| Title | PROMETRYNE OXIDATION BY SODIUM-HYPOCHLORITE ITS AQUEOUS-SOLUTION - KINETICS AND MECHANISM |
| Abstract | The reaction of the herbicide prometryne (C9H16N5-S-CH3) with sodium hypochlorite has been investigated from the kinetic and mechanistic stand point. Under the fixed experimental conditions: pH = 7, T = 25 degrees C, [NaClO]/[substrate] = (10(-3) M)/(10(-5) M), prometryne oxidation takes place according to the following pathway: R-S-CH3 (P) --> R-SO-CH3 (a) --> R-SO2-CH3 (b) --> R-O-SO2-CH3 (x) --> R-OH (c), where R stands for C9H16N5, i.e., the substituted triazine ring of prometryne and (x) is an unexpected intermediate never previously detected nor identified. After having synthesized the pure intermediates (a), (b), and (x), the values of the pseudo-first-order kinetic constants of the first three steps were experimentally obtained: [k(1) = (0.64 +/- 0.03) s(-1), k(2) = (1.81 +/- 0.05) x 10(-3) S-1 k(3) = (1.50 +/- 0.03) x 10(-4) s(-1)]. As for k(4), its value [(2.5 +/- 0.2) x 10(-5) s(-1)] has been calculated indirectly on the basis of the kinetic theory concerning consecutive reactions. All the steps were pseudo-first-order reactions with respect to their specific substrate. The effect of pH on the hydrolysis of (b) [(b) --> (c)], in the absence of NaClO, has been also assessed to better elucidate the mechanism of the overall pathway. |
| Source | Environmental science & technology 29 (12), pp. 2987–2991 |
| Journal | Environmental science & technology |
| Editor | American Chemical Society,, Easton, Pa., Stati Uniti d'America |
| Year | 1995 |
| Type | Articolo in rivista |
| DOI | 10.1021/es00012a015 |
| Authors | MASCOLO, G; LOPEZ, Z; FOLDENYI, R; PASSINO, R; TIRAVANTI, G |
| Text | 323853 1995 10.1021/es00012a015 ISI Web of Science WOS A1995TJ35400031 PROMETRYNE OXIDATION BY SODIUM HYPOCHLORITE ITS AQUEOUS SOLUTION KINETICS AND MECHANISM MASCOLO, G; LOPEZ, Z; FOLDENYI, R; PASSINO, R; TIRAVANTI, G Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche Via E De Blasio 5, 70123 Bari; Department of Chemical Technology, University of Veszprh, H 8201; Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche 00198 Roma, Via Reno 1, Italy The reaction of the herbicide prometryne C9H16N5 S CH3 with sodium hypochlorite has been investigated from the kinetic and mechanistic stand point. Under the fixed experimental conditions pH = 7, T = 25 degrees C, NaClO / substrate = 10 3 M / 10 5 M , prometryne oxidation takes place according to the following pathway R S CH3 P > R SO CH3 a > R SO2 CH3 b > R O SO2 CH3 x > R OH c , where R stands for C9H16N5, i.e., the substituted triazine ring of prometryne and x is an unexpected intermediate never previously detected nor identified. After having synthesized the pure intermediates a , b , and x , the values of the pseudo first order kinetic constants of the first three steps were experimentally obtained k 1 = 0.64 / 0.03 s 1 , k 2 = 1.81 / 0.05 x 10 3 S 1 k 3 = 1.50 / 0.03 x 10 4 s 1 . As for k 4 , its value 2.5 / 0.2 x 10 5 s 1 has been calculated indirectly on the basis of the kinetic theory concerning consecutive reactions. All the steps were pseudo first order reactions with respect to their specific substrate. The effect of pH on the hydrolysis of b b > c , in the absence of NaClO, has been also assessed to better elucidate the mechanism of the overall pathway. 29 PROMETRYNE OXIDATION BY SODIUM HYPOCHLORITE ITS AQUEOUS SOLUTION KINETICS AND MECHANISM 22.pdf Articolo in rivista American Chemical Society, 0013 936X Environmental science technology Environmental science technology Environ. sci. technol. Environmental science technology. ES T Environmental science and technology antonio.lopez LOPEZ ANTONIO giuseppe.mascolo MASCOLO GIUSEPPE |
