| 欧晓明,步海燕,裴 晖,唐德秀,黄明智,付启明,雷满香,喻 快.新除草剂甲硫嘧磺隆的水解动力学与机理研究[J].农业环境科学学报,2013,32(8):1537-1544. |
| 新除草剂甲硫嘧磺隆的水解动力学与机理研究 |
| Kinetics and Mechanisms of Novel Sulfonylurea Herbicide Methiopyrisulfuron Hydrolysis |
| |
| DOI：10.11654/jaes.2013.08.007 |
| 中文关键词: 磺酰脲类除草剂 甲硫嘧磺隆 水解动力学 水解机理 |
| 英文关键词: sulfonylurea herbicide methiopyrisulfuron（HNPC-C9908） hydrolysis mechanisms |
| 基金项目: |
|
| 摘要点击次数: 1877 |
| 全文下载次数: 2449 |
| 中文摘要: |
| 甲硫嘧磺隆，试验代号为HNPC-C9908，化学名称为2-（4-甲氧基-6-甲硫基嘧啶-2-基）氨基甲酰基氨基磺酰基苯甲酸甲酯，是我国具有自主知识产权的新型磺酰脲类除草剂品种，主要用于防除麦类作物田各种阔叶杂草和一些禾本科杂草，且对作物安全。采用HPLC和LC-MS等手段研究了甲硫嘧磺隆在水体中的水解动力学及机理，结果表明，甲硫嘧磺隆的水解遵循一级动力学反应，且受溶液pH、温度、粘土矿物和表面活性剂等因素的影响。在pH1~10时，甲硫嘧磺隆的水解速率先随pH值增加而缓慢降低，至pH值为7时达到最低，此后呈显著增加的趋势，至pH10达到最大值。甲硫嘧磺隆在pH5、7、9缓冲溶液中的水解速率随温度升高而明显加快，其水解主要是由反应的活化熵所驱动的。池塘水和稻田水中的微生物对甲硫嘧磺隆的降解无明显影响。表面活性剂0205、EL-40和NP-20对甲硫嘧磺隆的水解速率均有不同程度的影响，其中0205对甲硫嘧磺隆水解表现出明显的促进作用，EL-40对甲硫嘧磺隆的水解有一定的促进作用，而NP-20对甲硫嘧磺隆的水解表现出一定的抑制作用。膨润土对甲硫嘧磺隆的水解具有明显影响，甲硫嘧磺隆在含粘土矿物的水溶液中的水解速率明显低于重蒸水中。甲硫嘧磺隆的水解途径主要涉及到脲桥断裂，其主要降解产物为2-氨基-4-甲氧基-6-甲硫基嘧啶、2-氨基-4-甲氧基-6-甲基亚砜嘧啶，2-氨磺酰基苯甲酸甲酯和2-亚磺酸基苯甲酸甲酯。 |
| 英文摘要: |
| Methiopyrisulfuron（test code：HNPC-C9908）, chemical name：methyl 2-（4-methoxy-6-methylthio-pyrimidin-2-yl） carbamoylsulfamoyl benzoate, is a novel sulfonylurea herbicide researched and developed by Hunan Research Institute of Chemical Industry, which has been used for weed control in wheat. Hydrolysis kinetics and mechanisms of methiopyrisulfuron in the aqueous solutions were studied in the laboratory using HPLC and LC-MS. Results showed that the hydrolytic degradation of methiopyrisulfuron followed first-order kinetics, and the degradation of the herbicide was dependent on the factors such as pH, temperature, clay minerals and surfactants. In the range of pH 1~10, the hydrolysis rate of methiopyrisulfuron decreased slowly with the increasing pH value, and reached the lowest value at pH 7, and increased significantly after that, and reached the maximum at pH 10. The calculated half-lives of methiopyrisulfuron at pH 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 were 20.03, 25.48, 33.36, 36.10, 55.45, 64.78, 216.61, 169.06, 4.26 and 1.17 days, respectively. The hydrolysis rate of methiopyrisulfuron in the buffer solution of pH 5, 7 and 9 increased significantly with the increasing temperature. The average activation energy（Ea）, enthalpy（ΔH） and entropy（ΔS） was calculated as 310.86 kJ·mol-1, 308.37 kJ·mol-1 and 1.65×10-1 kJ·mol·K-1 at pH 5, 230.59 kJ·mol-1, 228.81 kJ·mol-1 and 2.22×10-2 kJ·mol·K-1 at pH7, and 148.67 kJ·mol-1, 146.17kJ·mol-1 and -5.13×10-2 kJ·mol·K-1 at pH 9, respectively, which is required for the hydrolytic degradation of the herbicide, indicating that the hydrolysis was largely driven by the activation entropy. There was less significant difference between the hydrolysis rate constant of methiopyrisulfuron in the sterilized water and non-sterilized water from pond water and rice fields, indicating that microorganisms in the water had little impact on hydrolysis of methiopyrisulfuron. The surfactant 0205 obviously promoted the hydrolysis of methiopyrisulfuron, but no obvious effect of surfactant EL-40 and NP-20 was found. Clay minerals such as bentonite slowed down hydrolysis of methiopyrisulfuron in the aqueous solution. Through the isolation and identification of hydrolysis products of methiopyrsulfuron in pH5, 7 and 9 solution by LC/MS, it was proposed that the major hydrolysis pathway of methiopyrisulfuron involved in the sulfonylurea bridge cleavage of the parent molecule to give the four main hydrolytic products such as 4-methoxy-6-（methylthio） pyrimidin-2-amine, 4-methoxy-6-（methylsulfinyl） pyrimidin-2-amine, methyl-2-sulfamoyl benzoate and methyl 2-sulfinyl benzoate. |
| HTML
查看全文
查看/发表评论 下载PDF阅读器 |
|
|
|
