Hydrolysis and Photolysis of Herbicide Clomazone in Aqueous Solutions and Natural Water Under Abiotic Conditions

作     者：CAO Jia DIAO Xiao-ping HU Ji-ye 

作者机构：School of AgricultureHainan University School of Chemistry and Biological EngineeringUniversity of Science and Technology Beijing 

出 版 物：《Journal of Integrative Agriculture》 (农业科学学报（英文版）)

年 卷 期：2013年第12卷第11期

页      面：2074-2082页

核心收录：

学科分类：082803[工学-农业生物环境与能源工程] 08[工学] 0828[工学-农业工程] 

基　　金：sponsored by Shandong Cynda Chemical Co Ltd.(Shandong China) the Project of Pesticide Registration Residue of Ministry of Agriculture of China(FRF-SD-12-010B) 

主　　题：clomazone hydrolysis photolysis photoproducts abiotic 

摘      要：The hydrolysis and photolysis of clomazone in aqueous solutions and natural water were assessed under natural and controlled conditions. Kinetics of hydrolysis and photolysis of clomazone were determined by HPLC-DAD. Photoproducts were identiifed by HPLC-MS. No noticeable hydrolysis occurred in aqueous buffer solutions （（25±2）°C, pH （4.5±0.1）, pH （7.4±0.1）, pH （9.0±0.1）;（50±2）°C, pH （4.5±0.1）, pH （7.4±0.1）） or in natural water up to 90 d. At pH （9.0±0.1） and （50±2）°C the half-life of clomazone was 50.2 d. Clomazone photodecomposition rate in aqueous solutions under UV radiation and natural sunlight followed ifrst-order kinetics. Degradation rates were faster under UV light （half-life of 51-59 min） compared to sunlight （half-life of 87-136 d）. Under UV light, four major photoproducts were detected and tentatively identiifed according to HPLC-MS spectral information such as 2-chlorobenzamide, N-hydroxy-（2-benzyl）-2-methylpropan-amide, 2-[2-phenol]-4,4-dimethyl-3-isoxazolidinone and 2-[（4,6-dihydroxyl-2-chlorine phenol）]-4,4-dimethyl-3-isoxazolidinone. These results suggested that clomazone photodegradation proceeds via several reaction pathways：1） dehalogenation;2） substitution of chlorine group by hydroxyl;3） cleavage of the side chain. Photosensitizers, such as H2O2 and ribolfavin, could enhance photolysis of clomazone in natural sunlight. In summary, we found that photoreaction is an important dissipation pathway of clomazone in natural water systems.