Replacement of para-chlorine by nitrogen in 2,4,6-trichlorophenol: An ion-radical mechanism

CHED 855

Evan W. Miller, Faith E. Jacobsen, and Victor Heasley. Department of Chemistry, Point Loma Nazarene University, 3900 Lomaland Drive, San Diego, CA 92106
The reaction of dilute 2,4,6-trichlorophenol with excess mono- and dichloramine in aqueous conditions results in the replacement of the para- chlorine and the formation of the corresponding N-chloro-immine. Although the formation of 2,6-dichloro-1,4-benzoquinone-4-(N-chloro) imine has been reported previously, no mechanism has been proposed. Ammonia, a stronger base than either mono- or dichloramine, did not form the imine. This eliminates the possibility of a direct, nucleophilic attack by nitrogen. Studies involving the formation of indophenols suggest an ion-radical mechanism that allows for the displacement of para- substituted chlorine by nitrogen. Our studies show experimental similarities to indopenol formation. We discuss the reactions and mechanism in order to propose that the displacement of para- substituted chlorine by nitrogen proceeds by an ion-radical mechanism.