Transformations of 4‐chloro‐<i>o</i>‐toluidine in soil: Generation of coupling products by one‐electron oxidation

Abstract

Abstract Four coupling products formed by one‐electron oxidation of 4‐chloro‐ o ‐toluidine were isolated from soil samples after 90 days of incubation with [ 14 C]chlordimeform (200 mg/kg). The metabolic compounds were identified as 4,4′‐dichloro‐2,2′‐dimethyl‐azobenzene, 4‐chloro‐6‐nitro‐ o ‐toluidine, N ‐(4‐chloro‐ o ‐tolyl)‐2‐methyl‐ p ‐benzoquin‐one monoimine and 2‐(4‐chloro‐ o ‐toluidino)‐ N ‐(4‐chloro‐o‐tolyl)‐6‐methyl‐ p ‐benzo‐quinone monoimine, respectively. Mechanisms of formation and possible significance of these substances as indicators for metabolic pathways to mineralisation of aniline derivatives are discussed. The chlordimeform soil concentrations (70–100 mg/kg) necessary for the formation of the azobenzene and the benzoquinone monoimines are at least 10 times higher than those occurring after actual field application.