15157-95-6Relevant articles and documents
Elson,I.H. et al.
, p. 335 - 341 (1975)
A shock tube, laser-schlieren study of the pyrolysis of isobutene: Relaxation, incubation, and dissociation rates
Santhanam,Kiefer,Tranter,Srinivasan
, p. 381 - 390 (2003)
Dissociation, vibrational relaxation, and unimolecular incubation have all been observed in shock waves in isobutene with the laser-schlieren technique. Experiments covered a wide range of high-temperature conditions: 900-2300 K, and post-incident shock pressures from 7 to 400 torr in 2, 5, and 10% mixtures with krypton. The surprising observation is that of vibrational relaxation, well resolved over the full temperature range. The resolved process is completely exponential, with relaxation times in the range 20-120 ns atm. Relaxation and dissociation are clearly separated for T > 1850 K, with estimated incubation times near 200 ns atm. Incubation is essential for modeling of the very low-pressure decomposition. Modeling of gradients with a chain mechanism initiated by CH fission produces an excellent fit and accurate dissociation rates that show severe falloff. A restricted-rotor, Gorin-model RRKM analysis fits these rates quite well with the known bond-energy as barrier and 〈ΔE〉down = 680 cm-1. The extrapolated k∞ is log k∞ (s-1) = 19.187-0.865 log T -87.337 (kcal/mol)/RT, in good agreement with previous work.
Tsang
, p. 929,933-935,943 (1973)
High-resolution discrete absorption spectrum of α-methallyl free radical in the vapor phase
Bayrakceken, Fuat,Telatar, Ziya,Ari, Fikret,Tuncyuerek, Lale,Karaaslan, Ipek,Yaman, Ali
, p. 143 - 146 (2006)
The α-methallyl free radical is formed in the flash photolysis of 3-methylbut-1-ene, and cis-pent-2-ene in the vapor phase, and then subsequent reactions have been investigated by kinetic spectroscopy and gas-liquid chromatography. The photolysis flash was of short duration and it was possible to follow the kinetics of the radicals' decay, which occurred predominantly by bimolecular recombination. The measured rate constant for the α-methallyl recombination was (3.5 ± 0.3) × 1010 mol-1 l s-1 at 295 ± 2 K. The absolute extinction coefficients of the α-methallyl radical are calculated from the optical densities of the absorption bands. Detailed analysis of related absorption bands and lifetime measurements in the original α-methallyl high-resolution discrete absorption spectrum image were also carried out by image processing techniques.
The Heat of Formation of the Allyl and Methallyl Radical
Roth, Wolfgang R.,Bauer, Frank,Beitat, Arndt,Ebbrecht, Thomas,Wuestefeld, Michael
, p. 1453 - 1460 (2007/10/02)
The decomposition of 1,5-hexadiene (1), 2-methyl-1,5-hexadiene (7), and 2,5-dimethyl-1,5-hexadiene into allyl- (2) and methallyl radicals (6) was studied by means of the shoke tube technique with and without oxygen as scavenger.From these data and from the temperature dependence of the equilibria 1 2 and 5 6, measured between 600 and 800 deg C, the heat of formation of the allyl (2) and methallyl radical (6) as well as the activation parameters for the recombination and disproportionation of these radicals have been deduced.
