Kinetics of naphthyl (C10H7) radical reactions monitored by C10H7OO
J. Park, Hue M. T. Nguyen, # Z. F. Xu and M. C. Lin
Department of Chemistry, Emory University, Atlanta, GA 30322
#Present address: Hanoi National University of Education, Hanoi, Vietnam
Motivation Schematic Diagram of CRDS Reaction Mechanism
As small aromatic radicals such as phenyl (C6H5), KrF Excimer Laser 1-C10H7 + C2H2 2-C10H7 + C2H2
LPX 105 BS M3
phenylvinyl (C6H5C2H2), naphthyl (C10H7), and their 248 nm
derivatives are believed to play a pivotal role in the M2 M4
Blacken Clothes
formation of naphthalene (C10H8), a possible route to Pinhole
M5
the formation of PAH’s, by HACA (H-Abstraction, Diffuse Glass Heater XeCl Excimer Laser
EMG 201 MSC 308nm
C2H2-Addition) reactions and cyclization reactions.
+ C2H2 Dye Laser
PMTube FL 3002
Fousing Lens Coumarin 307
Pinhole
504.8 nm
+ C2H2 -H
A = 0.00001
Oscillosocpe
LS140 Digital Pulse/Delay Generator
Competing oxidation processes to remove the Data Acqusition Systme by using
DG535
naphthyl radical, such as C10H7 + O2, similar to the LabVIEW Program through GPIB
Interface Card
removal of the phenyl radical by the C6H5 + O2
14
reaction, should be quite important to the kinetics of 12 high pressure limit (A) (A)
high pressure limit
soot formation in its incipient stages. 12
Log (k; cm mol s )
Log (k; cm mol s )
6
-1 -1
-1 -1
k1
C10H7 + O2 C10H7OO k 2 other products 10
k3
C10H7 + C2H2 C10H7C2H2
Results 0 10 atm
8
3
3
-6 1 atm 10 atm
0.020 6 1 atm
14 This work [O2] = 0.16 Torr -12
This work [O2] = 0.08 Torr 40 Torr Richter 40 Torr
0.018
[C2H2]0 = 0.63 Torr Linear fit 4
Abosorbance (1/tc - 1/to)
Kislov
Experimental (CRDS) 13 C6H5 + C2H2 ; Yu
-18 1 Torr
Log(k; cm mol s )
1 Torr C10H7C2H2
-1
0.016 1-C10H7 + C2H2 ; kislov
C10H7C2H2 Wang 2
-1
1-C10H7 + C2H2 ; Richter
12
1-C10H7 + C2H2 ; Wang
0.014
The kinetics for the 2-C10H7 + C2H2 reaction has 3500
3000 3 11 (B)
12
(B)
Log (k; cm mol s )
been measured at temperatures 303 - 448 K by [C2H2]0 = 0.00 Torr 2500
Log (k; cm mol s )
0.012
-1 -1
k1' + k3'
12 10
-1 -1
2000
10
indirectly monitoring C10H7O2 with the cavity ring- 0.010
1500
1000 8
9
down spectrometry (CRDS) using 2-C10H7Br as a 500 11
3
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
0.008
3
[C2H2]0
6
radical source by photolysis at 193 nm. 0 20 40 60 80 100 120 140 160
8
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 1 Torr
time (s) -1 10 4
1000/T; K 1 - 760 Torr
40 Torr
k k
' '
2
1/tc - 1/t0 B ' exp - k1 k 3 t exp k 2 t
' ' '
1 3 1 atm
Computational k 2 k1 k 3
' ' 9
0
C10H7C2H + H 10 atm C10H7C2H + H
1/tc - 1/t0 C D exp- P1 t exp P2 t
10 atm
8 -2
Optimization and Vibrational Frequency 0 1 2 3 4 5 0 1 2 3
-1
4 5
-1 1000/T; K
calculation B3LYP/6-311+G(d,p) k3 = (3.36 0.63) 1011 exp [-(817 34)/ T] cm3 mol-1 s-1 1000/T; K
PES : G2MS//B3LYP/6-311+G(d, p)
10
The microcanonical Rice-Ramsperger-Kassel- Kinetic Modeling
The potential energy surfaces, calculated by G2MS//b3LYP/6-311+G(d,p), show that
Marcus (RRKM) theory was employed to calculate
Concentration (mTorr)
8 2-C10H7
2-C10H7 = 1-C10H7 the reactions of 1- and 2-C10H7 with C2H2 occurs firstly by addition forming the
the rate constants of the reactions by VARIFLEX. 2-C10H7O2
2-C10H7 + C2H2 = 2-C10H7C2H2 6
excited naphthyl vinyl radicals, which can undergo isomerization to various
2-C10H7 + 2-C10H7 = C20H14
2-C10H7 + O2 = C10H7O2 4
structural isomers or elimination of a hydrogen atom by low barrier decomposition
Acknowledgement C10H7O2 = others 1-C10H7(x10 )
20
channels. The mechanisms for the decomposition of the two radicals were
2-C10H7C2H2 + O2 = C10H7C2H2O2 2 2-C10H7C2H2O2 (x100) predicted to be significantly different under experimental conditions: the excited 1-
C10H7C2H2O2 = C10H7CHO + HCO
DOE Grant No. DE-FG02-97-ER14784. 2-C10H7C2H2 (x100) C10H7C2H2 radical produces predominantly acenaphthylene due to its low formation
0
The Cherry L. Emerson Center of Emory 0 20 40 60 80 100 120 140 160
barrier, while the excited 2-C10H7C2H2 radical can be effectively stabilized by
University time (sec) collisional deactivation because of its high exit barrier.
7th International Conference on Chemical Kinetics, Jul 10 - 14, 2011, Massachusetts Institute of Technology (MIT), Cambridge, MA USA