Reliable and Selective Crystallization of the Metastable -Form Glycine by Seeding
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- 作者：Norihito Doki ; Masaaki Yokota ; Kanako Kido ; Shigeko Sasaki ; and Noriaki Kubota
- 刊名：Crystal Growth & Design
- 出版年：2004
- 出版时间：January 2004
- 年：2004
- 卷：4
- 期：1
- 页码：103 - 107
- 全文大小：165K
- 年卷期：v.4,no.1(January 2004)
- ISSN：1528-7505
文摘
This paper describes a reliable method to selectively produce metastable 
-form glycine crystals witha controlled size in batch cooling crystallization. Seeding had a large effect both on the polymorphism and the sizedistribution of the product crystals. In the case of sufficient seed loadings of the -form crystals, the metastable-form crystals were obtained selectively as a product. Simultaneously, the crystal size distribution became unimodalwith no fine crystals. However, at low seed loadings, mixtures of both the metastable - and stable 
-form crystalswere obtained. The measurement of supersaturation transient suggested that the low supersaturation caused bythe growth of sufficient seeds played a key role in suppressing nucleation of the metastable - and -form crystals,whereas, with no seeding, only the stable -form crystals were obtained. The seeding technique presented herecould be a general and practical method to produce metastable polymorphs with controlled crystal size.
-form glycine crystals witha controlled size in batch cooling crystallization. Seeding had a large effect both on the polymorphism and the sizedistribution of the product crystals. In the case of sufficient seed loadings of the -form crystals, the metastable-form crystals were obtained selectively as a product. Simultaneously, the crystal size distribution became unimodalwith no fine crystals. However, at low seed loadings, mixtures of both the metastable - and stable -form crystalswere obtained. The measurement of supersaturation transient suggested that the low supersaturation caused bythe growth of sufficient seeds played a key role in suppressing nucleation of the metastable - and -form crystals,whereas, with no seeding, only the stable -form crystals were obtained. The seeding technique presented herecould be a general and practical method to produce metastable polymorphs with controlled crystal size.