Photolysis of the herbicide dinitramine (N3,N3-diethyl-2,4-dinitro-6-trifluoromethyl-m-phenylenediamine)

Newsom, H.; Woods, William G.

doi:10.1021/jf60188a049

Cited by 18 publications

(15 citation statements)

References 2 publications

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“…The formation of F 4 could be well explained through the formation of an unstable intermediate (dihydroxybenzimidazoline) originated by cyclisation of F 1 , which was also reported by Newsom and Woods 11. The product F 4 was also reported as a photometabolite of fluchloralin2 and trifluralin 3…”

Section: Resultssupporting

confidence: 64%

Photolysis of fluchloralin in aqueous methanol

Saha¹,

Bhattacharyya²

2001

Pest Management Science

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The photodegradation of fluchloralin by UV irradiation or sunlight in aqueous methanolic solution has been examined. In the presence of titanium dioxide five photoproducts were obtained, but only four in its absence. One photoproduct, 2, 2'-azoxy-bis(alpha,alpha,alpha-trifluoro-6-nitro-p-toluidine) is reported for the first time as a metabolite of fluchloralin. In natural sunlight the rate of degradation was higher than in UV light and titanium dioxide had almost no effect on the rate of degradation.

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Section: Resultssupporting

confidence: 64%

Photolysis of fluchloralin in aqueous methanol

Saha¹,

Bhattacharyya²

2001

Pest Management Science

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“…The photodecomposition of pendimethalin involves mainly N-dealkylation and arylmethyl oxidation in addition to processes like nitro group reduction, nitro group elimination, and cyclization. It is suggested that photochemical N-dealkylation of 2,6-dinitroaniline herbicides proceeds via free-radical oxidation by atmospheric oxygen (Leitis and Crosby, 1971; Newsom and Woods, 1973;Plimmer and Klingebiel, 1974). Formation of compounds I11 and IV (Figure 1) was also observed when the methanol solution of I was photolyzed under a nitrogen atmosphere, suggesting homolytic fission of the nitrogen-carbon bond and abstraction of a hydrogen radical from the medium, leading to the formation of I11 and IV.…”

Section: Resultsmentioning

confidence: 99%

Photochemistry of pendimethalin

Pal¹,

Moza²,

Kettrup³

1991

J. Agric. Food Chem.

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Pendimethalin decomposed readily when irradiated in methanol a t wavelengths X 3 250 nm to form a number of products. In addition to the N-dealkylated intermediates, the principal products were 2-methyl-4,6-dinitro-5-[ (1-ethylpropyl)amino] benzaldehyde and 2-methyl-4,6-dinitro-5-[ (1-ethylpropy1)-amino] benzyl alcohol. The decomposition at sunlight wavelengths (A Z 290 nm) in methanol is relatively slower and also leads to N-dealkylation and arylmethyl oxidation. Neither acid nor alkali has an effect on the rate of disappearance of pendimethalin. At acidic p H N-dealkylation takes place, whereas at alkaline pH one of the NO2 groups is replaced by an OH group.Pendimethalin [N-( l-ethylpropyl)-2,6-dinitro-3,4-xylidine, I (Figure l)], a representative member of a growing list of N-substituted 2,6-dinitroanilines, is a selective herbicide that controls most annual grasses and certain broad-leaved weeds in cotton, soybean, and other crops.Soil persistence studies (Savage and Jordan, 1980) of this chemical indicated relatively rapid breakdown (half-life 4-6 days), while Walker and Bond (1977) reported a longer persistence in soil (half-life 72-172 days) with the persistence related to the moisture, temperature, and organic matter of the soil. Earlier studies (Parochetti and Dec, 1978) of the photodecomposition of I in soil exposed to sunlight showed much lower conversion (9.9% in 7 days) than other dinitroaniline herbicides previously studied (Leitis and Crosby, 1974). Recently, a number of photoproducts were identified when I was irradiated in methanol for 48 h (A = 300-400 nm). Photodecomposition was reported to involve oxidative dealkylation, nitro reduction, and cyclization (Dureja and Walia, 1989). A chemical present in the environment may undergo direct and indirect photochemical transformations. T h e latter may include photosensitized degradation, oxygenation, and photoinduced transformation. Earlier studies (Parochetti and Dec, 1978;Dureja and Walia, 1989) on the photodecomposition of I (A 3 300 nm) in solution and adsorbed on soil probably involve indirect photochemical processes. T o our knowledge, very little is known about the photochemistry of I at its maximum UV absorption (A < 250 nm). In the present work a comparative study of the photodecomposition of I under artificial sunlight exposure (A 3 290 and 250 nm) in an organic solvent (MeOH) is reported. In addition t o this, the effect of p H on the rate of degradation of I at X 3 290 nm is also examined. EXPERIMENTAL PROCEDURES Materials.Pendimethalin was obtained from Riedel-deHaen, FRG, and was purified by repeated crystallization from methanol, mp 56 O C (99% HPLC pure). 6-Nitro-3,4-xylidine (97% purity) was provided by Aldrich Chemical Co. and was used for comparison without purification. All the solvents used were of AR grade.Apparatus. The rate of disappearance of the pesticide was measured by a HPLC, Gibson-Abimed Model 302, equipped with a Shandon reverse-phase column (RP-18,25 X 0.4 cm) and a UV detector set at 240 nm; methanol was used as the ...

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“…A detailed mechanism for the formation of cyclic photoproducts from dinitramine, a dinitroaniline group of herbicide, has already been established. [26] Newsom, H.C.; Woods, W.G. Photolysis of herbicide dinitramine (N 3 , N 3 -diethyl-2,4dinitro-6-trifluromethyl-m-phenylenediamine).…”

Section: Display Full Sizementioning

confidence: 99%

Photodegradation of Oryzalin in aqueous isopropanol and acetonitrile

Pramanik

Joarder

Das

et al. 2016

Journal of Environmental Science and Health, Part B

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The phototransformation of Oryzalin was studied under UV light (λmax ≥ 290 nm) and sunlight (λmax ≥ 250 nm) in aqueous isopropanol and acetonitrile solution in absence and presence of TiO2 as sensitizer. The rate of photodegradation of Oryzalin in different solvent system followed first-order kinetics, and calculated half-lives were found to be in the range of 23.52-53.75 h for UV light and 41.23-61.43 h for sunlight. From this study, total 12 photoproducts were identified and characterized on the basis of column chromatography and Q-Tof micromass spectral data. The plausible mechanism of phototransformation involved was hydrolysis, breaking of sulfonic bond, and loss of amino and sulfonic acid group.

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Photolysis of the herbicide dinitramine (N3,N3-diethyl-2,4-dinitro-6-trifluoromethyl-m-phenylenediamine)

Cited by 18 publications

References 2 publications

Photolysis of fluchloralin in aqueous methanol

Photolysis of fluchloralin in aqueous methanol

Photochemistry of pendimethalin

Photodegradation of Oryzalin in aqueous isopropanol and acetonitrile

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