Effect of impurities on chirality conversion by grinding.

ABSTRACT

We study the effect of chiral impurities on Viedma ripening using a simple reaction model. The exponential amplification of the enantiomeric excess (EE) is greatly accelerated by a smaller growth rate of solids with monomers caused by the chiral impurities. From the analysis of the model, it is found that the time evolution of the EE is essentially described by a second-order differential equation. The effect of chiral impurities is that the unstable fixed point is shifted from the racemic point, which leads to the linear amplification behavior observed experimentally. The analysis also shows a possibility of an oscillatory decay of the EE.