J Phys Chem A 2010 Jul;114(27):7417-22
Department of Chemistry, College of Sciences, Shiraz University, Shiraz, 71454, Iran.
In this work the molecular electrostatic potential (MEP) is proposed as an effective approach in describing the influence of substituent on the rate constant of etherification reaction. A relationship on the basis of density functional theory has been established to show that the etherification rate constant should be proportional to the electrostatic potential on the atomic sites. Indeed, we employed the MEP at the atomic sites as a local quantum descriptor to estimate the reaction rate constant variation caused by substituent effect. Taking the experimental rate constants of 30 substituted phenols, the validity of the proposed method has been verified. Moreover, the atoms-in-molecules (AIM) charge scheme as another local descriptor was tested for its ability to represent variations in the kinetic data for etherification reaction of phenols. It was shown that the changes in these two descriptors were strongly correlated with the variation of experimental rate constant data. The outcome of good correlations in this study offers a relatively simple and effective method to compute the rate constant for etherification reaction of substituted phenols based on MEP and AIM charge.