Precipitation mechanism of stable and metastable polymorphs of L-glutamic acid
| Autor: | PJ Jansens, Joop H. ter Horst, C. P. Mark Roelands, Herman J. M. Kramer |
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| Rok vydání: | 2007 |
| Předmět: |
Supersaturation
Environmental Engineering Chromatography Aqueous solution General Chemical Engineering Sodium Nucleation Analytical chemistry chemistry.chemical_element Sulfuric acid equipment and supplies chemistry.chemical_compound Polymorphism (materials science) chemistry Metastability Phase (matter) Biotechnology |
| Zdroj: | AIChE Journal. 53:354-362 |
| ISSN: | 1547-5905 0001-1541 |
| DOI: | 10.1002/aic.11072 |
| Popis: | Precipitation of the polymorphic compound L-glutamic acid was initiated by premixing aqueous solutions of sodium L-glutamate and sulfuric acid. Samples of the supersaturated solution were either subjected to vigorous post-stirring or left under quiescent conditions. For low supersaturation (S ≤ 13) without post-stirring aggregated platelet-shaped crystals of the stable beta polymorph formed while post-stirring generated large prismatic crystals of the metastable alpha polymorph. For high supersaturation (S ≥ 17) first smooth spheres were observed which transformed into rough spherulitic crystals of the beta phase. For high supersaturation it is proposed that the spheres are a metastable phase consisting of droplets formed by liquid-liquid phase separation. Subsequently from these spheres crystals of the stable beta phase nucleate. For low supersaturation without post-stirring aggregated beta platelets form according to the same mechanism, while with post-stirring concentration fluctuations are equalized and metastable alpha crystals nucleate from the homogenized solution. © 2006 American Institute of Chemical Engineers AIChE J, 2007. |
| Databáze: | OpenAIRE |
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