Abstract
The kinetics of oxidative degradation of two significant triazole antibiotics (A), viz. fluconazole (Flz) and voriconazole (Vcz), was examined using chromium (VI) oxide (CrVI) in sulfuric and perchloric acid environments. The oxidation reactions were followed spectrophotometrically at fixed ionic strength and at different temperatures. In both acidic environments, the oxidative degradations of the two examined antibiotics were acid-catalyzed. The kinetics of the oxidative degradations in both acids were first order concerning to [CrVI] and fractional-first orders with regard to [A] and [H+] during their alteration. The rates of oxidative reactions exhibited insignificant influences upon disparity of ionic strengths and dielectric constants of the reactions’ media. No intervention of free radicals was detected during the degradation reactions. Some activation methods like heat and addition of certain metal cations (Mg2+ & Ca2+) were also investigated. Under analogous experimental circumstances, the degradation rates in perchloric acid environment were slightly higher than those occurred in sulfuric acid one and the degradation rates of Flz were higher than those of Vcz. The believable oxidative degradation mechanism consistent with the kinetic outcomes was proposed. The derived rate-law expression was set to be in a good harmony with the acquired results. The activation and thermodynamic parameters were computed and discussed. This study announce a simple, safe and inexpensive promising procedure involving a double benefit for the environment and human health: degradation of Flz and Vcz drugs and transformation of the extremely toxic and carcinogenic CrVI oxide to a safe CrIII compound.