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1,2-Pentadiene Decomposition



J Herzler, Jeffrey A. Manion, Wing Tsang


1,2-Pentadiene has been decomposed in single pulse shock tube experiments. There appear to be a large number of parallel decomposition and isomerization channels. The following rate expressions for isomerization in the temperature range 1100 K-1250 K and 2 bar pressure have been obtainedk(1,2-pentadiene {arrow} 1- pentyne) = 1x1013exp(-32700 900K/T) s^-1^k(1,2-pentadiene {arrow} 1,3-pentadiene(cis & trans)) = 1.1x1014exp(-33290 900K/T) s-1k(1,2-pentadiene {arrow} cyclopentene) = 1.2x1011exp(-25755 900 K/T) s^-1^From detailed balance the rate expression for 1,3 to 1,2-pentadiene isomerization has been found to bek(1,3-pentadiene {arrow} 1,2-pentadiene) = 8x1014exp(-42183 900 K/T) s-1The significance of the 1,3 to 1,2 isomerization process as a bridge between the two carbon and three carbon species in high temperature hydrocarbon decomposition systems is discussed.The decomposition processes involve bond breaking and retroene reactions. The rate expression for the latter has been found to bek(1,2-pentadiene {arrow} propyne + ethylene) = 6x1012 exp(-28000 900 K/T)s-1.The rate constants for the breaking of the C3-C4 and C4-C5 bonds appear to be close to each other. The resonance energy for the 1,3-butadien-2-yl radical is smaller than that for allyl by an amount that is equal to the extra stabilization in butadiene.
International Journal of Chemical Kinetics
No. 11


1, 2-pentadiene, decomposition, isomerization, kinetics, single pulse shock tube, unimolecular reactions


Herzler, J. , Manion, J. and Tsang, W. (2001), 1,2-Pentadiene Decomposition, International Journal of Chemical Kinetics, [online], (Accessed February 25, 2024)
Created November 1, 2001, Updated November 18, 2016