title: Solid-Phase and Oscillating Solution Crystallization Behavior of (+)- and (-)-N-Methylephedrine.
abstract: This work involves the study of the solid-phase and solution crystallization behavior of the N-methylephedrine enantiomers. A systematic investigation of the melt phase diagram of the enantiomeric N-methylephedrine system was performed considering polymorphism. Two monotropically related modifications of the enantiomer were found. Solubilities and the ternary solubility phase diagrams of N-methylephedrine enantiomers in 2 solvents [isopropanol:water, 1:3 (Vol) and (2R, 3R)-diethyl tartrate] were determined in the temperature ranges between 15°C and 25°C, and 25°C and 40°C, respectively. Preferential nucleation and crystallization experiments at higher supersaturation leading to an unusual oscillatory crystallization behavior as well as a successful preferential crystallization experiment at lower supersaturation are presented and discussed.
authors.affiliation: University of Cape Coast, College of Agriculture and Natural Sciences, School of Physical Sciences, Department of Chemistry, Industrial Chemistry Unit, Cape Coast, Ghana; Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
authors.forename: Samuel Kofi
authors.initials: SK
authors.lastname: Tulashie
authors.affiliation: Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Polenske
authors.affiliation: Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany; Institute of Chemical Engineering, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Seidel-Morgenstern
authors.affiliation: Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany. Electronic address: lorenz@mpi-magdeburg.mpg.de.
authors.forename: Heike
authors.initials: H
authors.lastname: Lorenz
mesh_terms: D003460:Crystallization / Q000379:methods; D004809:Ephedrine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D013237:Stereoisomerism; D013696:Temperature; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: C041707:N-methylephedrine; D004809:Ephedrine
keywords: chiral resolution; induction time; polymorphism; preferential crystallization; preferential nucleation; resolution by entrainment; solubility data