73761-32-7Relevant articles and documents
Reactions of Iron(III) Porphyrins with Peroxyl Radicals Derived from Halothane and Halomethanes
Brault, D.,Neta, P.
, p. 2857 - 2862 (1984)
The reactions of haloalkane-derived peroxyl radicals with ferric deuteroporphyrins in aerated acidic or alkaline aqueous 2-propanol solutions are investigated by means of pulse radiolysis.CCl3O2., CHCl2O2., CH2ClO2. and CF3CHClO. radicals (the latter one being derived from the anesthetic agent halothane, CF3CHClBr) are found to oxidize the ferric porphyrins with reaction rate constats ranging between 6*1E7 and 2.6*1E8 m-1 s-1.In keeping with an electron-transfer mechanism, the spectrum of the oxidized ferric porphyrin does not depend on the nature of the peroxyl radicals.Also, the rate constat for the reaction of CCl3O2. radicals with ferric porphyrins is lowered by a factor >20 when experiments are performed in the less polar solvents neat 2-propanol and neat carbon tetrachloride.The spectrum of the oxidized ferric porphyrin depends on pH with large changes around pH 2.3 which are attributed to the protonation of an alkoxide ligand of the iron ion.Smaller changes are observed with pKa ca. 7.4.The relevance of these reactions to cytochrome P450 mediated oxidative metabolism and toxicity of haloalkanes is outlined.
Unimolecular Decomposition of Peroxynitrates
Zabel, F.
, p. 119 - 142 (2007/10/02)
Thermal decomposition rate constants of peroxynitric acid (HO2NO2) and chloromethyl peroxynitrate (CH2ClO2NO2) were measured as a function of temperature and total pressure in a photochemical reaction chamber of 420 l volume.Peroxynitrate concentrations were monitored by long-path IR absorption using a Fourier transform spectrometer.Analysis of these results in terms of unimolecular reaction rate theories yields kinetic parameters which allow to calculate decomposition rate constants of HO2NO2 and CH2ClO2NO2 for all pressures and temperatures which are of interest for atmospheric applications.These results, together with kinetic data on the thermal decomposition of other peroxynitrates previously obtained in our laboratory, allow to rationalize the change of the bond energies in peroxynitrates (RO2-NO2) with the nature of the group R.Combination of the decomposition data with experimental results on the reverse reactions from the literature are used to determine thermochemical data of peroxynitrates. - Keywords: Peroxynitric acid / Peroxynitrates / Thermal decomposition
Reactivities of Chlorine Atoms and Peroxyl Radicals Formed in the Radiolysis of Dichloromethane
Alfassi, Z. B.,Mosseri, S.,Neta, P.
, p. 1380 - 1385 (2007/10/02)
Radiolysis of dichloromethane (DCM) leads to formation of primary oxidizing radicals and carbon-centered radicals.The latter react with oxygen to yield peroxyl radicals.The yields and chemical behavior of these intermediates were studied by pulse radiolysis of DCM solutions containing various solutes: phenols, anilines, dimethoxybenzene, hexamethylbenzene,cyclohexene, dimethyl sulfoxide, and zinc tetratolylporphyrin.At low concentrations, some of these solutes were found to be oxidized by two peroxyl radicals, CH2ClO2* and CHCl2O2*, with different rate constants.At higher concentrations, the solutes react also with the primary radicals: Cl atoms and the radical cations CH2Cl2(+*), with diffusion-controlled rate constants.The rates of these reactions were determined by competition kinetics because of the very short lifetimes of the species.Cl atoms were found to have a half-life of about 5 ns in DCM, reacting predominantly with the solvent by hydrogen abstraction.The radical cations decay within a fraction of a nanosecond.The total yield of these primary radicals was determined to be G = 3.6 and appears to be divided about equally between Cl and the radical cations.The total yield of oxidation, by the primary and the peroxyl radicals, was found to be G = 7.5.Cl atoms were found to be very reactive in electron transfer as well as addition and hydrogen abstraction reactions.
