TY - JOUR
T1 - Equilibrium studies on enantioselective liquid - liquid amino acid extraction using a cinchona alkaloid extractant
AU - Schuur, Boelo
AU - Winkelman, Jozef G.M.
AU - Heeres, Hero J.
PY - 2008/12/17
Y1 - 2008/12/17
N2 - The enantioselective extraction of aqueous 3,5-dinitrobenzoyl-R,S-leucine (AR,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 AR,S with C. Important parameters of this model were determined experimentally. The acid dissociation constant, Ka, of AR,S was (1.92 ± 0.07) x 10 -4 mol/L. The physical distribution coefficient of AR,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 104 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 ≫ pKa. The model was verified experimentally with excellent results (±7.9%).
AB - The enantioselective extraction of aqueous 3,5-dinitrobenzoyl-R,S-leucine (AR,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 AR,S with C. Important parameters of this model were determined experimentally. The acid dissociation constant, Ka, of AR,S was (1.92 ± 0.07) x 10 -4 mol/L. The physical distribution coefficient of AR,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 104 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 ≫ pKa. The model was verified experimentally with excellent results (±7.9%).
UR - http://www.scopus.com/inward/record.url?scp=64549085875&partnerID=8YFLogxK
U2 - 10.1021/ie800668e
DO - 10.1021/ie800668e
M3 - Article
AN - SCOPUS:64549085875
SN - 0888-5885
VL - 47
SP - 10027
EP - 10033
JO - Industrial & engineering chemistry research
JF - Industrial & engineering chemistry research
IS - 24
ER -