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A new mechanism for initiation of free‐radical chain reactions during high‐temperature, homogeneous oxidation of unsaturated hydrocarbons: Ethylene, propyne, and allene
Author(s) -
Wang Hai
Publication year - 2001
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.1066
Subject(s) - propyne , chemistry , allene , carbene , singlet state , photochemistry , chain reaction , ethylene , singlet oxygen , radical , reaction mechanism , oxygen , catalysis , organic chemistry , excited state , physics , nuclear physics
The initiation of free radical chain reactions by singlet carbene biradicals is proposed for homogeneous oxidation of typical unsaturated hydrocarbons, including ethylene, allene, and propyne. The mechanism features the production of singlet vinylidene and methylvinylidene by 1,1‐H 2 elimination and 1,2‐H shift, respectively, from ethylene and propyne. The singlet biradicals then react with molecular oxygen to initiate a free‐radical chain process. The analysis used quantum chemistry calculations and detailed modeling of ignition delay times. In all cases tested the carbene pathway was found to dominate the initial radical‐pool production. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 698–706, 2001