Solid−Liquid Phase Equilibria of <i>N</i>-Methylephedrine Enantiomers in Two Chiral Solvents

Kaemmerer, Henning; Tulashie, Samuel Kofi; Lorenz, Heike; Seidel‐Morgenstern, A.

doi:10.1021/je900572c

Cited by 11 publications

(17 citation statements)

References 17 publications

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“…Table 1 further contains thermodynamic information not acquired in our lab for Tröger's base discussed below as a model compound. [153][154][155][156][157][158][159][160][161][162][163][164][165][166][167][168][169] The systems studied show a wide variety of characteristics, such as polymorphy of the (Tables 1 and 2), which are both racemic compoundforming systems. In case of 3-chloromandelic acid for both the enantiomers and the racemic compound monotropic modifications exist.…”

Section: Illustration Of Selected Melt and Solution Equilibriamentioning

confidence: 99%

Processes To Separate Enantiomers

2014

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The provision of pure enantiomers is of increasing importance not only for the pharmaceutical industry but also for agrochemistry and biotechnology. In general, there are two rival approaches to provide pure enantiomers. The "chiral" approach is based on developing an asymmetric synthesis of just one of the enantiomers, while the "racemic" approach is based on separating mixtures of the two enantiomers. In the last few years remarkable progress has been achieved in the latter area. This Review focuses in particular on enantioselective crystallization processes and preparative chromatography, including hybrid processes and the incorporation of racemization steps. Several examples from our research are used for illustration purposes.

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Section: Illustration Of Selected Melt and Solution Equilibriamentioning

confidence: 99%

Processes To Separate Enantiomers

2014

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“…The 70:30 ratio was ascertained by checking the optimum viscosity of the [( S )-2-Pro-Me][NTF 2 ] chiral ionic liquid. The method used to perform the solubility equilibria was published in our previous articles. , It signifies an isothermal method, where a mixture comprising a 5 mL solvent and a considerable excess of the solid phase (weighing of the solid phase with an analytical balance, resolution of balance: ±0.01 mg) was placed into a thermostated vial, which was agitated by a magnetic stirrer and maintained at isothermal conditions (with an uncertainty: ±0.1 K, thermostat, RC6 CP Lauda, Germany) until equilibrium was attained. Subsequently, the solid and liquid phases were separated with a glass filter (pore size, 10 μm) and analyzed.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, enantioselective crystallization is seen as a suitable method for the separation of enantiomers. Unfortunately, all efforts channeled in our previous work into the application of chiral solvents in direct enantioselective crystallization from solution as a possible way for the separation of the N -methylephedrine enantiomers have been proven to be unsuccessful. − Therefore, there is the need to apply a suitable solvent that would be able to promote chiral recognition (asymmetry in the ternary solubility phase diagram) in the N -methylephedrine system. Recently, Vasiloiu et al reported that chiral ionic liquids can demonstrate strong chiral interactions, and also Reichert et al examined the prospect of applying complex solvents such as ionic liquids for crystallization processes.…”

Section: Introductionmentioning

confidence: 99%

Solid–Liquid Equilibria of N-Methylephedrine Enantiomers and Their Mixtures in Two Chiral Ionic Liquids

Tulashie

Lorenz

2019

J. Chem. Eng. Data

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Solubility equilibria of the chiral N-methylephedrine species in two chiral ionic liquids, (S)-2-( m e t h o x y c a r b o n y l ) p y r r o l i d i n i u m b i s -(trifluoromethylsulfonyl) amide ([(S)-2-Pro-Me][NTF 2 ]) a n d ( 1 R , 2 S ) -( − ) -d i m e t h y l e p h e d r i n i u m b i s -(trifluoromethylsulfonyl) amide, have been systematically studied. Solubility measurements were performed for [(S)-2-Pro-Me][NTF 2 ] at temperatures between 278 and 308 K and ( 1 R , 2 S ) -( − ) -d i m e t h y l e p h e d r i n i u m b i s -(trifluoromethylsulfonyl) amide at 308 K, both with different initial enantiomeric compositions of N-methylephedrine. Methanol as a cosolvent was used to decrease the viscosity of [(S)-2-Pro-Me][NTF 2 ]. The solubilities in [(S)-2-Pro-Me][NTF 2 ] increased with temperature increments. A considerable asymmetry was observed in the ternary solubility phase diagram of the chiral N-methylephedrine and (1R,2S)-(−)-dimethylephedrinium bis(trifluoromethylsulfonyl) amide system. The accuracy of the solubility data for Nmethylephedrine in (1R,2S)-(−)-dimethylephedrinium bis(trifluoromethylsulfonyl) amide at 308 K was ascertained by evaluating the mean absolute error.

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“…This composition change may influence the solubility of the enantiomers and thus the crystal product yield. Furthermore, design of the hybrid process must consider the shift of eutectic composition by the change of the solvent composition. , Finally, the solvent where the composition has changed cannot be recycled back to the SMB process without readjusting the composition. To avoid such complexity caused by evaporation, employing continuous nanofiltration units may partly resolve this problem if the molecular size difference between solvents is not significant.…”

Section: Introductionmentioning

confidence: 99%

“…eq, column (10) competitive Langmuir isotherm , m = feed, des, ext, raf is a binary variable which equals one only if the stream is supplied to or withdrawn from column k. product concentration (16) cyclic steady state for liquid phase cyclic steady state for adsorbent…”

Section: ■ Introductionmentioning

confidence: 99%

Optimal Design of Integrated SMB-Crystallization Hybrid Separation Process Using a Binary Solvent

Sreedhar

Shen

et al. 2017

Org. Process Res. Dev.

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Hybrid separation processes combining simulated moving bed chromatography and crystallization have been known to reduce the capital cost for enantiomer separation, but past studies have been limited to systems of single-component pure solvent. In this study, a model-based design strategy using a binary solvent is presented. Separation of D-and Lphenylalanine in a mixture of methanol and water was employed as a case study. Experimental data for solid−liquid equilibrium as well as chromatographic separation were obtained at various compositions of the solvent mixture to model the process. The experimental data were used to model and optimize the design of the hybrid separation process. The trade-offs between the solubility, temperature, chromatographic separation, and eutectic compositions were analyzed using the model-based optimization approach. In a case study, it was found that the productivity can be increased by over 18% when the temperature is increased from 10 to 50 °C because of the lower eutectic purity.

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Solid−Liquid Phase Equilibria of N-Methylephedrine Enantiomers in Two Chiral Solvents

Cited by 11 publications

References 17 publications

Processes To Separate Enantiomers

Processes To Separate Enantiomers

Solid–Liquid Equilibria of N-Methylephedrine Enantiomers and Their Mixtures in Two Chiral Ionic Liquids

Optimal Design of Integrated SMB-Crystallization Hybrid Separation Process Using a Binary Solvent

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