己唑醇的光化学降解

Photochemical Degradation of Hexaconazole

以低压汞灯为光源研究了己唑醇在溶液中的光化学降解。结果表明,在365nm紫外光照射下,己唑醇在正己烷中很稳定,说明己唑醇在自然光下难以降解;在254nm光照下己唑醇在丙酮、水、甲醇、乙酸乙酯、正己烷中发生光解,不同溶剂中的光解速率为:甲醇>正己烷>乙酸乙酯>水>丙酮。FeCl3、H2O2、FeCl3-H2O2、β-环糊精等光催化剂能加快己唑醇在紫外光下的降解,在本研究条件下,其催化能力为FeCl3-H2O2>β-环糊精>H2O2>FeCl3。对降解机理进行分析,认为己唑醇在溶液中是通过产生羟基自由基(HO·)而发生光解的。

Under low-pressure mercury lamps, a photochemical degradation study of hexaconazole was carried out. The results showed that hexaconazole decomposed rapidly when it was irradiated with 254 nm light, but the photodegradation was not observed with 365 nm light. Photochemical degradation rate of hexaconazole depends on different solvent. The order of photochemical degradation rate in different solvent is methanol>n-hexane>ethyl acetate>water>acetone. (Photocatalysts) such as FeCl_3, H_2O_2, β-cyclodextrin(β-CyD), FeCl_3-H_2O_2 can enhance photolysis of hexaconazole in aqueous solution. Under experimental conditions, FeCl_3-H_2O_2 is more sensitive than β-CyD, and further still than H_2O_2 and FeCl_3. From the experiments, it was assumed that mechanism of (photochemical) degradation of hexaconazole in aqueous solution is a photolysis by hydroxyl radical ((HO·)).