Kinetic of iodination of phenol and substituted phenols by pyridinium iodochloride in methanol

The kinetics of iodination of the phenol and substituted phenols using pyridinium iodochloride in methanol has been studied under varying conditions. The rates show first order kinetics each in pyridinium iodochloride and phenols. The rates of reactions are measured at different temperature and activation parameters for all phenols computed. Hammett plot is found to be valid and the corrletion between the enthalpies and free energies of activations is reasonably linear with an isokinetic temperature 359.55 K. Similarly log A values of all the phenols are optimized corresponding to Ea of phenols through the equation, log A = log kobs Ea / 2.303 RT.