Hydrolysis of the triazine herbicide, cyanazine

The hydrolysis of cyanazine Cyanazine is the proposed common name for the herbicide sold under the Shell registered trade name BLADEX. (2‐chloro‐4‐cyanoisopropylamino‐6‐ethylamino‐1,3,5‐triazine) has been studied using 14 C‐ring labelled compound over a temperature range of 25° to 75 °C and over a range of pH values from 1.5 to 12. The activation energies and the activation entropy changes during hydrolysis showed there was a different mechanism under acid and alkaline conditions. The only product identified after hydrolysis in acid solutions was 2‐hydroxy‐4‐carboxyisopropylamino‐6‐ethylamino‐1,3,5‐triazine. In alkaline solution the same hydroxy‐acid was the end‐product, but 2‐chloro‐4‐amidoisopropylamino‐6‐ethylamino‐1,3,5‐triazine was isolated as an intermediate. The variation of the specific rate constants with temperature for hydrolytic catalysis by H + , OH − was determined, thus enabling the hydrolytic half‐life of cyanazine to be calculated at any pH and temperature.