Title: Absolute rate coefficient of the OH+CH3C(O)OH reaction at T=287-802 K. The two faces of pre-reactive H-bonding
Authors: Khamaganov, Victor
Bui, Vung Xuan
Carl, Shaun
Peeters, Jozef # ×
Issue Date: Jan-2006
Publisher: Amer chemical soc
Series Title: Journal of Physical Chemistry A vol:110 issue:47 pages:12852-12859
Abstract: The rate constants for the reaction OH + CH3C( O) OH -> products ( 1) were determined over the temperature range 287-802 K at 50 and 100 Torr of Ar or N-2 bath gas using pulsed laser photolysis generation of OH by CH3C( O) OH photolysis at 193 nm coupled with OH detection by pulsed laser-induced fluorescence. The rate coefficient displays a complex temperature dependence with a sharp minimum at 530 K, indicating the competition between a reaction proceeding through a pre-reactive H-bonded complex to form CH3C( O) O + H2O, expected to prevail at low temperatures, and a direct methyl-H abstraction channel leading to CH2C-( O) OH + H2O, which should dominate at high temperatures. The temperature dependence of the rate constant can be described adequately by k(1)( 287-802 K) = 2.9 x 10(-9) exp {-6030 K/T} + 1.50 x 10(-13) exp {515 K/T} cm(3) molecule(-1) s(-1), with a value of ( 8.5 +/- 0.9) x 10(-13) cm(3) molecule(-1) s(-1) at 298 K. The steep increase in rate constant in the range 550-800 K, which is reported for the first time, implies that direct abstraction of a methyl-H becomes the dominant pathway at temperatures greater than 550 K. However, the data indicates that up to about 800 K direct methyl-H abstraction remains adversely affected by the long-range H-bonding attraction between the approaching OH radical and the carboxyl-C( O) OH functionality.
ISSN: 1089-5639
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Quantum Chemistry and Physical Chemistry Section
× corresponding author
# (joint) last author

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