In these studies both the kinetics of the reaction and the preparative conditions for the iodination of strongly deactivated compounds, such as benzoic acid and 3-nitrobenzotrifluoride, were investigated.


If the ring contains a strongly activating substituent such as –OH, –OR or amines, a catalyst is not necessary, for example in the bromination of p-cresol: However, if a catalyst is used with excess bromine, then a tribromide will be formed.

Halogenation of phenols is faster in polar solvents due to the dissociation of phenol, with phenoxide ions being more susceptible to electrophilic attack as they are more electron-rich.

Chlorination of toluene with chlorine without catalyst requires a polar solvent as well such as acetic acid.

In organic chemistry, an electrophilic aromatic halogenation is a type of electrophilic aromatic substitution.

This organic reaction is typical of aromatic compounds and a very useful method for adding substituents to an aromatic system.

A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid catalyst is required.

Typical Lewis acid catalysts include Al Cl The reaction mechanism for chlorination of benzene is the same as bromination of benzene.

Iron(III) bromide and iron(III) chloride become inactivated if they react with water, including moisture in the air.

Therefore, they are generated by adding iron filings to bromine or chlorine.

Here is the mechanism of this reaction: In another series of studies the powerful reagent obtained by using a mixture of iodine and potassium iodate dissolved in concentrated sulfuric acid was used.

Here the iodinating agent is the triiodine cation .

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