Solution-mediated transformation of α to β L-glutamic acid: Rate enhancement due to secondary nucleation

The ability to control the transformation process between polymorphs of crystalline materials is critical to ensure that the correct form is produced, and hence it is essential to learn which experimental factors affect this transformation reaction. In this contribution, the kinetics of the polymorphic transformation between metastable and stable forms of l-glutamic acid was studied using a number of techniques:  optical microscopy, FT-IR, Raman and UV spectroscopy. The effects of solution composition and in particular process scale were investigated. The role of secondary nucleation in which the surface of one polymorph acts as a template for the nucleation of another form is highlighted in this paper.

[1]  Benjamin K. Hodnett,et al.  Secondary nucleation of the β-polymorph of L-glutamic acid on the surface of α-form crystals , 2003 .

[2]  J. D. Bernal.  The Crystal Structure of the Natural Amino Acids and Belated Compounds , 1931 .

[3]  E. Ferrari,et al.  Nucleation control in solution mediated polymorphic phase transformations: The case of 2,6-dihydroxybenzoic acid , 2002 .

[4]  M. Kitamura.  Polymorphism in the crystallization of L-glutamic acid , 1989 .

[5]  John Garside,et al.  INVITED REVIEW SECONDARY CONTACT NUCLEATION: KINETICS, GROWTH AND SCALE-UP , 1980 .

[6]  K. Onuma,et al.  In Situ Observation of Growth Process of α-L-Glutamic Acid with Atomic Force Microscopy , 2000 .

[7]  E. Ferrari,et al.  Crystallization in Polymorphic Systems: The Solution-Mediated Transformation of β to α Glycine , 2003 .

[8]  J. Bernstein.  Polymorphism of l-glutamic acid: decoding the α–β phase relationship via graph-set analysis , 1991 .

[9]  R. Docherty,et al.  Polymorphism in Molecular Crystals: Stabilization of a Metastable Form by Conformational Mimicry , 1997 .

[10]  Mitsutaka Kitamura,et al.  Growth kinetics and morphological change of polymorphs of L-glutamic acid , 2000 .

[11]  Y. Ohashi,et al.  Structure of α Form of L-Glutamic Acid. α-β Transition , 1980 .

[12]  S. Hirokawa,et al.  A new modification of l‐glutamic acid and its crystal structure , 1955 .

[13]  J. Garside,et al.  Direct observation of secondary nuclei production , 1978 .