Kinetics of the reaction between cyclopentylperoxy radicals and HO2

The techniques of time-resolved UV spectroscopy and transient IR absorption are used to examine the kinetics of the c-C5H9O2 + HO2 reaction over the temperature range 214-359 K. Deconvolution of the UV spectra yield time-dependent concentrations of both the cyclopentylperoxy and HO2 reactants; the transient IR experiments separately monitor HO2. Fits of these data to the appropriate reaction model yield a rate constant of k(ro2+ho2) = (3.2(-1.1)(+15)) x 10(-13)e((1150+/-200)/T) cm(3) s(-1) for the title reaction. This result is compared to the single previous study of c-C5H9O2 + HO2 kinetics, and the implications for the atmospheric chemistry of peroxy radicals are discussed. As part of the present study, a relative rate of k(cl+c5h10)/k(cl+ch3oh) = (2.3 +/- 0.3)e((300+/-200)/T) has been measured for the reaction Cl + c-C5H10 --> c-C5H9 + HCl relative to Cl + CH3OH --> CH2OH + HCl.