Effect of Water–Ethanol Solvents on the Protonation Constants of Cryptand[2.2.2]

Abstract

The protonation constants of cryptand[2.2.2] are determined potentiometrically at 298 K in water–ethanol solvents of variable composition. An increase in the concentration of a solution’s nonaqueous component reduces the equilibrium constants of the reactions of mono- and biprotonated cryptand[2.2.2] formation. The contribution from the resolvation of reagents to the change in the Gibbs energy of the studied reactions is estimated. The reduction in the protonation constants of cryptand[2.2.2] in water–ethanol solvents is mainly due to enhancement of the solvation of protons in water–ethanol mixtures.