• 关键词：光催化  哒螨酮  机理  降解路线  中间产物  前线电子密度

• 基金项目：江苏省高校高新技术产业化资助项目(JH01010);国家“863计划”重大项目(2002AA302304)

• 朱馨乐
• 东南大学分子与生物分子电子学教育部重点实验室, 南京 210096

• 李萍
• 北京航空航天大学生物工程系, 北京 100083

• 胡俊喆
• 东南大学分子与生物分子电子学教育部重点实验室, 南京 210096

• 冯小刚
• 东南大学分子与生物分子电子学教育部重点实验室, 南京 210096

• 袁春伟
• 东南大学分子与生物分子电子学教育部重点实验室, 南京 210096

• 摘要：以TiO²为催化剂对非均相纳米光催化降解杀虫剂哒螨酮进行了机理研究.结果表明该反应遵循一级动力学方程.速率常数为0.02957min^-1, 半衰期为23.44min.重点利用气质联用(GCMS)结合与标准品, 合成化合物相对照的方法, 鉴定出反应过程中可能产生的8种中间产物.据此, 提出了降解路线.同时用PM3算法计算模拟前线电子密度(FED²).证明哒螨酮分子中S原子上分布的FED²最大, 是诱发降解系列反应的起始位点.此结论与实验结果---光催化降解哒螨酮的初始步骤是分子的苯环和杂环之间碳硫键的断裂相一致.

• Abstract：The degradation mechanism of pyridaben by TiO₂ photocatalysis was investigated. The results suggested that the reaction followed a pseudo-first-order equation with kinetic constant of 0.02957μmin^-1 and half-life time of 23.44μmin. The study focused on the identification of eight possible intermediates in the process of reaction by GC/MS technique accompanied with matching the standard and synthesized compounds. Based on the results, a degradation route was proposed. At the same time, computer simulation was carried out on PM3 level by frontier electron densities (FED²). The results suggested that the S atom bearing the highest FED² should be the starting position to promote a serious of degradation reaction. It was in consistency with the experimental conclusion that the initial photocatalytic degradation proceeded mainly via C-S bond cleavage between phenyl ring and heterocyclic group.

• Key words：photocatalysis  pyridaben  mechanism  degradation route  intermediates  frontier electron densities

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