Iodination and iodo-compounds. Part IV. The effect of substituents and solvent composition on the rate of aromatic iodination by means of the tri-iodine cation
The rate and products of the reaction between each of a range of deactivated substituted benzenes and the tri-iodine cation, in sulphuric acid solution, have been investigated. The rate constants may be correlated by the electrophilic substituent constants σ+ giving a value for the reaction constant ρ=–6·4. The kinetic isotope effect for the iodination of benzoic acid was found to be kH/kD= 2. Further details of the solvent effect are reported.