Ionic strength dependence of formation constant-XVI. Protonation of some nitrophenols and dihydroxybenzoic acids in aqueous (tetraethylammonium iodide) solution at 25 degrees.
The protonation of 2- and 3-nitrophenol (NO(2) Ph) and 2,X and 3,Y dihydroxybenzoic acids (DBA, X = 4,5,6; Y = 4,5) has been studied potentiometrically in aqueous tetraethylammonium iodide solutions, at T = 25 degrees in the ionic strength range 0.05:5 </= I </= 1M. Besides the species reported in the literature, we have also found some dimeric species of 2,4-DBA and 2,5-DBA. Also for this type of ligand, a simple equation for the dependence on ionic strength of protonation constants, already proposed for several inorganic and organic acids, has been used successfully. Moreover the behavior of protonation constants as a function of I can give information about the formation of polymeric species.
De Robertis
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Istituto di Chimica Analitica dell'Universita', Salita Sperone 31 (P.O. Box 31), I-98166 S. Agata di Messina, Messina, Italy.
Sammartano
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