Equilibrium studies on enantioselective extraction of oxybutynin enantiomers by hydrophilic β‐cyclodextrin derivatives |
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| Authors: | Kewen Tang Panliang Zhang Chunyue Pan Hongjian Li |
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| Affiliation: | 1. Dept. of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, Hunan, China;2. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China |
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| Abstract: | The enantioselective extraction of hydrophobic oxybutynin (OBN) enantiomers by hydrophilic β‐cyclodextrin (β‐CD) derivatives was studied. The efficiency of extraction depends strongly on a number of process variables such as types of organic solvents and β‐CD derivatives, concentration of selector, pH, and temperature. The experimental data were described by a reactive extraction model with a homogeneous aqueous phase reaction of R,S‐OBN with β‐CD. Important parameters of this model were determined experimentally. The physical distribution coefficients for molecular and ionic OBN were 4.96 × 10?3 and 9.52, respectively. The equilibrium constants of the complexation reactions were 1770 and 1340 L/mol for S‐ and R‐OBN, respectively. By modeling and experiment, an optimal extraction condition with pH of 5 and HP‐β‐CD concentration of 0.1 mol/L was obtained with enantioselectivity (α) of 1.26, which was close to the theoretical maximum of 1.32 and performance factor (pfi) of 0.036. The model was verified experimentally with excellent results. © 2011 American Institute of Chemical Engineers AIChE J, 2011 |
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| Keywords: | reactive extraction chiral separation oxybutynin enantiomers β ‐cyclodextrin modeling |
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