Ways of manipulating the polymorphism of glycine during supercritical fluid crystallisation

Andréanne Bouchard*, Nataša Jovanović, Gerard W. Hofland, Daan J.A. Crommelin, Wim Jiskoot, Geert Jan Witkamp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The precipitation of glycine from aqueous solution was studied using a mixture of supercritical carbon dioxide and ethanol as drying medium and as anti-solvent. Glycine, which has three polymorphs, was precipitated by a direct spraying process using a coaxial nozzle under high pressure. By simple manipulation of the solute concentration, the process could be tuned to selectively precipitate either pure α or β-glycine, as determined by X-ray powder diffraction. When decreasing the solute concentration or increasing the ethanol fraction in the system, the precipitation of the metastable β-glycine was preferred over the precipitation of α-glycine. Modelling of the mass transfer around a drop showed that the ethanol fraction inside the drop can reach significant values, and that the evaporation occurs in less than a second, leaving little space for recrystallisation. Even though the crystal growth rate was extreme (up to 800 μm/s), the product was crystalline.

Original languageEnglish (US)
Pages (from-to)422-432
Number of pages11
JournalJournal of Supercritical Fluids
Volume44
Issue number3
DOIs
StatePublished - Apr 1 2008
Externally publishedYes

Keywords

  • Anti-solvent
  • Aqueous solution
  • Polymorphism
  • Solute concentration

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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