7313-54-4Relevant articles and documents
Biomimetic simazine oxidation catalyzed by metalloporphyrins
Santos, Joicy Santamalvina Dos,Palaretti, Vinícius,Faria, André Luiz De,Crevelin, Eduardo José,Moraes, Luiz Alberto Beraldo De,Assis, Marilda Das Dores
scheme or table, p. 163 - 170 (2012/05/04)
The metalloporphyrin-mediated simazine oxidation was investigated, in order to evaluate whether metalloporphyrins were good biomimetic models for the oxidation of this herbicide. The commercially available second-generation metalloporphyrins: 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin metal(III) chloride, [M(TDCPP)]Cl; 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin metal(III) chloride, [M(TFPP)]Cl; and 5,10,15,20-tetrakis(N-methyl-4-pyridyl) porphyrin metal(III) chloride, [M(TMPyP)]Cl5 (metal = Fe or Mn), and the oxidants iodosylbenzene (PhIO), hydrogen peroxide, and 3-chloroperoxy benzoic acid (m-CPBA) were employed in this study. Results demonstrated that these metalloporphyrins can mimic both the in vivo and in vitro action of cytochrome P450 for simazine oxidation, with formation of the dechlorinated metabolites OEET and OEAT mainly, as well as production of two other unknown compounds, identified by HPLC/mass spectrometry as ODET and ODDT. Among the systems, [Fe(TDCPP)]Cl/m-CPBA was the most efficient for simazine oxidation, giving up to 49% total conversion. Although hydrogen peroxide did not afford the best results (about 14% simazine conversion), it can be considered the most efficient oxidant from the point of view of toxicity, because it leads to less toxic products, namely OAAT and OEAT. The effect of some reaction conditions was investigated, and product evolution as a function of time was also monitored. Based on these results, simplified reaction mechanisms have been proposed.
Atrazine photolysis: Mechanistic investigations of direct and nitrate- mediated hydroxy radical processes and the influence of dissolved organic carbon from the Chesapeake Bay
Torrents, Alba,Anderson, Brent G.,Bilboulian, Susanna,Johnson, W. Edward,Hapeman, Cathleen J.
, p. 1476 - 1482 (2007/10/03)
Direct and nitrate-mediated hydroxy radical photoprocesses were examined with respect to atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) transformation. Irradiation (λ > 290 nm) of aqueous solutions of atrazine in the presence of nitrate, which generates ·OH, yielded 20% of 6-amino-2- chloro-4-isopropylamino-s-triazine (CIAT), 10% of 6-amino-2-chloro-4- ethylamino-s-triazine (CEAT), 6% of 4-acetamide-2-chloro-6-isopropylamino-s- triazine (CDIT), 3% of 4-acetamide-2-chloro-6-ethylamino-s-triazine (CDET), 16% of chlorodiamino-s-triazine (CAAT), and 3% of hydroxy atrazine (OIET, 4- ethylamino-6-isopropylamino-2-hydroxy-s-triazine) at 87% atrazine conversion. Direct photolysis of atrazine was much slower and at 23% atrazine conversion gave rise to 14% OIET and ca. 9% of chloroalkyloxidized or chlorodealkylated compounds with the ratio of the reaction rate constants equal to 0.14 (κ(direct)/κ(indirect)). Results also suggest that DIET was not the product of a hydroxy radical process. The efficiency of the hydroxy radical process decreased more than 85%, with increasing DOC obtained from the surface layer of the Chesapeake Bay. However, only a slight decrease (15%) in efficiency was observed for direct photolysis, suggesting that in the presence of surface layer DOC direct photolysis may become more important relative to the ·OH processes.
