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New Experimental and Mechanistic Investigation on the KSCN‐H 2 O 2 ‐NaOH‐Cu(II)‐Catalyzed Oscillating System (Orbàn–Epstein Reaction): Inhibitory Effects by Diphenols
Author(s) -
Čupić Željko D.,
Greco Emanuela,
Cervellati Rinaldo
Publication year - 2015
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20894
Subject(s) - chemistry , briggs–rauscher reaction , arrhenius equation , hydroquinone , resorcinol , oscillation (cell signaling) , belousov–zhabotinsky reaction , activation energy , stoichiometry , catalysis , catechol , kinetics , thermodynamics , organic chemistry , physics , biochemistry , quantum mechanics
The KSCN‐H 2 O 2 ‐NaOH‐Cu(II)‐catalyzed system is one of the few reactions in which chemical oscillations can be observed in batch conditions. In the present paper, this oscillating reaction was revisited in a wide range of initial concentrations of all components in batch. A mixture with a long lasting oscillation time (1 h 34 min) and a great number of oscillations (24) was found and used to investigate the effect of temperature. An Arrhenius‐type temperature dependence was observed from which an apparent “average activation energy” E av = 76 ± 5 kJ for the overall oscillatory reaction was observed. A mechanistic study based on a modified model analyzed by the stoichiometric network analysis approach gave a satisfactory agreement between calculated and experimental oscillating behaviors and temperature dependence. The addition of the three diphenols (catechol, resorcinol, and hydroquinone) causes perturbations similar to those observed in the Briggs‐Rauscher oscillating system, i.e., an inhibition of the oscillatory regime. These inhibitory effects were described in detail, and a reasonable qualitative interpretation is given.