New application of the Crystal16™
Understand the solid state behaviour of chiral compounds.
Using the Crystal16®, a method was developed to distinguish between conglomerates, racemic mixtures and solid solutions of chiral compounds.
The method is fast and simple:
- Crystal16® is used to screen mixtures of enantiomers in different solvents
- Saturation temperatures are used to generate phase diagrams
- These phase diagrams can be used to establish the solid state behaviour of a mixture
The quantitative data from the phase diagram screen is essential information in identifying and designing chiral separation processes based on crystallization. The phase diagram screening method is therefore an interesting new and fast way to obtain an indication of the solid state behavior and the phase diagram of chiral compounds.
Sukanya Srisanga and Joop H. ter Horst, Racemic Compound, Conglomerate, or Solid Solution: Phase DiagramScreening of Chiral Compounds, Crystal Growth and Design, 2010, Vol. 10, 1808-1812
Crystallization in racemic solutions usually results in a racemic compound, a conglomerate or a solid solution. Resolution of a chiral compound strongly depends on the kind of solid state that it forms. Solid-liquid equilibria are related to the prevailing solid state of the chiral compound. A phase diagram screening of enantiomer mixtures in solution can therefore give important indications on the possibility of chiral resolution through crystallization. We describe a new simple and straightforward phase diagram screening method for chiral compounds in solution. Rather than determining the saturation concentration at a certain temperature, we more conveniently determined the saturation temperature of a certain solution composition. A number of chiral compounds were tested with the new method. Asparagine in water behaves as a conglomerate system, ibuprofen in hexane shows racemic compound/enantiopure compound formation, and atenolol shows solid solution behavior, consistent with observations elsewhere. Additionally, the method results in the ternary phase diagram of both enantiomers in a solution which may enable separation methods to be identified and designed.
Download a scientific poster, presented at the BACG on:
Racemic Compound, Conglomerate, or Solid Solution: Phase Diagram Screening of Chiral Compounds
S.Srisanga, J.H. ter Horst
Intensified Reaction and separation Systems, Process & Energy Laboatory, Delft University of Technology, Delft, The Netherlands