Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Thermodynamic dependencies and information are of prime importance to per- form a controlled selective crystallization process, e. g. to separate the enantiomers of chiral components. This study is focused on the determination of phase diagrams of a chiral system. The melting behavior and solubility equilibria (SLE) of diethyl- 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate (Mefenpyr- diethyl) in various ethanol/water mixtures in the temperature range between 273K to 293K were analyzed. The obtained results identify Mefenpyr-diethyl as a racemic compound-forming system. It has been found that the solubility behavior strongly de- pends on temperature. In certain concentration ranges, liquid-liquid equilibria (LLE) were detected. Liquid-liquid separation has to be prevented during cooling crystal- lization processes. The observed LLE-phenomena were quanti ed in this study under polythermal and isothermal conditions and the phase diagrams were derived based on the experimental data. With these diagrams it is possible to design a polythermal enantioselective crystallization process avoiding oiling out.