IODINATION OF AROMATIC COMPOUNDS WITH A MIXTURE OF IODINE AND PERACETIC ACID .3. AUTOCATALYSIS AND RELATIVE RATES

In acetic acid solution, the rate of reaction of m-xylene with a mixture of iodine and peracetic acid to give 4-iodo-1,3-dimethylbenzene can be expressed as v = k[I2][CH3CO3H] and is independent of [m-xylene], The reaction showed autocatalysis for aromatic compounds with reactivity greater than benzene. Addition of iodoaromatics to the system accelerates the reaction. Iodosobenzene and phenyl iodine diacetate are effective oxidizing agents for iodine, and a mixture of these materials and iodine can iodinate aromatic compounds. The autocatalysis seems to be due to the formation of aromatic iodoso compounds or aryl iodine diacetates by the oxidation of iodo-aromatics with peracetic acid. The relative rates of this iodination of some aromatic compounds were measured by competitive reactions. Electron-releasing substituents accelerate the reaction, suggesting that the iodinating species is electrophilic in nature. © 1968, American Chemical Society. All rights reserved.