Migration chemical induction

A quantitative description of the reactivity of monosubstituted benzenes to electrophilic substitution based on considerations of inductive effect parameters and con-jugative effect parameters from the 13 C chemical shifts of the aromatic compounds has been proposed.3 MO calculations on the proton migration in the ipso adducts formed in the reaction of CH3+ and SiH3+ with benzene have been described.4 With SiH3+ the ipso adduct is the most stable of possible isomers, whereas for CH3+ the >ara-protonated isomer is the most stable. 

Under normal conditions, oxidative reactions progress extremely slowly. Correspondingly, the associated oxidative stabiliser consumption is also slow. However, not only oxidation, but other chemical degradation processes can also destroy antioxidants. For example, phosphates and other antioxidants are hydrolysis-sensitive (Gugumus 1990). In addition to such chemical antioxidant depletion , there are physical depletion processes The concentration of the added antioxidants is reduced by extraction and migration processes while the plastic is stored and used (Pfahler and Lotzsch 1988). Such processes are usually the main cause of gradual loss of stabilisers at application temperatures. All these depletion processes determine induction time t 2 and thus service lifetime of the plastic. They... 

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