High-temperature rate constant measurements for OH plus xylenes

The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k(1)), m-xylene (k(2)). and p-xylene (k(3)) were measured behind reflected shock waves over 890-1406 K at pressures of 1.3-1.8 atm using OH laser absorption near 306.7 nm. Measurements were performed under pseudo-first-order conditions. The measured rate constants, inferred using a mechanism-fitting approach, can be expressed in Arrhenius form as: k(1) = 2.93 x 10(13) exp(-1350.3/T) cm(3) mol(-1) s(-1) (890-1406 K) k(2) = 3.49 x 10(13) exp(-1449.3/T) cm(3) mol(-1) s(-1) (906-1391 K) k(3) = 3.5 x 10(13) exp(-1407.5/T) cm(3) mol(-1) s(-1) (908-1383 K) This paper presents, to our knowledge, first high-temperature measurements of the rate constants of the reactions of xylene isomers with OH radicals. Low-temperature rate-constant measurements by Nicovich et al. (1981) were combined with the measurements in this study to obtain the following Arrhenius expressions, which are applicable over a wider temperature range: k(1) = 2.64 x 10(13) exp(-1181.5/T) cm(3) mol(-1) s(-1) (508-1406 K) k(2) = 3.05 x 10(9) exp(-400/T) cm(3) mol(-1) s(-1) (508-1391 K) k(3) = 3.0 x 10(3) exp(-440/T) cm(3) mol(-1) s(-1) (526-1383 K) (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.