28760-99-8Relevant articles and documents
One-Electron Reduction of Ferriporphyrins and Reactions of Ferric and Ferrous Porphyrins with a Halothane-Derived Radical
Brault, D.,Neta, P.
, p. 3405 - 3410 (1982)
The reduction of ferrideuteroporphyrin by α-hydroxyisopropyl radicals is investigated in acidic 2-propanol and acidic 2-propanol-water mixtures by means of steady-state and pulse radiolysis.The rate constant of the reaction is much higher (k ca. 1.3E9 M-1s-1) than that reported for neutral solutions emphasizing the effect of the positive charge carried by the ferric porphyrin in acidic solutions (due to protonation of the alkoxide ligand).Competition kinetic experiments using p-nitroacetophenone as a reference solute show that α-hydroxyisopropyl radicals are readily scavenged by halothane (CF3CHClBr), leading to radicals.Pulse irradiation of ferriporphyrin solutions containing halothane allows investigation of the reaction of radicals with either ferric or ferrous porphyrins depending on the halothane concentration.No reaction of radicals with ferriporphyrin can be detected (k -1s-1).On the other hand, a nearly diffusion-controlled reaction is observed between radicals and ferrous porphyrin leading to the ?-bonded alkyl complex of the ferric porphyrin (PFeIIICF3CHCl, where CF3CHCl stands for the alkyl anion).These results are discussed with regard to the reactivity of other alkyl radicals.The relevance to biological models of toxicity of halothane (a widely used anesthetic agent) is outlined.
Experimental Studies of Ozone Depletion by Chlorofluorocarbons (CFC's), Bromofluorocarbons (BFC's), Hydrochlorofluorocarbons (HCFC's), and CH3Br Using a 6-m3 Photochemical Chamber
Washida, Nobuaki,Imamura, Takashi,Bandow, Hiroshi
, p. 535 - 541 (1996)
Ozone destruction by CFC's (CFCl3 and CF2Cl2), BFC's (CF3Br and C2F4Br2), HCFC's (CH3CCl2F, CF3CHCl2, and CF3CHFCl), and CH3Br was demonstrated using a 6-m3 evacuable photochemical chamber equipped with UV-enhanced Xe arc lamps. The decay of ozone by a catalytic cycle involving Cl or Br atoms released from the photolysis of halocarbons by UV light was evident, although the chain length was far less than that in the real stratosphere: It was about 8 for CFCl3 and 40 for CF3Br. The rates of ozone decomposition were faster in the BFC's than in the CFC's. According to a box-model simulation, in the CFCl3 system 90% of the catalytic cycle proceeds from reactions of Cl+O3→ClO+O2 and ClO+O→Cl+O2. On the other hand, in the CF3Br system 90% of the catalytic cycle is governed by the following reactions: Br+O3→BrO+O2 and BrO+BrO→2Br+O2. The HCFC's and CH3Br can destroy the ozone with sufficient potential as CFC's and BFC's when they enter the stratosphere.
FTIR spectroscopic study of 1,1,1-trifluoro-2-chloroethyl and 1,1,1- trifluoro-2-chloroethylperoxyl radicals
Baskir,Korolev,Nefedov
, p. 519 - 522 (2007/10/03)
A combination of matrix isolation and FTIR spectroscopy was applied to investigate 1,1,1-trifluoro-2-chloroethyl (1) and 1,1,1-trifluoro-2- chloroethylperoxyl (2) radicals. Radical 2 was obtained by vacuum pyrolysis of 1,1,1-trifluoro-2-bromo-2-chloroethane (3). Corresponding peroxyl radicals was generated by co-condensation of pyrolysis products and molecular oxygen in an argon matrix. To assign the experimental bands DFT calculations (B3LYP/6-311G**) were carried out. The fundamental bands of O-O and C-O stretching vibrations of peroxyl radical CF3CHClOO (1102.1, 972.7, cm-1) were identified by their red shifts to 1044.7 and 954.1 cm-1 in the spectra of 18O substituted derivatives. UV photolysis of the radical 2 in the low- temperature matrix produced difluoroformaldehyde CF2O, radicals ClCO, CF3, as well as CO and HCl as the primary photoproducts.
