Determination of the absolute solvation free energy and enthalpy of the proton in solutions

• Published in: Journal of molecular liquids 2021-01, Vol.322, p.114919, Article 114919
• Main Authors: Malloum, Alhadji, Fifen, Jean Jules, Conradie, Jeanet
• Format: Article
• Language: English
• Subjects: Proton solvation; Solvation enthalpy; Solvation free energy; Solvation models; Thermodynamics of ions
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.114919

The absolute solvation energies (free energy and enthalpy) of the proton in solution is of great importance for biological and chemical processes in that solution. The absolute solvation free energy of the proton is used to compute the pKa (acids proton dissociation constant) of organic compounds. Furthermore, these absolute solvation energies are used in the development of continuum solvation models and force fields. They are also used to determine the absolute solvation energies of other ions. Despite their importance, the absolute solvation energies of the proton cannot be determined experimentally. In the last century, several methodological approaches have been proposed to determine the absolute solvation energies of the proton in solution. In this review, we present recent and important methodologies used in the last two decades to evaluate the absolute solvation energies of the proton in solutions. In addition, we reviewed and discussed the absolute solvation energies of the proton in water, methanol, ammonia, acetonitrile, dimethylsulfoxide (DMSO), ethanol and other solvents reported in the literature in the last two decades. Finally, featured directions and methodologies which could be very promising are presented and discussed as perspectives. •Recent advances in the determination of proton solvation free energy and enthalpy•Summary of proton solvation methodological approaches•Future directions in the determination of proton solvation free energy and enthalpy