Abstract
A wide range of inorganic substrates undergo autocatalytic oxidation by moderately concentrated (1-4 M) nitric acid. In addition to behaving as clock reactions in closed (batch) systems, several of these oxidations exhibit bistability in open continuous-flow stirred tank reactor (CSTR) systems and wave propagation in unstirred configurations. Analysis of experimental studies, combined with detailed numerical simulation, suggests several mechanistic features which are common to nitric acid oxidations. The mechanistic scheme also affords insight into why nitric acid oxidations, in contrast to many other autocatalytic reactions, have defied efforts to convert them into chemical oscillators.