Hydrogen Isotope Effects in Electrochemical Reductions of Organic Chloro Compounds |
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| Authors: | M Wahren P Kränke M Möder S Rummel E Winkler |
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| Institution: | 1. Institute of Organic Chemistry, University of Leipzig , Leipzig, Germany;2. Department of Analytical Chemistry , UFZ Centre for Environmental Research Leipzig-Halle , Leipzig, Germany;3. Institute of Surface Modification , Leipzig, Germany;4. Department of Ecological Modelling , UFZ Centre for Environmental Research Leipzig-Halle , Leipzig, Germany |
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| Abstract: | Abstract The kinetic hydrogen isotope effects in electrochemical reductions of CCl3COOD, CDCl2COOD, CCl4, CDCl3, benzyl chloride, 1-chloronaphthalene and 4-chlorobenzonitrile in deuterated reaction media were determined. The aliphatic chloro compounds are reduced with rather small isotope effects kH/kD = 1.2…1.7, as expected if anionic intermediates are formed and protonated. Benzyl chloride is reduced with an apparent kH/kD = 2.1, which is probably too high due to radical reactions. Aromatic chloro compounds are reduced with significant participation of a second mechanism via radical intermediates which abstract carbon-bound hydrogen atoms from the components of the reaction system. The resulting isotope effects are kH/kD = 1.2 for the part of the reduction which proceeds via anions and kH/kD ～ 2.5 for the competing radical reaction. |
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| Keywords: | Chloro compounds deuterium electrochemical reduction isotope effects protonation reaction mechanism |
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