Photoreduction of the chloropropionic acid of carfentrazone-ethyl in sodium sulfide crane flat meadow solutions

Under flooded rice-field conditions, the herbicide, carfentrazone-ethyl, hydrolyzes rapidly to carfentrazone-chloropropionic acid. Results are presented from a laboratory study that examined whether the conversion was due to photoreduction. Results indicated that carfentrazone-chloropropionic acid dissipated with pseudo-first-order kinetics in irradiated sodium sulfide solutions. In the direct photolysis experiment, 2-chloropropionic acid was comparably stable to the dark control, and the difference from carfentrazone-chloropropionic acid was attributed to the absence of the aryltriazolinone chromophore. Benzoquinone also increased photoreduction when present in the Na sub(2)S solution.