A novel approach in revealing mechanisms and particular step predictors of pH dependent tartrazine catalytic degradation in presence of Oxone®.

Autor: Popadić MG; University of Belgrade-Faculty of Chemistry, Studentski Trg 12-16, 11000, Belgrade, Serbia., Marinović SR; University of Belgrade-Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, Njegoševa 12, 11000, Belgrade, Serbia. Electronic address: sanja@nanosys.ihtm.bg.ac.rs., Mudrinić TM; University of Belgrade-Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, Njegoševa 12, 11000, Belgrade, Serbia., Milutinović-Nikolić AD; University of Belgrade-Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, Njegoševa 12, 11000, Belgrade, Serbia., Banković PT; University of Belgrade-Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, Njegoševa 12, 11000, Belgrade, Serbia., Đorđević IS; University of Belgrade-Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, Njegoševa 12, 11000, Belgrade, Serbia. Electronic address: ivana.djordjevic@ihtm.bg.ac.rs., Janjić GV; University of Belgrade-Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, Njegoševa 12, 11000, Belgrade, Serbia.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2021 Oct; Vol. 281, pp. 130806. Date of Electronic Publication: 2021 May 05.
DOI: 10.1016/j.chemosphere.2021.130806
Abstrakt: The degradation of tartrazine in the presence of cobalt activated Oxone® (potassium peroxymonosulfate) was investigated at different initial pH values. Aluminum pillared clay had the role of a support for catalytically active cobalt oxide species. The degradation of tartrazine and the formation of a mixture of degradation products were monitored using the Ultraviolet-Visible (UV-Vis) spectroscopy and gas chromatography-mass spectrometry (GC-MS). The exact qualitative composition of this mixture and the determination of the most probable mechanism of degradation (the primary goal) were obtained using GC-MS. Besides, the main reaction pathway (reaction with SO 4 ˙- radical anion) and secondary pathways were proposed depending on the pH value. At pH = 6 the reaction with HO˙ radical was proposed. At pH = 11 decarboxilation was suggested as the first step of the secondary proposed reaction pathway. The combination of results acquired from the deconvolution of UV-Vis spectra and the theoretical UV-Vis spectra of degradation products, whose occurrence was predicted by quantum-chemical calculations, was proven to be beneficial for the identification of tartrazine degradation products and for defining UV-Vis predictors of particular degradation steps. An additional contribution of this paper, from the reactivity aspect, was the establishment of the critical structural demand for the radical degradation of any diazo compound. The existence of a hydrogen atom bound to a diazo group was found to be the essential prerequisite for the radical cleavage of diazo compounds.
(Copyright © 2021 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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