RATE CONSTANTS FOR THE GAS-PHASE REACTIONS OF O3 WITH A SERIES OF ALKENES AT 296-K+/-2-K

The kinetics of the gas-phase reactions of O3 with a series of alkenes have been investigated at atmospheric pressure (ca. 740 torr) of air and 296 +/- 2 K, using a relative rate method in the presence of sufficient n-octane to scavenge any OH radicals generated in these reactions. Relative to k(O3 + propene) = 1.00, the rate constants obtained were: 1-butene, 0.975 +/- 0.030; 2-methylpropene, 1.14 +/- 0.04; 2-methyl-1,3-butadiene (isoprene), 1.21 +/- 0.02; 1,4-cyclohexadiene, 4.75 +/- 0.23; cyclohexene, 7.38 +/- 0.48; cis-2-butene, 12.8 +/- 0.8; trans-2-butene, 21.5 +/- 1.5; 2-methyl-2-butene, 42.1 +/- 2.8; cyclopentene, 64.9 +/- 4.3; and 2,3-dimethyl-2-butene, 123 +/- 11. These relative rate constants have been placed on an absolute basis using a rate constant for the reaction of O3 with propene of 1.01 x 10(-17) cm3 molecule-1 s-1 at 296 K derived from an analysis of the available literature data. The resulting rate constants then lead to a self-consistent set of room temperature data for the reactions of O3 with these alkenes.