Mechanisms for the Breakdown of Halomethanes through Reactions with Ground‐State Cyano Radicals |
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| Authors: | Pooria Farahani Prof Satoshi Maeda Prof Joseph S Francisco Dr Marcus Lundberg |
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| Institution: | 1. Department of Chemistry—?ngstr?m Laboratory, Uppsala University, Box 518, 751 20, Uppsala (Sweden);2. Department of Chemistry, Faculty of Science, Hokkaido University, Kita‐10‐jyo‐nishi‐8‐cho‐me, Kita‐ku, Sapporo, 060‐0810 (Japan);3. Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907 (USA) |
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| Abstract: | One route to break down halomethanes is through reactions with radical species. The capability of the artificial force‐induced reaction algorithm to efficiently explore a large number of radical reaction pathways has been illustrated for reactions between haloalkanes (CX3Y; X=H, F; Y=Cl, Br) and ground‐state (2Σ+) cyano radicals (CN). For CH3Cl+CN, 71 stationary points in eight different pathways have been located and, in agreement with experiment, the highest rate constant (108 s?1 M ?1 at 298 K) is obtained for hydrogen abstraction. For CH3Br, the rate constants for hydrogen and halogen abstraction are similar (109 s?1 M ?1), whereas replacing hydrogen with fluorine eliminates the hydrogen‐abstraction route and decreases the rate constants for halogen abstraction by 2–3 orders of magnitude. The detailed mapping of stationary points allows accurate calculations of product distributions, and the encouraging rate constants should motivate future studies with other radicals. |
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| Keywords: | gas‐phase reactions quantum chemistry radical reactions reaction mechanisms transition states |
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