Chiral separation by SMB chromatography

The paper deals with chiral separation by simulated moving bed (SMB) chromatography. A model for the prediction of the cyclic steady-state performance of the SMB, based on the analogy with the true moving bed (TMB), is developed assuming multicomponent adsorption equilibria, axial dispersion flow and the linear driving force approximation to describe the intraparticle mass transfer rate. The simulation package is used to predict the effect of operating variables on the process performance and to define the regions for enantiomers separation. The influence of mass transfer resistance in the separation region is analyzed. A practical tool for choosing the better SMB operating conditions as a function of the feed flow-rate is proposed. The experimental operation of a pilot unit of SMB, Licosep 12-26 (Novasep, France), is carried out for the separation of enantiomers and illustrated with two systems: the bi-naphthol and the chiral epoxide enantiomers. Experimental results and model predictions are compared in terms of process performance and internal concentration profiles. (C) 2000 Elsevier Science B.V. All rights reserved.