A theoretical investigation of the gas-phase oxidation reaction of the saturated tert-butyl radical.
The radical-radical reaction mechanisms and dynamics of ground-state atomic oxygen [O(3P)] with the saturated tert-butyl radical (t-C4H9) 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(3P) to t-C4H9 leads to the formation of an energy-rich intermediate (OC4H9) on the lowest doublet potential energy surface, which undergoes subsequent direct elimination or isomerization-elimination leading to various products: C3H6O + CH3, iso-C4H8O + H, C3H7O + CH2, and iso-C4H8 + OH. The respective microscopic reaction processes examined with the aid of statistical calculations, predict that the major addition pathway is the formation of acetone (C3H6O) + CH3 through a low-barrier, single-step cleavage. For the direct, barrierless H-atom abstraction mechanism producing iso-C4H8 (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).
Choi
Jong-Ho
JH
Department of Chemistry, Korea University, 1 Anam-Dong, Sungbuk-Gu, Seoul 136-701, Korea. jhc@korea.ac.kr
Nam
Mi-Ja
MJ
Youn
Sung-Eui
SE
D000096:Acetone / Q000138:chemical synthesis; D000475:Alkenes / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D008956:Models, Chemical; D010084:Oxidation-Reduction; D013237:Stereoisomerism
D000475:Alkenes; D005609:Free Radicals; D005740:Gases; D000096:Acetone; C008176:isobutylene