Thermochemical and kinetic studies of H-abstraction reaction of benzofurans and benzodioxins by H-atoms

Abstract

The thermo-kinetic data of the H-abstraction of benzofurans (benzofuran and dibenzofuran) and benzodioxins (1,4-benzodioxin and dibenzo-p-dioxin) have been obtained by the CCSD(T)-F12/CBS//CAM-B3LYP/6–311++G(d,p) method. Based on the Bonding Dissociation Energies (BDE) we have observed a stabilization effect exerted by the O-atom on the H-atoms located in β-position of it, thereby increasing their BDEs. In line with these BDEs, we have classified the H-atoms into four groups: group 1, H-atoms in the benzene ring unaffected by the stabilization effect of the oxygen atom; group 2, H-atoms in the benzene ring under the influence of the stabilization effect of the oxygen atom; group 3, H-atoms positioned in the dioxin ring and group 4, H-atoms located in the furan ring. We have calculated and evaluated the kinetic constants for the H-abstraction reactions for each of these H-atoms thereby deducing the average values for each type of the H-abstracted.