Continuous enantioselective crystallization of chiral compounds in coupled fluidized beds

Abstract

• Highly productive continuous enantioselective crystallization. • Exploitation of two coupled fluidized bed crystallizers. • Provision of narrow product crystal size distributions. • Validation of a reduced population balance model. • First results regarding high resolution CFD-DEM simulations. This review summarizes results of an interdisciplinary project devoted to improve the access to enantiopure components by applying an advanced continuous separation process exploiting the principle of kinetically controlled preferential crystallization within two coupled fluidized beds located in conically shaped tubular crystallizers. The process efficiently combines selective crystallization with integrated product classification. Along with summarizing the related literature, new original results are presented with respect to theoretical process description and experimental validation. Although only one chiral system is considered specifically, namely the separation of the enantiomers of a racemic mixture of asparagine monohydrate using water as solvent, general conclusions will be drawn to highlight the large potential of the process principle. The conceptual approaches presented are seen as useful tools for the development of productive continuously operating enantioselective crystallization processes. They are applicable to separate enantiomers of numerous chiral molecules.