Rate constants for the reactions of hydroxyl radicals with propane and ethane

The kinetics of the reaction OH + C3H6→ H2O + C2H7(1) have been studied in a discharge-flow system under first-order conditions. The OH radicals were generated by the reaction of H atoms with NO2 and the concentration of OH, monitored by resonance fluorescence, was followed as a function of reaction time in a large excess of the alkane. A value of k1=(7.2±1.1)× 108 dm3 mol–1 s–1 at 295 K was obtained.As a check on the technique the rate constant for the reaction OH + C2H6→ H2O + C2H5(2) was determined in a similar fashion. The value obtained, k2=(1.61±0.24)× 108 dm3 mol–1 s–1, is in excellent agreement with other literature values.