Descoberta de uma nova reação oscilante contendo clorato

Abstract

An oscillating reaction is a very special nonlinear dynamic behavior. One of the most studied is the oscillating reaction of Belousov-Zhabotinsky (BZ) based on the reaction with bromate (BrO3 -) in acid medium. Many oscillating reactions using bromate as an oxidizing species are known, both in flow and batch mode, but none containing chlorate (ClO3 -) as oxidant was known. Recently, the chlorate-iodine-nitrous acid clock reaction was found which indicate that this chemical system has a non-linear kinetic behavior, something that is necessary for the oscillating behavior. From the concentrations that produce the clock behavior, flux experiments involving the reagents (nitrite, iodine, iodide, chlorate and perchloric acid) were designed in a continuous stirred flow reactor (CSTR) inserted in a spectrophotometer and absorption measurement of light at a wavelength of 440 nm. The system was investigated using different initial concentrations for the reagents and different other reaction parameters in order to observe both oscillations and the bistability phenomenon. Finally, we observed the oscillatory behavior for a series of initial conditions of the system, but not the bistability phenomenon. The observed oscillations also have a frequency of 0.1 Hz, which is significantly higher than other known oscillating flux reactions. The discovery of this new oscillating reaction opens the possibility that a whole new family of oscillating chlorate-based reactions may exist.