Rate constants for the gas-phase reaction of ozone with 1, 1-disubstituted alkenes

✍ Scribed by Eric Grosjean; Daniel Grosjean

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 521 KB
• Volume: 28
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1996)28:12<911::aid-kin8>3.0.co;2-q

✦ Synopsis

The gas-phase reaction of ozone with eight alkenes including six I ,I-disubstituted alkenes has been investigated at ambient T (285-298 K) and p = 1 atrn. of air. The reaction rate constants are, in units of lo-" cm3 molecule-' s ~' . 9 50 5 1.23 for 3-methyl-I-butene. 13 I ? I 8 for 2-methyl-I-pentene, 1 1.3 ? 3.2 for 2-methyl-I .3-butadiene (isoprene), 7.75 ? I .08 for 2,3,3-trirnethyI-l-butene, 3.02 2 0.52 for 3-methyl-2-isopropyl-I-butene. 3.98 2 0 43 for 3.4diethyl-2-hexene, I39 ? 17 for 2,4,4-trimethyl-2-pentene, and > 370 for (cis + !rans)-3,4-dimethyl-3-hexene For isoprene, results from this study and earlier literature data are consistent with: f (cm3 molecule-' s-') = 5.59 ( + 3.51, -2 16) X e'-3606+279'RTi , n = 28, and R = 0.930 T h e 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 I , I-disubstituted alkenes) that bear H. CH,, and C2H, substituents, reactivity towards ozone is related to the alkene ionization potential. In h crn3 molecule-' s -l ) = (32.89 5 1.84) -(3.09 2 0 20) IP (eV), n = 12. and R = 0.979. This relationship overpredicts the reactivity of C, , I-alkenes, of 1, I-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 lohn Wiley & Sons, Inc