ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Rate constants for the unimolecular dissociation of 1,3-butadiene have been measured with the pulsed laser flash absorption technique, following butadiene disappearance at 222 nm. The results are in excellent agreement with previous laser-schlieren measurements interpreted with a ΔH°298 = 100 kcal/mol heat of dissociation. A new RRKM calculation agreeing with both sets of rate constants gives log k∞(s-1) = 17.03 ± 0.3 - 94(kcal/mol)/RT. These data and product measurements using ARAS, single-pulse product analysis, and time-of-flight mass spectrometry, in shock tubes, all provide independent evidence against any major participation by molecular reactions in the dissociation. The only dissociation channel, or combination of channels, consistent with all the measurements is C-C scission to two vinyl radicals. However, the extremely slow rate of H-atom formation seen in ARAS experiments then requires an unacceptably low rate of vinyl dissociation.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550201004
