Pulse radiolysis of alkanes: a time-resolved EPR study—part I. Alkyl radicals

摘要: Abstract Time-resolved EPR was applied to detect short-lived alkyl radicals in pulse radiolysis of liquid alkanes. Two problems were addressed: (i) the mechanism radical formation and (ii) chemically-induced spin polarization these radicals. The ratio yields penultimate interior n-alkanes at instant their generation found be ≈ 1.25 times greater than statistical quantity. This higher-than-statistical production indicates that proton transfer reaction involving excited cations must a prevailing route generation. relative hydrogen abstraction fragmentation for various branched alkanes are estimated. It is concluded occurs prior an precursor species. analysis spin-echo kinetics suggests gain emissive spur reactions. initial increases with shortening aliphatic chain. We suggest origin this ST − operating pairs atoms generated dissociation alkane molecules. also long-chain structure results much higher rate Heisenberg exchange recombination (up 30 times). That prominent steric effects or occurrence through-chain electron exchange. significance context cross-linking polyethylene paraffins discussed.