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首页> 外文期刊>Bulletin of the Chemical Society of Japan >Pathways and Kinetics of Anisole Pyrolysis Studied by NMR and Selective C-13 Labeling. Heterolytic Carbon Monoxide Generation
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Pathways and Kinetics of Anisole Pyrolysis Studied by NMR and Selective C-13 Labeling. Heterolytic Carbon Monoxide Generation

机译：NMR和选择性C-13标记研究的致吲哚热解的途径和动力学。 异质一氧化碳一代

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摘要

By applying C-13 and H-1 NMR spectroscopy the pyrolysis of site-selectively C-13-enriched (H313CO12C6H5) and normal anisole compounds was studied in the dark at 0.001-1.0M (M, mol dm(-3)) and at 400-600 degrees C (supercritical conditions). Conversion of the C-13-labeled methyl group was confined to the methoxy-originated fragments, (CO)-C-13 and (CH4)-C-13, and the reactive intermediate, (HCHO)-C-13*. The normal phenyl group, (C6H5)-C-12- was converted to benzene, (C6H6)-C-12 and phenol, (C6H5OH)-C-12 without ring disintegration. The pyrolysis consists of two elementary steps: (1) the rate-determining unimolecular ether-bond fission (k(1)) to generate the fragmented product C6H6 and energized intermediate (HCHO)-C-13* through the intramolecular proton transfer from the methoxy group to the phenyl, and (2) the fast bimolecular disproportionation (k(2)) through the intermolecular proton/hydride transfer from (HCHO)-C-13* to (H3COC6H5)-C-13 to produce (CO)-C-13, (CH4)-C-13, and C6H5OH. CO is generation by the heterolytic (ionic) mechanism in contrast to the homolytic (radical) one via the phenoxy radical intermediate (C6HSO center dot) in the literature despite the agreement of the rate constant (k(1)) and the activation energy.
机译：通过施加C-13和H-1 NMR光谱，在黑暗中在0.001-1.0m（m，mol dm（-3））和在400-600摄氏度（超临界条件）。将C-13标记的甲基的转化局限于甲氧基起源片段，（CO）-C-13和（CH 4）-C-13，和反应性中间体，（HCHO）-C-13 *。正常苯基（C6H5）-C-12-转化为苯，（C6H6）-C-12和苯酚，（C6H5OH）-C-12没有环崩解。热解包括两个基本步骤：（1）速率确定单分子醚 - 键裂解（K（1））通过分子内质子转移产生分子化产物C6H6和激励中间体（HCHO）-C-13 *将甲氧基给苯基，（2）通过（H3COC6H5）-C-13从（HCHO）-C-13 *至（H3COC6H5）-C-13中产生（H3COC6H5）-C-13来产生（CO） - C-13，（CH 4）-C-13和C6H5OH。尽管速率常数（k（1））和活化能量同时，所以通过文献中的苯氧基自由基中间体（C6HSO中心点）对比同源的异化（离子）机制。

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