Crystallization

Crystallization is one of the strongest techniques for the purification of organic compounds. In nearly all industrial processes crystallization is used as a method to produce, purify or recover solid compounds. Especially for pharmaceutical compounds, crystallization is usually the preferred isolation procedure and is critical for obtaining high-purity drug substances. In addition, crystallization is frequently used to improve the enantiomeric excess of partially enriched chiral compounds obtained by i.e. (catalytic) asymmetric synthesis or biocatalytic processes, enabling precise control of chirality and chiral crystallization.

Crystallization can also be used to separate the enantiomers of a racemate by diastereomeric salt formation or by preferential crystallization (Pasteurian resolution). Combined with in situ racemization, crystallization-induced resolutions can be turned into efficient high-yield processes, such as crystallization-induced diastereomeric transformation (CIDT), Viedma ripening, temperature cycling induced deracemization (TCID), or dynamic kinetic resolution.