The thermolysis of di-tert-butyl and di-t-amyl peroxides in n-decane and with poly(methyl methacrylate) and poly(ethylene glycol) in chlorobenzene has been studied in the presence of tri-tert-butylnitrosobenzene as a spin trap. The major reaction pathways of the resulting t-alkoxyl radicals were β-scission and hydrogen atom abstraction. Thermolysis of the same peroxides in the presence of methyl methacrylate and methyl acrylate led to the trapping of growing polymer chains alongside unreacted alkyl radicals (again formed via β-scission of the first generation t-alkoxyl radicals). In some of the spectra, hyperfine coupling to γ-protons was observed. The hydrogen abstracting ability of radicals present during thermolysis of both peroxides has been compared in the presence of MA.

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The thermolysis of three bis(tert‐alkylperoxy)alkanes and two 1,1‐bis(tert‐alkylperoxy)cycloalkanes was undertaken at various temperatures between 333 and 383 K and the radicals generated trapped employing DMPO, DEPMPO, PBN‐d14 and TTBNB. The appropriate tert‐alkoxyl radical was trapped during the thermolysis of all five peroxides and underwent β‐scission to give the appropriate alkyl radical and ketone. Although the appropriate ‘sister’ O‐centred 1‐(tert‐alkylperoxy)alkoxyl radicals (3) were not trapped, adducts of the radicals derived from them via β‐scission were observed. The ethyl radical was trapped during the thermolysis of 2,2‐bis(tert‐butylperoxy)butane (1a) and the ethoxycarbonylmethyl radical during the thermolysis of both ethyl‐3,3‐bis(tert‐butylperoxy)butyrate (1b) and ethyl 3,3‐bis(tert‐amylperoxy)butyrate (1c), thus establishing the thermolysis scheme for these bis(tert‐alkylperoxy)alkanes. In the case of 1,1‐bis(tert‐butylperoxy)cyclohexane (2a) it has been established that the sister O‐centred [1‐(tert‐butylperoxy)cyclohexyl]oxyl radical (6a) undergoes a rapid ring‐opening reaction to give the 5‐(tert‐butylperoxycarbonyl)pentyl radical (7a). Copyright © 2000 John Wiley & Sons, Ltd.

EPR spin-trapping experiments have been employed to study the radicals present during the thermolysis of two peroxydicarbonates, bis(4-tert-butylcyclohexyl) peroxydicarbonate (3) and bis(2-ethylhexyl) peroxydicarbonate ( 4), and two monoperoxycarbonates, OO-tert-butyl O-(2-ethylhexyl) monoperoxycarbonate ( 5) and OO-tertbutyl O-isopropyl monoperoxycarbonate (6). The appropriate alkoxycarbonyloxyl radical is trapped during the thermolysis of each of the four peroxides and the tert-butoxyl radical during the thermolysis of 5 and 6. The trapping of a range of second generation carbon-centred radicals is also reported. Evidence is presented that some of these carbon-centred radicals are formed via a 1,5 C to O hydrogen shift whilst others are formed by hydrogen atom abstraction from the parent peroxide.