农药学学报2012，Vol.14Issue(6)：641-646,6.DOI:10.3969/j.issn.1008-7303.2012.06.09
新农药O,O-二甲基-1-(2,4-二氯苯氧基乙酰氧基)乙基膦酸酯的水解
Study on hydrolysis of novel herbicide O,O-dimethyl-1-(2,4-dichlorophenoxy-acetoxy) ethyl phosphonate in buffered solutions
摘要
Abstract
HW-02, O, O dimethyl-l-(2, 4-dichlorophenoxy-acetoxy) ethyl phosphonate, is a novel herbicide discovered and developed by Huazhong Normal University, China. The hydrolysis kinetics and mechanisms of HW-02 were studied in buffered aqueous solutions under pH 5 - 9 at ambient temperature and under pH 7 with the stored temperature of 25℃- 55℃. The results showed that HW-02 hydrolyzed very rapidly in the buffered solutions. Its hydrolysis rate was characterized by the first-order kinetics and accelerated with the increasing of pH and temperature. The calculated half lives of HW-02 hydrolysis in the solutions of pH 5,7 and 9 were 191. 3 h,6. 2 h and 0. 2 h at 25℃, respectively. It is indicated that HW-02 was not stable in the aqueous environments. HW-02 hydrolyzed much faster in the basic solution than in acidic and neural solution at the same temperature. The hydrolysis rate of HW-02 increased as the temperature increases and its half lives in the buffered solution of pH 7 were 6.1 h,4. 2 h, 1. 8 h and 0.7 h at 25℃,35℃,45℃ and 55℃,respectively. The temperature coefficient of hydrolysis for HW-02 was 1. 46 -2. 64. There were no obvious correlation between the activation enthalpy of HW-02 hydrolysis and temperatures. Its average activation energy and activation enthalpy were 60. 51 kJ/mol and 57. 70 kJ/mol, respectively. The activation entropy absolute values of HW-02 hydrolysis increased with the increasing temperatures in the environment. The average value of -81.00 kJ/(mol·K) suggested that hydrolysis of HW-02 in the aqueous solutions was driven by the activation entropy. Through isolation and identification of HW-02 hydrolytic products using GC-MS detection, it was found that HW-02 was hydrolyzed through ester cleavage. The main degradation product was 2,4-dicholorphenoxyaceate.关键词
HW-02/水解动力学/水解机理/活化能/活化熵Key words
O,O-dimethyl-1-(2,4-dichlorophenoxy-acetoxy) ethyl phosphonate(HW-02)/hydrolysis kinetics/ hydrolytic mechanisms/ activation energy/ activation entropy分类
资源环境引用本文复制引用
侯志广,张浩,王岩,赵晓峰,王鑫宏,逯忠斌..新农药O,O-二甲基-1-(2,4-二氯苯氧基乙酰氧基)乙基膦酸酯的水解[J].农药学学报,2012,14(6):641-646,6.基金项目
农业部农药残留项目及吉林省科技厅青年基金资助(2010-0142). （2010-0142）
