Pulse radiolysis study of the kinetics of electron reactions in liquid n-hexane at room temperature

Abstract

The behaviour of solvated electrons, e^–_s, produced by the pulse radiolysis of n-hexane at 20°C has been followed using optical absorption techniques. Rate constants for the reaction of e^–_s with naphthalene, biphenyl, galvinoxyl, chloroform, carbon tetrachloride, perfluoromethylcyclohexane, carbon dioxide, nitrous oxide and oxygen have been determined and are in the range 0.1–1.8 × 10¹² dm³ mol^–1 s^–1.

The rate constant, k_r, for the recombination of e^–_s with solvent cations has been redetermined. If G(e^–_s)= 0.13 then k_r= 7.1(± 0.8)× 10¹³ dm³ mol^–1 s^–1.

The changes in the absorption spectrum of e^–_s which occur on the addition of alcohols and water have been investigated and the variation in mobility of e^–_s which accompanies these changes have been measured by observing e^– reaction rates in the mixtures.

The mechanism of solvation by alcohol is discussed and it is concluded that it occurs by electron diffusion to already formed clusters of alcohol rather than by aggregation of alcohol around the electron.