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A shock tube study of the pyrolysis of NO 2
Author(s) -
Röhrig Michael,
Petersen Eric L.,
Davidson David F.,
Hanson Ronald K.
Publication year - 1997
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1997)29:7<483::aid-kin2>3.0.co;2-q
Subject(s) - chemistry , arrhenius equation , shock tube , analytical chemistry (journal) , activation energy , work (physics) , atmospheric temperature range , thermodynamics , absorption (acoustics) , attenuation coefficient , range (aeronautics) , reaction rate constant , shock wave , kinetics , optics , materials science , physics , chromatography , composite material , quantum mechanics
NO 2 concentration profiles in shock‐heated NO 2 /Ar mixtures weremeasured in the temperature range of 1350–2100 K and pressuresup to 380 atm using Ar + laser absorption at 472.7 nm, IR emission at 6.25±0.25 μm,and visible emission at 300–600 nm. In the course of this study,the absorption coefficient of NO 2 at 472.7 nm was measured at temperaturesfrom 300 K to 2100 K and pressures up to 75 atm. Rate coefficients for thereactions NO 2 +M→NO+O+M (1), NO 2 +NO 2 →2NO+O 2 (2 a ), andNO 2 +NO 2 →NO 3 +NO (2b) were derived by comparing the measured andcalculated NO 2 profiles. For reaction (1), the following low‐ and high‐pressurelimiting rate coefficients were inferred which describe the measuredfall‐off curves in Lindemann form within 15% [FORMULA] The inferred rate coefficient at the low‐pressure limit, k 1 o , is in good agreementwith previous work at higher temperatures, but the energy of activationis lower by 20 kJ/mol than reported previously. The pressure dependenceof k 1 observed in the earlier work of Troe[1] was confirmed. The rate coefficient inferred for the highpressure limit, k 1∞ ,is higher by a factor of two than Troe's value, but in agreement with dataobtained by measuring specific energy‐dependent rate coefficients. For the reactions (2a) and (2b), least‐squares fits of thepresent data lead to the following Arrhenius expressions: [FORMULA] For reaction (2), the new data agree with previously recommendedvalues of k 2a and k 2b ,although the present study suggests a slightly higher preexponentialfactor for k 2a . © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 483–493, 1997.