Chiral purification using crystal growth and grinding

Understanding how single-handedness of biological molecules came about
has been of interest since Pasteur first separated mirror-image crystals
of tartaric acid. Based on an experiment by Viedma, we have developed a
method to convert a racemic mixture of chiral molecules to a single
handedness by grinding a slurry of crystals under racemizing conditions.
The handedness of the final state can be controlled in several ways,
including the use of additives and circularly polairzed light. This
provides a possible route for the origin of biological homochirality,
but also a method that can be used in the pharmaceutical industry to
produce chirally pure products.