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Methyl Vinyl Ketone+OH and Methacrolein+OH Oxidation Reactions: A Master Equation Analysis of the Pressure‐ and Temperature‐Dependent Rate Constants
Author(s) -
OchandoPardo Montserrat,
NebotGil Ignacio,
GonzálezLafont Àngels,
Lluch José M.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600529
Subject(s) - methacrolein , methyl vinyl ketone , reaction rate constant , arrhenius equation , chemistry , ketone , hydrogen atom abstraction , thermodynamics , reaction rate , acetone , hydrogen , catalysis , activation energy , photochemistry , organic chemistry , kinetics , physics , polymerization , quantum mechanics , methacrylic acid , polymer
High‐level electronic structure calculations and master equation analyses were carried out to obtain the pressure‐ and temperature‐dependent rate constants of the methyl vinyl ketone+OH and methacrolein+OH reactions. The balance between the OH addition reactions at the high‐pressure limit, the OH addition reactions in the fall‐off region, and the pressure‐independent hydrogen abstractions involved in these multiwell and multichannel systems, has been shown to be crucial to understand the pressure and temperature dependence of each global reaction. In particular, the fall‐off region of the OH addition reactions contributes to the inverse temperature dependence of the rate constants in the Arrhenius plots, leading to pressure‐dependent negative activation energies. The pressure dependence of the methyl vinyl ketone+OH reaction is clearly more important than in the case of the methacrolein+OH reaction owing to the weight of the hydrogen abstraction process in this second system. Comparison of the theoretical rate constants and the experimental measurements shows quite good agreement.