1,2-pentadiene decomposition

Citation
J. Herzler et al., 1,2-pentadiene decomposition, INT J CH K, 33(11), 2001, pp. 755-767
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS
ISSN journal
0538-8066 → ACNP
Volume
33
Issue
11
Year of publication
2001
Pages
755 - 767
Database
ISI
SICI code
0538-8066(200111)33:11<755:1D>2.0.ZU;2-S
Abstract
1,2-Pentadiene has been decomposed in single pulse shock tube experiments. There appear to be a large number of parallel decomposition and isomerizati on channels. The following rate expressions for isomerization in the temper ature range 1100-1250 K and pressures between 200 and 300 kPa have been obt ained k (1,2-pentadiene --> -pentyne) = 1.0 x 10(13) exp(-32300 +/- 900 K/T) s(-1 ) k(1,2-pentadiene --> cis/trans-1,3-pentadiene = 2.2 x 10(14) exp(-33900 +/- 900 K/T) s(-1) k(1,2-pentadiene --> cyclopentene) = 1.8 x 10(11) exp(-26080 +/- 900 K/T)s( -1) Overall, we estimate the 2 sigma uncertainty in the absolute rate constants to be about 30%. From detailed balance the rate expression for 1,3 to 1,2- pentadiene isomerization has been found to be k(1,3-pentadiene --> 1,2-pentadiene) = 1.2 x 10(15) exp(-42070 +/- 900 K/T) s(-1) The significance of the 13 to 1,2 isomerization process as a bridge between the two-carbon and three-carbon species in high temperature hydrocarbon de composition systems Is discussed. The decomposition processes involve bond breaking and retroene reactions. The rate expression for the latter has bee n found to be k(1,2-pentadiene --> propyne + ethylene) = 6.6 x 10(12) exp(-29240 +/- 900 K/T) s(-1) The rate constants for fission of the C-3-C-4 and C-4-C-5 bonds appear to b e close to each other, Our results indicate that the resonance energy of th e 1,3-butadiene-2-yl radical is smaller than that of allyl radical by an am ount equal to the pi bond conjugation energy of butadiene. (C) 2001 John Wi ley & Sons, Inc.