J Environ Manage
December 2024
Manganese (II) ions (Mn(II)) catalyse the oxidative degradation of Calmagite (CAL, 2-hydroxy-1-(2-hydroxy-5methylphenylazo)-4-naphthalenesulfonic acid) at room temperature using added and in situ generated hydrogen peroxide (HO), using 1,2-dihydroxybenzene-3,5-disulfonate, disodium salt and monohydrate (Tiron) as the co-catalyst for the in situ generation of HO. The percentage of CAL degradation with the in situ generated HO was 91.1 % after 30 min which is lower than that in the added HO/Mn(II) system (96.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
April 2015
The asymmetric unit of the title complex, [NiBr(NO){P(C6H5)3}2], comprises two independent mol-ecules each with a similar configuration. The Ni(II) cation is coordinated by one bromide anion, one nitrosyl anion and two tri-phenyl-phosphane mol-ecules in a distorted BrNP2 tetra-hedral coordination geometry. The coordination of the nitrosyl group is non-linear, the Ni-N-O angles being 150.
View Article and Find Full Text PDFThe kinetics and mechanism for the bleaching of Calmagite (H3CAL, 3-hydroxy-4-(2-hydroxy-5-methylphenylazo)naphthalene-1-sulfonic acid) in aqueous solution at pH 8.00 and 23 ± 1 °C using in situ generated H2O2 is described. Complete mineralisation of H3CAL results with turnover frequencies (TOF = moles of H3CAL bleached per mole of manganese per hour) of 40 h(-1).
View Article and Find Full Text PDFNucleophilic aromatic substitution of tetrachloro-o-benzoquinone by pyridine and reduction of the o-quinone to the catechol by hydroxylamine forms 1,2-dihydroxy-3,5,6-trichlorobenzene-4-pyridinium chloride. This compound reacts with manganese(II) acetate in air to form chlorobis(3,5,6-trichlorobenzene 4-pyridinium catecholate)manganese(III), which represents the first complex of this ligand class to be structurally characterized by X-ray diffraction; this complex is active in the catalytic reduction of dioxygen to hydrogen peroxide under ambient conditions and turnover frequencies (TOFs) >10,000 h(-1) can be obtained.
View Article and Find Full Text PDFHydrogen peroxide (H(2)O(2)) generated from the manganese(II) catalysed reduction of dioxygen has been shown to efficiently oxidize Calmagite (3-hydroxy-4-(2-hydroxy-5-methylphenylazo)naphthalene-1-sulfonic acid) in aqueous solution at pH 8.0 and 20 +/- 1 degrees C with de-protonated Tiron (1,2-dihydroxybenzene-3,5-disulfonate, disodium salt) acting as an essential co-ligand.
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