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Mechanisms for the Breakdown of Halomethanes through Reactions with Ground‐State Cyano Radicals
Author(s) -
Farahani Pooria,
Maeda Satoshi,
Francisco Joseph S.,
Lundberg Marcus
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402601
Subject(s) - radical , hydrogen atom abstraction , halogen , chemistry , reaction rate constant , fluorine , hydrogen , ground state , computational chemistry , photochemistry , abstraction , atomic physics , organic chemistry , kinetics , physics , philosophy , alkyl , epistemology , quantum mechanics
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 (CX 3 Y; X=H, F; Y=Cl, Br) and ground‐state ( 2 Σ + ) cyano radicals (CN). For CH 3 Cl+CN, 71 stationary points in eight different pathways have been located and, in agreement with experiment, the highest rate constant (10 8 s −1 M −1 at 298 K) is obtained for hydrogen abstraction. For CH 3 Br, the rate constants for hydrogen and halogen abstraction are similar (10 9 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.