【摘要】 用密度泛函理论（DFT）,在M06-2X/6-311G（d, p）级别上优化了噻虫胺（C₆H₈ClN₅O₂S）与OH自由基的反应机理，找到了抽氢、加成、抽氯三种反应机理。对反应体系中涉及的所有稳定点进行了简谐振动频率的验证，并且在相同级别上用内禀反应坐标证实了过渡态的真实性。用M06-2X/AUG-CC-PVTZ方法计算了反应体系中所有物种的单点能，用标准统计力学计算了反应的焓变和吉布斯自由能变，综合热力学和动力学因素，抽氢反应在常温可以自发反应。加成反应中OH自由基较易于加成到C原子上，抽氯反应由较高的势垒和较大的吉布斯自由能变，较难于发生。为实际生活中噻虫胺的环境风险评估和控制提供了理论依据。更多还原

【Abstract】 The reaction mechanism of C₆H₈ClN₅O₂S with OH radical was optimized using the M06-2X/6-311G（d, p）, and hydrogen abstraction, addition, and chlorine abstraction reaction mechanisms were identified. All stable points within the reaction system were verified through harmonic vibrational frequency, and the authenticity of the transition states was affirmed using the intrinsic reaction coordinate at the same level. Single-point energies（SP） of all species were computed using the M06-2X/AUG-CC-PVTZ. The enthalpy change and Gibbs free energy change of the reaction were calculated with standard statistical mechanics. Considering both thermodynamic and kinetic factors, C₆H₈ClN₅O₂S can spontaneously react with OH radical on the hydrogen abstraction at room temperature. In addition reaction, the OH radical was more easily added to the C atom. The chlorine extraction reaction is difficult to occur because of the higher barrier and the larger Gibbs free energy change. This offers a theoretical basis for the environmental risk assessment and control of clothianidin in real life.更多还原