呋虫胺水解机理的理论研究

发布时间：2018-01-16 09:34

本文关键词：呋虫胺水解机理的理论研究　出处：《重庆师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：呋虫胺作为第三代新烟碱类杀虫剂为现代农业作出了重大贡献,具有杀虫广谱,极强的吸收效果,高效的杀虫活性和独特的生物化学性。由于其广泛和频繁的应用,随着呋虫胺在农作物和水中的不断积累将对人类和动物造成潜在危害并且会破坏作物的正常生长。呋虫胺不含氯原子和芳香环,这点与其他已经存在的杀虫剂有很大的不同,因此为确保其安全性应该特别关注呋虫胺在环境中的降解机理。相关报道指出呋虫胺能够溶解在如甲醇和甲苯等有机溶剂中甚至可以达到37g/L,水解反应是呋虫胺在环境中的主要降解途径之一。据我们所知,近几年有部分关于呋虫胺水解的实验研究,然而对于呋虫胺的水解机理的研究很少并且其水解反应机理仍不清楚,因而对呋虫胺的水解机理进行理论研究具有很重要的意义。水溶液的酸碱性是呋虫胺在水溶液环境中降解的重要影响因素之一。在整篇文章中我们对呋虫胺在碱性、中性和酸性条件下的水解机理进行系统研究,主要采用M06-2X,B3LYP的方法并结合6-311++G(d,p)基组和MP2的方法结合6-311+G(d,p)基组进行计算。在气相条件当中,我们运用M06-2X以及B3LYP的方法分别对不同酸碱性条件下反应路径中的过渡态(TS)、反应物(RC)、中间体(INT)及产物(PC)的分子构型进行了全优化,同时也经过对虚频进行分析得出对应过渡态的准确性。此外,反应是在水溶液中进行的,因此我们也考虑了溶剂化效应对整个理论研究的影响,本研究对所有的稳定结构运用CPCM模型在M06-2X方法基础上进一步进行优化。数据显示,不管是在水溶液条件下还是在气相条件下,呋虫胺在碱性环境下的水解的活化能垒都是最低的,在碱性条件下反应最迅速,因而得出呋虫胺的水解为碱性水解。呋虫胺在碱性条件下的Path A是反应的最优路径,即呋虫胺阴离子中羟基上的H6原子迁移至N2原子上的反应路径。本论文对呋虫胺的水解理论计算进行了细致地论述,这能够为实验探究作出进一步验证,同时还可以为呋虫胺的进一步实验作出相应的预测,从而提高实验探究能力和效率。我们的研究也能够为类似的理论研究提供更多的参考价值。
[Abstract]:Furoxime as the third generation of new nicotinic insecticides has made a great contribution to modern agriculture, has a broad spectrum of insecticidal, very strong absorption effect. Highly effective insecticidal activity and unique biochemistry. Due to its extensive and frequent application. Furosemide, which contains no chlorine atoms and aromatic rings, can cause potential harm to humans and animals and damage the normal growth of crops as furfuramide accumulates in crops and water. This is very different from other pesticides that already exist. Therefore, in order to ensure its safety, we should pay special attention to the degradation mechanism of furosemide in the environment. It has been reported that furosemide can be dissolved in organic solvents such as methanol and toluene even up to 37 g / L. Hydrolysis is one of the major degradation pathways of furosemide in the environment. As far as we know, there have been some experimental studies on the hydrolysis of furosemide in recent years. However, there are few studies on the hydrolysis mechanism of furosemide and the mechanism of its hydrolysis is still unclear. Therefore, it is of great significance to study the hydrolysis mechanism of furosemide. The acidity and alkalinity of aqueous solution is one of the important factors that affect the degradation of furosemide in aqueous solution. Sex. The hydrolysis mechanism under neutral and acidic conditions was studied systematically. The method of M06-2XPB3LYP combined with 6-311 GTD was used. The p-) basis group and MP2 method were combined with the 6-311 G ~ (+) ~ (-) G ~ (2 +) base set to calculate in the gas phase condition. We have used M06-2X and B3LYP methods to study the transition state of TSN, the reactant RCin, in different reaction paths under different acid-base conditions, respectively. The molecular configuration of the intermediate (INT) and its product (PCC) were optimized, and the accuracy of the corresponding transition states was obtained through the analysis of the virtual frequency. In addition, the reaction was carried out in aqueous solution. Therefore, we also consider the solvation effect on the whole theoretical study. In this study, all stable structures are further optimized by using CPCM model based on M06-2X method. Whether in aqueous solution or in gas phase, the activation energy barrier of hydrolysis of furoxime in alkaline environment is the lowest, and the reaction is the most rapid in alkaline condition. It is concluded that the hydrolysis of furosemide is alkaline, and the Path A of furosemide in alkaline condition is the optimal route. In this paper, the theoretical calculation of the hydrolysis of furosemide is discussed in detail, which can be further verified for the experiment. At the same time, it can also make corresponding prediction for furoxime further experiments, so as to improve the ability and efficiency of experimental inquiry, and our research can also provide more reference value for similar theoretical research.
【学位授予单位】：重庆师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X592

【参考文献】