(692c) Effects of Inorganic Salts and Volume Reduction on Glycine Polymorphism | AIChE

(692c) Effects of Inorganic Salts and Volume Reduction on Glycine Polymorphism


Dela Cruz, I. J. C. - Presenter, University of the Philippines
Perez, J. V. D., University of the Philippines
Alamani, B., University of the Philippines Diliman
Myerson, A. S., Massachusetts Institute of Technology
Capellades, G., Massachusetts Institute of Technology
Studies have demonstrated that inorganic salts can drive polymorphic selectivity of glycine from the metastable α-polymorph to the stable γ-polymorph. Here, we explore the effect of NaCl and CaCl2 together with volume reduction on glycine nucleation. The salts were added to supersaturated aqueous solutions of glycine at a 2:1 Gly:NaCl/CaCl2 ratio at volumes from 1000 μL to 50 μL. Analysis showed that a primary γ-glycine nucleation event occurs for Gly:NaCl systems, with observed increase in induction times as volume was decreased. However, β-glycine primary nucleation was also detected for Gly:NaCl systems. Interestingly, it was observed that β-glycine nucleation is preferred over the salt-directed γ-glycine nucleation at a certain volume. The increase in induction times combined with a decrease in probability for γ-glycine nucleation may have allowed preferred nucleation of the β-polymorph. On the other hand, no nucleation events were observed for Gly:CaCl2 systems at a time span of 48 hours. These results provide insight on how polymorph modifiers act in confined environments.