| Summary: | 碩士 === 義守大學 === 生物技術與化學工程研究所碩士班 === 95 === The reactions of alkenes, allyl halides and propargyl halides with ozone has been investigated by using ab initio method and density functional theory. Applied the method of HF, MP2 and B3LYP levels at 6-311+g(d,p) basis set to calculate the optimization of the geometric configurations and the energies of reactions, intermediates, transition states, and products. The transition states and intermediates of the reactions are verified by the vibrational frequencies analysis, moreover, used IRC method to check the right reaction mechanism. Comparison of the calculated values with experimental results and literature, suggested that the calculations with B3LYP level give better agreement than others. The results show that allyl halides react with ozone form the primary ozonide first, and then decompose to two kinds of intermediates, which will cycle addition to form the second ozonide. Due to the substituent effect, more possible intermediates of the reaction of allyl halides with ozone are halide acetaldehyde and carbonyl oxide, however, the intermediates of the reaction of alkenes with ozone are formaldehyde and CHO2CH2R(R=H or CH3). The activation energy of primary ozonide decomposed to intermediates is greatest, therefore, this step is the rate determining step. Using B3LYP level to study the reaction of the propargyl halides with ozone, suggesting the reaction pathway is more comlicated than the reaction of allyl halides with ozone. The intermediates of reaction of propargyl halide with ozone are 4-(halomethyl)-1,2,3-trioxolene, 1-(halomethyl)-2,3,5-trioxa-bicyclo[2.1.0] pentane and the product is formic haloacetic anhydride.
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