Equilibrium Studies on Enantioselective Liquid-Liquid Amino Acid Extraction Using a Cinchona Alkaloid Extractant

Boelo Schuur, Jozef G. M. Winkelman, Hero J. Heeres*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

The enantioselective extraction of aqueous 3,5-dinitrobenzoyl-R,S-leucine (A(R,S)) by a cinchona alkaloid extractant (C) in 1,2-dichloroethane was studied at room temperature (294 K) in a batch system for a range of intake concentrations (10(-4)-10(-3) mol/L) and pH values (3.8-6.6). The experimental data were described by a reactive extraction model with a homogeneous organic phase reaction of A(R,S) with C. Important parameters of this model were determined experimentally. The acid dissociation constant, K(a), of A(R,S) was (1.92 +/- 0.07) x 10(-4) mol/L. The physical distribution coefficient of A(R,S) between the organic and aqueous phase was 8.04 +/- 0.39. The equilibrium constants of the organic phase complexation reaction were (9.31 +/- 0.76) x 104 L/mol and (2.71 +/- 0.76) x 10(4) L/mol for the S- and R-enantiomers, respectively. With these parameters an optimum performance factor, PF, of 0.19 was predicted. The PF was independent of the pH provided that pH >> pK(a). The model was verified experimentally with excellent results (+/- 7.9%).

Original languageEnglish
Pages (from-to)10027-10033
Number of pages7
JournalIndustrial and Engineering Chemistry Research
Volume47
Issue number24
DOIs
Publication statusPublished - 17-Dec-2008

Keywords

  • ENANTIO-SELECTIVE EXTRACTION
  • CHIRAL SEPARATION
  • REACTIVE EXTRACTION
  • DERIVATIVES
  • PARTITION
  • ALCOHOLS
  • ION
  • ENANTIOSEPARATION
  • CHROMATOGRAPHY
  • RECOGNITION

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