Free radical conversion, hydrogen transfer

To explain the conversion of the Fe to Fe, investigators have postulated that the two hydrated ions are linked by a structured chain of water molecules. The assumption is that one of the electrons of the Fe valence shell enters the valence shell of an oxygen atom of a neighboring water molecule. The water molecule releases a hydrogen-free radical (one hydrogen atom and one electron), which is transferred from water molecule to water molecule until it reaches a water molecule close to Fe, at which point the electron is transferred to Fe, yielding Fe. ... 

In both light and high energy irradiation induced reactions, phenyl-thiol, 2-mercaptomesitylene, and their sulfides inhibit nonchain processes,201202 e.g., the light-induced conversion of benzophenone in 2-propanol to benzopinacol and acetone.99 217 The reaction converts compounds into radicals by removal or addition of hydrogen atoms. The sulfur compounds in rapid hydrogen transfer processes convert the free radicals to stable molecules and may do so repeatedly.46 46... 

Free radical promoted hydrosilation of olefins typically gives poorer conversions than are produed by hydrosilation mediated by metal catalysts. However, they are not subject to isomerization of the olefin, a side reaction that can be a nuisance in metal-catalyzed hydrosilations. This is due to the extremely efficient hydrogen atom transfer reaction from Si-H to carbon radicals and the resulting very short lifetimes of the latter. The generally accepted mechanism for these processes is illustrated in Scheme 1. 

An alternative mechanism was suggested by Oxley and coworkers. [59] They concluded that above 160°C the decomposition occurs by a free-radical mechanisms while an ionic mechanism is important below this temperature. The decomposition of ADN leads to nitrous oxide, nitric acid or nitrate and nitrogen gas. It was assumed that the first step in ADN decomposition is hydrogen transfer to form ammonia and dinitramic acid. Several proposed decomposition pathways for ADN decomposition that involve conversion of the dinitramide ion to N2O have been proposed but they await confirmation.[59]... 

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