J . Phys. Chem. 1993,97, 10042-10046
10042
Reaction between CH3 and NO at Combustion Temperatures H. Yang, V. Lissianski,' J. U. Okoroanyanwu, and W. C. Cardiner, Jr. Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712
K. S. Shin Department of Chemistry, Soong Si1 University, Seoul I56-743, Korea Received: May 7, 1993; In Final Form: July 16, 1993'
The reaction between CH3 radicals and NO was investigated behind incident shock waves at temperatures between 1370 and 2500 K and densities near 3 mol/m3 by following the consumption of CH3 with time-resolved UV absorption measurements at 213.9 nm. The rate coefficient expression 1.2 X 1014exp(-14500 K/T)cm3 mol-' s-I for the total reaction of CH3 with NO was derived.
Introduction The production of nitrogen oxides in combustion processes has been studied for many years both as a challenge to understanding the basic chemistry and as a response to societal demands for reduction of emissions from industrial or residential combustion equipment. A conspicuous weak point in understanding of this process has been with regard to the ways that NO, chemistry interacts with the hydrocarbon chemistry through the reaction zone of fossil fuel flames. To achieve a clearer picture of the balance between NO formation and destruction in flames, it is important to identify and characterize these reactions. There is a rather obvious first candidate to study, the reaction of NO with CH3, the hydrocarbon radical consistently found to have the highest concentration in flames. The reaction of CH3 with N O initially forms a stable addition product CH3N0, which at high temperatures decomposes to form other products besides CH3 and NO. Theoretical study of the CH3NO potential surface by Meliusl has suggestedthat the major N O removal channels should be
CH,
+ NO = OH + H,CN
AH = 12 kcal/mol
(1)
CH,
+ NO = H,O + HCN
AH = -79 kcal/mol
(2)
From an analysis of N-species distributions in the burnt gases of fuel-rich ethylene flames, Haynes2suggested 2 X 10" cm3mol-l s-l as the total rate coefficient of irreversible CH3 reaction with NO at 2000 K. Wolff and Wagner3 measured the total rate of CH3 reaction with NO at temperatures between 1800 and 21 50 K. Extrapolation of their data to lower temperatures agrees with more recent measurements of kz by Lifshitz et al.4 Hoffmann et al.s measured kt at temperatures between 1470 and 2040 K; their measurements show that the contribution of channel 1 to the total rate of CH3 disappearance in the reaction with NO is not more than 40% at temperatures of about 1800 K. The purpose of the present investigation was to measure the total rate coefficient of the CH3 reaction with NO at combustion temperatures by spectroscopic measurements of CH, concentration profiles during the thermal decomposition of azomethane in the presence of a large excess of NO.
Experiment
Shock Tube System. The experiments were performed in incident shock waves in a 7.62-cm4.d. Monel shock tube that has been described in detail elsewhere.6 Shock parameters were ~~
To whom correspondence should be addressed. *Abstract published in Advance ACS Abstracts. September 1, 1993.
0022-365419312097-10042$04.00/0
computed from the measured incident shockvelocitiesby standard methods' using JANAF8and NASA9thermochemical data under the assumption of steady flow and no wall boundary layer formation. Optical System. The concentration of CH3 radicals was measured using the absorption of 213.9-nm light from a Pen-Ray Zn arc lamp (Ultra-Violet Products) directed through twoopposed sapphire windows and an interferencefilter of 9-nm (fwhm) bandpass and 19% peak transmission onto an EM1 9526B photomultiplier tube. The signal-to-noise ratio of transmitted light was about 50, resulting in a detection limit for CH3 measurements of about 0.2 mmol/m3. The transmitted light intensity was recorded with a Nicolet Explorer I1 storage oscilloscope. Because of the small amounts of azomethane in the test gas mixtures and the resulting low amplitude of the optical signals at 21 3.9 nm, the light beam was not constrained to enhance time resolution. As a result, CH3 formation and depletion occurred as the shock wave was passing through the probe beam, resulting in spatial averaging of the absorption across the window. To enablecomputed and observed absorption profiles to becompared, a careful measurement of the effectivewindow function was made by passing the beam through a rotating beam block within the shock tube. The intensity profile in the axial direction was found to be quite close to a Gaussian function. It was incorporated into thecomputer simulationsin the formf(x/cm) = exp(-(x/O. 18)2). It was found in a thorough study of the effects of this averaging, by computer modeling of a variety of shock-induced reactions, that spatial averaging of the signal leads in essence only to a shifting of the entire calculated profile to later times and does not affect the slope of the portion of profile that was used for deriving rate coefficients. Materials. Azomethane, synthesized according to the method of Renaud and Leitch,lo was used as a source of CH3 radicals; Ar (99.999%, Matheson) was used without further purification. The stated original impuritiesin NO (99.0%, Matheson) included CO (990 ppm), NO2 (GO00 ppm), and Nz (322 ppm). Nitric oxide was purified by freezing-pumping cycles in a dry ice/acetone mixture. Test gas mixtures were prepared manometrically and allowed to stand for 48 h before being used.
Experimental Results The removal of CH3 by NO was investigated behind incident shock waves at temperatures between 1370 and 2500 K and densities from 1.1 to 5.6 mol/". The mixture compositions studied are presented in Table I. Theconcentrationofazomethane was limited to 2000 ppm to suppress the contribution of CHI self-reactions and the influence of their reaction products. A high NO concentration was selected to increase the rate of the 0 1993 American Chemical Society
Reaction between CH3 and NO
The Journal of Physical Chemistry, Vol. 97, No. 39, 1993 10043
I
40
0 ~ " " " " " " " " " " 0 20 40 60
80
100
time, ps Figure 1. Sample experimental record for 214-nm absorption. Shock conditions: mixture 2, T2 = 1660 K,p2 = 3.72 mol/m3. Dashed line represents computer simulations.
TABLE I: Mixture Composition
we just used C H 3 0 and H as its products. Although the mechanism is not complete enough to describe the whole course of the reaction, because of the omission of any detailed description of ethylene and acetylene oxidation, it is large enough to describe the early part of the CH3 consumption. In the final data analysis, literature values of all rate coefficient parameters were used without variation except for those of reaction 3. Sensitivity calculations (Figure 2) showed that only reactions 3 and 30 contribute substantially to CH3 profiles and that the sensitivities to these reactions depend on temperature. At temperatures less than 1500 K, the recombination of methyl radicals is responsible for the most of the CH3 removal. As temperature increases, reaction 3 becomes more important, although its contribution to the CH3 disappearance profile even at temperatures from 1800 to 2500 K is only about 50-70%. For conditions where reaction 3 removes the main part of the CH3 radicals and the decomposition of azomethane is fast, the decrease of the CH3 concentration should come close to following first-order kinetics
mixture in Ar 1 2 3
500 lo00 2000
4.87 9.69 2.16
1505-2125 1365-2500 1645-2240
5.0-2.3 5.6-1.1 3.6-1.5
where ken = k3[NO] reaction 30
+ k-30[CH3].
For small contributions of
+
CH3 N O reaction. In our test gas mixtures the NO:C*HsN2 ratioswereabout lOOand 10. Tochecktheinfluenceofvibrational relaxation of NO on the results of the measurements,we conducted some experiments in NO-Ar mixtures. These measurements show that the vibrational relaxation times of NO in the mixture with 2% NO at temperatures of 1800 and 2300 K are less than 7 and 4 ps, respectively. These measurements agree with the findings of Wolff and Wagner,' who estimated a vibrational relaxation time of about 10 ps for a 5% NO mixture at 2000 K and 0.3 atm pressure. In evaluating the experimental absorption profiles, we always ignored the first few microseconds to avoid including in the data the direct influence of the changing NO contribution to the absorption profile caused by its vibrational relaxation. A sample 214-nm absorption profile is shown in Figure 1. The initial absorptionis due to absorptionby NO at room temperature. The rise in absorption due to azomethane decomposition and NO heating is followed by decay due to the reaction of CH3 with NO and the CH3 self-reactions. The absorption at long times is due mostly to NO and to a small degree to the products of reaction (CzH4, C2H2, and COz). Even though the contributions of the other species that absorb at this wavelengthwerevery small, they were also included in the computer simulations described below, using the extinction coefficients measured by Gardiner et under similar conditions. The reaction mechanism used to analyze the experimentaldata is shown in Table II.1z-38 It was constructed starting with the Hwang et al.12 mechanism of azomethane thermal decomposition, which had been optimized to describe CH3 concentration profiles in azomethaneargon mixtures shock-heated in the same apparatus to conditions (temperatures from 1300 to 1700 K, densities from 2 to 9 mol/m3) that were similar to ours. In the modeling we did not specify the products of reaction 3, because the measurementof CH3concentrationprofiles alonedoes not provide information about the products of this reaction. Thus, we can only determine the total rate coefficientof the CH3 reaction with NO. The influenceof what the products of this reaction actually are on the CH3 concentration profiles is discussed later. The product distribution of reaction 4 is a matter of current discussion in the literature; we found by testing the alternatives in simulations that the product distribution assumed for it does not affect calculated CH3 profiles at all for the conditions studied, and so to avoid taking any position about what the actual products are,
The absorption at 213.9 nm is almost entirely due to CH3 and NO
where d is the absorption path length. The absorption at later times is due to NO
log(zO/zm) = eNOINO]d Thus, the CH3 concentrationis related to the transmitted intensity by %H,' The decrease of CH3 then follows
-[ C H ~ IO lOg(~ca/~max)
(2)
[CHJ WL/ZI where Zmax is the transmitted intensity at the time of maximum absorption in an experiment. From eqs 1 and 2 the effective rate coefficient ken of CH3 disappearance is given by
(3) This analysis, based on the assumption of instantaneous azomethane decomposition and first-order decay, thus suggests that the right-hand side (rhs) of eq 3 is a suitable measure of the rate of CH3 disappearance, independent of its extinction coefficient, even though the actual removal mechanism is complicated. Figure 3 shows a plot of the rhs of eq 2 as a function of time for the conditions of the experiment shown in Figure 1. It shows that the intensity profile follows a first-order law closely for the main part of the observed disappearance of CH3. For small contributions of CH3 recombination the value of ken does not depend on the extinction coefficient of CH3 at all, and kc^ can therefore be used in general for comparisons between experimental and calculated absorption profiles with confidence that the rate coefficient increases will be isolated from the value of the CHI extinction coefficient. Asshown later, it also permitsan evaluation of the extinction coefficient of CH3 from measurements of I,-.
Yang et al.
10044 The Journal of Physical Chemistry, Vol. 97, No. 39, 1993
TABLE II: Mechanism of Azomethane Oxidation’ N reaction 3 CH3 + NO products 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 21 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
50 51 52 53 54 55
+ + +
-
+
CH3 OH CH3O H CH3 0 = CH20 + H CH4 OH CH3 H20 CH3O M = C H 2 0 + H + M CH2O 0 = HCO OH CH2O + H HCO + H2 CH20 + M = HCO + H + M CHzO CH3 HCO + CH4 CH2O OH = HCO H20 HCO M = C O + H M C2H6 OH = C2H5 + H20 CzH6 0 = CzH5 OH C2Hs + 0 = C2H4 + OH C2H5 + OH = C2H4 + H20 C2H4 OH C2H3 + H20 C2H3 + OH = CZHZ+ HzO C2H32 + OH = C2H + HzO C2H OH = CHCO H CHCO + M = CH + CO + M CH + OH = CH H OH + O H = H20 0 H + 0 2 = OH + 0 H + 02 + M = H0z + M Hz+ M = H + H M H2+ OH = H20 + H CzH6N2 = CH3 + CHI + Nz C2H6 CH3 CH3
+ +
+ +
+ + +
+ +
+ +
+
+
n
A
1.20 x 2.00 x 7.00 x 1.50 X 1.00 x 3.30 x 2.19 X 5.00 X 5.54 x 3.00 x 2.50 x 6.30 X 3.00 x 5.00 x 2.41 x
1014
1013 1013 lo6
2.13
2460 25120 1040 3000 76560 5860 1200 16820 650 5120
1.94 1.77 2.81
1013
1014
lo6 107 1013 1013
ref see text
0
1014
107 lo8 10l6 103
E 29050 0
2.00 2.00
0 0
3.00 x
1013 3000 5.00 X 10l2 0 2.71 x 1013 10500 2.41 X loi2 0 6.50 x 1015 59200 3.00 x 1013 0 5.36 X loL2 2100 9.33 x 1013 14800 7.00 x 1017 -0.80 0 2.23 X 10l2 0.50 92600 2.16 X lo8 1.51 3440 1.20 x 109 28470 1.81 x io58 -10.61 98660 falloffparameters: 1.06 X -2.79,93206, 0.31, 518,445 2.80 X 1012 CH3 CH3 = C2H5 H 9600 6.00 X 1012 CH3 CH3 = C2H4 H2 16507 1.70 x 109 0.56 12580 CH3 CH3 = CH4 CH2 CH3 + C2H6 = CH4 C2Hj 9.00 X 10-1 4.00 9700 4.20 X 10” 11100 CH3 + C2H4 C2H3 CH4 CH3 CzHs CzH4 + CH4 4.37 x 10-4 5.00 8300 1.32 x 1014 C2H6 + H = C2H5 H2 9400 4.68 X 104 -7.04 43540 CZH5 = C2H4 H falloffparameters: 4.97 X lolo, 0.732, 36890,0.278, 1.03 X lo5, 754 1.70 X 10l2 C2H5 H = C2H4 H2 0 CH3 + M = CH2 + H + M 1.oo x 10’6 91100 2.00 x 1013 CHI + CH3 = CzH4 H 0 CH4 = CHp H 6.31 x 1036 -5.25 107890 falloff parameters: 3.71 X lOI7,-0.56, 104980,0.48,4093,341.3 CH4+ H = CH3 + H2 9.64 x 104 2.57 6680 2.60 x 1017 79400 C2H4+ M CzH2 H2 M 2.60 x 1017 96650 C2H4 + M C2H3 H M CH2 + C2H4 + H = C2H3 + HZ 3.16 X 10” 0.70 8010 4.37 x 10-4 5.00 8300 CH3 + C2H3 CzHz + CH4 C2H3 + M =CzHz+ H + M 1.20 x 1039 -7.17 50600 2.00 x 1013 CzH3 + H = C2H2 H2 0 NO M = N 0 M 4.00 X 10” -1.50 151000 NO + NO = N20 0 1.30 X 10l2 64200 NO N N2 0 3.96 x 1013 0 H + NO + M = HNO M 5.40 X 10l5 -600 HNO HNO = H 2 0 N2O 3.00 X 10” 3500 NO + H = N OH 1.70 x 1014 49120
+
+
+ + +
+
+ +
+ + + +
+
+
+
+
+
+
+ +
+
+ + + +
+ + + +
+ +
+
+
+
+
+
13b 14 15 14 16 17 14 17 14 14 14 14 14 17 18 19 20 18 21 19 22 23 14 14 24 12 12,25 12 12 26 12 14 27 12,28 29 30 14 31 32 33 14 14 34 27 27 14 35 35 36 35 37 38
a Notes: units are cm3,mol, s, and cal. For reactions 30, 38, and 42 the tabulated parameters refer to the low pressure limit rate coefficients; the first three of the falloff parameters listed for these reactions are A, n, and E for their high pressure limit rate coefficients,and the remaining falloff parameters are the u, b, and c values that define the temperature dependence of the broadening factor.2’ The notation means that the reaction is taken as irreversible. Possible products of reaction 3 are C H 3 0 + H, CH20H + H,ICH2 + H20, and CH4 + 0.We found that product distribution of this reaction is not important for the calculated CH3 profiles.
-
The comparison of experimental results with calculations was made taking into account the self-reactionsof CH3 and the finite rate of azomethanedecomposition. The CH3 absorption profiles were simulated for the conditions of each run with the help of the mechanism in Table I1 using a predecessor of the LSODE39 program for the integration of the differential equations, and a value of k , was ~ extracted for comparison with the corresponding experimental value. The value of k3 was adjusted until the experimental and calculated values of ken coincided. A comparison between experimental and calculated profiles is shown in Figure 1.
The results Of k3 calculationsare presented in Figure 4 together with the results of Haynes,2 Wolff and Wagner? Lifshitz et a1.,4 and Hoffmann et al.5 Within the scatter of our measurements, about a factor of 2, no dependence on mixture composition can be seen. Least-squares regression of our data in the In k, 1/T plane gave
k, = 1.2 X
IOl4
exp(-l4500/T)
cm3 mo1-ls-I
From the absorption a t long times I,, taking into account the absorption of other possible products of the reaction (C2H4, C2H2 and COZ),with extinction coefficients from Gardiner et al.,” the
Reaction between CH3 and NO CH3+NO=Products
The Journal of Physical Chemistry, Vol. 97, No. 39, 1993 10045
I I
I
CH3+CH3=C2Hg
CH3+CH3=C2H5+H
L A
CH3+CH3=C2H4+H2
-0.2
-0.16
-0.12
-0.08
-0.04
0
0
500
1000
Figure 2. Sensitivity spectrum for the maximum CH3 concentrationfor the conditions of Figure 1. Sensitivities less than 0.01 are not shown.
0.2
c
YU 105; 22
26
30 34 38 time, ks
42
46
50
€
+ 4
5
6
7
8
'
1
I
1
5
' '
1
6
'
1
I
1
7
' '
I
I
8
' '
I
9
1 04/T
Figure 3. Pseudefirst-orderplot of CHI concentrationfor the experiment in Figure 1. See eq 2 and associated discussion in the text.
1 08 3
4
//
0 18
2500
temperature.
i
1
2000
Figure 5. Decadic absorptivity of NO at 213.9 nm as a function of
1,
0.6
1500
To, K
log sensitivity
Gardiner et al.," MBller et a1.,4I and Davidson et a1.42 Our results are close to those of Hwang et a1.,'2 who conducted experiments with the same Zn lamp and do not show any, or at most a very weak, dependence on temperature. Our values are much lower than the recent narrow line laser absorption coefficient values reported by Davidson et al.42 Part of this difference can be attributed to the different wavelengths used (Davidson et al.42 measured absorption at 216 nm, where the absorption spectrum has a maximum, while the zinc line at 214 nm is in a valley), but the difference is too large to be explained entirely by this reason. For temperatures from 1360 to 2300 K our value of CCH, is (6.5 f 3.5) X 105 cmZ/mol.
I 9
1
Figure 6. Decadic absorptivity of CH3 at 213.9 nm as a function of temperature: 0, our results; 1, Hwang et a1.;12 2, M6ller et (216 nm); 3, Gardiner et al.;Il 4, Davidson et a1.42 (216 nm).
0
1 04/T
Figure 4. Dependence of k3 on temperature: X represents our experimental results, and the solid line is a least-squaresfit to them: 0, Wolff and Wagner;) +, Baldwin and Golden;" A, Haynes2 for channel 2; 1, Lifshitz et ale4data for channel 2; 2, Hoffmann et aLs data for channel 1.
value of extinction coefficient of NO (CNO) can be calculated (Figure 5). For temperatures from 1360 to 2250 K the CNOdata can be described by cNo/cmz mol-' = 34.2T - 1400 At room temperature we measured the value of CNOto be 2.3 X 104 cm2/mol. Extrapolation of the high-temperature measurements to the room temperature shows good agreement. Because the value of Zmx mainly depends on k3, k-30, CNO, and CCH,, the extinction coefficient of CH3 can be found from the value of I,, and the known k3 and €NO values. The results are presented in Figure 6 together with those of Hwang et a1.,I2
Discussion The lowest temperature of our k3measurements is close to the highest temperature of the k2 experiments reported by Lifshitz et al.4 Although we do not have any evidence about the product distribution of reaction 3, comparison with the Lifshitz et data and accepting their identification of the products suggests that reaction 2 is the main channel of the CH3 reaction with NO under our conditions as well as theirs. The agreement of the absolute values of our measurements with those of Lifshitz et al.' is fairly good, although the inferred energies of activation are somewhat different. Our value of kz at 2000 K is about a factor of 2 lower than that reported by Haynes.2 Wolff and Wagner,3 who also inferred rate coefficients for the total reaction CH3 + NO by monitoring CH3 concentrations during thermal decomposition of azomethane in the presence of NO, report values about 3 times lower than ours. To find the reason for this disagreement, we repeated our calculationswith their rate coefficient expressions for reactions -30, 31, and 32, the most important CH3 selfreactions. For these reactions, they used rate coefficient ex-
10046 The Journal of Physical Chemistry, Vol. 97, No. 39, 1993
pressions that give much higher values than ours: k-30 = 2.14 X 1011 exp(3584/T) cm3 mol-' s-I from MiSller et al.41,k31 = 7.94 X lO14exp(-13351/T) cm3 mol-' s-1, and k32 = 1.0 X 10l6exp(-161 17/T) cm3 mol-' s-1 from Roth and Just;43 thus, the total rate of CH3disappearance in reactions -30,3 1, and 32 computed using their mechanism a t 1850 K is about 6 times higher than computed using ours. Reductions of our kerf data using their expressions for k-30, k31, and k32 gave values of k3 that are about 2.5 times lower than what we derived using our expressions. We conclude that the reason for thedisagreement between our results for k3 and those of Wolff and Wagner3 is to be found in the different rates assumed for the CH3 self-reactions. Because the rate coefficients of the whole set of reactions 29-55 in our mechanism were previously adjusted by Hwang et a1.12to describe 214-nm absorption profiles during the decomposition of azomethane recorded using the same apparatus at conditions close toours, we believethat our set of ratecoefficients for reactions 29-55 is more reliable. In our mechanism we used reaction 3 without specification of the product distribution. The products of this reaction could be active species that can react with CH3 and increase the rate of its disappearance, such as the channel 1 products OH and H2CN; at combustion temperatures, H2CN decomposes to produce HCN and H. To check the influence of additional active species generated by channel 1 on computed CH3 profiles, we introduced into our mechanism reactions 1, 2, and
+
H2CN M = HCN
+H +M
(56)
with kl = 1 X 1012exp(-10885/T) cm3mol-' s-l from Hoffmann et alasand k56 = 3 X loi4 exp(-11005/T) cm3 mol-I s-l from Miller and Bowman.& We repeated the fitting of CH3 profiles again using k2 as a parameter. These calculations showed that with this kl expression no influence,of secondary reactions of OH and H on the derived value of k3 = kl k2 could be seen.
+
Conclusions The decomposition of azomethane in the presence of N O was studied behind incident shock waves. The concentration of CH3 was measured with the help of time-resolved UV absorption a t 213.9nm. InmixtureswithhighexcessofNO, thedisappearance of CH3 is close to a first-order process. Modeling using a mechanism of 55 elementary reactions showed that most of the CH3 is removed in reaction with NO. At temperatures between 1360 and 2500 K the rate coefficient for the total reaction of CH3 with N O was found to be k3 = 1.2 X 1014exp(-14500 K/T) cm3 mol-1s-1, in reasonable agreement with Haynes'szresult and lower temperature measurements of Lifshitz et al.4 for the rate coefficient proposed by them for the reaction CH3 N O = HCN + H20. At temperatures around 1800 K our k3 results are about 3 times higher than those of Wolff and Wagner3 because of the different rate coefficient expressions for the CH3 self-reactions that were used by them.
+
Acknowledgment. This research was supported by the Gas Research Institute and the Robert A. Welch Foundation. References and Notes (1) Melius, C. F.Sandia National Laboratories, Livermore, California,
private communication. Cited by Hoffmann et a1.5 (2) Haynes, B. S.Prog. Astronaut. Aeronaut. 1978, 62, 359. (3) Wolff, Th.; Wagner, H. Gg. Ber. Bunsen-Ges.Phys. Chem. 1988,92, 678.
Yang et al. (4) Lifshitz, A.; Tamburu, C.; Frank, P.; Just, T. J . Phys. Chem. 1993, 97, 4085. (5) Hoffmann, A.; Wagner, H. Gg.; Wolff, Th.; Hwang, S. M. Ber. Bunsen-Ges. Phys. Chem. 1990, 94, 1411. ( 6 ) Hardy, J. E. Ph.D. Dissertation, The University of Texas, Austin, 1976. (7) Gardiner, W. C., Jr.; Walker, B. F.;Wakefie1d.C. B. InShock Waues in Chemistry, Lifshitz A., Ed.; Marcel Dekker: New York, 1981; Chapter 7. (8) Stull, D. R.; Prophet, H. JANAF Thermochemical Tables, 2nd ed.; NSRDS-NBS 37, 1971. (9) Gordon, S.;McBride, B. J. Computer Program for Calculation of ComplexChemical huilibrium Compositions.Rocket Performance, Incident and Reflected Shock Waves, and Chapman-Juguet Detonations, NASA SP273, NASA, Washington, DC; private communication with B. J. McBride, 1976. (10) Renaud, R.; Leitch, L. Can. J . Chem. 1954,32, 545. (1 1) Gardiner, W. C., Jr.; Hwang, S.M.; Rabinowitz, M. J. Energy Fuels 1987, I , 545. (12) Hwang, S.M.; Rabinowitz, M. J.;Gardiner, W. C., Jr. Chem. Phys. Lett. 1993, 205, 157. (13) Fraatz, W. Undersuchung der Reaction CH, + 02 Prcdukte in Stosswellenmit Hilfe der UV-Absorption. Dissertation,UniversitatGBttingen, 1990. (14) Warnatz, J. In Combustion Chemistry; Gardiner, W. C., Jr., Ed.; Springer-Verlag: New York, 1984; Chapter 5. (15) Baulch, D. L.; Bower, M.; Malcolm, D. G.; Tuckerman, R. T. J . Phys. Chem. Ref. Data 1986, 15, 465. (16) Herron, J. T. J . Phys. Chem. Ref. Data 1988, 17, 967. (17) Tsang, W.; Hampson, R. F. J. Phys. Chem. Ref. Data 1986, 15, 1087. (18) Frenklach, M.; Wang, H.; Rabinowitz, J. Prog. Energy Combust. Sci. 1992, 18, 47. (19) Lutz, A. E.; Kee, R. J.; Miller, J. A.; Dwyer, H. A,; Oppenheim, A. K. Twenty-Second Symposium (International) on Combustion; The Combustion Institute: Pittsburg, 1989; p 1683. (20) Liu, A.; Mulac, W. A.; Jonah, C. D. J . Phys. Chem. 1988.92.5942. (21) Frank, P.; Bhaskaran, K. A.; Just, T. Twenty-First Symposium (International) on Combustion;The Combustion Institute: Pittsburgh, 1986; p 885. (22) Sutherland, J. W.; Patterson, P. M.; Klemm, R. B. Twenty-Third Symposium (International) on Combustion; The Combustion Institute; Pittsburgh, 1991; p 51. (23) Masten, D. A.; Hanson, R. K.; Bowman, C. T. J. Phys. Chem. 1990, 94, 7119. (24) Michael, J. V.; Sutherland, J. W. J . Phys. Chem. 1988, 92, 3853. (25) Stewart, P.H.; Larson, C. W.; Golden, D. M. Combust. Flame 1989, 75, 25. (26) BBhland, T.; Dobe, S.;Temps, F.; Wagner, H. Gg. Ber. Bunsen-Ges. Phys. Chem. 1985,89, 1110. (27) Kiefer, J. H.; Budach, K. A. Int. J . Chem. Kinet. 1984, 16, 679. (28) Camilleri, P.;Marshall, R. M.; Purnell, H. J . Chem. Soc., Faraday Trans. 1974, I , 70, 1434. (29) Stewart, P. H.; Golden, D. M. Unpublished results, citation from Hwang et al.12 (30) Olson, D. B.; Tanzawa, T.; Gardiner, W. C., Jr. Int. J . Chem. Kinet. 1979, 11, 23. (31) Olson, D . B.; Gardiner, W. C., Jr. J . Phys. Chem. 1979, 83, 922. (32) Stewart, P.H. Privatecommunication. Citation from Hwang et al.12 (33) Rabinowitz, M. J.; Sutherland, J. W.; Patterson, P. M.; Klemm, R. B. J. Phys. Chem. 1991, 95,674. (34) Weissman, M. A.; Benson, S . W. J . Phys. Chem. 1988, 92, 4080. (35) Baulch, D. L.; Drysdale, D. D.; Horne, D. G.; Lloyd, A. C. Eualuated Kinetic Data for High Temperature Reactions; Butterworths: London, 1972; Vol. 2. (36) Monat, J. P.; Hanson, R. K.; Kruger, C. H. Seuenteenth Symposium (International) on Combustion;The Combustion Institute: Pittsburgh, 1978; p 543. (37) Wilde, K. A. Combust. Flame 1969, 13, 173. (38) Hanson, R. K.; Salimian, S.In Combustion Chemistry; Gardiner, W. C., Jr., Ed.; Springer-Verlag: New York, 1984; Chapter 6. (39) Hindmarsh, A. C. Lawrence Livermore Solver for Ordinary Differential Equations, Version of Sept 23, 1980. (40) Baldwin, C.; Golden D. M. Chem. Phys. Lett. 1978, 55, 350. (41) Mbller, W.; Mozzhukhin,E.; Wagner, H. Gg. Eer. Bunsen-Ges. Phys. Chem. 1986, 90, 854. (42) Davidson, D. F.;Chang, A. Y.; Di Rosa, M. D.; Hanson, R. K. J. Quant. Spectrosc. Radiat. Transfer 1993, 49, 559. (43) Roth, P.; Just, Th. Ber. Bunsen-Ges. Phys. Chem. 1979, 83, 577. (44) Miller, J. A.; Bowman, C. T. Prog. Energy Combust. Sci. 1989, 15, 287.
-
