Simple batch operation for selective crystallization of metastable crystalline phase

This paper describes effectiveness of a "short-time" batch operation for ob taining a metastable crystalline phase (L-glutamic acid, alpha-form) based on the following experimental results. Seed crystals of alpha-form are char ged initially into a crystallizer to commence crystallization. In the case of slowly cooled batch operation, the crystallization accompanying nucleati on of unwanted stable crystalline phase (beta-form). However, nucleation of beta-form can be reduced significantly by increasing the cooling rate ("sh ort-time" batch operation). Additionally, selection of the alpha-form seed crystals that do not include any other solid phase is effective for avoidin g the formation of unwanted (stable) nuclei.