【作者】 张伟；

【导师】 唐沂珍；

【作者基本信息】 青岛理工大学 ， 环境科学与工程， 2018， 硕士

【摘要】 近年来,大气臭氧层的破坏得到越来越多的关注,过氧自由基和卤素一氧化物XO（X=Cl、Br、I）在臭氧的循环中有重要催化作用,因此研究过氧自由基和卤素一氧化物XO（X=Cl、Br、I）的反应对于了解臭氧层的破坏具有现实的意义。本论文以C₂H₅O₂和卤素一氧化物XO（X=Cl、Br、I）反应机理作为研究对象,利用量子化学方法对三个反应的微观机理进行详细研究,对各反应的产物进行分析,从分子角度讨论反应过程中化学键的断裂、新键的生成,使人们更深入认识这类反应的大气化学性质,并为进一步实验研究提供理论依据。本论文采用QCISD（T）/6-311++G（2df,2p）//B3LYP/6-311++G（d,p）方法分别对三个反应C₂H₅O₂+XO（X=Cl、Br、I）的反应机理进行研究,在密度泛函B3LYP/6-311++G（d,p）和B3LYP/6-311++G（2df,2p）水平上优化了反应物（R）、过渡态（TS）、中间体（IM）和产物（P）的几何构型。对每一过渡态都进行内禀反应坐标计算,以确认它所连接的特定反应物和产物。为了得到更加精确的能量信息,各驻点采用QCISD（T）/6-311++G（2df,2p）方法进行点单点能计算,在此基础上对每个反应通道的计算结果进行了详细的分析。从计算结果可以看到,C₂H₅O₂+XO（X=Cl、Br、I）的反应在单重态和三重态的势能面上都可以发生,但主要通道多在单重态势能面上,三重态势能面上的通道大多因反应能垒较高或能量太高不稳定可忽略不计。主要结论概括如下:（1）C₂H₅O₂+BrO:反应过程中生成了4个中间体（CH₃CH₂OOOBr、CH₃CH₂OOBrO、CH₃CH₂OBrOO和CH₃CH₂BrOOO）、15个过渡态、13种可能的产物和20条反应通道,经过分析可得在大气标准状况下,主要的反应通道有2条,主要产物是CH₃CHO+HOBrO、CH₃CHO+HBrO₂和CH₃CH₂OOOBr、CH₃CH₂OOBrO、CH₃CH₂OBrOO。其他的产物由于高能垒或者是能量高不稳定,都可忽略不计。（2）C₂H₅O₂+IO:反应过程中生成了3个中间体（CH₃CH₂OOOI、CH₃CH₂OOIO和CH₃CH₂OIOO）、12个过渡态、11种可能的产物和17条反应通道,经过分析可得在300K条件下,主要的反应通道有4条,主要产物是C₂H₅O+IOO、CH₃CHO+HOIO、CH₃CHO+HIO₂和CH₃CH₂OOOI、CH₃CH₂OOIO。其他的产物由于高能垒或者是能量高不稳定,都可忽略不计。（3）C₂H₅O₂+ClO:反应过程中生成了4个中间体（CH₃CH₂OOOCl、CH₃CH₂OOClO、CH₃CH₂OClOO和CH₃CH₂ClOOO）、15个过渡态、13种可能的产物和16条反应通道,经过分析可得在标准状况下,主要的反应通道有4条,主要产物是C₂H₅O+ClOO、CH₃CHO+HOClO、¹CH₃CHOO+HOCl、C₂H₅OCl+O₂（³∑）和CH₃CH₂OOOCl、CH₃CH₂OOClO、CH₃CH₂OClOO。其他的产物由于高能垒或者是能量高不稳定,都可忽略不计。（4）卤素取代效应:通过对C₂H₅O₂+XO（X=Cl、Br、I）三个反应的分析,不管是中间体的结构还是对各反应通道、主要通道和主要产物的分析,都可以看出的卤素取代效应在该类反应中影响很小。不管是纵向比较:卤素一氧化物XO（X=Cl、Br、I）与C₂H₅O₂反应中的所有中间体ROOOX的同分异构体（R=C₂H₅）的相对能量的顺序从最稳定到最不稳定的结构的顺序是IM3（ROXO₂）>IM1（ROOOX）>IM2（ROOXO）>IM4（RXO₃）。还是横向比较:IM1、IM2、IM3的相对能量ΔE高低顺序为IO<BrO<ClO,对应的稳定性为ClO<BrO<IO,反应活性IO最强。这都意味着在RO₃X表面进行的卤素替代效应是没有意义的。更多还原

【Abstract】 In recent years,the destruction of atmospheric ozone layer has drawn more and more attention.Peroxide radicals and halogen monoxides XO（X=Cl,Br,I）have been playing important catalytic effects in the cycle of ozone,so the studies on the reactions of the peroxide radicals and the halogen monoxides XO（X=Cl,Br,I）have practical significance for understanding the destruction of the ozone layer.This paper taking the reaction mechanisms of C₂H₅O₂ and XO（X=Cl,Br,I）as its research object made a detailed study on the microcosmic mechanism of the three reactions with quantum chemistry methods,analyzed the products of each reaction,discussed the breaking and formation of chemical bonds at molecular level.It is expected to give further knowledge of the atmospheric chemical properties of these reactions,and provide useful theoretical data for further laboratorial investigations.This paper studied the mechanisms of the three reactions C₂H₅O₂+XO（X=Cl,Br,I）using QCISD（T）/6-311++G（2df,2p）//B3LYP/6-311++G（d,p）methods,optimized the geometric configuration of the Reactants（R）,transition states（TS）,intermediates（IM）and products（P）at the density functional of B3LYP/6-311++G（d,p）and B3LYP/6-311++G（2df,2p）level.The intrinsic reaction coordinates were calculated for each transition state to confirm the specific reactants and products to which they are attached.In order to obtain more accurate energy information,the QCISD（T）/6-311++G（2df,2p）method was used to calculate the single point energy.On this basis,the calculation results of each reaction channel are analyed in detail.The results indicate that the reactions of C₂H₅O₂+XO（X=Cl,Br,I）proceed on both singlet and triplet potential energy surfaces,and the main reaction channels proceed on the singlet potential energy surface,the reaction channels of the triplet potential energy surface is negligible due to high reaction energy barriers or unstable products.The main conclusions are summarized as follows:（1）C₂H₅O₂+BrO:4intermediates（CH₃CH₂OOOBr,CH₃CH₂OOBrO,CH₃CH₂OBrOO and CH₃CH₂BrOOO）,15 transition states,13 possible products and20 reaction channels were generated during the reaction.It is obtained that we can get two main reaction channels,and the main products are CH₃CHO+HOBrO,CH₃CHO+HBrO₂ and CH₃CH₂OOOBr,CH₃CH₂OOBrO,CH₃CH₂OBrOO after the analysis in the atmospheric standard conditions.Other products are negligible due to high energy barriers or unstable products.（2）C₂H₅O₂+IO:During the reaction,we can get 3 intermediates（CH₃CH₂OOOI,CH₃CH₂OOIO and CH₃CH₂OIOO）,12 transition states,11 possible products and 17reaction channels.After analysis,we can get four main reaction channels,and the main products are C₂H₅O+IOO,CH₃CHO+HOIO,CH₃CHO+HIO₂ and CH₃CH₂OOOI,CH₃CH₂OOIO below 300K.Other products are negligible due to high energy barrier or unstable products.（3）C₂H₅O₂+ClO:4 intermediates（CH₃CH₂OOOCl,CH₃CH₂OOClO,CH₃CH₂OClOO and CH₃CH₂ClOOO）,15 transition states,13 possible products and16 reaction channels were produced during the reaction.After analysis,there are four main reaction channels,and the main products are C₂H₅O+ClOO,CH₃CHO+HOClO,¹CH₃CHOO+HOCl,C₂H₅OCl+O₂（³Σ）and CH₃CH₂OOOCl,CH₃CH₂OOClO,CH₃CH₂OClOO under standard conditions.Other products can be ignored due to high energy barrier or unstable products.（4）Halogen Substitution Effect:From the analysis of the three reactions of C₂H₅O₂+XO（X=Cl,Br,I）,it can be seen that halogen substitution effects have little effect in such reactions,no matter the structure of the intermediates or the analysis of the reaction channels,major channels and major products.Whether it is longitudinal comparison that the relative energy order of the isomers of all the intermediates ROOOX（R=C₂H₅）in the reaction of the halogen monoxide XO（X=Cl,Br,I）with the C₂H₅O₂ from the most stable to the most unstable structure is IM3（ROXO₂）>IM1（ROOOX）>IM2（ROOXO）>IM4（RXO₃）,or horizontal comparison that the relative energyΔE of IM1,IM2,IM3 is in the order of IO<Br O<ClO and the corresponding stability is ClO<BrO<IO,IO is the most reactive,which infers that the halogen substitution effect on the RO₃X surface is meaningless.更多还原