Photolysis of a New Insecticide KH-502 [O,O-diethyl O-(1-phenyl-3- trifluoromethyl-5-pyrazolyn) thiophosphoric acid ester]

신규(新規) 살충제(殺蟲劑)인 KH-502 [O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester]의 광(光)에 의한 분해성(分解性)

Photolysis experiments were conducted to investigate the stability of a new insecticide, [O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester: KH-502] under the various conditions. In the photolysis experiment, KH-502 was, after being added into the acetone or acetonitrile solution, irradiated under the sunlight or UV lamp $(300{\sim}350nm)$, where acetone or acetonitrile solution was varied with water and $O_2$contents and was treated with humic acid, rosebengal or tryptophan. Results for stability and degradation pattern of KH-502 from the above experiment can be summarized as follows: 1. The significant difference in KH-502 decomposition due to photolysis was shown for between KH-502s irradiated at $300{\sim}350$ nm and non-irradiated. KH-502 was photolyzed in the acetone by the sensitizing effect, but was stable in the acetonitrile. 2. The degradation pattern of KH-502 in the photolysis was different as compared to that in the thermal decomposition, and the decomposed products were O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphoric acid ester (KH-502 oxo form), O,S-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphorothiolate(S-ethyl KH-502), 1-Phenyl-3-trifluoromethyl-5-hydroxy pyrazole (PTMHP) and several unknown compounds. 3. Treatments of acetone or acetonitrile solution with humic acid, rosebengal or tryptophan revealed no-sensitizing effect on the photolysis of KH-502. Dissolved oxygen in the acetone played as a cosensitizer with acetone competitively to enhance the photolysis of KH-502. 4. Treatments of acetone with humic acid or paddy soil water collected from fields decreased the photolysis of KH-502.

신규 살충제인 KH-502의 안전성을 조사하기 위하여 다양한 조건하에서 광(光) 분해(分解) 실험을 수행하였다. 이 실험에서 KH-502를 acetone 또는 acetonitrile 용액에 첨가한 뒤 태양광선 또는 자외선 $(300{\sim}350nm)$을 조사(照射)하였고, acetone 또는 acetonitrile 용액에는 수분함량, 산소함량이 달랐으며, 부식산,rosebengal 또는 tryptophan이 첨가 되었다. KH-502의 안전성 및 분해경향에 대한 결과를 요약하면 다음과 같다. 1. KH-502의 광분해(光分解)는 자외선을 조사(照射)한 경우와 그렇치 않은 경우에 매우 유의성있는 차이를 보여 주었다. KH-502는 acetone 용매에서 광관여효과에 의해 광분해(光分解)되었으나, acetonitrile 용매 하(下)에서는 광분해되지 않았다. 2. KH-502의 광분해 경향은 열 분해 경향과 판이하게 달랐으며, 광분해산물은 KH-502 oxo형, S-ethyl KH-502, PTMHP 및 몇가지 미지물질 등이었다. 3. acetone 또는 acetonitrile에 첨가된 부식산, rosebengal, tryptophan은 KH-502의 광분해에 광관여효과를 나타내지 않았다. acetone 용매의 용존산소는 acetone과 함께 경쟁적으로 광관여효과를 나타내어 KH-502의 분해를 촉진시켰다. 4. acetone 용매를 부식산 또는 논물로 처리했을때, KH-502의 광분해는 감소하였다.