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Solid‐Liquid Equilibrium of Tröger 's Base Enantiomers in Ethanol: Experiments and Modelling
Author(s) -
Worlitschek Jörg,
Bosco Marcello,
Huber Markus,
Gramlich Volker,
Mazzotti Marco
Publication year - 2004
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200490026
Subject(s) - chemistry , enantiomer , orthorhombic crystal system , ternary operation , thermodynamics , non random two liquid model , solubility , base (topology) , activity coefficient , crystal structure , organic chemistry , aqueous solution , mathematical analysis , physics , mathematics , computer science , programming language
Thermodynamic properties of the enantiomers of the Tröger 's base as crystals and in ethanol solutions have been studied by means of a suite of analytical techniques. We report the melting diagrams of the two enantiomers, providing evidence for the formation of a solid racemic compound. We present also ternary equilibrium data about the solubility of the two enantiomers in ethanol at 25°, 35°, and 50°. The melting‐diagram data are described well by the SchroederVan Laar and PrigogineVieland equations, when the melting temperatures and enthalpies of pure enantiomer and of the racemic compound are provided and with the assumption that the melting behavior is ideal. The ternary equilibrium data were well‐described when nonideality of mixtures of ethanol and the enantiomers is accounted for in terms of the non‐random two liquids (NRTL) model. Finally, we present the newly determined X‐ray crystal structure of an orthorhombic form of the pure Tröger 's base (+)‐enantiomer.