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Tropospheric degradation of ethylene glycol monovinyl and divinyl ethers: A mechanistic and kinetic study
Author(s) -
de la Luz Alexander Pérez,
Iuga Cristina,
AlvarezIdaboy Juan Raúl,
Ortíz Elba,
VivierBunge Annik
Publication year - 2012
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/qua.24159
Subject(s) - chemistry , reaction rate constant , ethylene glycol , kinetics , arrhenius equation , branching (polymer chemistry) , molecule , photochemistry , ethylene , double bond , molecular orbital , activation energy , computational chemistry , polymer chemistry , organic chemistry , catalysis , physics , quantum mechanics
In this work, we have performed a theoretical study on the mechanisms and kinetics of the • OH initiated oxidation of selected ethylene glycol vinyl ethers, using quantum chemistry and computational kinetics methods. We have found that the main reaction path is the • OH‐addition to vinyl double bonds, and especially to the vinyl terminal carbon atom. Branching ratios for addition at C 1 are larger than 94%. Although divinyl ethers could be expected to react approximately twice as fast as monovinyl ethers, it was found that, in fact, • OH rate constants of monovinyl and divinyl ethers are very similar, in agreement with experimental results. This effect is attributed to the sharing of the oxygen lone pairs effect, when the molecule contains two vinyl groups. Thus, in EGMVE, the vinyl group is more reactive than the one in divinyl ethers. The energy of its highest occupied molecular orbital (HOMO) is closer to that of the OH radical, thus favoring the interaction with the single occupied molecular orbital (SOMO) of the radical. Negative activation enthalpies are obtained for the three molecules studied, implying that the rate constant decreases as temperature increases. This anti‐Arrhenius behavior is commonly observed in • OH addition to alkenes. An excellent correlation is observed between experimental and calculated rate constants. © 2012 Wiley Periodicals, Inc.