Thermodynamic parameters for the protonation of urea at different temperatures and ionic strengths

Potentiometric measurements of aqueous urea solutions (less than2.5 mol-dm⁻³ of urea) were performed at different temperature and ionic strengths (10≤T≤45°C; 0.02≤I≤0.6 mol-dm⁻³) to determine thermodynamic protonation parameters. The formation of the species U₂H⁺ was hypothesized to explain the concentration dependence of the protonation constant.