ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The gas-phase reaction of ozone with eight alkenes including six 1,1-disubstituted alkenes has been investigated at ambient T (285-298 K) and p = 1 atm. of air. The reaction rate constants are, in units of 10-18 cm3 molecule-1 s-1, 9.50 ± 1.23 for 3-methyl-1-butane, 13.1. ± 1.8 for 2-methyl-1-pentene, 11.3 ± 3.2 for 2-methyl-1,3-butadiene (isoprene), 7.75 ± 1.08 for 2,3,3-trimethyl-1-butene, 3.02 ± 0.52 for 3-methyl-2-isopropyl-1-butene, 3.98 ± 0.43 for 3,4-diethyl-2-hexene, 1.39 ± 17 for 2,4,4-trimethyl-2-pentene, and 〉370 for (cis + trans)-3,4-dimethyl-3-hexene. For isoprene, results from this study and earlier literature data are consistent with: k (cm3 molecule-1 s-1) = 5.59 (+ 3.51, &minus 2.16) × 10-15 e(-3606±279/RT), n = 28, and R = 0.930. The reactivity of the other alkenes, six of which have not been studied before, is discussed in terms of alkyl substituent inductive and steric effects. For alkenes (except 1,1-disubstituted alkenes) that bear H, CH3, and C2H5 substituents, reactivity towards ozone is related to the alkene ionization potential: In k〈(10-18 cm3 molecule-1 s-1) = (32.89 ± 1.84) - (3.09 ± 0.20) IP (eV), n = 12, and R = 0.979. This relationship overpredicts the reactivity of C≥3 1-alkenes, of 1,1-disubstituted alkenes, and of alkenes with bulky substituents, for which reactivity towards ozone is lower due to substituent steric effects. The atmospheric persistence of the alkenes studied is briefly discussed. © 1996 John Wiley & Sons, Inc.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.8
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