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Free keywords:
chiral resolution; resolution by entrainment; seeded isothermal preferential crystallization; auto-seeded polythermal preferential crystallization; online monitoring; crystallization trajectory; mandelic acid
Abstract:
Recently the feasibility of preferential crystallization for enantioseparation of racemic compound forming systems has been demonstrated (Lorenz et al., Application of preferential crystallization to resolve racemic compounds in a hybrid process. Chirality 2006;18:828-840; Polenske et al., Separation of the propranolol hydrochloride enantiomers by preferential crystallization: thermodynamic basis and experimental verification. Cryst Growth Des 2007;7:1628-1634). Here, the development and the potential of an efficient separation process operated via two different techniques of preferential crystallization are studied: (1) seeded isothermal preferential crystallization and (2) auto-seeded polythermal preferential crystallization. Both techniques were investigated in the batch and in the cyclic operation mode. On the example of mandelic acid as a typical racemic compound forming system, it is demonstrated that a cyclic auto-seeded polythermal process is feasible and significantly more efficient than the seeded isothermal one.
Copyright © 2009 Wiley-Liss, Inc., A Wiley Company
[accessed July 24, 2009]