Photolysis of Chlorothalonil in Benzene

Kawamura, Yōko; Takeda, Masayuki; Uchiyama, Mitsuru

doi:10.1584/jpestics.3.397

Cited by 7 publications

(7 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar values were reported for polychlorobenzenes in cyclohexane. 31 Moreover, we demonstrated that there is also an efficient energy transfer on oxygen with a singlet-oxygen quantum yield close to unity. Thus, most of CT triplet excited state is deactivated in aerated solution, explaining the low CT quantum yield of photodegradation (Φ deg = (2 ( 0.2) Â 10 À2 ).…”

Section: ' Results and Discussionmentioning

confidence: 99%

“…The photolysis of aryl chlorides has been widely studied because of their environmental significance, 32,33 and several paths for the reductive photodechlorination have been proposed. 30,31,34,35 The homolytic cleavage of the CÀCl bond may occur (path a, scheme 1). Alternatively, the reaction may be initiated by an electron transfer by a H-donor molecule followed by a proton transfer to form two radicals (path b, scheme 1).…”

Section: ' Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Photoreduction of Chlorothalonil Fungicide on Plant Leaf Models

Monadjemi

Roz

Richard

et al. 2011

Environ. Sci. Technol.

View full text Add to dashboard Cite

Photodegradation is seldom considered at the surface of vegetation after crop spraying. Chlorothalonil, a broad-spectrum foliar fungicide with a very widespread use worldwide, was considered. To represent the waxy upper layer of leaves, tests were performed within thin paraffin wax films or in n-heptane. Laser flash photolysis together with steady-state irradiation in n-heptane allowed the determination of the photodegradation mechanisms Chlorothalonil ability to produce singlet oxygen was measured; noteworthy its efficiency is close to 100%. Additionally, chlorothalonil photodegradation mainly proceeds through reductive dechlorination. In these hydrophobic media, a radical mechanism was evidenced. Photochemical tests on wax films under simulated solar light show that formulated chlorothalonil is more reactive than pure chlorothalonil. The field-extrapolated half-life of photolysis on vegetation was estimated to 5.3 days. This value was compared to the half-lives of penetration and volatilization available in the literature. It appears that chlorothalonil dissipation from crops is ruled by both photodegradation and penetration. The relative importance of the two paths probably depends on meteorological factors and on physicochemical characteristics of the crop leaf cuticle.

show abstract

Section: ' Results and Discussionmentioning

confidence: 99%

Section: ' Results and Discussionmentioning

confidence: 99%

Photoreduction of Chlorothalonil Fungicide on Plant Leaf Models

Monadjemi

Roz

Richard

et al. 2011

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Such an auto-accelerating effect was never mentioned in the literature except by Kawamura et al who irradiated CT in benzene. 7 The decay prole obtained by irradiating CT (2 Â 10 À5 M, acetonitrile-water, 20/80) in deoxygenated solution is shown in Fig. 1B.…”

Section: Steady-state Irradiationmentioning

confidence: 99%

“…[4][5][6] Photolysis in organic solvents or in a solid form is also very slow. 7,8 Interestingly, an auto-accelerated photodegradation was reported in benzene. 7 Concerning photoproducts, different types of reactions are reported.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Photoreactivity of the fungicide chlorothalonil in aqueous medium

Bouchama

Sainte-Claire

Arzoumanian

et al. 2014

Environ. Sci.: Processes Impacts

View full text Add to dashboard Cite

The photoreactivity of chlorothalonil was studied by means of steady-state irradiation and laser-flash photolysis. Experiments were conducted in water containing acetonitrile as a co-solvent. This fungicide undergoes very slow phototransformation in the first stages of the reaction, but the consumption profile is auto-accelerated. To understand the reaction mechanism, we undertook a detailed study of the rates, products and transient species. The rates and photoproduct distribution vary greatly with the oxygen concentration. Concerning the transient species, we measured the absorption of the triplet, its yield of formation, and its reactivity with oxygen in various water-acetonitrile mixtures and with isopropanol. The reduced radical, CTH˙, could be produced and its transient spectrum was recorded. Combining all the experimental data, it is hypothesized that in the first step of the reaction CT is excited to the triplet state. The triplet has several possible fates including reduction by organic constituents to form the radical which gives photoproducts. Another characteristic of the CT triplet is its capacity to generate singlet oxygen. The production of this species was measured by phosphorescence and compared to the percentage of the triplet trapped by oxygen in air-saturated solutions. The yield varies from 0.88 in pure acetonitrile to 0.48 in water-acetonitrile (95 : 5, v/v). Therefore, in surface waters, chlorothalonil is expected to sensitize the photooxidation of micropollutants, and to be competitively phototransformed through reaction with any H donor or electron donor water constituents.

show abstract

Fungicides, Multisite Inhibitors—Broad Spectrum Surface Protectants

Uesugi¹

2002

Encyclopedia of Agrochemicals

View full text Add to dashboard Cite

Chemicals first used in agriculture to control pant diseases were inorganic fungicides such as elemental sulfur, lime sulfur, and copper fungicides, including Bordeaux mixture. Those fungicides are primarily applied to cover the surface of the plants to protect them from various plant pathogens. They are, therefore, broad‐spectrum surface protectants and have been used since the nineteenth century. However, their use has been limited because of their lower level of effectiveness, risk of their toxicity to the plants, and lack of compatibility in use with other fungicides and insecticides.

show abstract

Photolysis of Chlorothalonil in Benzene

Cited by 7 publications

References 6 publications

Photoreduction of Chlorothalonil Fungicide on Plant Leaf Models

Photoreduction of Chlorothalonil Fungicide on Plant Leaf Models

Photoreactivity of the fungicide chlorothalonil in aqueous medium

Fungicides, Multisite Inhibitors—Broad Spectrum Surface Protectants

Contact Info

Product

Resources

About