Study on viscosity mechanism of caffeine crystallization solutions--颗粒学报PARTICUOLOGY

Yu, L., & Su, M. (2024). Study on viscosity mechanism of caffeine crystallization solutions. Particuology, 91, 341-350. https://doi.org/10.1016/j.partic.2024.03.010

Study on viscosity mechanism of caffeine crystallization solutions

Linjing Yu, Min Su^*

School of Chemical Engineering, Hebei University of Technology, Tianjin, 300130, China

10.1016/j.partic.2024.03.010

Volume 91, August 2024, Pages 341-350

Received 16 January 2024, Revised 10 March 2024, Accepted 28 March 2024, Available online 12 April 2024, Version of Record 30 April 2024.

E-mail: sumin@tju.edu.cn; sumin@hebut.edu.cn

Highlights

• Process of forming a caffeine crystal suspension was investigated.

• Weak intermolecular interactions are responsible for viscosity.

• Effect of temperature and supersaturation ratio on viscosity was studied.

• Viscous mechanism of caffeine crystallization solutions was proposed.

Abstract

The solid-liquid viscous system formed by high viscosity crystallization solution impacts the flow and separation performance. Therefore, it is very important to study the viscosity mechanism to improve viscosity and regulate crystallization, ensuring a seamless production process. Herein, the viscosity of crystallization solution was taken as the measurement parameter of caffeine as a model drug. We investigated the viscosity mechanism of caffeine crystallization solutions by combining experiment and simulation. The results indicated that the weak interactions between caffeine and water result in increased viscosity of the caffeine crystallization solutions. Moreover, caffeine crystals possess elongated needle-like shapes, featuring a substantial specific surface area. Additionally, there is π-π stacking occurring between the (2 0 0) crystal face and (1 1 0) crystal face, effectively fostering coalescence of the crystals towards the radial side of the crystal along its elongated axis, resulting in a more viscous crystallization system. The results contribute to comprehending the viscosity mechanism of crystal systems and provide theoretical foundation to enhance engineering efficiency in crystallization.

Graphical abstract

Keywords

Crystallization; Caffeine; Viscosity mechanism; Molecular simulation

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