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Abstract

The photolysis of propicanazole in pure water, in water containing humic substances, and in natural water was investigated. The reaction rates were determined, and the main photoproducts were identified with the help of HPLC-mass spectrometry and by NMR. The quantum yield for direct photolysis was 0.11 ± 0.01 at the maximum of absorption (269 nm). Photocyclization after HCl-elimination and photohydrolysis of the cyclized intermediate were the main reaction pathways at 254 nm. By contrast, oxidation prevailed over dechlorination in simulated or natural solar light. Humic substances (10 mg L (E-1) and naturally occurring chromophores contained in natural water enhanced the rate of propicanazole photodegradation in solar light. Half-life in June in Clermont-Ferrand (latitude 46°N) was found to be 85 ± 10 h in pure water and 60 ± 10 h in natural water; showing that photodegradation of propicanazole in natural waters involves both direct photolysis and photoinduced reactions.

Additional information

Authors: VIALATON D ET AL, Ensemble Universitaire des Cezeaux, Aubiere (FR);LARSEN B, European Commission, Joint Research Centre, Ispra (IT)
Bibliographic Reference: An article published in: Journal of Agricultural and Food Chemistry Volume 49, Issue 11 (November 19, 2001), 5377-5382
Record Number: 200214355 / Last updated on: 2002-02-13
Category: PUBLICATION
Original language: en
Available languages: en