F. Markert et P. Pagsberg, UV SPECTRA AND KINETICS OF RADICALS PRODUCED IN THE GAS-PHASE REACTIONS OF CL, F AND OH WITH TOLUENE, Chemical physics letters, 209(5-6), 1993, pp. 445-454
The gas phase reactions of Cl, F and OH with toluene have been studied
by pulse radiolysis combined with time-resolved UV spectroscopy. The
formation of benzyl radicals via the abstraction reactions C6H5-CH3 X --> C6H5-CH2 + HX was observed with X = Cl, F and OH. In the reactio
n with chlorine atoms the benzyl radical was the only reaction product
observed. The addition reactions Y + C6H5-CH3 --> Y-C6H5-CH3 were obs
erved with Y = F and OH, and the ultraviolet absorption spectra of the
short-lived adducts have been recorded. Rate constants for the abstra
ction and addition reactions were derived from the observed formation
kinetics and the relative yields of benzyl radicals and radical adduct
s, respectively. For the reaction of OH with toluene we have determine
d an overall rate constant for the addition and abstraction channels o
f k = (6.4 +/- 0.7) x 10(-12) cm3 molecule-1 s-1 and a branching ratio
of 0.89 for the addition channel at 338 K.