Temperature-Induced Bifurcations in the Cu(II)-Catalyzed and Catalyst-Free Hydrogen Peroxide-Thiosulfate Oscillating Reaction

Abstract

We study the oxidation dynamics of thiosulfate ions by hydrogen peroxide in the presence of trace amounts of copper(II) using the reaction temperature as a control parameter in a continuous flow stirred tank reactor. The system displays period-doubling, aperodic, and mixed-mode oscillations at different temperatures. We are able to simulate these complex dynamics with a model proposed by Kurin-Csorgei et al. The model suggests that the Cu(2+)-containing term is not essential for the observed oscillations. We find small-amplitude and high-frequency oscillations in the catalyst-free experimental system. The reaction between H(2)O(2) and S(2)O(3)(2-) contains the core mechanism of the H(2)O(2)-S(2)O(3)(2-)-Cu(2+) and H(2)O(2)-S(2)O(3)(2-)-SO(3)(2-) oscillatory systems, while the Cu(2+) and SO(3)(2-) modulate the feedback loops so as to strengthen the oscillatory dynamics.

The Key Heterolysis Selectivity of Divalent Sulfur–Sulfur Bonds for a Unified Mechanistic Scheme in the Thiosulfatolysis and Sulfitolysis of the Pentathionate Ion

“…A wide range of “exotic” kinetic phenomena can be displayed in thiosulfate oxidation reactions, and the detailed mechanisms of the reactions are so complicated that no successful attempt has been made to unravel the complete mechanism in the whole system range , . Pentathionate can be formed as an intermediate of the oxidation reaction of thiosulfate and in detectable amounts during kinetic studies of hydrogen peroxide–thiosulfate, chlorite–thiosulfate, and hypochlorous acid–thiosulfate systems.…”

Stern–Brocot trees in cascades of mixed-mode oscillations and canards in the extended Bonhoeffer–van der Pol and the FitzHugh–Nagumo models of excitable systems

“…Mixed-mode oscillation is a ubiquitous phenomenon studied profusely in experiments and models of prototypic dynamical systems in chemistry [1][2][3][4][5][6][7][8][9][10], physics [11][12][13][14][15], and neuroscience [16][17][18][19][20][21]. Mixed-mode oscillations (MMOs) are complex oscillatory patterns consisting of trains of small amplitude oscillations followed by large excursions of relaxation type.…”

On the Phase Shifts in the Dynamics of the H2O2–Na2S2O3–H2SO4–CuSO4 Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

“…As a consequence of these findings for the hydrogen peroxide–thiocyanate oscillator, we decided to investigate whether similar differences in the potentiometric responses occur also for other homogeneous oscillatory processes, especially for those which involve similar reactants. An example is the H 2 O 2 – S 2 O 3 2− – H + – Cu 2+ system, discovered by Orbán and Epstein and studied also later , including its recent interesting application as a driver for the ribozyme activity . This system also contains hydrogen peroxide as the oxidant for another sulfur‐containing compound and requires the catalytic copper(II)/copper(I) couple.…”