Relative rate constants for the reaction of OH radicals with selected C6 and C7 alkanes and alkenes at 305 ± 2 K

Abstract

Measurements of the rates of disappearance of three alkenes and two alkanes relative to isobutene in environmental chamber photooxidation studies employing hydrocarbonNOx mixtures in air at 1 atmosphere have been used to obtain relative rate constants for the reaction of these compounds with the hydroxyl radical. Absolute rate constants at 305 ± 2 K obtained using a published rate constant for OH + isobutene of 3.05 × 1010Q mole−1 s−1 are (k × 10−9Q m s−1): cyclohexene, 47 ± 9; 1-methylcyclohexene, 58 ± 12; 1-heptene, 22 ± 5; 2,3-dimethylbutane, 3.1 ± 0.5; 2,2,3-trimethylbutane, 2.3 ± 0.5. No previous determinations of OH rate constants have reported for 1-heptene and 1-methylcyclohexene. For the remaining compounds these results are shown to be in good agreement with literature values reported for elementary, or relative rate constant determinations.