8 research outputs found
Oxidation of Tramadol by Ferrate: Kinetics, Identification of Oxidation Products, Transformation Pathways and Comparison to Ozone.
Kinetic and mechanistic investigations of the oxidation of tramadol by ferrate and ozone
A Framework to Evaluate the Impact of Armourstones on the Chemical Quality of Surface Water
Kinetic and Mechanistic Investigations of the Oxidation of Tramadol by Ferrate and Ozone
The kinetics and oxidation products (OPs) of tramadol (TRA), an opioid, were investigated for its oxidation with ferrate (Fe(VI)) and ozone (O<sub>3</sub>). The kinetics could be explained by the speciation of the tertiary amine moiety of TRA, with apparent second-order rate constants of 7.4 (±0.4) M<sup>–1</sup> s<sup>–1</sup> (Fe(VI)) and 4.2 (±0.3) × 10<sup>4</sup> M<sup>–1</sup> s<sup>–1</sup> (O<sub>3</sub>) at pH 8.0, respectively. In total, six OPs of TRA were identified for both oxidants using Qq-LIT-MS, LTQ-FT-MS, GC-MS, and moiety-specific chemical reactions. In excess of oxidants, these OPs can be further transformed to unidentified OPs. Kinetics and OP identification confirmed that the lone electron pair of the amine-N is the predominant site of oxidant attack. An oxygen transfer mechanism can explain the formation of <i>N</i>-oxide-TRA, while a one-electron transfer may result in the formation of N-centered radical cation intermediates, which could lead to the observed <i>N</i>-dealkylation, and to the identified formamide and aldehyde derivatives via several intermediate steps. The proposed radical intermediate mechanism is favored for Fe(VI) leading predominantly to <i>N</i>-desmethyl-TRA (ca. 40%), whereas the proposed oxygen transfer prevails for O<sub>3</sub> attack resulting in <i>N</i>-oxide-TRA as the main OP (ca. 90%)
Simultaneous heavy metal immobilization and antibiotics removal during synergetic treatment of sewage sludge and pig manure
Labile trace metal contribution of the runoff collector to a semi-urban river
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