Enantioselective extraction of clorprenaline enantiomers with hydrophilic selector of sulfobutylether-β-cyclodextrin by experiment and modeling

ZHOU Cong-shan(周从山)¹, XU Ping(徐萍)², TANG Ke-wen(唐课文)¹, JIANG Xin-yu(蒋新宇)², YANG Tao(杨涛)¹, ZHANG Pan-liang(张盼良)¹, ZHU Zheng(朱政)¹

(1. College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology,
Yueyang 414000, China;
2. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)

Abstract:Enantioselective extraction of hydrophobic clorprenaline (CPE) enantiomers from organic phase to aqueous phases with sulfobutylether-β-cyclodextrin (SBE-β-CD) as the selector was investigated with insight into a number of important process variables, such as the type of organic solvent, concentration of selector, pH, and temperature. Equilibrium of the extraction system was modeled using a reactive extraction model with a homogeneous aqueous phase reaction. The important parameters of this model were determined experimentally. The physical distribution coef？cients for molecular and ionic CPE were determined as 0.3 and 8.93, respectively. The equilibrium constants of the complexation reaction with SBE-β-CD were determined as 152 and 110 L/mol for R- and S-CPE, respectively. Results show that the experimental data agree with the model predictions perfectly. Comprehensively considering the experiment and model, the extraction conditions are optimized and the best extraction conditions are: pH of 6.0, SBE-β-CD concentration of 0.04 mol/L, and temperature of 5 °C, providing the enantioselectivity (α) of 1.25, the fraction of R-CPE (φ_R) in aqueous phase of 0.71 and performance factor (p_f) of 0.025.

Key words:clorprenaline; sulfobutylether-β-cyclodextrin; reactive extraction; chiral recognition; modeling