Desulfonation on:
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organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...
, the desulfonation reaction is the hydrolysis of sulfonic acid
In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is kn ...
s:
:RC6H4SO3H + H2O → RC6H5 + H2SO4
The reaction applied to aryl and naphthylsulfonic acids. It is the reverse of sulfonation
In organic chemistry, aromatic sulfonation is a reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid () group. Together with nitration and chlorination, aromatic sulfonation is a widely used electrophilic aromatic substi ...
.Otto Lindner, Lars Rodefeld "Benzenesulfonic Acids and Their Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. The temperature of desulfonation correlates with the ease of the sulfonation.
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Applications in synthesis
This reactivity is exploited in the regiospecific preparation of many di- and tri-substituted aromatic compounds. The approach exploits the meta-directing effect of the sulfonic acid group. 2-Chlorotoluene for example can be prepared by chlorination of p-toluenesulfonic acid, followed by hydrolysis. The method is also useful for the preparation of 2,6-dinitroaniline
Dinitroanilines are a class of chemical compounds with the chemical formula C6H5N3O4. They are derived from both aniline and dinitrobenzenes. There are six isomers: 2,3-dinitroaniline, 2,4-dinitroaniline, 2,5-dinitroaniline, 2,6-dinitroaniline, 3 ...
and 2-bromophenol via phenol-2,4-disulfonic acid.{{cite journal, title=o-Bromophenol, author=Ralph C. Huston , author2=Murel M. Ballard, journal=Org. Synth., year=1934, volume=14, page=14, doi=10.15227/orgsyn.014.0014
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