Enantiomeric enrichment by the use of density differences between racemic compounds and optically active enantiomers

Kozma, Dávid; Kassai, Csaba; Fogassy, Elemér

doi:10.1016/0040-4039(95)00454-k

Cited by 15 publications

(8 citation statements)

References 5 publications

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“…Another occurrence of the SDE via force field was described 34 using gravity-driven dispersion within a fixed density medium for three compounds, viz. phenylethyl ammonium hydrogen fumarate, 2-amino-1,3-dihydroxy-1-(4-nitrophenyl)-propane, and phenylalanine ( 1 ).…”

Section: Occurrences Of the Sde Phenomenonmentioning

confidence: 99%

The self-disproportionation of enantiomers (SDE): a menace or an opportunity?

et al. 2018

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Section: Occurrences Of the Sde Phenomenonmentioning

confidence: 99%

The self-disproportionation of enantiomers (SDE): a menace or an opportunity?

et al. 2018

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“…While recrystallization is a process that is well familiar to all practitioners as a means to obtain an enantiopure fraction from a nonracemic sample, by contrast, for many other physicochemical processes the SDE phenomenon is not widely appreciated, even for sublimation for which there are mounting examples . In addition to the aforementioned processes, other processes for which the SDE has been observed include force field and even distillation and moreover, the phenomenon has been observed to occur for a vast array of compounds. Regardless of the process, it should be emphasized that the isolation of the ee portion of a sample can vary greatly in efficiency (i.e., yield) depending on the conditions.…”

Section: Mplc Versus Gravity‐driven Column Chromatography For N‐acetymentioning

confidence: 99%

The self‐disproportionation of enantiomers (SDE): The effect of scaling down, potential problems versus prospective applications, possible new occurrences, and unrealized opportunities?

et al. 2019

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This commentary discusses an important, though not widely appreciated, chiral phenomenon of molecular chirality that effectively always occurs whenever nonracemic samples are subjected to practically any physicochemical process (e.g., force field, recrystallization, sublimation, even distillation, etc.) under totally achiral conditions external to the sample itself. The phenomenon is termed as the self‐disproportionation of enantiomers (SDE) and though ubiquitous, its presence may not always be readily apparent, or workers may be otherwise oblivious to its effects. In the particular case of chromatography, when the SDE is apparent, the enantiomeric excess (ee) of the chiral compound is observed to vary across an eluted peak, with anterior eluted portions either enantioenriched or enantiodepleted relative to the ee of the starting material, and conversely for the posterior eluted portions. Herein, we highlight various aspects of the SDE phenomenon as it pertains to chromatography and, in particular, the effect of scaling down chromatographic systems, the potential risk of problems that the SDE can cause, as well as opportunities for practical applications of the phenomenon, possible new occurrences of the SDE phenomenon to be searched for, and unrealized opportunities.

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“…This difference can be applied for the separation of the racemic and enantiopure fraction. For example, from a enantiomeric mixture of phenylalanine (Phe) having 50% enantiomeric purity, two phases of 90 and 13% enantiomeric purity, respectively, could be separated after stirring in an inert solvent of appropriate density, set between the densities of the racemic and enantiopure crystals (Scheme 3) [18,19].…”

Section: Gravity-based Enantiomer Separationmentioning

confidence: 99%

Separation of Chiral Compounds: Enantiomeric and Diastereomeric Mixtures

Pálovics¹,

Szeleczky²,

Szolnoki³

et al. 2018

Laboratory Unit Operations and Experimental Methods in Chemical Engineering

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Despite the dramatic development of enantioselective synthesis and chromatographic separation methods, optical resolution still remains the cheapest and operationally simplest method for producing pure enantiomers on a larger scale. No extreme conditions or expensive reagents are required, and the eventually expensive resolving agents can be recovered. This chapter is based mainly on the authors' long experience in the resolution of industrially important molecules, and it presents new observations and establishments as well. Several methods for separation of chiral mixtures, enantiomeric and diastereomeric mixtures, are shown, and possibilities for predicting the efficiency of resolution based on the analysis of physico-chemical properties of the reactants are also described.

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Enantiomeric enrichment by the use of density differences between racemic compounds and optically active enantiomers

Cited by 15 publications

References 5 publications

The self-disproportionation of enantiomers (SDE): a menace or an opportunity?

The self-disproportionation of enantiomers (SDE): a menace or an opportunity?

The self‐disproportionation of enantiomers (SDE): The effect of scaling down, potential problems versus prospective applications, possible new occurrences, and unrealized opportunities?

Separation of Chiral Compounds: Enantiomeric and Diastereomeric Mixtures

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