ELECTROCHEMICAL REDUCTION OF PROMETRYNE AND THE OTHER 2-METHYLTHIO-4,6-DIALKYLAMINO-S-TRIAZINE HERBICIDES AT MERCURY-ELECTRODES

The electrochemical behavior of the herbicide prometryne was studied i n aqueous solutions by DC polarography, differential pulse and cyclic voltammetry and by constant potential coulometry. Only the protonated form of prometryne can be reduced at pH < 6.5. The electrode process i ncludes two irreversible steps. The two-electron reduction of the C-S bond leads to its splitting and a release of methylthiol molecule. The triazine ring of the reduction product is immediately reduced under t he uptake of two electrons. Both the intermediate and final products o f constant potential electrolysis were identified using chromatographi c techniques and mass spectrometric analysis. The reduction mechanism of other 2-methylthio-4,6-dialkylamino-s-triazines is identical.