The Reduction of 2,6-Dimethoxy-4-chloro-1,3,5-triazine on Mercury Electrodes in Aqueous Solutions in Relation with the Reduction of s-Triazine Herbicides

This paper presents polarographic and voltammetric studies on the electroreduction of 2,6-dimethoxy-4-chloro-1,3,5-triazine on mercury electrodes in aqueous solutions and in the acidity range 2 M H2SO4 to pH 7. Above pH 6.5 no signals were obtained. In both DC and DP polarography and voltammetry, one or two partially overlapped reduction waves were observed, depending on the pH of the medium. The overall process corresponded to a four-electron irreversible reduction. In strongly acidic media (pH<4.5) the protonated reactant was reduced through a two-electron process to give a dechlorinated molecule that is subsequentely reduced at the potentials of the second wave. It was concluded that the reduction of the chlorinated s-triazine rings seems to occur through the reductive cleavage of the chlorine irrespective of the nature of the groups bonded to the ring in positions 2, 6.