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Free keywords:
3-chloromandelic acid; racemic compound; binary and ternary phase diagrams; polymorphism; X-ray diffraction; calorimetry (DSC); chirality; crystallization
Abstract:
A systematic study of binary melting point and ternary solubility phase diagrams of the enantiomeric 3-chloromandelic acid (3-ClMA) system was performed under consideration of polymorphism. The melting point phase diagram was measured by means of thermal analysis, that is, using heat-flux differential scanning calorimetry (DSC). The results reveal that 3-ClMA belongs to the racemic compound-forming systems. Polymorphism was found for both the enantiomer and the racemate as confirmed by X-ray powder diffraction analysis. The ternary solubility phase diagram of 3-ClMA in water was determined between 5 and 50°C by the classical isothermal technique. The solubilities of the pure enantiomers are extremely temperature-dependent. The solid–liquid equilibria of racemic 3-ClMA are not trivial due to the existence of polymorphism. The eutectic composition in the chiral system changes as a function of temperature. Further, solubility data in the alternative solvent toluene are also presented.
copyright 2010 Wiley-Liss, Inc. and the American Pharmacists Association [accessed September 30th 2010]
