Temperature dependence of the reactions of Cl with toluene and the xylenes

The temperature dependence of the rate coefficients for the reactions of Cl with toluene and the xylenes was examined from 290 to 362 K. Chemical analysis was by gas chromatography. The relative rate method was used for the kinetic analysis, and the relative rate coefficients were converted to absolute values using absolute rate coefficients for the reference reactions obtained from recent critical evaluations. Most of the measurements were made at a total pressure of approximately 100 kPa in argon. There was very little temperature dependence, and variation of the total pressure and the concentration of O2 had no effect. The values of the absolute rate coefficients were independent of the reference reaction used. The reaction of Cl with toluene was studied relative to the reactions of Cl with isobutane, ethane, propane, and n‐butane. The results were virtually independent of temperature, giving a mean value of (5 ± 1) × 10−11 cm3 molecule–1 s−1 for the absolute rate coefficient at 95% confidence. The reactions of Cl with the xylenes were studied relative to the reactions of Cl with isobutane, ethane, and propane. The rate coefficients were independent of the xylene isomer and had a very small negative dependence on temperature. The mean value of the absolute rate coefficient at 298 K was (1.4 ± 0.3) × 10−10 cm3 molecule−1 s–1 at the 95% confidence level. The results are in satisfactory agreement with those in the literature, all of which were measured at fixed temperatures very close to 298 K. The kinetic results are discussed in relation to published descriptions of the dynamics of reactions of Cl and OH with organic compounds.