Surface Photochemistry of Pesticides: An Approach Using Diffuse Reflectance and Chromatography Techniques
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- 作者：José ; P. Da Silva and Luis F. Vieira Ferreira
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：May 15, 2004
- 年：2004
- 卷：38
- 期：10
- 页码：2849 - 2856
- 全文大小：165K
- 年卷期：v.38,no.10(May 15, 2004)
- ISSN：1520-5851
文摘
The photochemistry of pesticides triadimenol andtriadimefon was studied on cellulose and 
chars/beta2.gif" BORDER=0 ALIGN="middle">-cyclodextrin(chars/beta2.gif" BORDER=0 ALIGN="middle">-CD) in controlled and natural conditions, using diffusereflectance techniques and chromatographic analysis. Thephotochemistry of triadimenol occurs from the chlorophenoxyl moiety, while the photodegradation of triadimefon alsoinvolves the carbonyl group. The formation of 4-chlorophenoxyl radical is one of the major reaction pathways forboth pesticides and leads to 4-chlorophenol. Triadimenolalso undergoes photooxidation and dechlorination, leadingto triadimefon and dechlorinated triadimenol, respectively.The other main reaction process of triadimefon involveschars/alpha.gif" BORDER=0>-cleavage from the carbonyl group, leading to decarbonylated compounds. Triadimenol undergoes photodegradationat 254 nm but was found to be stable at 313 nm, whiletriadimefon degradates in both conditions. Both pesticidesundergo photochemical decomposition under solarradiation, being the initial degradation of rate per unitarea of triadimefon 1 order of magnitude higher than theobserved for triadimenol in both supports. The degradationrates of the pesticides were somewhat lower in chars/beta2.gif" BORDER=0 ALIGN="middle">-CDthan on cellulose. Photoproduct distribution of triadimenoland triadimefon is similar for the different irradiationconditions, indicating an intramolecular energy transferfrom the chlorophenoxyl moiety to the carbonyl group in thelatter pesticide.
chars/beta2.gif" BORDER=0 ALIGN="middle">-cyclodextrin(chars/beta2.gif" BORDER=0 ALIGN="middle">-CD) in controlled and natural conditions, using diffusereflectance techniques and chromatographic analysis. Thephotochemistry of triadimenol occurs from the chlorophenoxyl moiety, while the photodegradation of triadimefon alsoinvolves the carbonyl group. The formation of 4-chlorophenoxyl radical is one of the major reaction pathways forboth pesticides and leads to 4-chlorophenol. Triadimenolalso undergoes photooxidation and dechlorination, leadingto triadimefon and dechlorinated triadimenol, respectively.The other main reaction process of triadimefon involveschars/alpha.gif" BORDER=0>-cleavage from the carbonyl group, leading to decarbonylated compounds. Triadimenol undergoes photodegradationat 254 nm but was found to be stable at 313 nm, whiletriadimefon degradates in both conditions. Both pesticidesundergo photochemical decomposition under solarradiation, being the initial degradation of rate per unitarea of triadimefon 1 order of magnitude higher than theobserved for triadimenol in both supports. The degradationrates of the pesticides were somewhat lower in chars/beta2.gif" BORDER=0 ALIGN="middle">-CDthan on cellulose. Photoproduct distribution of triadimenoland triadimefon is similar for the different irradiationconditions, indicating an intramolecular energy transferfrom the chlorophenoxyl moiety to the carbonyl group in thelatter pesticide.