Experimental and modeling of oxidation of acetylene, propyne, allene and 1,3-butadiene

Article abstract of DOI:10.1002/(SICI)1097-4601(1999)31:5<361::AID-KIN6>3.0.CO;2-K

The ignition delays of insaturated hydrocarbons-oxygen-argon mixtures were measured behind shock waves in the cases of acetylene, propyne, allene and 1,3-butadiene. Reflected shock waves permitted to obtain temperatures from 1000-1650 K and pressures from 8.5 to 10.0 atm. A particular effort has been made to build a detailed mechanism of the reactions of C₃-C₄ unsaturated species and benzene. This mechanism is based on the most recent kinetic data values published in the literature and is consistent with the thermochemistry. This mechanism has been validated by comparing the results of our simulations to the experimental results obtained in our shock tube experiments and to profiles of radicalar and molecular species measured in three premixed flames (acetylene and 1,3-butadiene) coming from the literature. The main reaction pathways have been derived in the case of the oxidation of these four insaturated hydrocarbons and for the formation of benzene.

Full text of DOI:10.1002/(SICI)1097-4601(1999)31:5<361::AID-KIN6>3.0.CO;2-K

Experimental and Modeling
of Oxidation of Acetylene,
Propyne, Allene and
1
,3-Butadiene
R. FOURNET, J. C. BAUGE, F. BATTIN-LECLERC
D e´ partement de Chimie-Physique des R e´ actions, UMR nЊ 7630 CNRS, INPL-ENSIC 1, rue Grandville-BP 451-54001
NANCY Cedex-France
Received 18 June 1998; accepted 30 December 1998
ABSTRACT: The ignition delays of insaturated hydrocarbons-oxygen-argon mixtures were mea-
sured behind shock waves in the cases of acetylene, propyne, allene and 1,3-butadiene. Re-
flected shock waves permitted to obtain temperatures from 1000–1650 K and pressures from
8
.5 to 10.0 atm.
A particular effort has been made to build a detailed mechanism of the reactions of C -C
3
4
unsaturated species and benzene. This mechanism is based on the most recent kinetic data
values published in the literature and is consistent with the thermochemistry.
This mechanism has been validated by comparing the results of our simulations to the
experimental results obtained in our shock tube experiments and to profiles of radicalar and
molecular species measured in three premixed flames (acetylene [1–2] and 1,3-butadiene [3])
coming from the literature. The main reaction pathways have been derived in the case of
the oxidation of these four insaturated hydrocarbons and for the formation of benzene.
᭧
1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 361–379, 1999
INTRODUCTION
Recently, our laboratory has developed a software
EXGAS) which permits to generate automatically de-
(
During the last decade, several experimental and theo-
retical studies have been attempted in order to under-
stand how the polycyclic aromatic hydrocarbons
tailed mechanisms of oxidation or combustion of par-
affins and iso-paraffins [7]. The mechanisms of oxi-
dation for alkanes involve the formation of butene,
propene and ethylene amongst primary products, and
the formation of 1,3-butadiene and acetylene amongst
secondary products. The reactions of these unsaturated
molecules lead to the formation of benzene at high
temperature. The development of a reaction data base
which can be added to detailed mechanisms produced
by EXGAS is then necessary in order to describe the
formation of aromatics during the oxidation of large
hydrocarbons.
(PAHs) are produced during the combustion of hydro-
carbons. It is now well established that PAHs represent
soot precursors and that the formation of single aro-
matics like benzene can be considered as a crucial
stage in the mechanism of particles production. Thus,
over the past few years, several reaction pathways and
submechanisms have been proposed for modeling the
formation of benzene, especially from small unsatu-
rated species (acetylene, ethylene, ...), at high temper-
ature in premixed flames or shock tube experiments
In the first part of this article, we describe the ex-
perimental oxidation of acetylene, propyne, allene,
and 1,3-butadiene in a shock tube and discuss the ig-
nition delays measured. In the second part, we develop
the construction of the reaction base for C -C unsat-
[1–6].
Correspondence to: R. Fournet
1999 John Wiley & Sons, Inc.
᭧
CCC 0538-8066/99/050361-19
3
4

3
62
FOURNET, BAUGE, AND BATTIN-LECLERC
urated species and benzene. In a third part, a compar-
ison is made between simulations using our mecha-
nism and experimental results obtained in our shock
tube experiments and in three premixed flames (acet-
ylene [1–2] and 1,3-butadiene [3]) coming from the
literature. In the last part, the major channels are de-
termined for the oxidation of these four reactants and
for the formation of benzene.
the incident shock velocity by using ideal one-dimen-
sional shock equations.
The onset of ignition was detected by OH radical
emission at 306 nm through a quartz window with a
photomultiplier fitted with a monochromator at the end
of the reaction part. Figure 1 shows typical experi-
mental results, which have permitted ignitions delays
to be derived; that is, a normalized OH radical emis-
sion signal and the relevant pressure profile given by
the pressure transducer, which is located at the same
place along the axis of the tube as the quartz window.
The pressure profile displays three rises, which are due
to the incident shock wave, the reflected shock wave,
and the ignition, respectively. The ignition delay time
was defined as the time interval between the pressure
rise due to the arrival of the reflected shock wave and
the rise of the optical signal by the photomultiplier up
to 10% of its maximum value.
The gases used in this study were purchased from
Air Liquide-Alphagaz. Fresh reaction mixtures were
prepared every day. Before each introduction of the
reaction mixture, the reaction section was flushed with
pure argon and evacuated, in order that the residual
gas was mainly argon.
This study has been performed in the follow-
ing experimental conditions (after the reflected
shock):
MEASUREMENTS OF IGNITION DELAYS
IN A SHOCK TUBE FOR ACETYLENE,
PROPYNE, ALLENE, AND 1,3-BUTADIENE
As it is already described in detail in a previous paper
[8], we will just recall here the main features of this
experimental device. Autoignition delays were mea-
sured in a stainless steel shock tube; the reaction and
the driver parts were respectively 400.6 and 89 cm in
length and were separated by two terphane dia-
phragms. These diaphragms were ruptured by decreas-
ing suddenly the pressure in the space separating them.
The driver gas was helium. The incident and reflected
shock velocities were measured by piezo-electric pres-
sure transducers located along the reaction section.
The state of the test gas behind the incident and the
reflected shock waves was derived from the value of
Figure 1 Ignition delays in shock tube. Typical experimental results: pressure profile, normalized
OH emission signal and computed OH concentration profile. Mixture containing 3% acetylene with
⌽
equal to 3 (T ϭ 1086 K, P ϭ 9.22 atm).

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
363
•
•
•
Temperature range from 1000–1650 K
Pressure range from 8.5–10.0 atm
Mixtures (Argon : hydrocarbon : Oxygen, in mo-
lar percent) were respectively (91 : 1 : 8), (95 :
diene. In agreement with what Curran et al. [9] have
observed, propyne and allene exhibit very similar be-
haviors. For these two compounds, the ignitions delays
obtained in this study in a pressure range from 8.5–
9.5 atm are approximately four times shorter than
those obtained by Curran et al. [9] for similar mixtures,
except at 3.5 atm.
1
: 4), and (85 : 3 : 12)
which permitted corresponding delays from 7–2500
s to be obtained, and to avoid the deposition of too
␮
important amounts of soot on the wall of the tube.
Figures 2 to 3 present the experimental results ob-
tained respectively with acetylene (Fig. 2a), propyne
WRITING OF A REACTION DATABASE
FOR C -C UNSATURATED
3
6
(Fig. 2b), allene (Fig. 3a), and 1,3-butadiene (Fig. 3b).
HYDROCARBONS
These results show that, in each case, ignition delays
increase with equivalence ratio and decrease with di-
lution. Acetylene is the most reactive of these four
hydrocarbons, as it starts to react at a temperature
around 200 K lower than propyne, allene, and buta-
This reaction base (C -C reaction base) has been built
3
6
from a review of the recent literature (Westmoreland
et al., 1989 [5]; Tsang, 1991 [10]; Miller et al., 1992
[11]; Leung et al., 1995 [12]; Linstedt et al., 1996 [13];
Figure 2 Ignition delays in shock tube. Mixture containing acetylene (a) or propyne (b). Points
correspond to experimental results and lines to simulations.

3
64
FOURNET, BAUGE, AND BATTIN-LECLERC
Figure 3 Ignition delays in shock tube. Mixture containing allene (a) or butadiene (b). Points
correspond to experimental results and lines to simulations.
Hidaka et al., 1996 [14]; Wang et al., 1997 [6]...) and
is an extension of the C -C reaction base developed
in our laboratory by Barb e´ et al. in 1995 [15].
1. The reactions leading to the formation of species
including more than two carbon atoms have
been discarded as they are taken into account in
the C -C reaction base.
0
2
3
4
2
. In order to be able to correctly model combus-
tion processes in slightly diluted systems, effi-
ciency factors have been included for reactions,
whose rate constant is pressure dependent.
These factors were taken from the reaction base
of Leeds: http://chem.leeds.ac.uk/Combustion/
Combustion.html.
The C -C Reaction Base [15]
0
2
The C -C reaction base includes all the unimolecular
0
2
or bimolecular reactions involving radicals or mole-
cules containing less than three carbon atoms. The ki-
netic data used in this base were taken from the liter-
ature and are mainly those proposed by Baulch et al.
[
16] and Tsang et al. [17].
3. Oxygenated compounds such as peroxides,
which only play a role at low temperature, have
been discarded from the original C -C reaction
The C -C reaction base presented in the paper of
0
2
Barb e´ et al. [15] has been updated in the following
ways:
0
2
base in order to accelerate the CHEMKIN II

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
365
simulations, especially in the case of premixed
flame modeling, where transport coefficients
matrix rapidly increases the size of the binary
file.
. The reactions, which have been added or whose
rate constant has been modified, are summarized
in Table I.
Even if this process is relatively complicated and im-
plies multiple isomerizations [36], it seems that ex-
perimental observations have corroborated this hy-
pothesis [41]. By analogy with reaction (174), we also
considered the combination of a propargyl with an al-
4
lyl radical, a-C H
и
[37]. The last channel concerns
Diels Alder reactions and especially the reactions of
,3-butadiene with ethylene or acetylene, followed by
3
5
1
successive dehydrogenation of the cyclohexene or cy-
clohexadiene formed.
The C -C Reaction Base
3
6
The mechanism, described here and given in Table II,
is presented as a file which can be used to run simu-
lations using CHEMKIN II [40]. It has been built from
data of the literature and involves the reaction of the
main C -C unsaturated molecules and radicals, as
well as the formation of benzene at high temperature
and found in the literature. The detailed chemical for-
mula of the radicals mentioned in this paper can also
be found in Table II.
In addition to benzene formation pathways, reac-
tions involving C H ии
, C H , C H (allene and pro-
и
3
2
3 3 3 4
pyne), C H (three isomers), C H , C H , C H , C H
и
3 5 3 6 4 2 4 4 4 6
(1,3-butadiene, 1,2-butadiene, methyl-cyclopropene,
1-butyne, and 2-butyne) have been considered from a
systematic analysis of reactions found in the literature.
However, due to a lack of reaction and kinetic data, it
has not been possible to build this database in a way
as comprehensive as in the case of the C -C reaction
3
4
0
2
The formation of benzene through a C pathway,
base.
4
as proposed mainly by Wang et al. [6] or Westmore-
land et al. [5], has been written. In this pathway, the
aromatic ring is formed by considering the addition of
Thermochemical data have been estimated by the
software THERGAS developed in our laboratory [42],
which is based on the methods proposed by S. W.
Benson [43]. The kinetic data adopted in our reaction
base have been obtained from an analysis and a com-
parison between all the values found in the literature.
Few kinetic values have been estimated:
acetylene to n-C H
и
and n-C H
и
5
radicals followed
4
3
4
by a cyclisation to give benzene or phenyl radical.
Taking into account the work of Miller et al. [11] con-
cerning the flame of acetylene, we have also consid-
ered the stabilized radicals i-C H
и
and i-C H . A
и
4
5
4
3
second pathway for the formation of benzene has been
more recently proposed by several authors [11,36] and
was adopted in our mechanism. This channel is related
to the recombination of propargyl radical:
• Kinetic data for the methatheses on propyne and
1,2-C H were taken equal to those proposed by
4
6
Tsang [10] in the case of propene
• Kinetic data for the reaction of n-C H
и
with H
и
4
3
and OH to give C H are taken equal to the val-
и
4 2
иC3H3 ϩ
и
C H !: benzene
ues proposed by Miller [11] for the similar re-
3
3
or
phenyl ϩ H
и
(174, 174’).
actions with i-C H3и
4
n
Table I Changes in the C -C Reaction Base. The Rate Constants Are Given at 1 atm (k ϭ A T exp(ϪE /RT) in cc,
0
2
a
mol, s, cal units. Reference Numbers Are Given in Brackets When They Appear for the First Time.
Reactions
A
n
Ea
Reference
CH ϩ H"C ϩ H2
C2H2 ϩ O"CH2 ϩ CO
C2H2 ϩ O"HCCOZ ϩ H
C3H3 ϩ OH"R10C2H3V ϩ R5CHO
HCO ϩ H"H2 ϩ CO
O2 ϩ CH"CO ϩ OH at 760 Torr
O2 ϩ C2H3"HCHO ϩ HCO
O2 ϩ C2H3"O ϩ CH2CHO at 20–90 torr
O2 ϩ C2H3"HCHO ϩ HCO
O2 ϩ C2H3"O ϩ CH2CHO
7.8E13
2.17E06
5.06E06
4.0E13
9.0E13
3.2E13
8.6E21
1.2E13
1.6E21
2.5E12
0.
2.1
2.1
0.
0.
0.
Peeters 96 [18]a
Leeds
Leeds
Wang 97 [6]
Baulch 94 [16]b
Peeters 97
Wang 97
Wang 97a
Wang 97
Wang 97a
1.6E3
1.6E3
0.
0.
0.
3.3E3
1.7E3
2.5E3
0.
Ϫ2.97
Ϫ0.12
Ϫ2.78
0.057 0.9E3
a
New reaction which was not considered in the previous C -C reaction base.
0
2
b
There was an error on this rate constant in the previous C -C reaction base.
0
2

3
66
FOURNET, BAUGE, AND BATTIN-LECLERC
Table II C -C Reaction Base for Compounds Containing No Oxygen Atoms. The Rate Constants Are Given at 1 atm
3
4
n
(
k ϭ A T exp(ϪE /RT)) in cc, mol, s, cal units. Reference Numbers Are Given in Brackets When They Appear for the
a
First Time.
Reactions
A
n
Ea
References
REACTIONS OF C3 SPECIES
Reactions of C3H2 (CH#CCHии
CH ϩ C2H2"C3H2 ϩ H
C3H2 ϩ O"C2H ϩ H ϩ CO
C3H2 ϩ OH"C2H2 ϩ CHO
C3H2 ϩ O2"CHCO ϩ CO ϩ H
)
2.1E14
3.0E13
5.0E13
5.0E13
0.0
0.0
0.0
0.0
Ϫ0.5E3
0.0
0.0
(1) Miller 92 [11], Baulch 94 [16]
(2) Peeters 96 [18]
(3) Miller 92
0.0
(4) Miller 92
Reactions of C3H3 (CH#CCH2
CH2 ϩ C2H2"C3H3 ϩ H
C3H3 ϩ H"C3H2 ϩ H2
C3H3 ϩ O"C2H ϩ HCHO
C3H3 ϩ OH"C3H2 ϩ H2O
C3H3 ϩ OH"C2H3 ϩ CHO
C2H2 ϩ CHCO"C3H3 ϩ CO
C3H3 ϩ O2"CH2CO ϩ CHO
и
, resonance stabilized propargyl radicals)
1
1.8E14
2.0E13
1.4E14
2.0E13
4.0E13
1.0E11
3.0E10
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0E3
2.9E3
(5) Miller 92, Baulch 94
(6) Miller 92, Braun-Unkhoff 89 [19]
(7) Miller 92, Slagle 91 [20]
(8) Miller 92
(9) Wang 97 [6]
(10) Miller 92
(11) Miller 92
Reactions of pC3H4 (CH#CCH3, propyne)
pC3H4 Q aC3H4
2.1E12
4.7E18
3.5E12
4.2E16
6.7E19
6.5E12
5.8E12
1.7E5
0.0
0.0
0.0
0.0
Ϫ2.08
0.0
0.0
2.5
3.5
0.0
3.5
3.5
0.0
0.7
0.0
2.0
0.0
0.0
2.6
60.0E3
80.0E3
0.0
100.0E3
31.6E3
1.7E3
3.1E3
2.5E3
5.7E3
0.0
4.7E3
6.6E3
2.1E3
7.6E3
Ϫ0.8E3
0.3E3
51.0E3
8.0E3
13.9E3
(12) Hidaka 89 [21]
(13) Hidaka 89
(14) Tsang 86 [17]
(15) Wu 87 [4]
(16) Dean 87 [22]
(17) Wagner 72 [23]
(18) Wagner 72
(19) Tsang 91 [9] a
(20) Tsang 91 a
(21) Tsang 91 a
(22) Tsang 91 a
(23) Tsang 91 a
(24) Warnatz 84 [24]
(25) Tsang 91 a
pC3H4 ϩ M"C3H3 ϩ H ϩ M
3
C2H2 ϩ CH2"pC3H4
pC3H4"C2H ϩ CH3
C2H2 ϩ CH3"pC3H4 ϩ H
pC3H4 ϩ H"tC3H5
pC3H4 ϩ H"sC3H5
pC3H4 ϩ H"C3H3 ϩ H2
pC3H4 ϩ CH3"C3H3 ϩ CH4
pC3H4 ϩ C2H"C3H3 ϩ C2H2
pC3H4 ϩ C2H3"C3H3 ϩ C2H4
pC3H4 ϩ C2H5"C3H3 ϩ C2H6
pC3H4 ϩ O"CHCO ϩ CH3
pC3H4 ϩ O"OH ϩ C3H3
pC3H4 ϩ OH"CH2CO ϩ CH3
pC3H4 ϩ OH"C3H3 ϩ H2O
pC3H4 ϩ O2"C3H3 ϩ HO2
pC3H4 ϩ HO2"C2H4 ϩ CO ϩ OH
pC3H4 ϩ HO2"C3H3 ϩ H2O2
Reactions of aC3H4 (CH2"C"CH2, allene)
aC3H4 Q pC3H4
2.2E0
3.6E12
2.2E0
2.2E0
1.5E13
6.0E10
4.3E11
3.1E6
5.0E12
6.0E9
(26) Boodaghians 87 [25]
(27) Tsang 91 a
(28) Dagaut 90 [26]
(29) Tsang 86 a
9.6E3
(30) Tsang 91 a
2.5E12
2.0E18
1.3E14
3.0E13
4.0E12
8.5E13
2.0E13
7.8E12
2.0E12
2.0E12
4.0E13
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
59.0E3
80.0E3
Ϫ0.3E3
0.0
2.7E3
2.0E3
0.0
1.6E3
Ϫ0.2E3
Ϫ0.2E3
61.5E3
(31) Hidaka 89
(32) Hidaka 89
(33) Baulch 94
(34) Miller 92
(35) Wagner 72
(36) Wagner 72
(37) Miller 92
(38) Herbrechstmeier 72 [27]
(39) Liu 88 [28]
(40) Liu 88
aC3H4 ϩ M"C3H3 ϩ H ϩ M
C2H4 ϩ CH"aC3H4 ϩ H
3
C2H3 ϩ CH2"aC3H4 ϩ H
aC3H4 ϩ H"aC3H5
aC3H4 ϩ H"tC3H5
3
iC4H3 ϩ CH2"aC3H4 ϩ C2H
aC3H4 ϩ O"C2H4 ϩ CO
aC3H4 ϩ OH"CH2CO ϩ CH3
aC3H4 ϩ OH"HCHO ϩ C2H3
aC3H4 ϩ O2"C3H3 ϩ HO2
(41) Dagaut 90
Reactions of aC3H5 (CH2"CHCH2
aC3H5 ϩ H"C3H6
aC3H5 ϩ CH3"aC3H4 ϩ CH4
aC3H5 ϩ CH3"C4H8
aC3H5 ϩ C2H3"aC3H4 ϩ C2H4
aC3H5 ϩ C2H5"aC3H4 ϩ C2H6
aC3H5 ϩ O"C2H3 ϩ HCHO
и
, resonance stabilized allyl radicals)
2.0E13
3.0E12
1.0E14
2.4E12
2.0E13
1.8E14
0.0
Ϫ0.32
Ϫ0.32
0.0
0.0
0.0
0.0
Ϫ0.1E3
Ϫ0.1E3
0.0
Ϫ0.1E3
0.0
(42) Tsang 91
(43) Tsang 91
(44) Tsang 91
(45) Tsang 91
(46) Tsang 91
(47) Slagle 90 [29], Leung 95 [12]
(Continued)

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
367
Table II (Continued)
Reactions
A
n
Ea
References
(48) Tsang 91
(49) EXGAS [7] a
(50) Tsang 91
aC3H5 ϩ OH"HCHO ϩ C2H4
aC3H5 ϩ HO2"OH ϩ CHO ϩ C2H4
aC3H5 ϩ aC3H4 ϩ C3H6
1.5E13
5.0E12
8.4E10
1.2E13
0.0
0.0
0.0
0.0
0.0
0.0
Ϫ0.3E3
0.0
aC3H5 ϩ aC3H5"C6H10
(51) Baulch 94
Reactions of sC3H5 (
sC3H5"aC3H5
и
CH"CHCH3, 2-methyl vinyl radicals)
5.0E13
6.0E11
0.0
0.0
37.0E3
7.7E3
(52) Weissman 89 [30]
(53) Baulch 94
CH3 ϩ C2H2"sC3H5
Reactions of tC3H5 (
tC3H5 ϩ H"aC3H4 ϩ H2
и
C(CH3)"CH2, 1-methyl vinyl radicals)
3.3E12
1.0E11
1.0E12
1.0E12
1.8E14
4.3E12
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
(54) Dagaut 90
(55) Dagaut 90
(56) Leung 95
(57) Leung 95
(58) Leung 95
(59) Dagaut 90
tC3H5 ϩ CH3"aC3H4 ϩ CH4
tC3H5 ϩ C2H3"aC3H4 ϩ C2H4
tC3H5 ϩ C2H5"aC3H4 ϩ C2H6
tC3H5 ϩ O"CH2CO ϩ CH3
tC3H5 ϩ O2"CH3 ϩ CO ϩ HCHO
Reactions of C3H6 (CH2"CHCH3, propene)
C2H4 ϩ CH2"C3H6
C2H4 ϩ CH2"C3H6
C2H3 ϩ CH3"C3H6
C2H4 ϩ CH3"C3H6 ϩ H
1
9.6E13
3.2E12
2.5E13
6.6E11
9.0E12
1.1E14
4.6E5
8.0E5
1.7E5
2.2E0
8.4E-1
1.3E0
2.2E0
3.6E6
1.7E11
2.9E12
3.1E6
1.1E6
2.1E6
1.9E12
9.6E3
0.0
0.0
0.0
0.0
0.0
0.0
2.5
2.5
2.5
3.5
3.5
3.5
3.5
2.15
0.7
0.0
2.0
2.0
2.0
0.0
2.6
0.0
5.1E3
0.0
15.9E3
0.0
(60) Baulch 94
(61) Baulch 94
(62) Tsang 86
(63) Tsang 86
(64) Tsang 86
(65) Baulch 94
(66) Tsang 91
(67) Tsang 91
(68) Tsang 91
(69) Tsang 91
(70) Tsang 91
(71) Tsang 91
(72) Tsang 91
(73) Tsang 91
(74) Tsang 91
(75) Tsang 91
(76) Tsang 91
(77) Tsang 91
(78) Tsang 91
(79) Walker 93 [31]
(80) Tsang 91
3
1
C2H5 ϩ CH2"C3H6 ϩ H
C2H6 ϩ CH"C3H6 ϩ H
C3H6 ϩ H"sC3H5 ϩ H2
C3H6 ϩ H"tC3H5 ϩ H2
Ϫ0.3E3
9.8E3
12.3E3
2.5E3
5.7E3
11.7E3
12.9E3
6.6E3
Ϫ0.8E3
5.9E3
Ϫ0.9E3
Ϫ0.3E3
1.45E3
2.8E3
39.0E3
13.9E3
C3H6 ϩ H"aC3H5 ϩ H2
C3H6 ϩ CH3"aC3H5 ϩ CH4
C3H6 ϩ CH3"sC3H5 ϩ CH4
C3H6 ϩ CH3"tC3H5 ϩ CH4
C3H6 ϩ C2H5"aC3H5 ϩ C2H6
C3H6 ϩ O"H ϩ CH3 ϩ CH2CO
C3H6 ϩ O"aC3H5 ϩ OH
C3H6 ϩ OH"HCHO ϩ C2H5
C3H6 ϩ OH"aC3H5 ϩ H2O
C3H6 ϩ OH"sC3H5 ϩ H2O
C3H6 ϩ OH"tC3H5 ϩ H2O
C3H6 ϩ O2"aC3H5 ϩ HO2
C3H6 ϩ HO2"aC3H5 ϩ H2O2
REACTIONS OF C4 SPECIES
Reactions of C4H2 (CH#CC#CH, diacetylene)
C2H ϩ C2H"C4H2 1.8E13
C2H2"C4H2 ϩ H2
C2H2 ϩ C2H Q C4H2 ϩ R1H
C4H2 ϩ H Q C2H2 ϩ C2H
0.0
0.0
0.0
0.0
0.0
0.0
0.0
42.7E3
0.0
15.4E3
1.72E3
Ϫ0.4E3
(81) Tsang 86
(82) Leung 95
(83) Baulch 94
(84) Colket 86 [32]
(85) Warnatz 84
(86) Perry 84 [33]
2
1.5E13
9.0E13
6.0E14
2.7E13
6.7E12
C4H2 ϩ O"C3H2 ϩ CO
C4H2 ϩ OH"CHO ϩ C3H2
Reactions of nC4H3 (CH#CCH"CH
nC4H3 (ϩM)"C4H2 ϩ H (ϩM)
и
)
1.0E14
0.0
36.0E3
/1.0
(87) Miller 92
1.0 1.0E8/
K0
/1.0E14
0.0
30E3/
Troe’s coefficients
C3H3 ϩ CH"nC4H3 ϩ H
nC4H3 ϩ H"iC4H3 ϩ H
nC4H3 ϩ H"C4H2 ϩ H2
7.0E13
1.0E14
5.0E13
1.0E12
1.8E13
3.0E13
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
64.1E3
0.0
(88) Miller 92
(89) Miller 92
(90) Miller 92 a
(91) Leung 95
(92) Tsang 86
(93) Miller 92 a
2
C2H2"nC4H3 ϩ H
C2H ϩ C2H3"nC4H3 ϩ H
nC4H3 ϩ OH"C4H2 ϩ H2O
0.0
(Continued)

3
68
FOURNET, BAUGE, AND BATTIN-LECLERC
Table II (Continued)
Reactions
A
n
Ea
References
Reactions of iC4H3 (CH#C ؒ C"CH2, resonance stabilized radicals)
iC4H3"nC4H3
1.5E13
1.0E14
0.0
0.0
67.8E3
55.0E3
/1.0
0.8E3
66.1E3
0.0
0.0
0.0
0.0
0.0
(94) Leung 95
(95) Miller 92
1.0 1.0E8/
(96) Baulch 94 a
(97) Leung 95
(98) Miller 92
(99) Miller 92
(100) Miller 92
(101) Miller 92
(102) Miller 92
iC4H3 (ϩM)"C4H2 ϩ H (ϩM)
K0
C3H2 ϩ CH2"iC4H3 ϩ H
C2H2"iC4H3 ϩ H
C3H3 ϩ CH"iC4H3 ϩ H
iC4H3 ϩ H"C4H2 ϩ H2
iC4H3 ϩ O"CH2CO ϩ C2H
iC4H3 ϩ OH"C4H2 ϩ H2O
iC4H3 ϩ O2"CH2CO ϩ CHCO
/2.0E15
0.0
48E3/
Troe’s coefficients
3
1.2E14
2.0E12
7.0E13
5.0E13
2.0E13
3.0E13
1.0E12
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2
Reactions of C4H4 (CH#CCH"CH2, vinylacetylene)
3
C3H3 ϩ CH2"C4H4 ϩ H
C2H3 ϩ C2H2 Q C4H4 ϩ H
C4H4 ϩ H Q C2H3 ϩ C2H2
C2H4 ϩ C2H Q C4H4 ϩ H
C4H4 ϩ H Q iC4H3 ϩ H2
iC4H3 ϩ H2 Q C4H4 ϩ H
C4H4 ϩ H Q nC4H3 ϩ H2
nC4H3 ϩ H2 Q C4H4 ϩ H
C2H ϩ C4H4 Q C2H2 ϩ iC4H3
C2H2 ϩ iC4H3 Q C2H ϩ C4H4
C2H3 ϩ C4H4 Q C2H4 ϩ nC4H3
nC4H3 ϩ C2H4 Q C2H3 ϩ C4H4
C2H3 ϩ C4H4 Q C2H4 ϩ iC4H3
iC4H3 ϩ C2H4 Q C2H3 ϩ C4H4
aC3H4 ϩ aC3H4"C2H4 ϩ C4H4
C4H4 ϩ O"aC3H4 ϩ CO
C4H4 ϩ OH"nC4H3 ϩ H2O
C4H4 ϩ OH"iC4H3 ϩ H2O
Reactions of nC4H5 (CH2"CHCH"CH
nC4H5 (ϩM)"H ϩ C4H4 (ϩM)
K0
4.0E13
2.0E13
2.0E13
1.2E13
3.1E14
4.2E12
8.0E13
2.8E12
4.0E13
3.0E13
5.0E11
3.5E11
5.0E11
1.3E11
1.0E15
3.0E13
7.5E6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.0
2.0
0.0
(103) Miller 92
(104) Dout e´ 95 [34]
(105) Dout e´ 95
(106) Tsang 86
(107) Colket 86
(108) Colket 86
(109) Colket 86
(110) Colket 86
(111) Colket 86
(112) Colket 86
(113) Colket 86
(114) Colket 86
(115) Colket 86
(116) Colket 86
(117) Hidaka 89
(118) Leung 95
(119) Miller 92
(120) Miller 92
25.1E3
12.4E3
0.0
14.5E3
21.9E3
14.5E3
11.2E3
0.0
27.9E3
16.3E3
13.4E3
16.3E3
24.1E3
48.0E3
1.8E3
5.0E3
2.0E3
1.0E7
и
)
1.0E14
/1.00E14
1.5E13
1.0E14
1.0E14
2.5E12
4.2E10
1.0E12
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
37.0E3
30000/
0.0
0.0
43.9E3
0.0
(121) Miller 92
nC4H5 ϩ H"C4H4 ϩ H2
nC4H5 ϩ H"iC4H5 ϩ H
nC4H5"C2H2 ϩ C2H3
nC4H5 ϩ OH"C4H4 ϩ H2O
nC4H5 ϩ O2"C2H4 ϩ CO ϩ CHO
nC4H5 ϩ O2"C4H4 ϩ HO2
(122) Wang 97
(123) Miller 92
(124) Hidaka 96 [14]
(125) Wang 97
(126) Wang 97
2.5E3
0.0
(127) Westbrook 82 [35] a
Reactions of iC4H5 (CH2"CH ؒ C"CH2, resonance stabilized radicals)
iC4H5"nC4H5
1.5E13
1.0E14
/2.0E15
3.0E13
1.2E22
5.50E12
1.0E12
0.0
0.0
67.8E3
50.0E3
42000/
0.0
13.7E3
0.0
(128) Leung 95
(129) Miller 92
iC4H5 (ϩM)"H ϩ C4H4 (ϩM)
K0
0.0
0.0
Ϫ2.44
0.0
0.0
iC4H5 ϩ H"C4H4 ϩ H2
(130) Wang 97
(131) Wang 97
(132) Wang 97
(133) Westbrook 82 a
2
C2H3"iC4H5 ϩ H
iC4H5 ϩ OH"C4H4 ϩ H2O
iC4H5 ϩ O2"C4H4 ϩ HO2
3.0E3
Reactions of 1,3-C4H6 (CH2"CHCH"CH2, 1,3-butadiene)
C2H3 ϩ C2H3"1,3-C4H6
9.8E14
2.5E15
1.4E15
5.0E11
1.3E6
Ϫ0.5
0.0
0.0
0.0
2.53
0.0
(134) Hidaka 96
(135) Hidaka 96
(136) Hidaka 96
(137) Tsang 86
(138) Wang 97
(139) Wang 97
(140) Wu 87
1
1
,3-C4H6"C4H4 ϩ H2
,3-C4H6"iC4H5 ϩ H
94.7E3
98.0E3
7.3E3
12.2E3
9.2E3
18.5E3
C2H4 ϩ C2H3"1,3-C4H6 ϩ H
1,3-C4H6 ϩ H"nC4H5 ϩ H2
1,3-C4H6 ϩ H"iC4H5 ϩ H2
1,3-C4H6 ϩ CH3"nC4H5 ϩ CH4
6.6E5
7.0E13
2.53
0.0
(Continued)

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
369
Table II (Continued)
Reactions
A
n
Ea
References
(141) Wu 87 a
(142) Hidaka 96
(143) Hidaka 96 a
(144) Leung 95,
Brezinsky 84 [36]
(145) Wang 97
1
1
1
1
,3-C4H6 ϩ CH3"iC4H5 ϩ CH4
,3-C4H6 ϩ C2H3"nC4H5 ϩ C2H4
,3-C4H6 ϩ C2H3"iC4H5 ϩ C2H4
,3-C4H6 ϩ O"aC3H5 ϩ H ϩ CO
7.0E13
5.0E14
5.0E14
6.0E08
0.0
0.0
0.0
1.45
15.5E3
22.8E3
19.8E3
0.9E3
1
1
1
1
1
1
1
1
,3-C4H6 ϩ OH"nC4H5 ϩ H2O
,3-C4H6 ϩ OH"iC4H5 ϩ H2O
,3-C4H6 ϩ OH"aC3H5 ϩ HCHO
,3-C4H6 ϩ OH"CH3CH2CHO ϩ CH3
,3-C4H6 ϩ OH"CH3CHO ϩ C2H3
,3-C4H6 ϩ O2"iC4H5 ϩ HO2
6.2E6
3.1E6
2.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
3.4E3
0.4E3
(146) Wang 97
2.8E12
2.8E12
2.8E12
4.0E13
1.0E13
1.0E13
Ϫ0.9E3
Ϫ0.9E3
Ϫ0.9E3
57.9E3
22.5E3
19.5E3
(147) Lindstedt 96
(148) Lindstedt 96
(149) Lindstedt 96
(150) Leung 95
(151) Hidaka 96
(152) Hidaka 96 a
,3-C4H6 ϩ C3H3"nC4H5 ϩ aC3H4
,3-C4H6 ϩ C3H3"iC4H5 ϩ aC3H4
Reactions of 1,2-C4H6 (CH2"C"CHCH3, 1,2-butadiene)
1
1
1
1
1
1
1
1
1
1
1
,2-C4H6"1,3-C4H6
,2-C4H6"C3H3 ϩ CH3
,2-C4H6"iC4H5 ϩ H
3.0E13
1.0E12
4.2E15
4.0E11
6.0E12
1.7E5
2.2E0
2.2E0
1.7E11
3.1E6
9.6E3
0.0
0.0
0.0
0.0
0.0
2.5
3.5
3.5
0.7
2.0
2.6
65.0E3
59.5E3
92.6E3
0.0
2.1E3
2.5E3
5.7E3
6.6E3
5.9E3
Ϫ0.3E3
13.9E3
(153) Hidaka 96
(154) Leung 95
(155) Leung 95
(156) Leung 95
(157) Hidaka 96
(158) Tsang 91 a
(159) Tsang 91 a
(160) Tsang 91 a
(161) Tsang 91 a
(162) Tsang 91 a
(163) Tsang 91 a
,2-C4H6 ϩ H"C2H3 ϩ C2H4
,2-C4H6 ϩ H"CH3 ϩ aC3H4
,2-C4H6 ϩ H"C4H5 ϩ H2
,2-C4H6 ϩ CH3"iC4H5 ϩ CH4
,2-C4H6 ϩ C2H5"iC4H5 ϩ C2H6
,2-C4H6 ϩ O"iC4H5 ϩ OH
,2-C4H6 ϩ OH"iC4H5 ϩ H2O
,2-C4H6 ϩ HO2"iC4H5 ϩ H2O2
Reactions of cC4H6 (methyl-cyclopropene)
1
CH2 ϩ pC3H4"cC4H6
1.8E14
3.0E13
3.0E13
0.0
0.0
0.0
0.0
42.3E3
43.8E3
(164) Leung 95
(165) Leung 95
(166) Leung 95
cC4H6"1,3-C4H6
cC4H6"1,2-C4H6
Reactions of 1-C4H6 (CH#CCH2CH3, 1-butyne)
1
1
1
1
-C4H6"1,2ϭC4H6
-C4H6"C3H3 ϩ CH3
-C4H6 ϩ H"CH3 ϩ aC3H4
-C4H6 ϩ H"C2H5 ϩ C2H2
2.5E13
2.0E11
1.3E5
0.0
0.0
2.5
2.5
65.0E3
59.5E3
1.0E3
(167) Hidaka 96
(168) Wu 87
(169) Hidaka 96
(170) Hidaka 96
6.5E4
1.0E3
Reactions of 2-C4H6 (CH3C#CCH3, 2-butyne)
2
2
2
-C4H6"1,3-C4H6
-C4H6"1,2-C4H6
-C4H6 ϩ H"CH3 ϩ pC3H4
3.0E13
3.0E13
2.6E5
0.0
0.0
2.5
65.0E3
67.0E3
1.0E3
(171) Hidaka 96
(172) Hidaka 96
(173) Hidaka 96
REACTIONS OF FORMATION OF Cϩ SPECIES
Aromatic and linear compounds are noted by respectively the symboles # and 1.
C3H3 ϩ C3H3"C6H6# (shock tube)
C3H3 ϩ C3H3"C6H5# ϩ H (flames)
C3H3 ϩ C3H5"C6H5# ϩ 2H
aC3H4 ϩ C3H3"C6H6# ϩ H
C4H2 ϩ C2H Q C6H2 ϩ H
1.0E12
1.0E12
5.6E20
1.4E12
4.0E13
9.3E14
3.0E-11
1.64E9
2.77E-7
29.6
6.17E15
1.73E11
1.9E12
7.0E14
0.0
0.0
Ϫ2.54
0.0
0.0
0.0
6.48
0.73
5.59
3.33
Ϫ1.51
Ϫ0.41
0.0
0.0
0.0
1.7E3
10.0E3
0.0
15.1E3
6.6E3
12.2E3)
6.0E3
9.6E3)
4.8E3
4.0E3)
2.5E3
6.4E3
9.2E3)
(174) STein 90 [37]
(174’) Stein 90]
(175) Marinov 96 [38]
(176) Hidaka 89
(177) Colket 86
(178) Colket 86
C6H2 ϩ H Q C4H2 ϩ C2H
nC4H3 ϩ C2H2"C6H4# ϩ H
(179) Westmoreland 89 [5]b
(
nC4H3 ϩ C2H2"1C6H4 ϩ H
nC4H3 ϩ C2H2"1C6H5
(180) Westmoreland 89b
(181) Westmoreland 89b
(
(
C4H4 ϩ C2H3"C6H6# ϩ H
nC4H3 ϩ C2H2"C6H5#
(182) Lindstedt 96
(183) Westmoreland 89b
Ϫ0.86
Ϫ3.89
(3.33E24
(Continued)

3
70
FOURNET, BAUGE, AND BATTIN-LECLERC
Table II (Continued)
Reactions
A
n
Ea
References
nC4H5 ϩ C2H2"1C6H6 ϩ H
3.47E-15
1.17E-15
2.38E8
7.73
7.84
1.18
2.5E3
2.0E3)
3.7E3
4.2E3)
4.0E3
3.6E3)
6.3E3
5.2E3)
Ϫ0.2E3
5.0E3)
0.1E3
1.0E3)
0.8E3
1.5E3)
Ϫ3.6E3
Ϫ1.9E3)
2.4E3
9.9E3)
6.3E3
14.0E3)
35.0E3
3.2E3
9.3E3)
4.0E3
9.6E3)
27.0E3
65.0E3
1.4E3
5.0E3
4.3E3
15.0E3
5.0E3
50.0E3
0.4E3
(184) Westmoreland 89b
(
(
(
(
(
(
(
(
(
(
nC4H5 ϩ C2H2"C6H6# ϩ H
nC4H5 ϩ C2H2"1C6H7
(185) Westmoreland 89b
(186) Westmoreland 89b
(187) Westmoreland 89b
(188) Westmoreland 89b
(189) Westmoreland 89b
(190) Westmoreland 89b
(191) Westmoreland 89b
(192) Westmoreland 89b
(193) Westmoreland 89b
1.90E7
1.47
7.24E14
8.74E12
7.12E21
1.96E19
3.55E-43
8.28E-28
1.50E13
2.90E15
8.53E13
5.50E15
1.84E-13
2.80E-7
4.15E-11
2.28E12
5.48E-15
1.0E10
Ϫ1.38
Ϫ1.27
Ϫ3.64
Ϫ3.35
16.16
11.89
Ϫ0.075
Ϫ0.78
Ϫ1.11
Ϫ1.67
7.07
5.63
6.39
Ϫ0.24
8.20
1.05
nC4H5 ϩ C2H2"C6H7#
C2H3 ϩ nC4H5"1C6H7 ϩ H
C2H3 ϩ nC4H5"1C6H8
C2H3 ϩ nC4H5"C6H8#
C2H3 ϩ nC4H5"C6H6# ϩ H2
C2H3 ϩ 1,3-C4H6"C6H8# ϩ H
C2H3 ϩ 1,3-C4H6"1C6H8 ϩ H
1
,3-C4H6 ϩ C2H2"C6H8#
2.3E12
0.0
(194) Westmoreland 89
(195) Westmoreland 89b
C2H3 ϩ 1,3-C4H6"1C6H9
1.48E12
5.48E28
7.06E13
1.64E29
2.3E10
3.5E13
1.7E10
3.0E7
4.0E13
2.0E12
7.5E6
3.0E14
2.3E11
5.0E15
5.0E15
Ϫ0.17
Ϫ5.31
Ϫ1.35
Ϫ6.12
0.0
0.0
0.0
2.0
0.0
0.0
2.0
0.0
0.0
0.0
0.0
(
(
C2H3 ϩ 1,3-C4H6"C6H9#
(196) Westmoreland 89b
1
,3-C4H6 ϩ C2H4"C6H10#
C6H5# Q 1C6H5
C6H5 Q C6H5#
(197) Westmoreland 89
(198) Colket 86
(199) Colket 86
(200) Miller 92
(201) Colket 86
(202) Zhang 89 [39]
(203) Miller 92
(204) Colket 86
(205) Colket 86
(206) Dean 85 [40]
(207) Dean 85
1
C6H6# ϩ H"C6H5# ϩ H2
C6H6# ϩ H"C6H7#
C6H6# ϩ CH3 Q C6H5# ϩ CH4
C6H6# ϩ OH"C6H5# ϩ H2O
C6H7# Q 1C6H7
1
C6H7 Q C6H7#
C6H8#"C6H7# ϩ H
C6H10#"C6H9# ϩ H
72.33E3
81.4E3
a
Rate constant estimated from the value given in references.
The first sate of values was used for simulations of the shock tube experiments, the second set of data was used for simulations in flames.
b
•
For the oxidation of C H
и
radicals, the kinetic
COMPARISON BETWEEN OUR
SIMULATIONS AND THE
EXPERIMENTAL RESULTS OF THE
LITERATURE
4
5
data have been estimated from the values pro-
posed by Warnatz [24] for vinyl radicals, an ac-
tivation energy of 3 kcal/mol has been taken into
account in the case of to i-C H5и, due to its res-
4
onance stabilization
A key point of these simulations is that they have all
been performed by using the same mechanism, that is,
the mechanism above described, without any adjust-
ment of the kinetic data. The quality of the simulations
given by this model should be analyzed as a whole,
keeping in mind that it has permitted to reproduce the
results obtained in two different experimental devices,
•
For the methatheses of vinyl and propargyl rad-
icals with butadiene, according to Wang et al. [6],
a difference of 3 kcal/mol has been taken into
account between the activation energy of the re-
actions leading to n-C H
to the resonance stabilization of i-C H5и
и and to i-C H5и, due
4
5
4
.
4

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
371
a shock tube and a flame, for five compounds, meth-
ane, acetylene, propyne, allene and 1.3-butadiene.
These simulations have been run by using the codes
SHOCK and PREMIX of the CHEMKIN II [40] soft-
ware library.
computed and experimental results in the cases of acet-
ylene (Fig. 2a), propyne (Fig. 2b), allene (Fig. 3a), and
butadiene (Fig. 3b). The agreement obtained is basi-
cally satisfactory; it slightly deteriorates at low tem-
perature for the mixtures containing 1% hydrocarbons
and 4% oxygen, and in the case of butadiene at high
temperature for the mixtures containing 3% butadiene
and 4% oxygen. It is worth considering that the mea-
surements performed at high temperatures which cor-
respond to short ignition delays are less accurate.
Ignition Delays in Shock Tube
Figure 1 shows a typical normalized computed OH
concentration profile, from which a calculated ignition
delay has been obtained. Due to problems in the mod-
eling of heat transfer in the code SHOCK of CHE-
MKIN II, the decrease of the calculated concentration
of OH does not reproduce the shape of the experi-
mental signal; but during the rise, which is the part of
the curve important to calculate ignition delays, the
agreement is correct.
Concentration Profiles in Flames
(
Experimental Results of the Literature)
For each flame, the calculation has been performed by
taking as an input the experimental temperature pro-
file, which is given on the first figure relevant to the
flame considered.
Figures 2 and 3 present the comparisons between
Figure 4 Modeling of the flame of methane of Sanogo [44]. Profiles of some stable (a) and radicalar
b) species. Points correspond to experimental results and lines to simulations and temperature
profile.
(

3
72
FOURNET, BAUGE, AND BATTIN-LECLERC
Flame of Methane. To demonstrate the ability of the
on C H
that time [4].
и and C H5и, as it was commonly accepted at
4
3
4
C -C reaction base to model reactions in a laminar
0
2
premixed flame, Figure 4 presents a comparison be-
tween our computed profiles and the experimental re-
sults obtained by O. Sanogo [44] on a premixed lam-
inar flame stabilized on a burner at 4.2 kPa with a
mixture (Argon : Methane : Oxygen) equal to (0.49 :
More recently, several authors [11,36] proposed a
new way of benzene formation that occurs by propar-
gyl–propargyl (C H ) recombination. Several rear-
и
3
3
rangements implying H-atom shifts and cyclization
[36] led to the formation of phenyl radical or benzene.
It interested us to revisit these simulations with an up-
to-date mechanism.
0
.17 : 0.34). To keep this article reasonably short, this
comparison is presented only in the cases of methane,
carbon dioxide and ethylene (Fig. 4a) and for the im-
Figure 5 presents our simulations in the case of sta-
ble species, C H (Fig. 5a), CO (Fig. 5a), H (Fig. 5a),
portant radicals, H
but the agreement is satisfactory for all the species.
и
,
и
O
и
, OH
и
and CH3 (Fig. 4b);
и
2
2
2
C H (Fig. 5b), C H (Fig. 5b), and benzene (Fig. 5b).
4 2 4 4
Figure 6 presents our computed profiles in the case of
some important radical species, OH (Fig. 6a), H
(Fig. 6a), C H (Fig. 6a) and C H (Fig. 6a). For all
species, the agreement is satisfactory; except in the
case of H , which is overpredicted by a factor 2. Bas-
Flames of Acetylene. In 1988 Bastin et al. [2] studied
a laminar premixed flame of acetylene stabilized at 2.6
kPa with a mixture (Argon : Acetylene : Oxygen)
equal to (0.45 : 0.275 : 0.275). They performed sim-
ulations by using a mechanism in which the formation
of benzene only derived from the addition of acetylene
и
и
и
и
2
3
2
и
tin et al. [2] have reported the same discrepancy in the
case of their simulations. In the cases of C H , CO,
2
2
Figure 5 Modeling of the flame of acetylene of Bastin et al. [2]. Profiles of some stable species.
Points correspond to experimental results and lines to simulations and temperature profile.

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
373
H , C H
и
, C H
и
, C H and C H the agreement that
in studying the formation of benzene, due to the pos-
sibility of branching between C , C , and C chains.
2
2
3
2
4
2
4
4
we obtained is slightly better than that presented by
Bastin et al.
2
3
4
In 1984, Bresinsky et al. [35] studied 1,3-butadiene
pyrolysis and oxidation in a flow reactor at 1100 K for
several equivalence ratios. They gave a qualitative de-
scription of the reactant consumption based on three
possible pathways: an H-addition followed by a beta-
As Bastin et al. have not detected any C species,
we have performed additional simulations on the lam-
inar premixed flame studied by Westmoreland et al.
3
[
1] at 2.67 kPa with a mixture (Argon : Acetylene :
Oxygen) equal to (0.05 : 0.465 : 0.465); that is, in the
same conditions as Bastin et al. [2] except for the di-
lution in argon. Figure 7 presents a comparison be-
tween our computed profiles and the experimental re-
scission, leading to C species; an O-addition leading
to acroleine by H-transfer, and a third way based on
2
an H
и
or OH
и
abstraction leading n-C H
и
radicals.
4
5
Further reactions of these radicals permit the expla-
nation of the formation of important species, such as
vinyl-acetylene (C H ) or allene and propyne (aC H ,
sults of Westmoreland et al. [1] for C H and C H
и
3
3
4
3
and shows that we obtained also a satisfactory agree-
4
4
3
4
ment for those C compounds, especially in the case
pC H ). At the same time, Cole et al. [3] studied the
3
3 4
of propargyl radicals, whose recombination could be
important to explain the formation of benzene.
structure of a laminar premixed flame stabilized at
2.67 kPa with a mixture (Argon : Butadiene : Oxygen)
equal to (0.03 : 0.295 : 0.675). In 1996, Linstedt and
Skevis [13] were the first to present a mechanism in
order to reproduce this flame structure; but their mech-
Flame of Butadiene. As explained by Lindsted et al.
[13], 1.3-butadiene is an interesting molecule to use
Figure 6 Modeling of the flame of acetylene of Bastin et al. [2]. Profiles of some radicalar species.
Points correspond to experimental results and lines to simulations.

3
74
FOURNET, BAUGE, AND BATTIN-LECLERC
Figure 7 Modeling of the flame of acetylene of Westmoreland et al. [1]. Profiles of C H and
3
4
C H . Points correspond to experimental results and lines to simulations and temperature profile.
3
3
Figure 8 Modeling of the flame of 1,3-butadiene of Cole et al. [3]. Profiles of some stable (a) and
radicalar (b) species. Points correspond to experimental results and lines to simulations and tem-
perature profile.

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
375
anism differs markedly from our model about the me-
tatheses on butadiene and the formation of i-C H
radicals. The formation of these resonance-stabilized
radicals is important as it competes directly with the
prediction of C H , whose formation is mainly due to
4 4
и
the reaction of i-C H5и with oxygen.
4
5
4
formation of n-C H5и radicals, which could be pre-
4
cursors of benzene.
FLOW RATE ANALYSIS
Figures 8 and 9a present our simulations in the case
of stable species, 1,3-C H (Fig. 8a), CO (Fig. 8a),
Figures 10 and 11 show schemes of the reactions,
whose flow rates are significant in the conditions of
this study. Gray arrows represent the channels, which
are of importance only in flames. The fate of a radical
is only presented on the figure where it appears for the
first time.
Figure 12 shows the reactions, whose flow rates are
significant in flames, to explain the formation of ben-
zene. Light gray arrows represent the channels, which
are of importance only in flames of acetylene.
4
6
CO (Fig. 8a), C H (Fig. 8b), C H (Fig. 8b), C H
2
2
2
2
4
3
4
(Fig. 8b), C H (Fig. 9a), C H (Fig. 9a), and benzene
4 2 4 4
(
Fig. 9a). Figure 9b presents our computed profiles in
, H
. For all species, the agreement is satisfac-
tory; except for the case of H , which is overpredicted
by a factor of 2 and for C H , whose maximum is well
the case of some important radical species, OH
и и
and C H3
и
3
и
2
2
located, but with a concentration underpredicted by a
factor of 2. It is worth noting that we have a very good
Figure 9 Modeling of the flame of 1,3-butadiene of Cole et al. [3]. Profiles of some radicalar
species. Points correspond to experimental results and lines to simulations.

3
76
FOURNET, BAUGE, AND BATTIN-LECLERC
For each insaturated hydrocarbon studied, we will
Combustion of Acetylene (Fig. 10a )
also discuss the main results obtained from the sensi-
tivity analyses related to ignition delays. It must be
kept in mind that the rate constant of the branching
Acetylene react mainly by additions. Additions of
и и
O
atoms on the triple bond lead to the formation of CO
3
step involving H
и
and O , to give
и
O
и
and OH
и
rad-
and CH ии or of
и
CHCO. Additions of H atoms
и
2
2
icals, is always a most sensitive parameter, since this
reaction leads to an exponential increase of the number
of radicals and to an acceleration of the overall exo-
thermic reaction, which is responsible for the temper-
ature/pressure rise of the auto-ignition. Detailed sen-
sitivity analyses concerning the ignition delays can be
found in Baug e´ ’s Ph.D. Thesis [45].
produce vinyl radicals. Vinyl radicals can react with
oxygen by two channels. One of these channels in-
volves the formation of
dehyde; the second channel is a branching step pro-
ducing atoms and CH CO radicals. Sensitivity
и
CHO radicals and formal-
и
O
и
и
2
analyses show that this branching step and the fast
initiation reaction between acetylene and oxygen ex-
Figure 10 Scheme of the major reaction channels in the cases of acetylene (a) and 1,3-butadiene (b).

OXIDATION OF ACETYLENE, PROPYNE, ALLENE AND 1,3-BUTADIENE
377
Figure 11 Scheme of the major reaction channels in the cases of allene and propyne.
plain the high reactivity of acetylene-oxygen mixtures,
which has been observed in a shock tube.
In these conditions, vinyl radicals can also react by
metathesis with formaldehyde and produce ethylene.
3
In flames above 1400 K, the addition of CH ии
2
needs also to be considered. This addition leads to the
formation of propargyl radicals, whose recombination
is important to explain the production of benzene. The
major consumption channels of propargyl radicals in
Combustion of Propyne and Allene
(
Fig. 11)
For both allene and propyne, isomerization is the most
important reaction channel according to flow rates
analysis. Nevertheless, in the time preceding auto-ig-
flames are reactions with OH
и
radicals leading either
CHO radicals.
to C H2ии and H O or to C H3и and
и
3
2
2
Figure 12 Scheme of the major benzene formation channels.

3
78
FOURNET, BAUGE, AND BATTIN-LECLERC
nition, equilibrium is not yet reached and ignition de-
lays are not very sensitive to the rate constants of these
isomerizations. Propyne react mainly by metatheses to
give propargyl radicals. Major consumption reactions
In 1,3-butadiene flame, the propargyl-propargyl re-
combination remains the principal source of benzene
production. Some other ways must be underlined, the
recombination of allyl radical aC H
и
with propargyl
, the reaction between allene and propargyl and
3
3
5
of allene include the addition of
its dimerization leading ultimately to C H and C H .
и
O
и
or H
и
atoms and
C H
3
и
the direct reactions of 1,3-butadiene with acetylene or
vinyl radical followed by successive dehydrogenations
of the products thus formed. Nevertheless, in the con-
ditions of our study and with the mechanism presented
below, the contributions to the formation of benzene
of the reactions involving n-C H3и and n-C H5и seem
2
4
4
4
For both reactants, ignition delays are very sensitive
to the rate constants of the initiation reactions leading
to H atoms and propargyl radicals; that can explain
и
their very similar ignition behaviors. Major consump-
tion channels of propargyl radicals in these conditions
4
4
are their reaction with oxygen leading to
CHO radicals and their recombination; propargyl
radicals can also react with allene to give H atoms
и
CH CO and
to be negligible.
2
и
и
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