First and Second Dissociation Constants of Some Dicarboxylic Acids and Related Thermodynamic Functions in Water-1,4-Dioxane Medium

摘要

First and second dissociation constants (K1 and K2) of succinic acid, tartaric acid, malonic acid, maleic acid, malic acid and phthalic acid in 20 wt % 1,4-dioxane have been determined at different temperatures (30-60 °C) by using a precise electromotive force method. The thermodynamic functions of dissociation of the acids viz., ΔG°, ΔH° and ΔS° for the first and the second dissociation reactions of these acids have been computed, analyzed and discussed in terms of solute-solvent interactions. An extra thermodynamic analysis has been done in the light of the isoequilibrium temperature values for both reactions indicating that these reactions are entropy controlled reactions.