Investigation of Metastable Zone Width and Nucleation Kinetics of 2-cyanoguanidine by Cooling Crystallization
Ning Zhang, Yongsheng Ren*, Chengqi Liu and Haipeng Zhao* Author for corresponding; e-mail address: renys@nxu.edu.cn; ys-ren@126.com
Volume: Vol.44 No.4 (October 2017)
Research Article
DOI:
Received: 22 October 2015, Revised: -, Accepted: 24 Febuary 2016, Published: -
Citation: Zhang N., Ren Y., Liu C. and Zhao H., Investigation of Metastable Zone Width and Nucleation Kinetics of 2-cyanoguanidine by Cooling Crystallization , Chiang Mai Journal of Science, 2017; 44(4): 1633-1645.
Abstract
Metastable zone widths (MSZW) of 2-cyanoguanidine in water, methanol, and ethanol are determined at different cooling rates ((6-30) K×h-1) using polythermal method, respectively. The metastable zone widths of solute in the three solvents increase linearly with the cooling rate increasing. Three nucleation theories are employed to estimate nucleation kinetic parameters based on measured MSZW data. The apparent nucleation order m is computed by Self-consistent Nývlt-like approach and Kubota’s model, which suggests that the nuclei are formed by instantaneous nucleation in methanol and ethanol, while the 2-cyanoguanidine nucleate in water shows the occurrence of progressive nucleation mechanism. The activation energy Esat for nucleation of crystals in solution also is estimated by Arrhenius-type equation.