Photoreduction of the Chloropropionic Acid of Carfentrazone-Ethyl in Sodium Sulfide Crane Flat Meadow Solutions

Abstract

The purpose of this study was to determine whether the conversion of carfentrazone-chloropropionic acid to carfentrazone-propionic acid in sunlit rice paddies is attributed to photoreduction. Model solutions (Na2S with quinoids) irradiated by laboratory ultraviolet light dechlorinated carfentrazone-chloropropionic acid (1.6-28.4% yield of carfentrazone-propionic acid), though Na2S alone was also reactive. Minor conversion (0-2.5%) occurred in the dark, along with dehydrochlorination to carfentrazone-cinnamic acid. Carfentrazone-propionic acid formed proportionally to the Na2S concentration (0-50.7% at 1.3-91 mM), whereas acidic pH inhibited reactivity. Photoreduction with Na2S was verified with 2-chloropropionic acid conversion to propionic acid (53.5%) and by minor 4-chlorophenoxyacetic acid dechlorination. Dissolved Na2S was the primary photoreductant, whereas reduced quinones degraded carfentrazone-chloropropionic acid by an alternate reaction. A survey of ambient rice field conditions indicates that carfentrazone-chloropropionic acid photoreduction is not directly attributed to H2S/HS- in this environment, though reduced quinones may be involved to an unknown extent.

Enhanced Photoreduction of Nitro-aromatic Compounds by Hydrated Electrons Derived from Indole on Natural Montmorillonite

“…Few prior studies have investigated the photodegradation process for some chloroaromatic and nitro-group containing pesticides, e.g. carfentrazone-chloropropionic acid 14 and nitrofen 15 in sunlit rice paddies. Further research is needed to elucidate other possible photodegradation pathways for organic contaminants, especially NACs under anaerobic conditions.…”

A Kinetic and Mechanismic Study of Plasma-Induced Degradation of Monochloropropionic Acids in Water by Means of Anodic Contact Glow Discharge Electrolysis

“…Recently, the attraction has also been devoted to the other CACAs, which have more carbon atoms in the carbon chain. The decomposition of them has been done by bioprocesses [21,22]; the decompositions kinetics of 2-MCPA and 3-MCPA have also been investigated [23], while few researches by AOPs have been reported yet [24].…”