Kinetics of methylidyne (CH X 2Π) radical reactions with ammonia and methylamines

S. Zabarnick, J. W. Fleming, Ming-Chang Lin*

*此作品的通信作者

研究成果: Article同行評審

21 引文 斯高帕斯(Scopus)

摘要

Laser photolysis/laser-induced fluorescence (LIF) was employed to measure the rate constants for CH (X 2Π) radical reactions with NH3, CH3NH2, (CH3)2NH, and (CH3)3N. The ground state CH radicals were generated by the multiphoton dissociation of CHBr3 at 266 nm. The relative CH concentration was probed by LIF at 429.8 nm. The experiments were performed on flowing gas mixtures thus allowing pressure and temperature studies to be performed. No variation of the measured rate constants with pressure was observed over the range 30 to 100 Torr total pressure (mostly argon). The following Arrhenius equations, covering the temperature range 297 to 677 K, are derived: CH + NH3, k2 = (8.6±0.6 )×10-11 exp [(230±30) /T] cm3 s-1; CH + CH3NH2, k2 = (3.1±0.2)×10-10 exp [(170±30)/T] cm3s-1; CH + (CH3)2NH, k2 = (2.4±0.2)×10-10 exp [(290±30)/T] cm3 s-1; CH + (CH3)3N, k2 = (2.6±0.2)×10-10 exp [ (230±30)/T] cm3 s-1. The observed temperature and pressure dependences are in accord with an insertion-elimination mechanism. On a per bond basis, CH reactivity toward NH bonds is only slightly larger than its reactivity toward CH bonds. The observed large rate constants for the methylamine reactions could be attributed to the change in ionization potential (lowering) and polarizability (increasing) as compared with alkanes.

原文English
頁(從 - 到)407-411
頁數5
期刊Chemical Physics
132
發行號3
DOIs
出版狀態Published - 15 四月 1989

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