Ultrasound-assisted intensified crystallization of L-glutamic acid: Crystal nucleation and polymorph transformation

Chen Fang; Weiwei Tang; Songgu Wu; Jingkang Wang; Zhenguo Gao; Junbo Gong

doi:10.1016/j.ultsonch.2020.105227

Ultrasound-assisted intensified crystallization of L-glutamic acid: Crystal nucleation and polymorph transformation

Ultrason Sonochem. 2020 Nov:68:105227. doi: 10.1016/j.ultsonch.2020.105227. Epub 2020 Jun 16.

Authors

Chen Fang¹, Weiwei Tang¹, Songgu Wu¹, Jingkang Wang¹, Zhenguo Gao², Junbo Gong³

Affiliations

¹ School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China.
² School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China. Electronic address: zhenguogao@tju.edu.cn.
³ School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China. Electronic address: junbo_gong@tju.edu.cn.

PMID: 32615404
DOI: 10.1016/j.ultsonch.2020.105227

Abstract

In this paper, the crystallization of L-glutamic acid with application of ultrasound was explored in detail, including the process of nucleation, polymorphic control and polymorphic transformation. The induction time and metastable zone widths (MSZWs) were measured with and without ultrasound during the nucleation process. The induction time and MSZWs were decreased by ultrasound and the induction time was further decreased by higher ultrasonic power. The calculated nucleation parameters (such as interfacial energy, critical nucleus size and critical Gibbs energy) showed an obvious decrease in the presence of ultrasound, indicating that the nucleation was enhanced with application of ultrasound. By adjusting the ultrasonic power in the quench cooling process, the difference in nucleation temperatures would determine the distribution of polymorphs. In further, the polymorphic transformation was investigated quantitatively, and to the best of our knowledge, it was the first time to study the transformation kinetics with ultrasound using Avrami-Erofeev model. In the transformation process, the crystallization mechanism of the stable form was modified by ultrasound. The ultrasound eliminated the nucleation element in the rate-limiting step and facilitated the crystal growth of stable form. Thus, the ultrasound has a profound influence on L-glutamic acid crystallization.

Keywords: L-glutamic acid; Nucleation; Polymorphic transformation; Ultrasound.