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Theoretical study on the pyrolysis mechanism and kinetics of β‐hydroxyketones
Author(s) -
Feng Wenlin,
Wang Yan,
Zhang Shaowen
Publication year - 1997
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1997)62:3<297::aid-qua8>3.0.co;2-r
Subject(s) - chemistry , kinetics , transition state theory , reaction rate constant , decomposition , thermal decomposition , computational chemistry , ab initio , elementary reaction , reaction mechanism , transition state , thermodynamics , organic chemistry , catalysis , physics , quantum mechanics
The mechanism and kinetics for the decomposition of β‐hydroxypropaldehyde, primary and secondary β‐hydroxyketones, were studied by using ab initio RHF/6–31G and RHF/6–31G * methods. The activation barriers of these reactions were refined to be 39.57, 40.10, and 36.80 kcal mol −1 at the MP2/ /RHF/6–31G * level, respectively. The calculated results show that each decomposition is a concerted process with hydrogen transferring and bond breaking via a six‐membered cyclic transition state. The thermal rate constants of the decomposition of primary and secondary β‐hydroxyketones were obtained by calculating microcanonical probability fluxes through each transition state. It is theoretically confirmed that methyl substitution at the hydroxyl carbon of β‐hydroxyketones causes a small enhancement in rates. The theoretical investigations of the mechanism and the rate constants are in agreement with the experimental results. © 1997 John Wiley & Sons, Inc.