Thermodynamic properties of ethanol solution of chiral camphors and its derivatives

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

“…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. Previous studies have shown that, excess enthalpies for many (R + S)-chiral systems in polar or non-polar solution decreased with the decreasing mole fraction [9,10,14], especially in dilute solution, excess enthalpies changed rapidly, which were similar to the behaviours of (R + S)-limonene in solutions.…”

“…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]. Those solutions showed unique concentration dependence.…”