118364-97-9Relevant articles and documents
Thermal decomposition mechanisms of tert-alkyl peroxypivalates studied by the nitroxide radical trapping technique
Nakamura,Busfield,Jenkins,Rizzardo,Thang,Suyama
, p. 16 - 23 (2007/10/03)
The thermolysis of a series of tert-alkyl peroxypivalates 1 in cumene has been investigated by using the nitroxide radical-trapping technique. tert-Alkoxyl radicals generated from the thermolysis underwent the unimolecular reactions, β-scission, and 1,5-H shift, competing with hydrogen abstraction from cumene. The absolute rate constants for β-scission of tert- alkoxyl radicals, which vary over 4 orders of magnitude, indicate the vastly different behavior of alkoxyl radicals. However, the radical generation efficiencies of 1 varied only slightly, from 53 (R = Me) to 63% (R = Bu(t)), supporting a mechanism involving concerted two-bond scission within the solvent cage to generate the tert-butyl radical, CO2, and an alkoxyl radical. The thermolysis rate constants of tert-alkyl peroxypivalates 1 were influenced by both inductive and steric effects [Taft-Ingold equation, log(rel k(d)) = (0.97 ± 0.14)Σσ* - (0.31 ± 0.04)ΣE(s)(c), was obtained].
