| Autor: |
Suehiro, Tadashi, Masuda, Seiichi, Nakausa, Ryuichi, Taguchi, Masamichi, Mori, Atsushi, Koike, Akemi, Date, Munehiro |
| Zdroj: |
Bulletin of the Chemical Society of Japan; September 1987, Vol. 60 Issue: 9 p3321-3330, 10p |
| Abstrakt: |
The decay processes of aryldiazenyl radicals were studied by using a time-resolved ESR method. The first order rate constants of decomposition were determined at -117–-48 °C in cyclopropane solutions in the presence or absence of olefins. Aryldiazenyl radicals were relatively persistent and the k1of phenyldiazenyl-d5at -96 °C in cyclopropane was 34 s-1. The k1of 20 aryldiazenyl radicals at -96 °C afforded a ? value of +1.53 (r=0.91) in a Hammett plot. Activation energies ranged from 46.2 to 25.2 kJ mol-1and the frequency factors, log A, from 13.2 to 8.2 s-1. The second-order decay rates were measured at the initial period of the decay process at lower temperatures, in a batch system (cyclopropane) and in a flow system (isohexane). The rate constant of phenyldiazenyl-d5in cyclopropane was 9.2·10-5M-1s-1at -93 °C and the Arrhenius parameters were Ea=23.5 kJ mol-1and logA=12.77 M-1s-1, respectively. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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