Electron spin resonance measurements of the termination rate constants for t-butyl radicals in solution

Abstract

The rate constants, 2k_t, for the mutual termination of t-butyl radicals in liquid isobutane and cyclopentane have been measured in the temperature range 170–330 K, by kinetic e.s.r. spectrometry. The results are in excellent agreement with values of 2k_t reported recently for termination in a series of n-alkanes. It is concluded that the termination reaction is completely diffusion-controlled in both solvents. The value of 2k_t(11 × 10⁹ dm³ mol^–1 s^–1) at 298 K is in good agreement with that derived from recent gas phase measurements (2k_t= 9 × 10⁹ dm³ mol^–1 s^–1) at the same temperature.