Conductimetric study of the kinetics of electrons in pulse irradiated n-hexane and cyclohexane at room temperature

Abstract

Measurements of the ion current following an electron pulse have given values of k_r/µ(where k_r is the ion recombination rate constant and µ the electron mobility) and Gµ(extrapolated to zero field) of 1.00(± 0.08)× 10^–6 V cm and 1.13(± 0.05)× 10^–2 cm² V^–1 respectively for n-hexane, and 0.91(± 0.07)× 10^–6 V cm and 5.0(± 0.3)× 10^–2 cm² V^–1 for cyclohexane. For n-hexane these and results obtained optically are consistent with k_r= 6(± 1)× 10¹³ dm³ mol^–1 s^–1, G= 0.13 and µ= 0.09 cm² V^–1 s^–1. Using µ= 0.35 cm² V^–1 for cyclohexane, k_r= 1.93(± 0.14)× 10¹⁴ dm³ mol^–1 s^–1. Rate constants for reaction of solutes with electrons in n-hexane have been measured which confirm those obtained optically. For electron reactions in cyclohexane k(e^–+ S)× 10^–11 dm³ mol^–1 s^–1 are 1.70, 43, 43, 33, 66, 90 and 3.5 when S is O₂, CO₂, CCl₄, Ph₂, diphenylanthracene, galvinoxyl and perfluoromethylcyclohexane respectively. The mobility of the electron in n-hexane + alcohol mixtures is found to be unaffected until the alcohol concentration approaches 30 mmol dm^–3 and at these low concentrations the electron reacts with the alcohol.