| Gas chromatography and the relative rate method were used to measure the rate constants for the reaction of chlorine atoms with chlorotoluene and fluorotoluene isomers at 298 K and 1 atm. The chlorine atom rate constants for the reaction with ortho-, mew-, and para- chlorotoluene and --fluorotoluene were determined to be (3.3 +/- 0.3) x 10--11, (3.4 +/- 0.4) x 10--11 , (4.5 +/- 0.3) x 10--11, (2.9 +/- 0.4) x 10--11, (3.3 +/- 0.3) x 10--11, and (5.3 +/- 0.2) x 10--11 cm3molecules --1 s--1, respectively. The chlorine atom rate constant for para-chlorotoluene and para-fluorotoluene are larger than for the ortho and meta isomers, which had similar rate constants. The kinetic isotope effect (KIE) and product studies for the reaction of chlorine atoms with chloro- and fluoro-toluene indicate that the reaction mechanism proceeds via hydrogen atom abstraction from the methyl group. Comparisons to similar reaction systems are discussed and several factors were used to explain the observed trends seen for the chloro- and fluoro-toluene isomers. The significance to atmospheric and incinerator systems are also discussed. |
