A Theoretical Investigation of the Gas-Phase Oxidation Reaction of the Saturated tert-Butyl Radical

✍ Scribed by Jong-Ho Choi; Mi-Ja Nam; Sung-Eui Youn

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 138 KB
• Volume: 7
• Category: Article
• ISSN: 1439-4235
• DOI: 10.1002/cphc.200600473

✦ Synopsis

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).