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A Theoretical Investigation of the Gas‐Phase Oxidation Reaction of the Saturated tert ‐Butyl Radical
Author(s) -
Choi JongHo,
Nam MiJa,
Youn SungEui
Publication year - 2006
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.200600473
Subject(s) - chemistry , isomerization , potential energy surface , reaction mechanism , basis set , density functional theory , radical , oxygen , activation energy , transition state , gas phase , ground state , computational chemistry , photochemistry , molecule , organic chemistry , catalysis , physics , quantum mechanics
Abstract The radical‐radical reaction mechanisms and dynamics of ground‐state atomic oxygen [O( 3 P)] with the saturated tert ‐butyl radical ( t ‐C 4 H 9 ) are investigated using the density functional method and the complete basis set model. Two distinctive reaction pathways are predicted to be in competition: addition and abstraction. The barrierless addition of O( 3 P) to t ‐C 4 H 9 leads to the formation of an energy‐rich intermediate (OC 4 H 9 ) on the lowest doublet potential energy surface, which undergoes subsequent direct elimination or isomerization–elimination leading to various products: C 3 H 6 O+CH 3 , iso ‐C 4 H 8 O+H, C 3 H 7 O+CH 2 , and iso ‐C 4 H 8 +OH. The respective microscopic reaction processes examined with the aid of statistical calculations, predict that the major addition pathway is the formation of acetone (C 3 H 6 O)+CH 3 through a low‐barrier, single‐step cleavage. For the direct, barrierless H‐atom abstraction mechanism producing iso ‐C 4 H 8 (isobutene)+OH, which was recently reported in gas‐phase crossed‐beam investigations, the reaction is described in terms of both an abstraction process (major) and a short‐lived addition dynamic complex (minor).