Chemical and electrochemical behaviour of nitric and nitrous acids in sulpholane.
With a glass electrode filled with mercury as indicator electrode for hydrogen ions, the acidity constant of nitric acid and the stability constants of the complexes HA(-)(2) (A Cl(-), NO(-)(3)) in sulpholane at 303 K have been determined potentiometrically. The acidity constant of nitrous acid has also been determined in supholane medium because of the low stability of this acid in aprotic media. On the basis of the results, some aspects of the electrochemical and thermodynamic properties of oxygen-nitrogen compounds are discussed in order to explain the catalytic effect of NO(+) in aromatic nitration by N(2)O(4) and/or N(2)O(3) in aprotic solvents.
Boughriet
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A
Laboratoire de Chimie Analytique et Marine, Université des Sciences et Techniques de Lille, Flandres-Artois, 59655 Villeneuve d'Ascq Cedex, France.
Wartel
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M