Computational Kinetics of Hydroperoxybutylperoxy Isomerizations and Decompositions: A Study of the Effect of Hydrogen Bonding.

Hydroperoxyalkylperoxy (OOQOOH) radicals are important intermediates in combustion chemistry. The conventional isomerization of OOQOOH radicals to form ketohydroperoxides has been long believed to be the most important chain branching reaction under the low-temperature combustion conditions. In this work, the kinetics of competing pathways (alternative isomerization, concerted elimination, and H-exchange pathways) to the conventional isomerization of different β-, γ- and Δ-OOQOOH butane isomers are investigated.

High-Pressure Limit Rate Rules for α-H Isomerization of Hydroperoxyalkylperoxy Radicals.

Hydroperoxyalkylperoxy (OOQOOH) radical isomerization is an important low-temperature chain branching reaction within the mechanism of hydrocarbon oxidation. This isomerization may proceed via the migration of the α-hydrogen to the hydroperoxide group. In this work, a combination of high level composite methods-CBS-QB3, G3, and G4-is used to determine the high-pressure-limit rate parameters for the title reaction.

PAH growth initiated by propargyl addition: mechanism development and computational kinetics.

Polycyclic aromatic hydrocarbon (PAH) growth is known to be the principal pathway to soot formation during fuel combustion, as such, a physical understanding of the PAH growth mechanism is needed to effectively assess, predict, and control soot formation in flames. Although the hydrogen abstraction C2H2 addition (HACA) mechanism is believed to be the main contributor to PAH growth, it has been shown to under-predict some of the experimental data on PAHs and soot concentrations in flames. This article presents a submechanism of PAH growth that is initiated by propargyl (C3H3) addition onto naphthalene (A2) and the naphthyl radical.

Heterogeneous ozonolysis of folpet and dimethomorph: a kinetic and mechanistic study.

The research study discussed in this paper concerns determination of the kinetic rate constants for heterogeneous degradation of the pesticides folpet and dimethomorph by ozone at room temperature. The study also involves identification of the degradation products of the analyzed compound in the condensed phase by solid-phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS). The heterogeneous O3 reactivity of the identified degradation product of dimethomorph, 4-chlorophenyl 3,4-dimethoxyphenyl methanone (CPMPM), is also evaluated experimentally.