Enthalpies of mixing and apparent molar volumes of ethanol solution of chiral dicarboxylic acids

Enthalpies of mixing of R- and S-enantiomers of dicarboxylic acids such as 2-methylbutanedioic acid (MBA), 2-hydroxylbutanedioic acid (HBA), 2-methylpentanedioic acid (MPA) and 2-hydroxyl-2-methylbutanedioic acid (HMBA) in ethanol solution have been measured for a large range of mole fraction of heterochiral dicarboxylic acid at 298.15 K. Also densities of ethanol solution of the dicarboxylic acids were determined. Enthalpies of mixing were exothermic for all the concentrations. Enthalpic stabilization on mixing was increased with decreasing concentration of all dicarboxylic acids measured. Sequence of enthalpic stabilization on mixing was MBA mixing was MBA<DHBA<MPA<HMBA<HBS at 0.5 mass%.