Theoretical Investigation of Rate Rules for H-Intermigration Reactions for Cyclic Alkylperoxy Radicals

As a starting channel, the H-intermigration reaction of alkylperoxy radicals (ROO radicals) that yields hydroperoxyl alkyl (QOOH determines low-temperature chemistry alkanes. In this work, type was investigated for typical cyclic alkanes, which are important fuel components and soot precursors, using theoretical ab initio methods. First, all molecular geometries vibrational frequencies were computed density functional theory method single point energies refined post-Hartree fork (M062X/6-311G(d,p)//DLPNO-CCSD(T)/CBS). Then, high-pressure limit rate constants evaluated with tight transition state theory, tunneling effects considered Eckart model low-frequency torsion modes modeled as hindered rotors. Pressure-dependent also calculated channels. Rate expressions in Arrhenius form 91 reactions proposed. All categorized into seven types rule each estimated uncertainty factors three to six. These rules can be potentially used development kinetic mechanisms cycloalkanes. A comparison between different performed favorable channels discussed.