High-temperature rate constant measurements for OH + xylenes

High-temperature rate constant measurements for OH + xylenes



dany, J. Badra, A. Farooq*

Combustion and Flame 162, 2348-2353, (2015)

A. Elwardany, J. Badra, A. Farooq*
Xylene, Hydroxyl radical, Shock tube, Laser absorption, Rate constant

The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k1), m-xylene (k2), and p-xylene (k3) 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:

k1=2.93×1013exp(-1350.3/T)cm3mol-1s-1 (890–1406 K)

k2=3.49×1013exp(-1449.3/T)cm3mol-1s-1 (906–1391 K)

k3=3.5×1013exp(-1407.5/T)cm3mol-1s-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:

k1=2.64×1013exp(-1181.5/T)cm3mol-1s-1 (508–1406 K)

k2=3.05×109exp(-400/T)cm3mol-1s-1 (508–1391 K)

k3=3.0×109exp(-440/T)cm3mol-1s-1 (526–1383 K)
DOI: 10.1016/j.combustflame.2015.02.001