ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Enantioselective extraction of hydrophilic 2-chloromandelic acid enantiomers by hydroxypropyl-β-cyclodextrin: experiments and modeling

Cong-Shan Zhou, Ping Xu, Ke-Wen Tang, Xin-Yu Jiang, Tao Yang, and Pan-Liang Zhang

College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang, 414006, Hunan, China

E-mail: tangkewen@sina.com

Abstract: Enantioselective extraction of hydrophilic 2-chloromandelic acid (CMA) enantiomers from organic to aqueous phase with hydroxypropyl-β-cyclodextrin (HP-β-CD) as the selector was investigated. Equilibrium of the extraction system was modeled using a reactive extraction model with a homogeneous aqueous phase reaction. The influence of important process variables on the extraction efficiency, such as the type of the organic solvent and β-cyclodextrin derivatives (β-CDs), concentration of the selector, pH and temperature, was investigated by experiment and modeling. Important parameters of this model were determined experimentally. Results showed that the experimental data agree with the model prediction perfectly and the model was further applied to accurately predict the extraction efficiency influenced simultaneously by pH and the concentration of HP-β-CD. Combining the experiment and the model data, the best extraction conditions were: pH of 2.5, HP-β-CD concentration of 0.05 mol L⁻¹, and temperature of 5°C, providing the enantioselectivity of 1.285 and the performance factor (pf) of 0.011.

Keywords: 2-chloromandelic acid – hydroxypropyl-β-cyclodextrin – reactive extraction – reaction mechanism – modeling

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-012-0268-6

Chemical Papers 67 (2) 155–163 (2013)