Effects of salt on the protonation in aqueous solution of triethylenetetramine and tetraethylenepentamine

Protonation constants of triethylenetetramine (trien) and tetraethylenepentamine (tetren) were determined, in NaCl aqueous solutions, at different ionic strengths, at 25°C, using the the pH-metric technique. The behavior of protonation constants as a function of ionic strength can be explained by a model which takes into account the formation of the species AH _q Cl _p A=amine; q=1...4, p=1,2 (trien); q=1...5, p=1.3 (tetren)].