Systematic design of chemical oscillators. 45. Kinetics and mechanism of the oscillatory bromate-sulfite-ferrocyanide reaction

Abstract

The reaction of bromate, sulfite, and ferrocyanide ions in a continuous stirred tank reactor (CSTR) exhibits sustained oscillations at temperatures of 20, 30, and 40 O C . The oscillations, the behavior in a closed (batch) system, and the observed bistability in a CSTR are all in excellent agreement with simulations using a nine-step mechanism in which the reaction of BrO,-with Fe(CN)6& plays a key role. The relationship between the present system and the 'mixed Landolt" oscillator, in which bromate is replaced by iodate, is discussed. IntroductionWith the Belousov-Zhabotinskii (BZ) reaction serving as the prototype, bromate oscillators3 have played a dominant role in the study of chemical oscillation. They have provided a fruitful ground for mechanistic studies starting with the classic FieldKoros-Noyes (FKN) mechanism4 and have also served as prime examples of how, given a general mechanistic understanding of the parent system, one may generate new oscillators by well-chosen modifications of an existing oscillating r e a c t i~n .~Here we investigate the reaction of bromate, sulfite, and ferrocyanide ions. The present system is derived from the iodatesulfite-ferrocyanide oscillator recently discovered by Edblom, OrbBn, and Epstein (EOE)6 by replacing the iodate ion of that "mixed Landolt" reaction by bromate. As anticipated, we do indeed obtain oscillatory behavior in a continuous stirred tank reactor (CSTR), though that behavior differs from that of the iodate system in several unforeseen ways. We have also studied the mechanism for this system and find that it must depart significantly from that p r o p o~e d~.~ for the analogous iodate reaction

A Pendulum-Like Motion of Nanofiber Gel Actuator Synchronized with External Periodic pH Oscillation

“…In our experiment, the average diameter at the flow rate 2.0 mL/h (302 nm) was thicker than at 1.0 mL/h (233 nm). In order to drive the nanofibrous gel actuator synchronized with autonomous pH oscillation, we focused on the Landolt pH-oscillator, based on a bromated/ sulfite/ ferrocyanide reaction discovered by Edblom et al [20,21]. This reaction causes the autonomous cyclic pH changes with a wide range at room temperature.…”

Novel Self-Oscillating Polymer Actuators for Soft Robot

“…In our experiment, the average diameter at the flow rate 2.0 mL/h (302 nm) was thicker than at 1.0 mL/h (233 nm). In order to drive the nanofibrous gel actuator synchronized with autonomous pH oscillation, we focused on the Landolt pH-oscillator, based on a bromated/ sulfite/ ferrocyanide reaction discovered by Edblom et al [39,40]. This reaction causes the autonomous cyclic pH changes with a wide range at room temperature.…”

“…[21][22][23][24][25][26][27] The energy source of self-oscillating polymer systems is chemical energy like a living organism, that is, the polymer system cause the self-oscillation induced by the Belouzov-Zhabotinsky (BZ) reaction or the pH oscillating reaction. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] The Self-oscillating reactions have been widely studied for their relevance to nonlinear, chaotic dynamics and biological signals. In previous investigations, the self-oscillating behaviors of polymer systems induced by the Belousov-Zhabotinsky (BZ) or the pH oscillating reactions were realized.…”

Self‐oscillating pH‐responsive cryogels as possible candidates of soft materials for generating mechanical energy

“…Four feed solutions, namely KBrO 3 (0.065 M), K 4 Fe(CN) 6 .3H 2 O (0.02 M), Na 2 SO 3 (0.075 M), and H 2 SO 4 (0.01 M) were pumped into the reactor through four inlet tubes by means of a Heidolph Pumpdrive PD 5201 peristaltic pump. Note that the concentration of the reactants was taken as those given before, 9 which provided satisfactory pH oscillation under certain flow rates. Readings of pH were taken using a pH electrode placed close to the gel sample and they were collected using a PC.…”

“…4,7 Crook et al 8 used poly(methacrylic acid) (PMAAc) gel in a Landolt oscillating reaction system consisting of bromate, sulfite and ferrocyanide ions. 9 Although the actual mechanism of this bromate oscillation system is complicated, the overall reaction consists of two main steps: (i) the oxidation of sulfite by bromate and (ii) the oxidation of ferrocyanide by bromate, i.e., 8 …”