| 2,4-滴异辛酯的水解及光解特性 |
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投稿时间：2018-09-03
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| 引用本文：张双,纪明山,谷祖敏,等.2,4-滴异辛酯的水解及光解特性[J].农药学学报,2019,21(1):125-130. |
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| 中文摘要:为明确2，4-滴异辛酯的环境行为规律，采用室内模拟试验方法，研究了2，4-滴异辛酯在不同温度、pH值、水体及初始浓度下的水解特性及其在不同pH值、水体、光源和初始浓度下的光解特性。结果表明：中性（pH = 7）条件下，初始质量浓度为5 mg/L的2，4-滴异辛酯在15、25 和35 ℃ 下的水解半衰期分别为346.6、231.0和173.3 h；25 ℃下，5 mg/L的2，4-滴异辛酯在pH值分别为4、7 和9 的缓冲溶液中的水解半衰期分别为77.0、231.0 和138.6 h；2，4-滴异辛酯在稻田水、自来水和河水中的水解速率高于其在蒸馏水中的水解速率，4 种条件下的半衰期分别为23.1、25.7、40.8 和63.0 h；初始质量浓度分别为1、3和5 mg/L的2，4-滴异辛酯在pH值为7的缓冲溶液中的水解半衰期分别为231.0、173.3和138.6 h。300 W汞灯照射下，2，4-滴异辛酯在酸性条件下的光解速率大于其在中性和碱性条件下，半衰期分别为49.5、77.0 和138.6 h；2，4-滴异辛酯在河水和稻田水中的光解速率高于其在自来水和蒸馏水中的光解速率，4 种条件下的半衰期分别为6.7、7.6、43.3 和46.2 h；2，4-滴异辛酯在不同光源下的光解速率依次为500 W汞灯 > 300 W汞灯 > 500 W氙灯；初始质量浓度分别为1、3和5 mg/L的2，4-滴异辛酯在pH值为7的缓冲溶液中的光解半衰期分别为63.0、43.3和40.8 h。2，4-滴异辛酯水解及光解的主要产物是2，4-滴，其降解机制主要是酯水解反应。研究结果可为2，4-滴异辛酯的合理使用及其环境风险评估提供参考。 |
| 中文关键词:2,4-滴异辛酯 水解 光解 环境行为 半衰期 风险评估 |
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| The hydrolytic and photolytic properties of 2,4-D isooctyl ester |
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| Abstract:In order to clarify the environmental behavior of 2,4-D isooctyl ester, the hydrolytic properties of 2,4-D isooctyl ester under different temperatures, pH values, types of water and initial concentrations, and its photolytic properties under different pH values, types of water, light sources and initial concentration were studied by the indoor simulation test method. The results showed that the hydrolysis half-lives of 2,4-D isooctyl ester with initial concentration of 5 mg/L were 346.6, 231.0 and 173.3 h at 15, 25 and 35 ℃, respectively, under neutral (pH 7) conditions. The hydrolysis half-lives of 2,4-D isooctyl ester in buffer solutions with pH values of 4, 7 and 9 were 77.0, 231.0 and 138.6 h, respectively, at 25 ℃. The hydrolysis rates of 2,4-D isooctyl ester in paddy water, tap water and river water were higher than that in the distilled water, the half-lives were 23.1, 25.7, 40.8 and 63.0 h, respectively. The hydrolysis half-lives of 2,4-D isooctyl ester with the initial concentration of 1, 3 and 5 mg/L in buffer solution with pH value of 7 were 231.0, 173.3 and 138.6 h, respectively. Under the irradiation of 300 W mercury lamp, the photolysis rates of 2,4-D isooctyl ester under the acidic condition was higher than that under the neutral and alkaline conditions, the half-lives were 49.5, 77.0 and 138.6 h, respectively. The photolysis rates of 2,4-D isooctyl ester in river water and paddy water were higher than that in tap water and distilled water, the half-lives were 6.7, 7.6, 43.3 and 46.2 h, respectively. The order of photolysis rates of 2,4-D isooctyl ester under different light sources were 500 W mercury lamp > 300 W mercury lamp > 500 W xenon lamp. The photolysis half-lives of 2,4-D isooctyl ester with initial concentration of 1, 3 and 5 mg/L in buffer solution with pH value of 7 were 63.0, 43.3 and 40.8 h, respectively. The main product of the hydrolysis and photolysis of 2,4-D isooctyl ester is 2,4-D. The main degradation mechanism is the hydrolysis of esters. The results can provide references for the rational use and environmental risk assessment of 2,4-D isooctyl ester. |
| Key words:2,4-D isooctyl ester hydrolysis photolysis environmental behavior half life risk assessment |
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