Kinetic Studies of OH Reactions with a Series of Acetates

Abstract

Absolute rate constants have been measured for the gas phase reactions of hydroxyl radicals with a series of aliphatic acetates: methyl acetate (k1), ethyl acetate (k2), n-propyl acetate (k3), n-butyl acetate (k4), and n-pentyl acetate (k5). Experiments were carried out using the pulsed laser photolysislaser induced fluorescence technique over the temperature range 243−372 K. The obtained kinetic data were used to derive the Arrhenius expressions, and since the Arrhenius plots were slightly curved they were fitted, using a three-parameter expression. The Arrhenius expressions obtained are: k1 = (0.53 ± 0.09) × 10-12 exp[−(128 ± 102)/T] ; k2 = (0.48 ± 0.09) × 10-12 exp[(397 ± 103)/T]; k3 = (1.03 ± 0.12) × 10-12 exp[(370 ± 69)/T] ; k4 = (2.10 ± 0.28) × 10-12 exp[(299 ± 81)/T], and k5 = (2.75 ± 0.46) × 10-12 exp[(302 ± 102)/T] (in units of cm3 molecule-1 s-1). At room temperature, the rate constants obtained (in units of 10-12 cm3 molecule-1 s-1) were as follows: methyl acetate, 0.32 ± 0.03; ethyl acetate...