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

Jędrusiak, Mikołaj; Matyszczak, Grzegorz; Orlik, Marek

doi:10.1002/kin.21071

Cited by 2 publications

(1 citation statement)

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“…As a starting point we used the model of the H 2 O 2 -S 2 O 2− 3 -Cu(II) flow system published by Jedrusiak et al (2017) recently, which an extended version of the original mechanism proposed by Kurin-Csörgei et al (1996). This model consists of 8 reactions and 9 variables (Table 1) which is capable of simulating not only the pH oscillations but the time evolution of the concentration of the copper(II) and copper(I) species in the form of thiosulfate complexes.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Chemical Oscillations With Sodium Perborate as Oxidant

et al. 2020

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The peroxo compounds H 2 O 2 and K 2 S 2 O 8 represent one of the major constituents in many oscillatory chemical systems. In this contribution we demonstrate that beside H 2 O 2 and S 2 O 8 2− the sodium perborate (NaBO 3 •H 2 O) can act as alternative oxidizing agent in oscillatory reactions. So far the H 2 O 2 has been successfully substituted with NaBO 3 in two oscillators: in the BO − 3-S 2 O 3 2−-Cu(II) flow system potential and pH oscillations, in the strongly alkaline Cu(II)-catalyzed BO − 3-SCN − batch reaction, which are rather different in their chemistry and dynamics, potential oscillations were observed. In spite of the significant differences in the oxidizing nature of H 2 O 2 and NaBO 3 we assume that the oscillatory cycle in the BO − 3-substrate and in the H 2 O 2-substrate systems is similar in many aspects, therefore the numbers of this new subgroup of the oscillators may be considered to be borate-mediated H 2 O 2 oscillators. Mechanisms are suggested and simulations are shown to describe the oscillatory behaviors observed in the perborate chemistry based oscillators by using the assumption that the oxidation reactions of the intermediates (HO) 3 B(OOH) − and (HO) 2 B(OOH) − 2 anions, which are dominant species in alkaline and neutral pH solutions of perborate, are much faster than that of H 2 O 2 .

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Section: Numerical Simulationsmentioning

confidence: 99%

Chemical Oscillations With Sodium Perborate as Oxidant

et al. 2020

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The Boundary between Two Modes of Gas Evolution: Oscillatory (H2 and O2) and Conventional Redox (O2 Only), in the Hydrocarbon/H2O2/Cu(II)/CH3CN System

Shchapin

Nekhaev

2023

Hydrogen

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During the oxidation of hydrocarbons using hydrogen peroxide solutions, the evolution of gaseous oxygen is a side and undesirable process, in which the consumption of the oxidizer is not associated with the formation of target products. Therefore, no attention is paid to the systematic study of the chemical composition of the gas and the mechanisms of its formation. Filling this gap, the authors discovered a number of new, previously unidentified, interesting facts concerning both gas evolution and the oxidation of hydrocarbons. In a 33% H2O2/Cu2Cl4·2DMG/CH3CN system, where DMG is dimethylglyoxime (Butane-2,3-dione dioxime), and is at 50 °C, evidence of significant evolution of gaseous hydrogen, along with the evolution of gaseous oxygen was found. In the authors’ opinion, which requires additional verification, the ratio of gaseous hydrogen and oxygen in the discussed catalytic system can reach up to 1:1. The conditions in which only gaseous oxygen is formed are selected. Using a number of oxidizable hydrocarbons with the first adiabatic ionization potentials (AIPs) of a wide range of values, it was found that the first stage of such a process of evolving only gaseous oxygen was the single electron transfer from hydrogen peroxide molecules to trinuclear copper clusters with the formation, respectively, of hydrogen peroxide radical cations H2O2•+ and radical anions Cu3Cl5•− (AIP = 5 eV). When the conditions for the implementation of such a single electron transfer mechanism are exhausted, the channel of decomposition of hydrogen peroxide molecules into gaseous hydrogen and oxygen is switched on, which is accompanied by the transition of the system to an oscillatory mode of gas evolution. In some cases, the formation of additional amounts of gaseous products is provided by the catalytically activated decomposition of water molecules into hydrogen and oxygen after the complete consumption of hydrogen peroxide molecules in the reaction of gaseous oxygen evolution. The adiabatic electron affinity of various forms of copper molecules involved in chemical processes is calculated by the density functional theory method.

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

Cited by 2 publications

References 14 publications

Chemical Oscillations With Sodium Perborate as Oxidant

Chemical Oscillations With Sodium Perborate as Oxidant

The Boundary between Two Modes of Gas Evolution: Oscillatory (H2 and O2) and Conventional Redox (O2 Only), in the Hydrocarbon/H2O2/Cu(II)/CH3CN System

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