EPR STUDIES OF THE FORMATION OF ALKENE CATIONS DUE TO ION-MOLECULE REACTIONS IN THE 77 K RADIOLYSIS OF PENTANE AND HEXANE CONTAINING ADDITIVES

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 H-2 from the parent n-alkane radical cations to the alk-1-ene additives to form the alkene radical cations of the parent molecules.