60531-51-3Relevant academic research and scientific papers
Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures
Orlando, John J.,Iraci, Laura T.,Tyndall, Geoffrey S.
, p. 5072 - 5079 (2007/10/03)
The Cl-atom initiated oxidation mechanisms of both cyclopentane and cyclohexane have been studied as a function of temperature using an environmental chamber/FTIR technique. The oxidation of cyclohexane leads to the formation of the cyclohexoxy radical, the chemistry of which is characterized by a competition between ring-opening (R5) and reaction with O2 (R6) to form cyclohexanone. The yield of cyclohexanone is shown to increase with decreasing temperature, and a rate coefficient ratio k6/k5 = (1.3 ± 0.3) × 10-27 exp(5550 ± 1100/T) cm3 molecule-1 is obtained. The energy barrier to ring-opening is estimated to be 11.5 ± 2.2 kcal/mol. The dominant fate of the cyclopentoxy radical, formed in the Cl-atom initiated oxidation of cyclopentane, is ring-opening under all conditions studied here (230-300 K, 50-500 Torr O2), with only a minor contribution from the O2 reaction at the lowest temperatures studied. The barrier to ring-opening for the cyclopentoxy radical is probably less than 10 kcal/mol.
Thermal stability of peroxynitrates
Kirchner,Mayer-Figge,Zabel,Becker
, p. 127 - 144 (2007/10/03)
Peroxynitrates are thermally unstable intermediates (at ambient temperatures) in the atmospheric degradation of hydrocarbons. In this work, thermal lifetimes of nine peroxynitrates have been measured as a function of temperature and, for two of them, also, as a function of total pressure. In the presence of excess NO, relative concentrations of the peroxynitrates were followed in a 420 I reaction chamber as a function of time by means of long-path IR absorption using a Fourier transform spectrometer. Original data on the unimolecular decomposition rate constants are presented for the peroxynitrates RO2NO2 with R = C6H11, CH3C(O)CH2, C6H5CH2, CH2I, CH3C(O)OC(H)CH3, C6H5OCH2, (CH3)2NC(O), C6H5OC(O), and C2H5C(O). Thermal lifetimes at room temperature and atmospheric pressure are very short (in the order of seconds) for substituted methyl peroxynitrates (i.e., R′CH2O2NO2) but rather long for substituted formyl peroxynitrates (i.e., R″C(O)O2NO2). Kinetic data from this and previous work from our laboratory are used to derive structure-stability relationships which allow an estimate of the thermal lifetimes of peroxynitrates from readily available 13C n.m.r. shift data.
