Photodegradation of atrazine, atraton and ametryne in aqueous solution with acetone as a photosensitiser

The use of acetone as a photosensitiser on the rate of photodegradation of atrazine, atraton and ametryne in diluted aqueous solutions increased degradation 3‐ to 11‐fold. The mechanism of the sensitised photoreaction was studied. The photochemical stability increased in the order methylthio‐<chloro‐.<methoxy‐l,3,5‐triazines. Sensitised photolysis of atrazine, ametryne and atraton yielded the analogous two de‐ N ‐alkyl‐ and the de‐ NN ′‐dialkyl‐ products as well as the corresponding hydroxy‐triazines; irradiation of ametryne also resulted in the formation of de(methylthio)‐1,3,5‐triazines. With the exception of de(methylthio)triazine formation, sensitised photodecomposition of these triazine herbicides yields no other breakdown products than those obtained by enzymatic and chemical reactions.