Experimental and theoretical studies of the kinetics of the reactions of OH and OD with acetone and acetone-d6 at low pressure

The kinetics of the reactions of OH and OD with acetone and acetone-d6 were studied from 2-5 Torr and 258-402 K using a discharge flow system with laser induced fluorescence or resonance fluorescence detection of the OH radical. The rate constants at 300 K for the reaction of OH with acetone and acetone-d6 were (1.73 ± 0.06) × 10−13 and (3.36 ± 0.32) × 10−14 cm3 molecule−1 s−1, respectively. The rate constants at 300 K for the reaction of OD with acetone and acetone-d6 were (2.87 ± 0.22) × 10−13 and (3.69 ± 0.12) × 10−14 cm3 molecule−1 s−1, respectively. Above room temperature, the temperature dependence of the rate constants for the OH + acetone and acetone-d6 display Arrhenius behavior and are described by the equations kH(T) = (3.92 ± 0.81) × 10−12 exp(−938 ± 70/T) and kD(T) = (8.19 ± 1.45) × 10−12 exp(−1647 ± 58/T) cm3 molecule−1 s−1 for acetone and acetone-d6, respectively. Measurements of kH and kD below room temperature begin to display non-Arrhenius behavior, consistent with previous measurements at higher pressures. Theoretical calculations of the kinetic isotope effect as a function of temperature are in good agreement with the experimental measurements using a hydrogen abstraction mechanism that proceeds through a hydrogen-bonded complex.