2, C6H6, C8H6, C12H10, C18H12
• Diacetylene superimposed (fragment peaks)
• Only PAH with even number of rings !
0.0 0.5 1.0 1.50
1
[C6H
5I] / [
C6H
5I] 0
t / ms
1247 K 1375 K 1492 K 1593 K
0.0 0.5 1.0 1.50.0
0.1
0.2
0.3
[C8H
6] /
[C6H
5I] 0
t / ms
1593 K 1440 K 1247 K
0.0 0.5 1.0 1.50.0
0.2
0.4
0.6
[C6H
6] /
[C6H
5I] 0
t / ms
1593 K 1375 K 1247 K
150 175 200 225
-0.05
0.00
1558 K; 1.04 bart: 15 - 150 µs4000 ppm C
6H
5I
1.23 % C2H
2
C12
H8? C
12H
10 C14
H10
I / V
m / z
0.0 0.5 1.0 1.50.0
0.5
1.0
1.5
2.0
0.0 0.5 1.0 1.50.00
0.25
0.50
0.75
1.00
1.25
[C6H
6],
[C8H
6] / 1
0-8 m
ole
/ cm
3
t / ms
benzene phenylacetylene benzene phenylacetylene
1553 K; 1.14 bar
[C6H
5I] /
10-8
mol
e cm
-3
t / ms
• Iodobenzene: 3300 or 2000 ppm
• C2D2: C6H5 = 3 or 8.5
• C2D2 to separate naphthalene and HI peaks
• BUT: no naphthalene was observed
• Products: C 6H6, C8H6, C12H10, C14H10
Pyrolytic Reactions of the Phenyl Radical in the Pre sence of Acetylene: Experimental Data
+ C2H2
-H2,+H
+C2H2
-H
a, b
c, b
c
c
+C2H2
a, b
b, d
-H
a, b
+C2H2
b, d
