Potential of a chiral solvent in enantioselective crystallization of two chiral systems

In this work a systematic study of the potential of chiral solvents in enantioselective crystallization on the example of two chiral systems mandelic acid (compound forming system) and N-Methylephedrine (conglomerate forming system) in (L)-(+)-Diethyl tartrate (chiral solvent) have been investigated. To be able to realize this study a detailed knowledge regarding the underlying solid-liquid equilibria (ternary solubility phase diagram) and metastable zone width measurements is required. Based on these reasons, solubility measurements for mandelic acid and N-Methylephedrine in (L)-Diethyl tartrate at different temperatures were carried out. Also metastable zone width measurements with regard to primary nucleation at various temperatures have been carried out. In all these measurements different analytical technique were used. According to these initial investigations enantioselective (resolution) experiments were designed. The enantioselective crystallization was very successful and with little difficulties associated with very fine crystals blocking the filter holes in the sampling bypass, which prevented liquid phase flow. Further experiments conducted for the enantioselective crystallization in case of racemic-mandelic acid/water, which was used as a reference to compare with racemic-mandelic acid/(L)-Diethyl tartrate, so as to assess the effect magnitude of chiral solvents