Thermal isomerization and decomposition of 1,2-butadiene in shock waves

✍ Scribed by Yoshiaki Hidaka; Tetsuo Higashihara; Natsuhiko Ninomiya; Takashi Oki; Hiroyuki Kawano

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 568 KB
• Volume: 27
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550270404

✦ Synopsis

1,a-Butadiene diluted with Ar was heated behind reflected shock waves over the temperature and the total density ranges of 1100-1600 K and 1.36 X mol/cm3. The major products were 1,3butadiene, 1-butyne, 2-butyne, vinylacetylene, diacetylene, allene, propyne, CzHs, CzH4, CzH2, CH4, and benzene, which were analyzed by gas chromatography. The UV kinetic absorption spectroscopy at 230 nm showed that 1,2-butadiene rapidly isomerizes to 1,3-butadiene from the initial stage of the reaction above 1200 K. In order to interpret the formation of 1,3-butadiene, 1-butyne, and 2-butyne, it was necessary to include the parallel isomerizations of 1,2-butadiene to these isomers. The present data were successfuly modeled with a 82 reaction mechanism. From the modeling, rate constant expressions were derived for the isomerization 1,2-butadiene = 1,3-butadiene to be k3 = 2.5 X 1013 exp(-63 kcal/RT) s-l and for the decomposition 1,2-butadiene = C3H3 + CH3 to be k6 = 2.0 X loi5 exp(-75 kcal/RT) s-', where the activation energies, 63 kcal/mol and 75 kcal/mol, were assumed. These rate constants are only applicable under the present experimental conditions, 1100-1600 K and 1.23-2.30 atm.