Effect of bromide concentration on the induction period of the cerium-catalysed Belousov-Zhabotinsky oscillating reaction

Abstract

Temporal oscillations of the cerium(IV)-catalysed Belousov-Zhabotinsky reaction under addition of various Brconcentrations are investigated. The relationship between the induction period and Brconcentration, which is a controlling species in the BZ oscillating reaction, is reported. The oscillations of the Ce(IV) catalyst are followed by using UV-Vis spectrophotometric methods under closed batch and oxygen free systems. Experimental observations demonstrate that increasing Brconcentration decreases the induction period exponentially, whereas it increases the oscillation period linearly. The results reveal that the oscillations without induction period are observed by the addition of 1.0 × 10 −2 M Brconcentration. Addition of Brinto the BZ solution mainly involves the process A of the FKN mechanism. Numerical results reveal that the addition of Brincreases the production of BrMA, but decreases the induction period.

Self-Similar Patterns from Abiotic Decarboxylation Metabolism through Chemically Oscillating Reactions: A Prebiotic Model for the Origin of Life

“…Halogen compounds play a central role in oscillating reactions. Specifically, in the BZ reaction, the bromate anion is the key oxidizer compound [ 57 ], and the bromide ion acts as an important intermediate species, controlling the dynamics of the oscillations, including the length of the induction period [ 58 ]. Additional examples of the implication of halogen species acting as oxidants or reductants in COR include: (i) iodine, which is present in the first homogeneous isothermal chemical oscillator described, known as the Bray–Liebhafsky (BL) reaction [ 59 ]; (ii) chlorine oscillators [ 60 ], where chlorine compounds act as the oxidizer of the oscillating reaction; and (iii) reactions where both iodine and chlorine compounds are present, such as in the first systematically designed oscillating reaction, the so-called arsenite–iodate–chlorite system [ 61 ], and in the chlorate–iodine clock reactions [ 62 ].…”

An Alternative Spectrophotometric Determination of Carbaryl Insecticide Residues in Water Samples Using the Cerium-Catalyzed Belousov-Zhabotinsky Oscillating Reaction

“…In this work, the optimized BZ condition was employed based on previous report. 26 The BZ solution was consisted of 0.1 mol L -1 malonic acid, 0.03 mol L -1 sodium bromate, 4.0 × 10 -4 mol L -1 cerium(IV) sulfate tetrahydrate, and 1.0 mol L -1 sulfuric acid. The concentrations were fixed and used throughout the experiments since the oscillation dynamics of this oscillatory system was dependent on the reactant concentrations.…”

“…The average value of T u for the reaction condition without an addition of carbaryl was 85.7 ± 2.1 s. The deviation of two seconds is acceptable in the studied batch system. 26 Figure 1b presented an oscillation profile under the same BZ condition with an addition of 200 mg L -1 carbaryl. The perturbation point, where carbaryl was introduced into the system, was indicated by an arrow.…”

“…The BZ reaction was very sensitive to the change of bromide concentration as it was the bromide control system. [26][27][28] Bromine was another important compound, produced from the reaction between bromate and bromide in the process A. It was slowly reacted with malonic acid in enol form to generate bromomalonic acid, one of the most important products in the BZ reaction.…”

Coupled X-ray Absorption/UV-vis Monitoring of a Prototypical Oscillating Reaction

“…MA (70 mM), H 2 SO 4 (1.75 M), NaBrO 3 (70.2 mM), KBr (5.6 mM) and Ce­(NH 4 ) 4 (SO 4 ) 4 (34 mM) were mixed in aqueous solution at 25 °C in a reactor cell (see Figure S1). Such conditions were chosen to obtain relatively frequent oscillations while reducing the induction period, thus allowing us to collect good quality XAS spectra in a reasonable time interval. , Under these experimental conditions, periodic oscillations in the concentration of the Ce 4+ ion are established, as evidenced by the UV-vis kinetic trace at λ = 420 nm shown in Figure b. Inspection of the UV-vis spectra of the Ce 4+ and Ce 3+ sulfuric acid standard aqueous solutions (see Figures S2 and S3) indicates that the UV-vis absorbance at λ = 420 nm may be fully ascribed to the Ce 4+ species.…”