Iodination Of Aromatic Compounds Research Articles

Mild and Efficient Iodination of Aromatic Compounds with Pyridine–Iodine Monochloride Complex (PyICI)

A wide range of aromatic compounds has been effectively iodinated with pyridine-iodine monochloride complex, PylCl.

Oxidative halogenation of aromatic compounds in the Pb3O4-Hal?-CF3CO2H system

Chlorination, bromination, and iodination of aromatic compounds may be carried out in the Pb3O4-Hal−-CF3CO2H system at room temperature. Halogenation under these conditions is not complicated by side reactions which are usual when lead tetraacetate is taken as the oxidizing agent.

Iodination of aromatic compounds with a mixture of iodine and peracetic acid. III. Autocatalysis and relative rates

Iodination of aromatic compounds with a mixture of iodine and peracetic acid. III. Autocatalysis and relative rates

The iodination of aromatic compounds with iodine in 20% oleum

The first page of this article is displayed as the abstract.

Iodination of aromatic compounds with a mixture of peroxyacetic acid and iodine

A method for the iodination of water-insoluble aromatic compounds in a homogeneous system is reported; an acetic acid solution of peroxyacetic acid is introduced into a solution of iodine and excess aromatic compound. The yields of iodobenzene and iodotoluenes were 60·5 and 84·6%, respectively. Iodic acid is formed simultaneously, and is the main product in the absence of aromatic compounds. A kinetic study comparing the rate equation and rate constants for the iodination of benzene with those for the reaction of iodine with peroxyacetic under similar conditions has been made. The acidity of the solution has no appreciable effect on the rate and the data suggest a mech- anism which involves a rate-determining formation of iodine acetate or hypoiodous acid followed by a rapid condensation with benzene to form iodobenzene.

Studies on the iodination of aromatic compounds by a mixture of peroxyacetic acid and iodine

The iodination of aromatic compounds by a mixture of peroxyacetic acid and iodine in an acetic acid solution has been studied with a special interest concerning effects of acidity, temperature and the nature of peroxy acid. The addition of sulfuric acid catalyst to the reaction system increased the yield of the corresponding iodinated compound with benzene, halobenzene and benzoic acid, while it decreased the yield with alkylbenzenes. The benzenes having electron-releasing groups and naphthalene are iodinated more satisfactorily with lower temperature and without sulphuric acid catalyst. The use of peroxybenzoic acid instead of peroxyacetic acid gives an unsatisfactory result, which suggests that acetyl hypoiodite is an attacking species.

The Iodination of Aromatic Compounds. IV. The Iodination of Aromatic Hydrocarbons and Nuclear-substituted Phenols

Salicylic acid and p-nitrophenol are almost quantitatively diiodinated when treated in alcoholic solution with iodine, hydrogen peroxide, and sulphuric, nitric, hydrochloric, or phosphoric acid. In glacial acetic acid solution salicylic acid gives good yields of the diiodo compound only in the presence of hydrochloric acid. No appreciable iodination occurs in the presence of sulphuric or nitric acid whilst 3,5-dibromosalicylic acid is formed with hydrobromic acid. Cinnamic acid reacts slowly with iodine, hydrogen peroxide, and sulphuric acid in methanol and ethanol solutions to give the corresponding α-iodo-β-alkoxy-β-phenylpropionic acids. Benzene homologues are readily iodinated in alcoholic solution in the presence of sulphuric or nitric acid although benzene does not react appreciably under similar conditions.

The Iodination of Aromatic Compounds. III. Halogenation of Aromatic Ethers in the Presence of Hydrogen Peroxide

Aromatic ethers are rapidly iodinated when treated in alcoholic solution with iodine and hydrogen peroxide in the presence of a strong mineral acid. High yields of the mono-iodo-derivatives are obtained with anisole and the 2-naphthyl ethers whilst both mono- and diiodination occur readily with the dimethoxybenzenes. In the absence of a mineral acid the reaction is very slow and only poor yield of the iodo-ethers result. A convenient process is described for the preparation of p-chloro- and p-bromo- anisole, and other chloro- and bromo-ethers, the ether being treated with hydrochloric acid and with potassium bromide and sulphuric acid respectively in the presence of hydrogen peroxide.

The Iodination of Aromatic Compounds. I. The Action of Iodine on Aniline in the Presence of Mercuric Oxide

A satisfactory process for the preparation of p-iodo- and 2,4-diiodo-aniline has been developed, aniline being treated with iodine in the presence of mercuric oxide. Acetanilide was also iodinated by this procedure. When lead, calcium, and ferric oxides were employed the yields of p-iodo-aniline proved to be only slightly greater than that obtained by the action of iodine alone, whilst zinc oxide lowered the yield considerably. The influence of added iodides, acids, and mercuric iodide on the rate of reaction of iodine and aniline was investigated. A theory has been proposed to explain the role of mercuric oxide in effecting the iodination of aniline.

The Iodination of Aromatic Compounds. II. The Iodination of Aromatic Ethers and of 2-Naphthol

A rapid process for the iodination of aromatic ethers is described, the ether in 95 per cent. ethanol being treated with iodine and mercuric oxide at an elevated temperature. Anisole and the 2-alkoxy-naphthalenes give high yields of iodo- compounds by this process. 1-Iodo-2-naphthol is readily prepared by the action of iodine and alkali or iodine and mercuric oxide on 2-naphthol. A mechanism is suggested for the iodination of phenols and ethers in the presence of mercuric oxide.