Tetraalkylammonium -toluenesulfonates

Since the initial reports, polypyrrole films have been prepared under both po tentiostatic and galvanostatic conditions on a large number of substrates [94,95] with various electrolytes. Best depositions are obtained by oxidation of O.I M pyrrole in acetonitrile, 0.1 tetraalkylammonium />toluenesulfonate [96]. 

The choice of the anion is most important in anodic reactions. Perchlorates have been found very useful as they are difficult to oxidize and are often soluble both in water and nonaqueous solvents. In anodic (Section VI, F) or cathodic (Section IV, A) substitution reactions the nucleophilicity of the anion is of interest. High concentrations of tetraalkylammonium p-toluenesulfonates in water make the solubility of organic compounds higher than in pure water, and such solutions combine a low ohmic resistance with good dissolving power. 

Thiazole A -oxides can easily be alkylated on the oxygen. For example, Ar-(alkoxy)-5-(p-methoxyphenyl)-4-methylthiazole-2(377)-thiones were prepared from Ar-(hydroxy)-5-( -methoxyphenyl)-4-methylthiazole-2(3//)-thione tetraethylammonium salt and an appropriate alkyl chloride or tosylate in moderate to good yields <20060BC2313>. A -Methoxythiazole-2(377)-thiones were synthesized from the A -hydroxythiazole-2(3//)-thiones by treatment first with a tetraalkylammonium hydroxide in methanol and then methyl ra-toluenesulfonate in DMF <2005EJ0869>. 

The aromatic sulfonates have been employed mostly for reductions, but they would be expected to be reasonably stable toward oxidation. To obtain a reasonable hydrotropic effect, rather high concentrations are used in the original hydrodimerization reaction of acrylonitrile, the medium may be regarded as either a solution of tetraalkylammonium p-toluenesulfonate in water or the salt containing some water. 

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