Photodegradation Rate and Products of Acetochlor in Aqueous Solution

Photodegradation of acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphe myl) acetamide] was carried out in water and water-H₂O₂ solution under high pressure mercery lamp(HPML) or sunlight illuminating. The result shown that the photodegradation of acetochlor followed the first-order kinetics. The photolysis rate constants were 1.04 times 10^-1 min^-1 by HPML illuminating and 1.93 times 10^-2 h^-1 under sunlight illuminating, respectively. H₂O₂ increased the photodegradation rate of acetochlor in water solution. At least 12 photodegradation products of acetochlor were found by GC-MS analyses. Among them, three components, namely 8-methyl-1 -methoxymethyl-4-methyl-2-oxo-1,2,3,4-tet rahydroquinone( I ), 2 - methyl - 6 - N - methoxyethyl - N - oxacycloethylene - aniline( II), N- chloroacetyl - 7 - ethyl - 2, 3 - dihydroindole(III), were identified by TLC and GC-MS.