Bond dissociation energy of the phenol O{single bond}H bond from ab initio calculations

Abstract

The phenol O{single bond}H bond dissociation energy (BDE) is currently disputed, despite its importance in combustion chemistry and in the reactions of antioxidants such as vitamin E. We have studied this BDE using the computational methods G3, G3B3 and CBS-APNO, with bond-isodesmic work reactions. These calculations yield a BDE of 89.0 ± 1.0 kcal mol-1, which supports other recent calculations [B.J. Costa Cabral, S. Canuto, Chem. Phys. Lett. 406 (2005) 300]. From our BDE we determine the enthalpy of formation of the phenoxy radical to be 13.9 ± 1.0 kcal mol-1. Comparison of the phenol C{single bond}H BDE with the vinyl alcohol H{single bond}CH{double bond, long}CHOH BDE reveals the bond in ..