Carboxylic-perfluoroalkane sulfonic

In the preparation of mixed carboxylic-perfluoroalkane sulfonic anhydrides from the corresponding acids, water formahon is responsible for the low yields of the acylation product. By removing water from the reaction mixture by azeotropic distillation and adsorption onto molecular sieves, the yield of benzoylahon of para-xylene with BAC in the presence of perfluorobutanesulfonic acid (10% mol) is improved to 90%. 

Germain and Commeyras have found that perfluorosulfonic esters and fluorosulfates are formed in high yields by direct anodic oxidation of Rfl in perfluoroalkane sulfonic acids and fluorosulfuric acid (Eqs. 34 and 35). With diiodo compounds, the mono- and diesters can be selectively obtained (Eq. 36). These are useful precursors to valuable perfluoro carboxylic acids. 

Perfluoroalkane carboxylic and sulfonic acids and their derivatives have been synthesized by Zn-Barbier reactions using iodoperfluoroalkanes in dimethyl-sulfoxide (DMSO) as solvent [71]. A Zn/Cu (100 1) couple was used for most of the reactions but other couples such as Zn-Pb, Zn-Cd or Zn-Hg led to the same results ... 

The perfluorosulfonyl fluorides obtained by the electrochemical fluorination process can be readily converted into the corresponding acids and salts used as surfactants (Fig. 2.4). Hydrolysis yields the perfluoroalkane sulfonic acid (I) or its salt (II). Primary or secondary amines yield sulfonamides (III), which can be converted to a carboxylic acid (IV) or an alcohol (V). The alcohol is an intermediate for nonionic surfactants (VI), phosphates (VII), or sulfates (VIII). The tertiary aminosulfonamide (IX) can form a cationic surfactant (X), a amphoteric surfactant (XI), or an amine salt (XII). 

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