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Initiation Chemistries in Hydrocarbon (Aut)Oxidation
Author(s) -
Sandhiya Lakshmanan,
Zipse Hendrik
Publication year - 2015
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.201502384
Subject(s) - chemistry , homolysis , benzaldehyde , radical , toluene , benzoic acid , endothermic process , photochemistry , benzyl alcohol , dissociation (chemistry) , standard enthalpy of formation , yield (engineering) , organic chemistry , bond dissociation energy , enthalpy , medicinal chemistry , catalysis , materials science , adsorption , metallurgy , physics , quantum mechanics
For the (aut)oxidation of toluene to benzyl hydroperoxide, benzyl alcohol, benzaldehyde, and benzoic acid, the thermochemical profiles for various radical‐generating reactions have been compared. A key intermediate in all of these reactions is benzyl hydroperoxide, the heat of formation of which has been estimated by using results from CBS‐QB3, G4, and G3B3 calculations. Homolytic OO bond cleavage in this hydroperoxide is strongly endothermic and thus unlikely to contribute significantly to initiation processes. In terms of reaction enthalpies the most favorable initiation process involves bimolecular reaction of benzyl hydroperoxide to yield hydroxy and benzyloxy radicals along with water and benzaldehyde. The reaction enthalpy and free energy of this process is significantly more favorable than those for the unimolecular dissociation of known radical initiators, such as dibenzoylperoxide or dibenzylhyponitrite.