DFT study on reaction mechanism of di-tert-butylphenol to di-tert-butylhydroxybenzoic acid

Abstract

Experimental studies on the Kolbe-Schmitt reaction and its side reactions have made great progresses, however the relative theoretical studies fall behind. In order to study the mechanism of Kolbe-Schmitt reaction with 2,6-di-tert-butylphenol and 2,4-di-tert-butylphenol as reactants, we carried out theoretical calculation studies at M06-2X/Def2-SVP/SMD level of theory using Gaussian 09 D.01 software package.For the reactant 2,6-di-tert-butylphenol, the main product and side product can convert to each other due to the dynamic equilibrium. However for 2,4-di-tert-butylphenol, the main product is thermodynamically favorable due to its lower Gibbs free energy, while the side product is kinetically favorable due to the lower activation energy barrier. We hope the study can shed light on Kolbe-Schmitt reaction.