Rate constants for the reaction of OH radicals with a series of alkenes and dialkenes at 295 ± 1 K

Abstract

AbstractUsing a relative rate technique, rate constants for the gas phase reactions of the OH radical with n‐butane, n‐hexane, and a series of alkenes and dialkenes, relative to that for propene, have been determined in one atmosphere of air at 295 ± 1 K. The rate constant ratios obtained were (propene = 1.00): ethene, 0.323 ± 0.014; 1‐butene, 1.19 ± 0.06; 1‐pentene, 1.19 ± 0.05; 1‐hexene, 1.40 ± 0.04; 1‐heptene, 1.51 ± 0.06; 3‐methyl‐1‐butene, 1.21 ± 0.04; isobutene, 1.95 ± 0.09; cis‐2‐butene, 2.13 ± 0.05; trans‐2‐butene, 2.43 ± 0.05; 2‐methyl‐2‐butene, 3.30 ± 0.13; 2,3‐dimethyl‐2‐butene, 4.17 ± 0.18; propadiene, 0.367 ± 0.036; 1,3‐butadiene, 2.53 ± 0.08; 2‐methyl‐1,3‐butadiene, 3.81 ± 0.15; n‐butane, 0.101 ± 0.012; and n‐hexane, 0.198 ± 0.017. From a least‐squares fit of these relative rate data to the most reliable literature absolute flash photolysis rate constants, these relative rate constants can be placed on an absolute basis using a rate constant for the reaction of OH radicals with propene of 2.63 × 10−11 cm3 molecule−1 s−1. The resulting rate constant data, together with previous relative rate data from these and other laboratories, lead to a self‐consistent data set for the reactions of OH radicals with a large number of organics at room temperature.