Reaction Paths and Transition States of C-H Bond Rupture in Aromatics; Benzene and Toluene Molecules

Applying the Density Functional Theory (DFT) method the C-H bond rupture reaction path is calculated for benzene and toluene reactions. It is found that, for benzene the molecule maintains its (C2v) coplanar property along the reaction path. The values for the activation and reaction energies are 169.456 kcal/mol and 118.346 kcal/mol respectively. As for toluene different reaction mechanisms are calculated. The reaction proceeds coplanarly for the Hmeta and Hpara atoms only. For the ortho-H atom a participation of a CH3 H atom is predicted to yield a H2 molecule in a concerted reaction manner. The reaction for a CH3 bond rupture proceeds in a non-coplanar manner yielding the benzyl radical as end product. For all considered reactions the geometry and energy of the transition states are obtained.