Rates of reactions of O(3P) with benzene and toluene

Absolute rate coefficients for the reaction of O(3P) with C6H6 (k1), C6D6 (k2), C6H5CH3 (k3), and C6H6CD3 (k4) were measured, over the temperature range 298 to 950 K, by using the technique of flash photolysis-resonance fluorescence. The measured bimolecular rate coefficients increase monotonically with temperature and yield the following Arrhenius expressions (in units of cm3 molecule-1 s-1):k1 = (4.62 +- 0.68) x 10-11 exp[-(2.47 +- 0.08) x 103/T], k2 = (4.4 +- 1.1) x 10-11 exp[-(2.45 +- 0.13) x 103/T], k3 = (4.26 +- 0.58) x 10-11 exp[-(1.91 +- 0.07) x 103/T], and k4 = (3.71 +- 0.77) x 10-11 exp[-(1.88 +- 0.10) x 103/T]. The isotopic substitution of ring hydrogen in the case of benzene and the side-chain hydrogen in the case of toluene did not affect the rate coefficient, i.e., k1 approx. = k2 and k3 approx. = k4. Kinetic and mechanistic information derived from these measurements is discussed