Comment on “Relation between metastable zone width and induction time of butyl paraben in ethanol” by H. Yang, CrystEngComm, 2015, 17, 577

Abstract

In a recent paper, Yang (CrystEngComm, 2015, 17, 577) proposed a complicated summation equation to relate the induction time to the metastable zone width (MSZW) in cooling crystallization based on the classical nucleation theory. In Yang's model, nucleation is assumed to occur when the accumulated nucleation potential approaches the critical nucleation potential in both the induction time and the MSZW experiments. However, the definition of the accumulated nucleation potential and critical nucleation potential is ambiguous. In this comment, the MSZW limit is defined, the same as the induction time as the time needed for the number density of accumulated crystals to reach a fixed (but unknown) value, f_N. An integral equation is developed to predict MSZW from the induction time results based on the classical nucleation theory.