The mechanism of polymorph nucleation of L-glutamic acid
| Autor: | Huei Chia Chang, 張惠嘉 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 A kinetic model is developed in this work to describe the homogeneous nucleation mechanism governed by the aggregation and disruption of solute molecules. Solute molecules in a supersaturated solution can aggregate and form clusters due to the Brownian motion. A disruption kernel is incorporated into the proposed model to account for gradual dissociation or binary dissociation of the solute clusters smaller than a critical nucleus size due to the thermodynamic instability. By fitting the proposed model with the experimental induction time data of L-glutamic acid in the literature and from our experiments (for various supersaturation and temperature, effects of ultrasound and impurities), the collision efficiency and disruption rate constant are recovered. The results reveal that aggregation plays an important role and dissociation can nearly be neglected during the nucleation. Finally, OM、 SEM are applied in the study to investigate the polymorph of L-glutamic acid. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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