Kinetics of radical polymerization. XVIII. Inhibition of radical polymerization with quinones

The inhibitory effect of multiring quinones on the polymerization of styrene was examined. The logarithm of the relative reactivity of quinones also contains, besides a member which reflects the changes in the oxidation‐reduction potential, a member corresponding to the changes in resonance energy which accompany quinoid r̊ benzenoid structural transformation. The observation that the experimental values of the stoichiometric coefficient are generally much smaller than the theoretical ones can be interpreted by the aid of the hot‐radical hypothesis.