The kinetics of the reactions of Br atoms with the xylenes: an experimental and theoretical study

Abstract

This work reports the temperature dependence of the rate coefficients for the reactions of atomic bromine with the xylenes that are determined experimentally and theoretically. The experiments were carried out...

Photo-oxidation reaction of tert-butyl chloride with OH radicals and Cl atoms in the troposphere and its implications

“…The rate coefficients reported in the literature show that in most cases, the reactions of saturated VOCs with Cl atoms are faster than with OH radicals, which are in turn faster than the reactions with Br atoms. 35,44 This is also observed in part for title reactions, where the rate coefficients for the reaction (R2) are ∼35 times greater than those of reaction (R1). However, there is no available data for the reaction of TBC with Br atoms.…”

“…The stabilization of the complexes observed here is similar to the reactions of OH with other VOCs. 31–38 Stabilization of RCg is comparable to other H-bonded reactant complexes formed during the reactions of VOCs and OVOCs with OH radicals. Illés et al 31 reported the formation of H-bonded and van der Waals complexes with relative energies of 5.45 kcal mol −1 and 1.24 kcal mol −1 , respectively, in the reaction of tetrahydrofuran with OH radicals.…”

“…The relative energies of the product complex PCg (−19.81 kcal mol −1 ) and PCa (−17.94 kcal mol −1 ) formed in reaction (R1) are also comparable to that of the product complexes formed during the reaction of OH radicals with other OVOCs, which lie in the range of ∼19–28 kcal mol −1 . 35 The greater stabilization due to H-bonding compared to a van der Waals interaction is also apparent in the case of the product complexes formed in the title reaction, where PCg is ∼2 kcal mol −1 more stable than PCa.…”

“…The reactions involving H-abstraction from VOCs by OH radicals and Cl atoms tend to be exothermic 53–55 whereas they are usually endothermic for the reactions with Br atoms. 35 Reactions with OH radicals which produce water molecules are known to be highly exothermic compared to Cl-initiated reactions. In this work, we determined that reaction (R1) is highly exothermic whereas reaction (R2) is endothermic.…”

A kinetic study of the reactions of atomic bromine with the trimethylbenzenes

“…The results are used to elucidate the detailed mechanisms of these reactions. 1–6 Some of the more prominent reactive species that have been linked to atmospheric photo-oxidation of volatile organic compounds (VOCs) are OH, Cl and Br and the kinetics and mechanisms of many of these processes have been extensively reviewed. 7–12 These reviews lead to the generalization that the order of reactivity with a given VOC is roughly Cl > OH > Br.…”