EPR studies of the formation of alkene cations due to ion–molecule reactions in the 77 K radiolysis of pentane and hexane containing additives

Abstract

Radiolysis of the two systems, pentane containing 3 mol% octane, and hexane containing 3 mol% nonane, has been investigated at 77 K in the presence of 1 mol% alkenes, EPR studies of alk-2- and -3-ene additives show the formation of the corresponding alk-2- and -3-ene radical cations, whereas alk-1-enes with linear C—C chains are observed to give (E)-pent-2-ene radical cations in the pentane systems and (E)-hex-3-ene radical cations in the hexane systems. The effects of the alk-1-ene additives are attributed to the ion–molecule reaction, i.e.. transfer of H₂ from the parent n-alkane radical cations to the alk-1-ene additives to form the alkene radical cations of the parent molecules.