2143-59-1Relevant academic research and scientific papers
Atmospheric Chemistry of Cyclohexane: UV Spectra of c-C6H11. and (c-C6H11)O2. Radicals, Kinetics of the Reactions of (c-C6H11)O2. Radicals with NO and NO2, and the Fate of the Alkoxy Radical (c-C6H11)O.
Platz,Sehested,Nielsen,Wallington
, p. 2688 - 2695 (1999)
pulse radiolysis technique was used to measure the UV absorption spectra of c-C6H11. and (c-C6H11)O2. radicals over the ranges 230-290 and 220-300 nm, σ(c-C6H11.)250nm = (7.0 ± 0.8) × 10-18 and σ((cC6H11)O2.)250 nm = (5.7 ± 0.6) × 10-18 cm2 molecule-1. The rate constant for the self-reaction of c-C6H11. radicals was k3 = (3.0 ± 0.4) × 10-11 cm3 molecule-1 s-1. The addition reaction of c-C6H11. radicals with O2 proceeds with a rate constant k2 = (1-3 ± 0.2) × 10-11 cm3 molecule-1 s-1. Rate constants for reactions of (c-C6H11)O2 radicals with NO and NO2 were k4 = (6.7 ± 0.9) × 10-12 and k5 = (9.5 ± 1.5) × 10-12 cm3 molecule-1 s-1, respectively. FTIR-smog chamber techniques were used to record the IR spectrum of the peroxynitrate (c-C6H11)O2NO2, determine that the reaction between (c-C6H11)O2. radicals and NO produces a (16 ± 4)% yield of the nitrate (c-C6H11)ONO2, and study the atmospheric fate of cyclohexoxy radicals. Decomposition via C-C bond scission and reaction with O2 are competing fates of the cyclohexoxy radical. In 700-750 Torr total pressure at 296 ± 2K, the rate constant ratio kdecomp/kO2 = (8.1 ± 1.5) × 1018 molecule cm-3. At 296 K in 1 atm of air, 61% of cyclohexoxy radicals decompose and 39% react with O2. These results are discussed with respect to the literature data concerning the atmospheric chemistry of cyclohexane and analogous compounds.
Observation of the A - X electronic transitions of cyclopentyl and cyclohexyl peroxy radicals via cavity ringdown spectroscopy
Thomas, Phillip S.,Chhantyal-Pun, Rabi,Miller, Terry A.
, p. 218 - 231 (2010)
The A-X electronic absorption spectra of cyclopentyl, cyclohexyl, and cyclohexyl-d11 peroxy radicals have been recorded at room temperature by cavity ringdown spectroscopy. By comparing the experimental spectra with predictions from ab initio a
Metal-free oxygenation of cyclohexane with oxygen catalyzed by 9-mesityl-10-methylacridinium and hydrogen chloride under visible light irradiation
Ohkubo, Kei,Fujimoto, Atsushi,Fukuzumi, Shunichi
supporting information; scheme or table, p. 8515 - 8517 (2011/09/16)
Photooxygenation of cyclohexane by O2 occurs efficiently under visible-light irradiation of an O2-saturated acetonitrile solution containing 9-mesityl-10-methylacridinium ions (Acr+-Mes) and HCl to yield cyclohexanone, cyclohexanol and hydrogen peroxide. The photocatalytic reaction is initiated by electron transfer from Cl- to the mesitylene radical cation moiety. The Royal Society of Chemistry 2011.
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.
UV Absorption Spectrum and Self-Reaction of Cyclohexylperoxy Radicals
Rowley, David M.,Lightfoot, Phillip D.,Lesclaux, Robert,Wallington, Timothy J.
, p. 3221 - 3226 (2007/10/02)
The kinetics and mechanism of the self-reaction of cyclohexylperoxy radicals: 2c-C6H11O2 --> 2c-C6H11O + O2 (1a) --> c-C6H10O + c-C6H11OH + O2 (1b) have been studied using both time-resolved and end-product analysis techniques.Determination of the product yields from the photooxidation of Cl2-c-C6H12-O2-N2 mixtures using FTIR spectrometry demonstrates that the branching ratio for the radical-producing channel (1a) is 0.29 +/- 0.02 at 295 K.Furthermore, the dependence of the product yields on oxygen partial pressure shows that ring-opening of the cyclohexyloxy radical formed in channel (1a): c-C6H11O + M --> CH2(CH2)4CHO + M (4) competes with the reaction with oxygen: c-C6H11O + O2 --> c-C6H10O + HO2 (2) under atmospheric conditions.Flash photolysis-UV absorption experiments were used to obtain the UV spectrum of the cyclohexylperoxy radical and the kinetics of reaction (1).The spectrum of c-C6H11O2 is similar to those of other alkylperoxy radicals with a maximum cross-section of (4.95 +/- 0.51) x 1018 cm2 molecule-1 at 250 nm, measured relative to a value of 4.55 x 10-18 cm2 molecule-1 for CH3O2 at 240 nm.Reaction (1) is slow compared to the self-reactions of primary alkylperoxy radicals, but is significantly faster than that of isopropylperoxy radicals at room temperature.Experiments as a function of temperature from 253 to 373 K give: kobs (2.0 +/-0.4) x 10-13 exp cm3 molecule-1 s-1 for reaction (1).The room-temperature branching ratio measurement enables a value of 2.84 x 10-14 cm3 molecule-1 s-1 to be assigned to k1 at 298 K.The calibration cross-section, absolute uncertainities in the values of the cyclohexylperoxy cross-sections and kobs are 16percent and 17percent, respectively.
