Gas Antisolvent Fractionation: a New Method to Obtain Enantiopure Compounds, a Case Study on Mandelic Acid

  • Márton Kőrösi Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Hungary http://orcid.org/0000-0002-1224-4788
  • Attila Sedon Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Hungary http://orcid.org/0000-0002-3872-7753
  • Kinga Komka Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Hungary
  • Tamás Sohajda CycloLab Cyclodextrin Research and Development Laboratory Ltd., Budapest, Hungary
  • Edit Székely Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Hungary http://orcid.org/0000-0002-6935-0071

Abstract

Micronization processes involving supercritical carbon dioxide are rapid methods to produce fine particles. They also might offer the possibility of using less organic solvent than conventional crystallization methods leading to an environmentally friendlier processing. The separation capabilities of such processes are now demonstrated on the diastereomeric resolution of mandelic acid using (R)-1-phenylethanamine as a resolving agent, utilizing the batch type gas antisolvent fractionation as the separation method. A detailed study was conducted on the effects of the operational parameters pressure (12-20 MPa), temperature (35-55 °C) and co-solvent concentration (33-99 mg/ml). At 12 MPa, 35 °C and 99 mg/ml methanol concentration, a selectivity of 0.52 and a diastereomeric excess of 62% was reached. The same operational parameters were applied during the investigation of the recrystallization-based further purification of the diastereomeric salts, applying the resolving agent in molar equivalent quantity to a non-racemic mixture of mandelic acid. It has been found that the more stable (R)-1-phenylethylammonium-(R)-mandelate salt can be purified to de>98% through four additional recrystallization steps following the initial, half-molar equivalent resolution step.

Keywords: supercritical carbon dioxide, optical resolution, enantiomer, chiral, recrystallization
Published online
2018-04-04
How to Cite
Kőrösi, M., Sedon, A., Komka, K., Sohajda, T. and Székely, E. (2019) “Gas Antisolvent Fractionation: a New Method to Obtain Enantiopure Compounds, a Case Study on Mandelic Acid”, Periodica Polytechnica Chemical Engineering, 63(1), pp. 130-137. doi: https://doi.org/10.3311/PPch.11741.
Section
Articles