110-05-4Relevant articles and documents
Solvent effect on the rate of β-scission of the tert-butoxyl radical
Tsentalovich, Yuri P.,Kulik, Leonid V.,Gritsan, Nina P.,Yurkovskaya, Alexandra V.
, p. 7975 - 7980 (1998)
The transient absorption spectrum of the tert-butoxyl radical in the UV region was obtained by the laser flash photolysis technique. The rate constants for β-scission and self-termination reactions of tert-butoxyl radicals were measured in five solvents; the Arrhenius parameters of the rate constant for β-scission kβ were determined. It was shown that both the solvent polarity and ability for hydrogen bonding accelerate the reaction of β-scission. The solvent effect on the rate constant of the β-scission reaction is discussed in terms of a simple Onzager-Betcher model, a point dipole model, and a model of the H-bonded complex of the radical with the solvent molecule.
Autoxidation of Biological Molecules. 2. The Autoxidation of a Model Membrane. A Comparison of the Autoxidation of Egg Lecithin Phosphatidylcholine in Water and in Chlorobenzene
Barclay, L.R.C.,Ingold, K.U.
, p. 6478 - 6485 (1981)
The kinetics of autoxidation of egg lecithin phosphatidylcholine in homogeneous solution in chlorobenzene and as a bilayer dispersion in 0.1 M aqueous NaCl has been studied at 30 deg C under 760 torr of O2.The autoxidations were initiated by the thermal decomposition of di-tert-butyl hyponitrile.The efficiency of chain initiation, e, was determined by the induction period method using α-tocopherol as the chain-breaking antioxidant.In chlorobenzene e was ca. 0.66 but in the aqueous dispersion e was only ca. 0.091.The reduced efficiency of initiation in the bilayeris attributed to a reduction in the fraction of tert-butoxyls which escape from the solvent cage, and this in turn is due to the fact that the bilayer has a high microviscosity.The rate of autoxidation of the egg lecithin in chlorobenzene is proportional to the lecithin concentration and to the square root of the rate of chain initiation, and is virtually independent of the oxygen pressure, which means that this autoxidation follows the usual kinetic rate law.In the aqueous dispersion the concentration of egg lecithin in the bilayer cannot be altered, but since the rate of autoxidation is proportional to the square root of the rate of chain initiation and is virtually independent of the oxygen pressure, the usual kinetic rate law would also appear to be followed.The oxidizability of egg lecithin in chlorobenzene is 0.61 M-1/2 s-1/2, and in the aqueous dispension it is 0.0165 M-1/2 s-1/2.The reduction in oxidizability in the bilayer is attributed to the diffusion of the peroxyl radical center, which is a polar moiety, out of the autoxidizable, nonpolar, interior region of the bilayer and into the nonautoxidizable, polar surface region.As a consequence, chain progogation will be retarded and chain termination will be accelerated.
Interaction of 9-substituted anthracenes with oxidation systems tert-butylhydroperoxide-metal tert-butoxide
Stepovik,Malysheva,Fukin
, p. 1401 - 1411 (2015)
9-R-Anthracenes (R = Me, Ph) are effective acceptors of peroxyl and metalalkoxyl radicals in the systems tert-butylhydroperoxide-metal tert-butoxide (M = Al, V, Cr; C6H6, 20°C). Isolation of 9-R-9,10-dihydro-9,10-di-tert-butylperoxyanthracenes, 10-R-10-tert-butylperoxy-9-anthrones as major products reliably confirms the formation of tert-butylperoxy radicals and can be used for quantitative assessment of their content.
Titanium tetra-tert-butoxide-tert-butyl hydroperoxide oxidizing system: Physicochemical and chemical aspects
Stepovik,Gulenova,Martynova,Mar'Yasin,Cherkasov
, p. 266 - 276 (2008)
The reaction of titanium tetra-tert-butoxide with tert-butyl hydroperoxide (1: 2) (C6H6, 20 C) involves the steps of formation of the titanium-containing peroxide (t-BuO)3TiOOBu-t and peroxytrioxide (t-BuO)3TiOOOBu-t. The latter decomposes with the release of oxygen, often in the singlet form, and also homolytically with cleavage of both peroxy bonds. The corresponding alkoxy and peroxy radicals were identified by ESR using spin traps. The title system oxidizes organic substrates under mild conditions. Depending on the substrate structure, the active oxidant species can be titanium-containing peroxide, peroxytrioxide, and oxygen generated by the system.
Kinetic study of the reactions of tert-butyl radicals in the liquid phase in the presence and absence of oxygen
Costello, Andrew R.,Lindsay Smith, John R.,Stark, Moray S.,Waddington, David J.
, p. 3497 - 3507 (1996)
The photolyses of solutions of 2,2′-azoisobutane and 2,2,4,4-tetramethylpentan-3-one in decane in glass and metal cells, have been used to generate tert-butyl and, by reaction with oxygen, tert-butylperoxyl radicals. Time-dependent product yields from reactions in oxygenated and oxygen-free solutions have been measured over a range of temperatures (298-398 K). For each precursor, for a given set of conditions, the general features of the reactions are independent of the cell used, although the absolute rates of product formation are different. The major difference between the reactions of the two precursors lies in the initial photochemical step. For 2,2′-azoisobutane this leads directly to two tert-butyl radicals whereas the ketone gives a tert-butyl and a 2,2-dimethylpropanoyl radical. The product distributions can be accounted for in terms of the reactions of these radicals within a solvent cage in competition with cage escape and subsequent reaction. A single kinetic model that accounts for the reactions of both precursors, in the presence or absence of oxygen, at the temperatures studied, is described.
Induced decomposition of di(tert-butyl)trioxide
Khursan,Khalizov,Shereshovets
, p. 884 - 887 (1997)
Thermal decomposition of di(tert-butyl)trioxide (ButOOOBut) in a wide range of concentrations was studied by visible and IR chemiluminescence. Induced decomposition of ButOOOBut caused by its reaction with the peroxy radicals formed in the solvent (CH2Cl2) was found and investigated.
The role of onium salts in the oxidation of hydrocarbons by O2 catalysed by cationic phase-transfer reagents
Csanyi,Palinko,Rockenbauer,Jaky,Korecz
, p. 3801 - 3805 (2000)
Systematic investigations by Fukui et al. concluded that the oxidation of hydrocarbons (p-xylene, cumene, etc) can be accelerated not only by ammonium salts, but also by other onium salts, such as sulfonium, phosphonium, selenonium, arsonium, and the telluronium salts. An explanation for the long-observed fact that the catalytic activities of cationic phase transfer catalysts depend on the nature of the counteranions in the onium salts was presented. Such decomposition of the model substance tert-butyl hydroperoxide (t-BHP) results in O2, tert-butanol (90-95%), di-tert-butyl peroxide (5-10%), and traces of CO2. It was assumed that the interaction between hydroperoxide and onium cation was mainly electrostatic in nature and that its effectivity depended on the positive charge density on the onium cation, which was controlled by the nature and dimensions of the counteranion. The role of water in the decomposition of t-BHP was also revealed.
Recombination of Tertiary Butyl Peroxy Radicals. Part 1.-Products Yields between 298 and 373 K
Kirsch, Leslie J.,Parkes, David A.
, p. 293 - 308 (1981)
Overall product distributions resulting from the recombination of t-butyl peroxy radicals have been studied over the temperature range 298-373 K.The results indicate that over this range there is a switch from the terminating channels (forming alcohol and aldehyde/ketone) towards non-terminating channels (forming two alkoxy radicals) for the two further recombination processes that follow the initial combination of t-butyl peroxy radicals:.There is also direct evidence for the presence of a terminating channel to form di-t-butyl peroxide.This reaction proceeds at a rate of ca. 0.14 of the non-terminating recombination rate at 298 K, but this fraction falls to 0.025 at 333 K and the reaction is not evident at 373 K.Our results demonstrate the importance of abstraction reactions involving alkoxy radicals (t-butoxy and methoxy) and one of the principal recombination products, t-butyl hydroperoxide.Rate constant ratios involving these processes have been derived from the product distributions and from additional studies in which t-butyl hydroperoxide was added.Rate constants of ca. 10-13 cm3 molecule-1 s-1 for these abstraction processes are consistent with our results.
HETEROGENEOUS CATALYSIS IN THE LIQUID-PHASE OXIDATION OF OLEFINS. - 4. THE ACTIVITY OF A SUPPORTED VANADIUM OR CHROMIUM OXIDE CATALYST IN THE DECOMPOSITION OF t-BUTYL HYDROPEROXIDE.
Takehira,Hayakawa,Ishikawa
, p. 2103 - 2110 (1980)
The liquid-phase decomposition of t-butyl hydroperoxide (t-BuOOH) has been carried out in benzene under an N//2 atmosphere using a vanadium or chromium oxide, supported on gamma -Al//2O//3 or SiO//2 as the catalyst, for the purpose of clarifying the reaction mechanism of the cyclohexane oxidation. The decomposition of t-BuOOH on the supported oxide catalyst was a first-order reaction; the main products were t-butyl alcohol, di-ti-butyl peroxide, and acetone, suggesting that t-BuOOH is decomposed homolytically on the catalyst by the Haber-Weiss mechanism. The effect of the vanadium-chromium binary system formation was small, but the interaction between metal oxides and the supports appeared to be important in the t-BuOOH decomposition.
Kinetic Electron Paramagnetic Resonance Study of the Reactions of t-Butylperoxyl Radicals in Aqueous Solution
Bennett, John E.
, p. 3247 - 3252 (1990)
The kinetics of reactions of t-butylperoxyl radicals in aqueous solution have been measured using electron paramagnetic resonance, ultraviolet absorption spectroscopy and gas chromatography.The rate constants for the overall self-reaction, the separate terminating and non-terminating reactions are very similar to those observed in non-polar solvents and the gas phase.The t-butoxy radicals, formed by the non-terminating reaction, can either undergo scission, which leads to methylperoxyl radicals, or react with further t-butyl hydroperoxide to regenerate t-butylperoxy radicals.The cross-termination reaction between methylperoxyl and t-butylperoxyl radicals is an important route in the overall termination sequence.The propagation reaction occurs significantly only at high concentrations of t-butyl hydroperoxide, ( > 0.3 mol dm-3) and its rate constant is much lower than that in non-polar solutions.
