Thermodynamic parameters for the protonation of some polyamines C(2n-2)NnH(5n-2) NaCl aqueous solution at different ionic strengths

This work reports thermodynamic parameters (obtained by potentiometric measurements with an H-glass electrode) for the protonation of polyamines (ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine) in aqueous NaCl solution at different temperatures and ionic strengths, together with the parameters which define the dependence on ionic strength. The results regarding the dependence on ionic medium were interpreted in terms of complex formation of protonated polyamines with the chloride ion. Empirical relationships are reported for the dependence of thermodynamic parameters on ionic strength and of the stability of chloride complexes on the stoichiometry of the formation reaction.