除草剤ベンチオカーブの光分解 Photodegradation of Benthiocarb Herbicide

^<14>C-標識および非標識化合物を用いて, 紫外線および太陽光線下でのベンチオカーブの光分解を研究した.水溶液中でベンチオカーブは紫外線により速やかに分解し, 比較した他の7種類の農薬より速やかに分解した.ベンチオカーブの分解生成物として, ベンチオカーブスルホキシド, デスエチルベンチオカーブ, 4-クロルベンジルアルコール, 4-クロルベンツアルデヒド, 4-ヒドロキシベンツアルデヒド, 4-クロル安息香酸のほか, 同定された化合物8種類および未同定の化合物約20種類が検出された.これらのうち, 4-クロルベンジルアルコールおよび4-クロルベンツアルデヒドが多量に生成した.太陽光線下でも水溶液中でベンチオカーブは速やかに分解し, そのさい検出された分解物の大部分は紫外線照射で生成した分解物と同じものであった.ガラス板上の薄層へ紫外線を照射した場合も, 水溶液と同様の分解物が生成した.

The photodegradation of benthiocarb (S-4-chlorobenzyl N, N-diethythiocarbamate) under ultraviolet lights or sunlight was investigated using ^<14>C-labelled and unlabelled compounds. Benthiocarb in the aqueous solution was more rapidly degraded by irradiation with ultraviolet lights than seven common pesticides tested. The irradiation resulted in the formation of many degradation products such as benthiocarb sulfoxide, desethyl benthiocarb, 4-chlorobenzyl alcohol, 4-chlorobenzaldehyde, 4-chlorobenzoic acid, 4-hydroxy analogues of the alcohol, the aldehyde and the acid, 8 other identified compounds and about 20 unidentified compounds. Among these, 4-chlorobenzaldehyde and the alcohol were the major products. The degradation in the aqueous solution under sunlight was also considerably rapid, and most of the degradation products detected were the same as those produced by irradiation with ultraviolet lights. The irradiation on the thin film of benthiocarb on glass plate also resulted in the formation of the same degradation products as those in the aqueous solution.