The effect of aqueous alcohols (methanol, t-butanol) and sulfolane on the dissociation constants and thermodynamic properties of alkanolamines

The dissociation constants of protonated monoethanolamine, N-methyldiethanolamine have been determined in aqueous mixtures of methanol, t-butanol–water and sulfolane solvents. The mole fractions of the organic compounds ranged from (0.2 to 0.95) and the temperatures from (283 to 353) K. Standard state thermodynamic properties like ΔrG, were derived from the results. The basic strength of the protonated alkanolamine decreased with decreasing dielectric constant and increase in temperature of the solvent.