Critical evaluation of protonation constants. Literature analysis and experimental potentiometric and calorimetric data for the thermodynamics of phthalate protonation in different ionic media

摘要

The protonation constants of phthalate were determined in aqueous NaCl (0.1 <= I <= 5mol . L-1) and in aqueous Me4NCl (0.1 mol . L-1 <= I <= 3 mol . L-1) at t = 25 degrees C. Experimental data were employed in conjunction with literature data from studies in different ionic media (Et4NI: 0 <= I <= 1mol . L-1; NaClO4: 0.05 mol . L-1 <= I <= 2 mol . L-1) to study the dependence on ionic strength using different models, such as the SIT and Pitzer equations, and an Extended Debye-Huckel type equation. Experimental calorimetric data in NaCl and protonation constants at different temperatures in Et4NI (5 <= t <= 45 degrees C) and in NaClO4 ( 15 <= t <= 35 degrees C) were also used to study their dependence on temperature. Recommended equilibrium data are reported together with a short discussion of a prospective protocol for drawing these data.