A new twist in eutectic composition: deracemization of a racemic compound amino acid by Viedma ripening and temperature fluctuation.

Viedma ripening and Temperature fluctuation are process based on solution phase racemization and dissolution-growth of racemic or scalemic conglomerates resulting in solid-phase deracemization. The dissolution-growth process is performed by abrasive grinding in the first case and by the temperature fluctuation in the second. But both methods have the intrinsic drawback of being only applicable to conglomerates, accounting for only 10% of all chiral molecules and are not suitable for the 90% of chiral compounds that crystallize as racemic compound. Herein we show that the enantiomeric excess in the eutectic point formed by a racemic compound and one of its enantiomers in suspension changes dramatically by continuous nucleation-growth-dissolution of the crystals, converting the racemic compound into the desire enantiomer. With this new finding the scope of Viedma ripening and temperature fluctuation could be significantly expanded and can shed new ideas about the origin of biological homochirality on earth.