Ionic equilibria in mixed solvents. Monoprotic organic acids

Abstract

An equation correlating the thermodynamic ionization constants of monoprotic (carboxylic) organic acids in a mixed solvent and a reference solvent (water) is derived employing a curve-fitting program. The equation covers the range of bulk dielectric constant represented by that of pure water and that of very concentrated organic component. An equation for interconversion of the ionization constants between two solvents is also described. The form of the equations is similar to that of Born's equation. Interionic distances between hydrated proton and the hydrated anions were calculated for a large number of acids using the constants of the equations, and these distances are of the right order of magnitude. The bulk dielectric constant of the organic component of the solvent may be computed utilizing the constants of the equation; the computed values of bulk dielectric constants of solvents were less than 7% off from the experimental values. © 1970.