Thermodynamic Properties of d- and l-Tartaric Acid in Aqueous and Ethanol Solution at 298.15 K

Abstract

Enthalpies of mixing and excess volumes of D-and L-tartaric acid in aqueous and ethanol solution were measured at 298.15 K. Excess enthalpies of mixing were observed for three different concentrations of aqueous and ethanol solutions of tartaric acid. Enthalpies of mixing were exothermic for all the concentrations in both solvents. Enthalpic stabilization on mixing was increased with decreasing concentration of tartaric acid for both solvents. Excess volumes of D-and L-tartaric acid in aqueous solution showed volume contraction on mixing, but those of D-and L-tartaric acid in ethanol solution showed volume expansion on mixing. Volume contractions of aqueous solution were increased with decreasing concentration of tartaric acid.

Thermodynamic properties of ethanol solution of chiral camphors and its derivatives

“…In addition, those volume changes had an effect on the enthalpic behaviour of solutions, as occurred in the chiral solution of tartaric acid. [11] Excess volumes were determined by equation (5), listed in table 3 and are shown in figure 3…”

“…In addition, another reliability test of the microcalorimeter system and the procedures used had been performed using a binary mixture of {(1 À x)1,4-dimethybenzene + x1,3-dimethylbenzene} and {(1 À x)1,4-dimethylbenzene + x1,2-dimethylbenzene} as reported previously [15] for the exothermic and endothermic systems. Details of the calorimetric procedure have been described previously [11][12][13][14][15]. The sample densities were measured using a vibrating-tube densitometer (Anton Paar DMA60) at T = (298.15 ± 0.001) K. The details of the densitometric procedures were the same as those described previously [16].…”

“…However, very little literature exists on the mixing enthalpies in solution. Excess enthalpies of aqueous and ethanol solution of 2,3-dihydroxylbutanedioic acid were observed for three different concentrations of aqueous and ethanol solutions of 2,3-dihydroxylbutanedioic acid [11]. Enthalpies of mixing were exothermic for all the concentrations in both solvents, while enthalpic stabilization on mixing was increased with decreasing concentration of 2,3-dihydroxylbutanedioic acid for both solvents.…”

Thermodynamic properties of chiral fenchones in some solutions at T=298.15K

“…With the decreasing of the specified mole fraction of fenchone in ethanol solution, excess enthalpies for mixing of R-and S-orientated chiral solutions increased, and became close to zero. The negative slope for the nearly linear dependence of H E 0:5 on its mole fraction x in ethanol solution was first found for fenchone compared with five dicarboxylic acids and camphor and its five derivatives [9,10,14]. On the contrary, with the decreasing of the specified mole fraction of limonene x in ethanol solution, excess enthalpies for mixing of (R + S)-limonene in solutions decreased from positive to negative; while the mole fractions of the pseudo-two-components x were smaller than 0.1, the excess enthalpies decreased sharply.…”

“…To elucidate stereospecific intermolecular interactions arising from the chiral structures of molecules and to understand chiral discrimination based on structural properties of liquids and solutions, the thermodynamic properties of mixing of many couples of (R)-and (S)-enantiomers, and enantiomers in polar and non-polar solutions were systematically studied in our laboratory [5][6][7][8][9][10][11][12][13][14][15][16]. Non-polar chiral compounds of chiral limonenes in whole concentrations of ethanol solutions have been investigated [14], and enthalpic behaviours of chiral limonenes in non-polar solvents of benzene, hexane, cyclohexane, and carbon tetrachloride have been determined and their unique concentration dependence reported [15,16].…”