Radiolysis methyl iodide

Thomas JK (1967) Pulse radiolysis of aqueous solutions of methyl iodide and methyl bromide. The reactions of iodine atoms and methyl radicals in water. J Phys Chem 71 1919-1925 Tsang W, Hampson RF (1986) Chemical kinetic data base for combustion chemistry, part I. Methane and related compounds. J Phys Chem Ref Data 15 1086-1279 UlanskiP, von Sonntag C (1999) The OFI-radical-induced chain reactions of methanol with hydrogen peroxide and with peroxodisulfate. J Chem Soc Perkin Trans 2 165-168 Ulanski P, Bothe E, Hildenbrand K, von Sonntag C, Rosiak JM (1997) The influence of repulsive electrostatic forces on the lifetimes of polyfacrylic acid) radicals in aqueous solution. Nukleonika 42 425-436... 

The effect of Linear Energy Transfer (let) on the radiolysis of methyl iodide has been studied by Sturm and Schwarz The increase of the yields of ethane, methane, hydrogen, ethylene and acetylene with let supports the view of Gillis et that these products are formed by diffusion-controlled reactions of radicals... 

The effect of the electron scavenger, CS2, is explained as due to preventing the neutralization of the cations in the system and subsequent reaction of in the state with cyclopropane or with the radiolytic products of the substrate. In the presence of CS2 the major product is methyl iodide similarly to the major product of Br found by De Jong and coworkers . However the analog to the main product in the case of I2 or O2 as scavenger, namely, n-propyl bromide was not found at all by De Jong and co workers. They found the second and third major products to be allyl bromide and cyclopropyl bromide while Certout and Schleifer did not find the respective iodides at all. It is not clear if this is due to the difference between Br and I or due to the different amount of radiolysis induced by each of them. 

The irradiation of alkyl halides results in cleavage of the carbon-halogen bond. The radiolysis of methyl iodide, for example, yields ethane and molecular iodine. 

At the normal dose rates used in radiolysis this abstraction reaction is not quantitative (37) owing to competing radical-radical reactions, so that the methane produced is not a true measure of the radical yield. For example, for methyl chloride solutions the methane observed in the absence of radical scavengers is only 75% of the methyl radical detected with iodine. For methyl iodide the methyl iodide is itself a radical scavenger... 

Reactions of radicals which cannot be interfered with present another possible difficulty. For example the radiolysis of methyl iodide solutions produces appreciable methane which cannot be scavenged by iodine despite the fact that the thermal methyl radicals present readily react with the iodine (20,65). At 0.1 M CH3I a G(CH4)unBCaveiigeabie = 0-6 is observed (65). This could be produced by the abstraction of hydrogen by hot methyl radicals or, as suggested by Hamill (53) and by Holroyd (26), more likely by a diffusion-controlled recombination of the products of Reaction 9. 

Steady-state pulse radiolysis of methylene chloride solutions containing ferric deute-roporphyrin or the chemical reduction of ferric deuteroporphyrin solutions containing methyl iodide led to iron methyl o-bonded species which were spectrophotometrically characterized ... 

Habersbergerova, A., Sistek, I. Radiolysis of methyl iodide in aerated borate spray solution. Radiat. Phys. Chem. 19, 409-413 (1982)... 

Paquette, J., Ford, B. L. The radiation-induced formation of iodoalkanes and the radiolysis of iodomethane. Proc. 2. CSNI Workshop on Iodine Chemistry in Reactor Safety, Toronto, Can., 1988 Report AECL-9923 (1989), p. 48-73 Paquette, J., Sunder, S., Torgerson, D. F., Wren, C. J., Wren, D. J. The chemistry of iodine and cesium under reactor accident conditions. Proc. 3. BNES Conf. Water Chemistry in Nuclear Reactor Systems, Bournemouth 1983, Vol. 1, p. 71—79 Parsly, L. F. Chemical and physical properties of methyl iodide and its occurrence under reactor accident conditions. Report ORNL-NSIC-82 (1971)... 

The value of Eox for BH 4 is not known, but the borohydride radical, BH4 has been characterized by e.s.r and UV spectroscopy in oxidations of the anion by hydroxyl or azide radicals under pulse-radiolysis conditions (Symons et al., 1983 Horii and Taniguchi, 1986). Most borohydride reductions seem to be straightforward hydride transfers, but stepwise processes occur in the reductions of aryl bromides or iodides under photochemical or di-t-biftyl peroxide initiation. Radical intermediates are shown by the formation of 3-methyl-2,3-dihydrobenzofuran in the reduction of o-allyloxyiodobenzene (Abeywickrama and Beckwith, 1986). 

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