direct crystallization of enantiomers by heterogeneous nucleation stereoselettiva membrane

摘要

The invention concerns a procedure for the separation of optical isomers or for the production of an enantiomeric excess from a racemic mixture or from a mixture having any composition of D and L enantiomers, through direct crystallization by stereoselective nucleation on membranes functionalized with chiral detectors, or prepared starting from materials having stereoselective properties, or made by means of molecular imprinting techniques, or anyhow endowed with the ability of recognizing a specific enantiomer. The membrane carries out the double function of: i) controlling the level of supersaturation of the enantiomeric solution by means of the selective transport of solvent (or, possibly, of antisolvent), taking into account that the trans-membrane transport rate depends both on the structural parameters of the membrane and on the operation conditions; and H) promoting, on the surface of the membrane itself, the heterogeneous selective nucleation of the specific enantiomer, D or L, that preferentially interacts with the same membrane.