Abstract: The kinetics of oxidation of four hydroquinones and ascorbic acid by 1-phenyl-3- pyrazolidone radicals have been examined in aqueous solution from pH 6.5 to 9.5. For the hydroquinones, the kinetics are markedly autocatalytic unless sulfite is present in the solutions. The autocatalysis is apparently due to accumulation of a significant quantity of semiquinone formed via reproportionation of the quinone product with unreacted ...
