Hydrolytic desulfonation

Naphthalenediol. This compound darkens rapidly in air. It can be made by fusion of the sultone of 8-hydroxy-1-naphthaIenesulfonic acid with 50 wt % sodium hydroxide at 200—230°C, or by the hydrolytic desulfonation of l,8-dihydroxy-4-naphthalenesulfonic acid. The diol also reacts with ammonia to give 1,8-naphthalenediamine. 

Naphthalenediol. This diol is made by the hydrolytic desulfonation of 2,3-naphthalenediol-6-sulfonic acid at ca 180°C. It is used as a coupler forming a2o dyes which are appHed in reprographic processes. 

Sulfonic acids may be hydrolytically cleaved, using high temperatures and pressures, to drive the reaction to completion. As would be expected, each sulfonic acid has its own unique hydrolytic desulfonation temperature. Lower alkane sulfonic acids possess excellent hydrolytic stability, as compared to aromatic sulfonic acids which ate readily hydrolyzed. Flydrolytic desulfonation finds use in the separation of isomers of xylene sulfonic acids and other substituted mono-, di-, and polysulfonic acids. 

Reactions of the dihydrates, although leading to Ar2Hg, do provide considerable yields of products of hydrolysis, hydrolytic desulfonation and mercuration, e.g., -(-Hg-CgX4S03-)- or (HCgX4S03Hg)2C6X4 species. More mercuration products are found for polyfluoro- than for polychlorophenyl derivatives. 

Trifluoromethanesulfonic acid, the strongest, known proton acid, which is extremely stable and non-oxidizing, has been used for Friedel-Crafts type acylations and hydrolytic desulfonation... 

Although the sulfonic acid-based polysulfones show better proton conductivity, they are highly susceptible to hydrolytic desulfonation (i.e. loss of sulfonic acid unit through hydrolysis) at elevated temperatures [39]. Hence, it is required to either find a solution of this critical issue or develop phosphonic acid based... 

Kerres et al. [38] reported that the sulfonation close to electron-donating substituents (i.e. ortho-to-ether position) of the main aromatic polymer chain is normally more easily activated for hydrolytic desulfonation in acidic media compared to sulfonation close to electron-withdrawing substituents (i.e. ortho-to-sulfone position). An electrophilic route does not allow acidic ionic groups to be located on the ortho-to-sulfone position in the arylene sulfone segment where it should be, at least slightly, more dissociated than an acidic ionic function located at the ortho-to-ether position in the arylene ether segment. 

Klebe reported that the chlorosulfonation reaction on P3O was best carried out in nitromethane solvent. Sulfonation under these conditions takes place exclusively on the backbone of the polymer. When carried out in chloroform solution cross-linking reactions took place. This polymer was utilized by Hodgdbn to make a fuel cell membrane. Sulfonated PPO and P3O undergo slow desulfonation reactions at 100°C in the presence of water. In order to force the sulfonation reaction to take place on the pendent phenyl groups, and hence give a more hydrolytically stable polymer, the polymer was first brominated on the backbone followed by sulfonation. ... 

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