| 2-氯吡啶光氯化取代反应机理的量子化学研究 |
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| 引用本文： | 曹映玉,杨恩翠,华芳,杨琨,赵妍,王万得,郝金库.2-氯吡啶光氯化取代反应机理的量子化学研究[J].天津师范大学学报(自然科学版),2004,24(1):8-12. |
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| 作者姓名： | 曹映玉 杨恩翠 华芳 杨琨 赵妍 王万得 郝金库 |
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| 作者单位： | 天津师范大学,化学与生命科学学院,天津,300074 |
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| 基金项目： | 天津市自然科学基金资助项目(003602011);天津市教委基金资助项目(990710);天津师范大学青年基金资助项目 |
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| 摘 要： | 用PM3方法研究了2-氯吡啶光氯化取代反应的过渡态.研究结果表明,生成2,6-二氯吡啶、2,5-二氯吡啶、2,4-二氯吡啶、2,3-二氯吡啶不同产物的每一个反应通道都存在两个过渡态;反应体系沿反应坐标的变化为反应物→反应物络合物→第1过渡态→中间体→第2过渡态→产物络合物→产物;第2过渡态为主过渡态,生成2,6-二氯吡啶反应路径主过渡态的能量及活化能最低,分别为-139612.06和135.39kJ/mol,反应优先生成2,6-二氯吡啶.生成二氯吡啶反应过程中吡啶环反应部位CCl键的形成主要与共轭双键断裂同步,而CH键的断裂主要与共轭双键的重新形成同步.
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| 关 键 词： | 氯代吡啶 光氯化 反应机理 过渡态 PM3 |
| 文章编号： | 1671-1114(2004)01-0008-04 |
| 修稿时间： | 2003年9月5日 |
Theoretical Study on Substitute Mechanism of Chlorine Radical with 2-Chloropyridine |
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| CAO Ying-yu,YANG En-cui,HUA Fang,YANG Kun,ZHAO Yan,WANG Wan-de,HAO Jin-ku.Theoretical Study on Substitute Mechanism of Chlorine Radical with 2-Chloropyridine[J].Journal of Tianjin Normal University(Natural Science Edition),2004,24(1):8-12. |
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| Authors: | CAO Ying-yu YANG En-cui HUA Fang YANG Kun ZHAO Yan WANG Wan-de HAO Jin-ku |
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| Abstract: | The substitute mechanism of 2-chloropyridine reacting with chlorine radical was studied theoretically by semi-empirical method- PM3. The results showed that there were two transition states in each reaction path for obtaining 2,3-,2,4-,2,5-and 2,6-dichloropyridine respecively. The energy of chief transition state and activation barrier of leading to 2,6-dichloropyridine were lowest among four reaction paths, which is -139 612.06 and 135.39 kJ/mol respectively. Thus, 2,6-dichloropyridine was prior product. The formation ofC (Cl) and the breaking of conjugate double bond was mainly synchronous during the process of producing the dichloropyridine, so did the breaking of C H bond and the re-formation of conjugate double bond. |
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| Keywords: | 2-chloropyridine photochemical chlorination reaction mechanism transition state PM3 |
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