Determination of metastable zone width, induction period and primary nucleation kinetics for cooling crystallization of L-asparaginenohydrate

摘要

A systematic investigation is carried out to determine the induction time and metastable zone width (MSZW) for unseeded batch cooling crystallization of L-asparagine monohydrate. The induction period was measured at three different temperatures at different supersaturation ratios. The induction time measurements reveal a homogeneous nucleation region at high supersaturations and a heterogeneous nucleation region at low supersaturations. The induction time data are analyzed using classical nucleation theory to calculate interfacial energy and various nucleation parameters, such as the radius of critical nucleus, the critical free energy of nucleus, nucleation rate, etc. The MSZW was measured at three different cooling rates and the nucleation kinetic parameters are estimated from MSZW data using classical Nyvlt theory.