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

the kinetics of iodination of the phenol and substituted phenols using pyridiniumiodochloride in methanol has been studied under varying conditions. the rates show first orderkinetics each in pyridinium iodochloride and phenols. the rates of reactions are measured atdifferent temperature and activation parameters for all phenols computed. hammett plot is foundto be valid and the corrletion between the enthalpies and free energies of activations isreasonably linear with an isokinetic temperature 359.55 k. similarly log a values of all thephenols are optimized corresponding to ea of phenols through the equation, log a = log kobs + ea/ 2.303 rt.