A DFT Study on the Degradation of Chlorobenzene to p-chlorophenol via Stable Hydroxo Intermediate Promoted by Iron and Manganese Monoxides

Yougen Wu, Yuchen Zhang and

Abstract

The reaction paths for the conversion of chlorobenzene to p-chlorophenol are presented in detail using iron and manganese monoxides via the hydroxo insertion intermediate, HO–M–C6H4Cl (M=FeO, MnO). The molecular geometries and electronic structures for the reactants, intermediates, transition states, and products were optimized and analyzed in detail by density functional methods. The reaction potential surface profiles indicate that the metaloxo species can activate the para C–H bond of the chlorobenzene to lead to the p-chlorophenol via the successive formation and the dissociation of the metal carbon bond, followed by removal of the metal atom (Fe or Mn). The intrinsic reaction co-ordinate (IRC) analyses indicated that no crossover point was searched for between the high-spin and low-spin potential energy surfaces; thus, no spin crossing was found between these two states potential energy surfaces. The low-spin potential energy surface lies above the high-spin one for the entire reaction pathway. Our theoretical study on the possible reaction pathways for the conversion of chlorobenzene to p-chlorophenol will also be useful for analyzing the catalytic functions of C–H bond activation and metal–carbon bond formation by transition metal complexes.